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This article is about the planet. For the deity, see Mars (mythology). For other uses, see Mars (disambiguation).

Mars
Orange-brown globe with white snow caps
Mars in true color,[a] as captured by the Hope orbiter. The Tharsis Montes can be seen at the center, with Olympus Mons just to the left and Valles Marineris at the right.
Designations
AdjectivesMartian
Symbol♂
Orbital characteristics[1]
Epoch J2000
Aphelion249261000 km
(1.66621 AU)[2]
Perihelion206650000 km
(1.3814 AU)[2]
227939366 km
(1.52368055 AU)[3]
Eccentricity0.0934[2]
686.980 d
(1.88085 yr; 668.5991 sols)[2]
779.94 d
(2.1354 yr)[3]
24.07 km/s[2]
19.412°[2]
Inclination
49.57854°[2]
2022-Jun-21[5]
286.5°[3]
Satellites2 (Phobos and Deimos)
Physical characteristics
3389.5±0.2 km[b][6]
Equatorial radius
3396.2±0.1 km[b][6]
(0.533 Earths)
Polar radius
3376.2±0.1 km[b][6]
(0.531 Earths)
Flattening0.00589±0.00015[5][6]
1.4437×108 km2[7]
(0.284 Earths)
Volume1.63118×1011 km3[8]
(0.151 Earths)
Mass6.4171×1023 kg[9]
(0.107 Earths)
Mean density
3.9335 g/cm3[8]
3.72076 m/s2 (0.3794 g0)[10]
0.3644±0.0005[9]
5.027 km/s
(18100 km/h)[11]
1.02749125 d[12]
24h 39m 36s
1.025957 d
24h 37m 22.7s[8]
Equatorial rotation velocity
241 m/s
(870 km/h)[2]
25.19° to its orbital plane[2]
North pole right ascension
317.269°[13]
North pole declination
54.432°[13]
Albedo
Temperature209 K (−64 °C) (blackbody temperature)[15]
Surface temp. min mean max
  −110 °C[16] −60 °C[17] 35 °C[16]
Surface absorbed dose rate8.8 μGy/h[18]
Surface equivalent dose rate27 μSv/h[18]
−2.94 to +1.86[19]
−1.5[20]
3.5–25.1″[2]
Atmosphere[2][21]
Surface pressure
0.636 (0.4–0.87) kPa
0.00628 atm
Composition by volume

Mars is the fourth planet from the Sun. The surface of Mars is orange-red because it is covered in iron(III) oxide dust, giving it the nickname "the Red Planet".[22][23] Mars is among the brightest objects in Earth's sky, and its high-contrast albedo features have made it a common subject for telescope viewing. It is classified as a terrestrial planet and is the second smallest of the Solar System's planets with a diameter of 6,779 km (4,212 mi). In terms of orbital motion, a Martian solar day (sol) is equal to 24.5 hours, and a Martian solar year is equal to 1.88 Earth years (687 Earth days). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos.

The relatively flat plains in northern parts of Mars strongly contrast with the cratered terrain in southern highlands – this terrain observation is known as the Martian dichotomy. Mars hosts many enormous extinct volcanoes (the tallest is Olympus Mons, 21.9 km or 13.6 mi tall) and one of the largest canyons in the Solar System (Valles Marineris, 4,000 km or 2,500 mi long). Geologically, the planet is fairly active with marsquakes trembling underneath the ground, dust devils sweeping across the landscape, and cirrus clouds. Carbon dioxide is substantially present in Mars's polar ice caps and thin atmosphere. During a year, there are large surface temperature swings on the surface between −78.5 °C (−109.3 °F) to 5.7 °C (42.3 °F)[c] similar to Earth's seasons, as both planets have significant axial tilt.

Mars was formed approximately 4.5 billion years ago. During the Noachian period (4.5 to 3.5 billion years ago), Mars's surface was marked by meteor impacts, valley formation, erosion, and the possible presence of water oceans. The Hesperian period (3.5 to 3.3–2.9 billion years ago) was dominated by widespread volcanic activity and flooding that carved immense outflow channels. The Amazonian period, which continues to the present, has been marked by the wind as a dominant influence on geological processes. Due to Mars's geological history, the possibility of past or present life on Mars remains of great scientific interest.

Since the late 20th century, Mars has been explored by uncrewed spacecraft and rovers, with the first flyby by the Mariner 4 probe in 1965, the first orbit by the Mars 2 probe in 1971, and the first landing by the Viking 1 probe in 1976. As of 2023, there are at least 11 active probes orbiting Mars or on the Martian surface. Mars is an attractive target for future human exploration missions, though in the 2020s no such mission is planned.

Natural history

Main article: Geological history of Mars

Scientists have theorized that during the Solar System's formation, Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than on Earth; these elements were probably pushed outward by the young Sun's energetic solar wind.[24]

After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment. About 60% of the surface of Mars shows a record of impacts from that era,[25][26][27] whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. However, more recent modeling has disputed the existence of the Late Heavy Bombardment.[28] There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300 mi), or roughly four times the size of the Moon's South Pole–Aitken basin, which would be the largest impact basin yet discovered if confirmed.[29] It has been hypothesized that the basin was formed when Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet.[30][31]

A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago.[32] This ring system may have been formed from a moon, 20 times more massive than Phobos, orbiting Mars billions of years ago; and Phobos would be a remnant of that ring.[33][34]

The geological history of Mars can be split into many periods, but the following are the three primary periods:[35][36]

  • Noachian period: Formation of the oldest extant surfaces of Mars, 4.5 to 3.5 billion years ago. Noachian age surfaces are scarred by many large impact craters. The Tharsis bulge, a volcanic upland, is thought to have formed during this period, with extensive flooding by liquid water late in the period. Named after Noachis Terra.[37]
  • Hesperian period: 3.5 to between 3.3 and 2.9 billion years ago. The Hesperian period is marked by the formation of extensive lava plains. Named after Hesperia Planum.[37]
  • Amazonian period: between 3.3 and 2.9 billion years ago to the present. Amazonian regions have few meteorite impact craters but are otherwise quite varied. Olympus Mons formed during this period, with lava flows elsewhere on Mars. Named after Amazonis Planitia.[37]

Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 million years ago. Water flows in the grabens called the Cerberus Fossae occurred less than 20 million years ago, indicating equally recent volcanic intrusions.[38] The Mars Reconnaissance Orbiter has captured images of avalanches.[39][40]

Physical characteristics

Main article: Geology of Mars
Mars to scale among the Inner Solar System planetary-mass objects beside the Sun, arranged by the order of their orbits outward from the Sun (from left: Mercury, Venus, Earth, the Moon, Mars and Ceres)

Mars is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land.[2] Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. Mars is the only presently known example of a desert planet, a rocky planet with a surface akin to that of Earth's hot deserts. The red-orange appearance of the Martian surface is caused by ferric oxide, or rust.[41] It can look like butterscotch;[42] other common surface colors include golden, brown, tan, and greenish, depending on the minerals present.[42]

Internal structure

Internal structure of Mars as of 2024.[43][44]
Mapped gravity field of Mars

Like Earth, Mars is differentiated into a dense metallic core overlaid by less dense rocky layers.[45][46] The outermost layer is the crust, which is on average about 42–56 kilometres (26–35 mi) thick,[47] with a minimum thickness of 6 kilometres (3.7 mi) in Isidis Planitia, and a maximum thickness of 117 kilometres (73 mi) in the southern Tharsis plateau.[48] For comparison, Earth's crust averages 27.3 ± 4.8 km in thickness.[49] The most abundant elements in the Martian crust are silicon, oxygen, iron, magnesium, aluminium, calcium, and potassium. Mars is confirmed to be seismically active;[50] in 2019 it was reported that InSight had detected and recorded over 450 marsquakes and related events.[51][52]

Beneath the crust is a silicate mantle responsible for many of the tectonic and volcanic features on the planet's surface. The upper Martian mantle is a low-velocity zone, where the velocity of seismic waves is lower than surrounding depth intervals. The mantle appears to be rigid down to the depth of about 250 km,[44] giving Mars a very thick lithosphere compared to Earth. Below this the mantle gradually becomes more ductile, and the seismic wave velocity starts to grow again.[53] The Martian mantle does not appear to have a thermally insulating layer analogous to Earth's lower mantle; instead, below 1050 km in depth, it becomes mineralogically similar to Earth's transition zone.[43] At the bottom of the mantle lies a basal liquid silicate layer approximately 150–180 km thick.[44][54]

Mars's iron and nickel core is completely molten, with no solid inner core.[55][56] It is around half of Mars's radius, approximately 1650–1675 km, and is enriched in light elements such as sulfur, oxygen, carbon, and hydrogen.[57][58]

Surface geology

Further information: Martian soil
Curiosity's view of Martian soil and boulders after crossing the "Dingo Gap" sand dune

Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt,[59] although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found.[60] Much of the surface is deeply covered by finely grained iron(III) oxide dust.[61]

Although Mars has no evidence of a structured global magnetic field,[62] observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One hypothesis, published in 1999 and re-examined in October 2005 (with the help of the Mars Global Surveyor), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded.[63]

The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth. They are necessary for growth of plants.[64] Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% perchlorate by weight,[65][66] concentrations that are toxic to humans.[67][68]

Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted hypotheses include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils.[69] Several other explanations have been put forward, including those that involve water or even the growth of organisms.[70][71]

Environmental radiation levels on the surface are on average 0.64 millisieverts of radiation per day, and significantly less than the radiation of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars.[72][73] For comparison the radiation levels in low Earth orbit, where Earth's space stations orbit, are around 0.5 millisieverts of radiation per day.[74] Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day, featuring lava tubes southwest of Hadriacus Mons with potentially levels as low as 0.064 millisieverts per day,[75] comparable to radiation levels during flights on Earth.

Geography and features

Main article: Geography of Mars
Further information: Areoid
See also: Category:Surface features of Mars
Animation showing major features of Mars

Although better remembered for mapping the Moon, Johann Heinrich von Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars.[76]

Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; smaller valleys are named for rivers.[77]

Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, Nix Olympica (the snows of Olympus) has become Olympus Mons (Mount Olympus).[78] The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum.[79] The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe.[80]

A MOLA-based topographic map showing highlands (light colors) dominating the Southern Hemisphere of Mars, lowlands (dark colors) the northern. Volcanic plateaus delimit regions of the northern plains, whereas the highlands are punctuated by several large impact basins.

Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton E. Davies, Harold Masursky, and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection.[81][82][83]

Because Mars has no oceans, and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the areoid[84] of Mars, analogous to the terrestrial geoid.[85] Zero altitude was defined by the height at which there is 610.5 Pa (6.105 mbar) of atmospheric pressure.[86] This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm).[87]

For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains.[88] In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft.[89] A related, but much more detailed, global Mars map was released by NASA on 16 April 2023.[90]

Volcanoes

Main article: Volcanism on Mars
Picture of the tallest volcano on Mars, Olympus Mons. It is approximately 550 km (340 mi) across.

The vast upland region Tharsis contains several massive volcanoes, which include the shield volcano Olympus Mons. The edifice is over 600 km (370 mi) wide.[91][92] Because the mountain is so large, with complex structure at its edges, giving a definite height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21 km (13 mi),[92] a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over 1,000 km (620 mi) to the northwest, to the summit approaches 26 km (16 mi),[93] roughly three times the height of Mount Everest, which in comparison stands at just over 8.8 kilometres (5.5 mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at 20–25 km (12–16 mi).[94]

Impact topography

The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300 mi) in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System.[95][96][97]

Mars is scarred by a number of impact craters: a total of 43,000 observed craters with a diameter of 5 kilometres (3.1 mi) or greater have been found.[98] The largest exposed crater is Hellas, which is 2,300 kilometres (1,400 mi) wide and 7,000 metres (23,000 ft) deep, and is a light albedo feature clearly visible from Earth.[99][100] There are other notable impact features, such as Argyre, which is around 1,800 kilometres (1,100 mi) in diameter,[101] and Isidis, which is around 1,500 kilometres (930 mi) in diameter.[102] Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter.[103]

Martian craters can[discuss] have a morphology that suggests the ground became wet after the meteor impact.[104]

Tectonic sites

Valles Marineris, taken by the Viking 1 probe

The large canyon, Valles Marineris (Latin for "Mariner Valleys", also known as Agathodaemon in the old canal maps[105]), has a length of 4,000 kilometres (2,500 mi) and a depth of up to 7 kilometres (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277 mi) long and nearly 2 kilometres (1.2 mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 kilometres (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement.[106][107]

Holes and caves

Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons.[108] The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters".[109] Cave entrances measure from 100 to 252 metres (328 to 827 ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315 ft) deep. Because light does not reach the floor of most of the caves, they may extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430 ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface.[110][111]

Atmosphere

Main article: Atmosphere of Mars
Image of Mars
A broad view of Mars's atmosphere by Hope orbiter

Mars lost its magnetosphere 4 billion years ago,[112] possibly because of numerous asteroid strikes,[113] so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer.[114] Both Mars Global Surveyor and Mars Express have detected ionized atmospheric particles trailing off into space behind Mars,[112][115] and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30 Pa (0.0044 psi) on Olympus Mons to over 1,155 Pa (0.1675 psi) in Hellas Planitia, with a mean pressure at the surface level of 600 Pa (0.087 psi).[116] The highest atmospheric density on Mars is equal to that found 35 kilometres (22 mi)[117] above Earth's surface. The resulting mean surface pressure is only 0.6% of Earth's 101.3 kPa (14.69 psi). The scale height of the atmosphere is about 10.8 kilometres (6.7 mi),[118] which is higher than Earth's 6 kilometres (3.7 mi), because the surface gravity of Mars is only about 38% of Earth's.[119]

The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water.[2][120][114] The atmosphere is quite dusty, containing particulates about 1.5 μm in diameter which give the Martian sky a tawny color when seen from the surface.[121] It may take on a pink hue due to iron oxide particles suspended in it.[22] The concentration of methane in the Martian atmosphere fluctuates from about 0.24 ppb during the northern winter to about 0.65 ppb during the summer.[122] Estimates of its lifetime range from 0.6 to 4 years,[123][124] so its presence indicates that an active source of the gas must be present. Methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars,[125] or by Martian life.[126]

Escaping atmosphere on Mars (carbon, oxygen, and hydrogen) by MAVEN in UV[127]

Compared to Earth, its higher concentration of atmospheric CO2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above.[128][129]

Auroras have been detected on Mars.[130][131][132] Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth;[133] rather than being mostly restricted to polar regions as is the case on Earth, a Martian aurora can encompass the planet.[134] In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month.[134][135]

Climate

Main article: Climate of Mars

Mars has seasons, alternating between its northern and southern hemispheres, similar to on Earth. Additionally the orbit of Mars has, compared to Earth's, a large eccentricity and approaches perihelion when it is summer in its southern hemisphere and winter in its northern, and aphelion when it is winter in its southern hemisphere and summer in its northern. As a result, the seasons in its southern hemisphere are more extreme and the seasons in its northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30 °C (54 °F).[136]

Martian surface temperatures vary from lows of about −110 °C (−166 °F) to highs of up to 35 °C (95 °F) in equatorial summer.[16] The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure (about 1% that of the atmosphere of Earth), and the low thermal inertia of Martian soil.[137] The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight.[138][139]

Mars without (on left) and with a global dust storm in July 2001 (on right), including different visible water ice cloud covers, as seen by the Hubble Space Telescope

Mars has the largest dust storms in the Solar System, reaching speeds of over 160 km/h (100 mph). These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase global temperature.[140]

Rendering of the change of CO2 ice (not water ice) coverage on the north (left) and south (right) poles of Mars between northern and southern summer.

Seasons also produce dry ice covering polar ice caps. Large areas of the polar regions of Mars

Hydrology

Main article: Water on Mars
Mars contains water, though mostly as dust covered polar layers of ice, as mapped in this image.
As top surface layer water appears readily visible at some places on Mars, as in this polar crater called Korolev.

While Mars contains water in larger amounts, most of it is dust covered water ice at the Martian polar ice caps.[141][142][143][144][145] The volume of water ice in the south polar ice cap, if melted, would be enough to cover most of the surface of the planet with a depth of 11 metres (36 ft).[146]

Water in its liquid form cannot prevail on the surface of Mars due to the low atmospheric pressure on Mars, which is less than 1% that of Earth,[147] only at the lowest of elevations pressure and temperature is high enough for water being able to be liquid for short periods.[46][148]

Water in the atmosphere is small, but enough to produce larger clouds of water ice and different cases of snow and frost, often mixed with snow of carbon dioxide dry ice.

Past hydrosphere

Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava.[149][150] One of the larger examples, Ma'adim Vallis, is 700 kilometres (430 mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12 mi) and a depth of 2 kilometres (1.2 mi) in places. It is thought to have been carved by flowing water early in Mars's history.[151] The youngest of these channels is thought to have formed only a few million years ago.[152]

Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases.[153]

Along craters and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice,[154][155] although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust.[156][157] No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active.[155] Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history.[158] Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence.[159] Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water.[160]

History of observations and findings of water evidence

Main article: Chronology of discoveries of water on Mars

In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars.[161][162] The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity.[163][164][165] It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200–1,000 metres (660–3,280 ft).[166][167]

On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock.[168][169] Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24 in), during the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain.[168] In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes.[170][171][172] These streaks flow downhill in Martian summer, when the temperature is above −23 °C, and freeze at lower temperatures.[173] These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface.[174] However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process.[175] A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive.[176][177]

Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial.[178] In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of protium to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium (D/H = 9.3 ± 1.7 10-4) is five to seven times the amount on Earth (D/H = 1.56 10-4), suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water.[179] Near the northern polar cap is the 81.4 kilometres (50.6 mi) wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530 cu mi) of water ice.[180]

In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior (which is 12,100 cubic kilometers[181]).[182][183] During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system.[184]

Orbital motion

Main article: Orbit of Mars
See also: Timekeeping on Mars

Mars circling the Sun further and slower than Earth
Orbit of Mars and other Inner Solar System planets

Mars's average distance from the Sun is roughly 230 million km (143 million mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds.[185] A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours.[2] The gravitational potential difference and thus the delta-v needed to transfer between Mars and Earth is the second lowest for Earth.[186][187]

The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth.[2] As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day, the orientation of the north pole of Mars is close to the star Deneb.[21]

Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.002, much less than that of Earth today.[188] Mars's cycle of eccentricity is 96,000 Earth years compared to Earth's cycle of 100,000 years.[189]

Mars has its closest approach to Earth (opposition) in a synodic period of 779.94 days. It should not be confused with Mars conjunction, where the Earth and Mars are at opposite sides of the Solar System and form a straight line crossing the Sun. The average time between the successive oppositions of Mars, its synodic period, is 780 days; but the number of days between successive oppositions can range from 764 to 812.[189] The distance at close approach varies between about 54 and 103 million km (34 and 64 million mi) due to the planets' elliptical orbits, which causes comparable variation in angular size.[190] At their furthest Mars and Earth can be as far as 401 million km (249 million mi) apart.[191] Mars comes into opposition from Earth every 2.1 years. The planets come into opposition near Mars's perihelion in 2003, 2018 and 2035, with the 2020 and 2033 events being particularly close to perihelic opposition.[192][193][194]

see caption
Mars seen through a 16-inch amateur telescope, at 2020 opposition

The mean apparent magnitude of Mars is +0.71 with a standard deviation of 1.05.[19] Because the orbit of Mars is eccentric, the magnitude at opposition from the Sun can range from about −3.0 to −1.4.[195] The minimum brightness is magnitude +1.86 when the planet is near aphelion and in conjunction with the Sun.[19] At its brightest, Mars (along with Jupiter) is second only to Venus in apparent brightness.[19] Mars usually appears distinctly yellow, orange, or red. When farthest away from Earth, it is more than seven times farther away than when it is closest. Mars is usually close enough for particularly good viewing once or twice at 15-year or 17-year intervals.[196] Optical ground-based telescopes are typically limited to resolving features about 300 kilometres (190 mi) across when Earth and Mars are closest because of Earth's atmosphere.[197]

An animation to explain the (apparent) retrograde motion of Mars, using actual 2020 planet positions

As Mars approaches opposition, it begins a period of retrograde motion, which means it will appear to move backwards in a looping curve with respect to the background stars. This retrograde motion lasts for about 72 days, and Mars reaches its peak apparent brightness in the middle of this interval.[198]

Moons

Main articles: Moons of Mars, Phobos (moon), and Deimos (moon)
Enhanced-color HiRISE image of Phobos, showing a series of mostly parallel grooves and crater chains, with Stickney crater at right
Enhanced-color HiRISE image of Deimos (not to scale), showing its smooth blanket of regolith

Mars has two relatively small (compared to Earth's) natural moons, Phobos (about 22 kilometres (14 mi) in diameter) and Deimos (about 12 kilometres (7.5 mi) in diameter), which orbit close to the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit.[199]

Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle.[200] Mars was the Roman equivalent to Ares. In modern Greek, the planet retains its ancient name Ares (Aris: Άρης).[96]

From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbit – where the orbital period would match the planet's period of rotation – rises as expected in the east, but slowly. Because the orbit of Phobos is below a synchronous altitude, tidal forces from Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet.[201]

The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits near the equator, which is unusual for captured objects, and the required capture dynamics are complex. Accretion early in the history of Mars is plausible, but would not account for a composition resembling asteroids rather than Mars itself, if that is confirmed.[202] Mars may have yet-undiscovered moons, smaller than 50 to 100 metres (160 to 330 ft) in diameter, and a dust ring is predicted to exist between Phobos and Deimos.[203]

A third possibility for their origin as satellites of Mars is the involvement of a third body or a type of impact disruption. More-recent lines of evidence for Phobos having a highly porous interior,[204] and suggesting a composition containing mainly phyllosilicates and other minerals known from Mars,[205] point toward an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's satellite. Although the visible and near-infrared (VNIR) spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class.[205] It is also possible that Phobos and Deimos were fragments of an older moon, formed by debris from a large impact on Mars, and then destroyed by a more recent impact upon the satellite.[206]

Human observations and exploration

Main articles: Exploration of Mars and History of Mars observation

The history of observations of Mars is marked by oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to Earth.[192]

Ancient and medieval observations

Galileo Galilei was the first to see Mars via telescope.

The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh.[207] In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead".[208] The existence of Mars as a wandering object in the night sky was also recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet.[209] By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets.[210][211] In Ancient Greece, the planet was known as Πυρόεις.[212] Commonly, the Greek name for the planet now referred to as Mars, was Ares. It was the Romans who named the planet Mars, for their god of war, often represented by the sword and shield of the planet's namesake.[213]

In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away.[214] Ptolemy, a Greek living in Alexandria,[215] attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection later called the Almagest (from the Arabic for "greatest"), which became the authoritative treatise on Western astronomy for the next fourteen centuries.[216] Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE.[217] In the East Asian cultures, Mars is traditionally referred to as the "fire star" based on the Wuxing system.[218][219][220]

During the seventeenth century A.D., Tycho Brahe measured the diurnal parallax of Mars that Johannes Kepler used to make a preliminary calculation of the relative distance to the planet.[221] From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Kepler showed that Mars sped up as it approached the Sun and slowed down as it moved farther away, in a manner that later physicists would explain as a consequence of the conservation of angular momentum.[222]: 433–437  When the telescope became available, the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments.[223] The only occultation of Mars by Venus observed was that of 13 October 1590, seen by Michael Maestlin at Heidelberg.[224] In 1610, Mars was viewed by Italian astronomer Galileo Galilei, who was first to see it via telescope.[225] The first person to draw a map of Mars that displayed any terrain features was the Dutch astronomer Christiaan Huygens.[226]

Martian "canals"

Main article: Martian canals
A 1962 map of Mars published by the U.S. Aeronautical Chart and Information Center, showing canals snaking through the Martian landscape. At the time, the existence of canals was still highly controversial as no close-up pictures of Mars had been taken (until Mariner 4's flyby in 1965).

By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition to Mars occurred. The Italian astronomer Giovanni Schiaparelli used a 22-centimetre (8.7 in) telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which were later shown to be an optical illusion. These canali were supposedly long, straight lines on the surface of Mars, to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals".[227][228]

Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894, and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public.[229][230] The canali were independently observed by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time.[231][232]

The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summers) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight canali were observed. During observations in 1909 by Antoniadi with an 84-centimetre (33 in) telescope, irregular patterns were observed, but no canali were seen.[233]

Robotic exploration

Self-portrait of Perseverance rover and Ingenuity helicopter (left) at Wright Brothers Field, 2021

Dozens of crewless spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, India, the United Arab Emirates, and China to study the planet's surface, climate, and geology.[234] NASA's Mariner 4 was the first spacecraft to visit Mars; launched on 28 November 1964, it made its closest approach to the planet on 15 July 1965. Mariner 4 detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space.[235]

Once spacecraft visited the planet during NASA's Mariner missions in the 1960s and 1970s, many previous concepts of Mars were radically broken. After the results of the Viking life-detection experiments, the hypothesis of a dead planet was generally accepted.[236] The data from Mariner 9 and Viking allowed better maps of Mars to be made, and the Mars Global Surveyor mission, which launched in 1996 and operated until late 2006, produced complete, extremely detailed maps of the Martian topography, magnetic field and surface minerals.[237] These maps are available online at websites including Google Mars. Both the Mars Reconnaissance Orbiter and Mars Express continued exploring with new instruments and supporting lander missions. NASA provides two online tools: Mars Trek, which provides visualizations of the planet using data from 50 years of exploration, and Experience Curiosity, which simulates traveling on Mars in 3-D with Curiosity.[238][239]

As of 2023, Mars is host to ten functioning spacecraft. Eight are in orbit: 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, ExoMars Trace Gas Orbiter, the Hope orbiter, and the Tianwen-1 orbiter.[240][241] Another two are on the surface: the Mars Science Laboratory Curiosity rover and the Perseverance rover.[242]

Planned missions to Mars include:

  • NASA's EscaPADE spacecraft, planned to launch in late 2024.[243]
  • The Rosalind Franklin rover mission, designed to search for evidence of past life, which was intended to be launched in 2018 but has been repeatedly delayed, with a launch date pushed to 2028 at the earliest.[244][245][246] The project was restarted in 2024 with additional funding.[247]
  • A current concept for a joint NASA-ESA mission to return samples from Mars would launch in 2026.[248][249]
  • China's Tianwen-3, a sample return mission, scheduled to launch in 2030.

As of February 2024, debris from these types of missions has reached over seven tons. Most of it consists of crashed and inactive spacecraft as well as discarded components.[250][251]

In April 2024, NASA selected several companies to begin studies on providing commercial services to further enable robotic science on Mars. Key areas include establishing telecommunications, payload delivery and surface imaging.[252]

Map of Mars
Interactive image map of the global topography of Mars, overlaid with the position of Martian rovers and landers. Coloring of the base map indicates relative elevations of Martian surface.
Clickable image: Clicking on the labels will open a new article.
(   Active •   Inactive •   Planned)
Bradbury Landing
Deep Space 2
Mars Polar Lander
Perseverance
Schiaparelli EDM
Spirit
Viking 1

Habitability and the search for life

Main article: Life on Mars
Curiosity rover's robotic arm showing drill in place, February 2013

During the late 19th century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water.[253] However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars it is in quantities too small to be detected by spectroscopes then available".[253] That observation contradicted many of the measurements of the time and was not widely accepted.[253] Campbell and V. M. Slipher repeated the study in 1909 using better instruments, but with the same results. It was not until the findings were confirmed by W. S. Adams in 1925 that the myth of the Earth-like habitability of Mars was finally broken.[253] However, even in the 1960s, articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars.[254]

The current understanding of planetary habitability – the ability of a world to develop environmental conditions favorable to the emergence of life – favors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to extend from within the orbit of Earth to about that of Mars.[255] During perihelion, Mars dips inside this region, but Mars's thin (low-pressure) atmosphere prevents liquid water from existing over large regions for extended periods. The past flow of liquid water demonstrates the planet's potential for habitability. Recent evidence has suggested that any water on the Martian surface may have been too salty and acidic to support regular terrestrial life.[256]

The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water instead sublimes to a gaseous state). Mars is nearly, or perhaps totally, geologically dead; the end of volcanic activity has apparently stopped the recycling of chemicals and minerals between the surface and interior of the planet.[257]

Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The Viking probes of the mid-1970s carried experiments designed to detect microorganisms in Martian soil at their respective landing sites and had positive results, including a temporary increase in CO2 production on exposure to water and nutrients. This sign of life was later disputed by scientists, resulting in a continuing debate, with NASA scientist Gilbert Levin asserting that Viking may have found life.[258] A 2014 analysis of Martian meteorite EETA79001 found chlorate, perchlorate, and nitrate ions in sufficiently high concentrations to suggest that they are widespread on Mars. UV and X-ray radiation would turn chlorate and perchlorate ions into other, highly reactive oxychlorines, indicating that any organic molecules would have to be buried under the surface to survive.[259]

Small quantities of methane and formaldehyde detected by Mars orbiters are both claimed to be possible evidence for life, as these chemical compounds would quickly break down in the Martian atmosphere.[260][261] Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinite.[125] Impact glass, formed by the impact of meteors, which on Earth can preserve signs of life, has also been found on the surface of the impact craters on Mars.[262][263] Likewise, the glass in impact craters on Mars could have preserved signs of life, if life existed at the site.[264][265][266]

The Cheyava Falls rock discovered on Mars in June 2024 has been designated by NASA as a "potential biosignature" and was core sampled by the Perseverance rover for possible return to Earth and further examination. Although highly intriguing, no definitive final determination on a biological or abiotic origin of this rock can be made with the data currently available.

Human mission proposals

A NASA ISRU system concept for autonomous robotic excavation and processing of Mars soil to extract water for use in exploration missions.

Several plans for a human mission to Mars have been proposed throughout the 20th and 21st centuries, but none have come to fruition. The NASA Authorization Act of 2017 directed NASA to study the feasibility of a crewed Mars mission in the early 2030s; the resulting report eventually concluded that this would be unfeasible.[267][268] In addition, in 2021, China was planning to send a crewed Mars mission in 2033.[269] Privately held companies such as SpaceX have also proposed plans to send humans to Mars, with the eventual goal to settle on the planet.[270] As of 2024, SpaceX has proceeded with the development of the Starship launch vehicle with the goal of Mars colonization. In plans shared with the company in April 2024, Elon Musk envisions the beginning of a Mars colony within the next twenty years. This enabled by the planned mass manufacturing of Starship and initially sustained by resupply from Earth, and in situ resource utilization on Mars, until the Mars colony reaches full self sustainability.[271]Any future human mission to Mars will likely take place within the optimal Mars launch window, which occurs every 26 months. The moon Phobos has been proposed as an anchor point for a space elevator.[272] Besides national space agencies and space companies, there are groups such as the Mars Society[273] and The Planetary Society[274] that advocates for human missions to Mars.

In culture

Main articles: Mars in culture and Mars in fiction
See also: Planets in astrology § Mars
The War of the Worlds by H. G. Wells, 1897, depicts an invasion of Earth by fictional Martians.

Mars is named after the Roman god of war. This association between Mars and war dates back at least to Babylonian astronomy, in which the planet was named for the god Nergal, deity of war and destruction.[275][276] It persisted into modern times, as exemplified by Gustav Holst's orchestral suite The Planets, whose famous first movement labels Mars "the bringer of war".[277] The planet's symbol, a circle with a spear pointing out to the upper right, is also used as a symbol for the male gender.[278] The symbol dates from at least the 11th century, though a possible predecessor has been found in the Greek Oxyrhynchus Papyri.[279]

The idea that Mars was populated by intelligent Martians became widespread in the late 19th century. Schiaparelli's "canali" observations combined with Percival Lowell's books on the subject put forward the standard notion of a planet that was a drying, cooling, dying world with ancient civilizations constructing irrigation works.[280] Many other observations and proclamations by notable personalities added to what has been termed "Mars Fever".[281] High-resolution mapping of the surface of Mars revealed no artifacts of habitation, but pseudoscientific speculation about intelligent life on Mars still continues. Reminiscent of the canali observations, these speculations are based on small scale features perceived in the spacecraft images, such as "pyramids" and the "Face on Mars".[282] In his book Cosmos, planetary astronomer Carl Sagan wrote: "Mars has become a kind of mythic arena onto which we have projected our Earthly hopes and fears."[228]

The depiction of Mars in fiction has been stimulated by its dramatic red color and by nineteenth-century scientific speculations that its surface conditions might support not just life but intelligent life.[283] This gave way to many science fiction stories involving these concepts, such as H. G. Wells's The War of the Worlds, in which Martians seek to escape their dying planet by invading Earth; Ray Bradbury's The Martian Chronicles, in which human explorers accidentally destroy a Martian civilization; as well as Edgar Rice Burroughs's series Barsoom, C. S. Lewis's novel Out of the Silent Planet (1938),[284] and a number of Robert A. Heinlein stories before the mid-sixties.[285] Since then, depictions of Martians have also extended to animation. A comic figure of an intelligent Martian, Marvin the Martian, appeared in Haredevil Hare (1948) as a character in the Looney Tunes animated cartoons of Warner Brothers, and has continued as part of popular culture to the present.[286] After the Mariner and Viking spacecraft had returned pictures of Mars as a lifeless and canal-less world, these ideas about Mars were abandoned; for many science-fiction authors, the new discoveries initially seemed like a constraint, but eventually the post-Viking knowledge of Mars became itself a source of inspiration for works like Kim Stanley Robinson's Mars trilogy.[287]

See also

Notes

  1. ^ The light filters are 635 nm, 546 nm, and 437 nm, roughly corresponding to red, green and blue respectively
  2. ^ a b c Best-fit ellipsoid
  3. ^ Temperatures taken are the average mean daily minimum and maximum on per year basis, data taken from Climate of Mars#Temperature

References

  1. ^ Simon J, Bretagnon P, Chapront J, et al. (February 1994). "Numerical expressions for precession formulae and mean elements for the Moon and planets". Astronomy and Astrophysics. 282 (2): 663–683. Bibcode:1994A&A...282..663S.
  2. ^ a b c d e f g h i j k l m n o p Williams D (2018). "Mars Fact Sheet". NASA Goddard Space Flight Center. Archived from the original on 17 March 2020. Retrieved 22 March 2020.; Mean Anomaly (deg) 19.412 = (Mean Longitude (deg) 355.45332) – (Longitude of perihelion (deg) 336.04084) Public Domain This article incorporates text from this source, which is in the public domain.
  3. ^ a b c Allen CW, Cox AN (2000). Allen's Astrophysical Quantities. Springer Science & Business Media. p. 294. ISBN 978-0-387-95189-8. Archived from the original on 1 March 2024. Retrieved 18 May 2022.
  4. ^ Souami D, Souchay J (July 2012). "The solar system's invariable plane". Astronomy & Astrophysics. 543: 11. Bibcode:2012A&A...543A.133S. doi:10.1051/0004-6361/201219011. A133.
  5. ^ a b "HORIZONS Batch call for 2022 perihelion" (Perihelion occurs when rdot flips from negative to positive). Solar System Dynamics Group, Jet Propulsion Laboratory. Archived from the original on 8 September 2021. Retrieved 7 September 2021.
  6. ^ a b c d Seidelmann PK, Archinal BA, A'Hearn MF, et al. (2007). "Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006". Celestial Mechanics and Dynamical Astronomy. 98 (3): 155–180. Bibcode:2007CeMDA..98..155S. doi:10.1007/s10569-007-9072-y.
  7. ^ Grego P (6 June 2012). Mars and How to Observe It. Springer Science+Business Media. p. 3. ISBN 978-1-4614-2302-7 – via Internet Archive.
  8. ^ a b c Lodders K, Fegley B (1998). The Planetary Scientist's Companion. Oxford University Press. p. 190. ISBN 978-0-19-511694-6.
  9. ^ a b Konopliv AS, Asmar SW, Folkner WM, et al. (January 2011). "Mars high resolution gravity fields from MRO, Mars seasonal gravity, and other dynamical parameters". Icarus. 211 (1): 401–428. Bibcode:2011Icar..211..401K. doi:10.1016/j.icarus.2010.10.004.
  10. ^ Hirt C, Claessens SJ, Kuhn M, et al. (July 2012). "Kilometer-resolution gravity field of Mars: MGM2011" (PDF). Planetary and Space Science. 67 (1): 147–154. Bibcode:2012P&SS...67..147H. doi:10.1016/j.pss.2012.02.006. hdl:20.500.11937/32270. ISSN 0032-0633. Archived from the original on 1 March 2024. Retrieved 25 August 2019.
  11. ^ Jackson AP, Gabriel TS, Asphaug EI (1 March 2018). "Constraints on the pre-impact orbits of Solar system giant impactors". Monthly Notices of the Royal Astronomical Society. 474 (3): 2924–2936. arXiv:1711.05285. doi:10.1093/mnras/stx2901. ISSN 0035-8711. Archived from the original on 23 April 2022. Retrieved 23 April 2022.
  12. ^ Allison M, Schmunk R. "Mars24 Sunclock — Time on Mars". NASA GISS. Archived from the original on 24 January 2017. Retrieved 19 August 2021.
  13. ^ a b Archinal BA, Acton CH, A'Hearn MF, et al. (2018). "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015". Celestial Mechanics and Dynamical Astronomy. 130 (3): 22. Bibcode:2018CeMDA.130...22A. doi:10.1007/s10569-017-9805-5. ISSN 0923-2958.
  14. ^ Mallama, A. (2007). "The magnitude and albedo of Mars". Icarus. 192 (2): 404–416. Bibcode:2007Icar..192..404M. doi:10.1016/j.icarus.2007.07.011.
  15. ^ "Atmospheres and Planetary Temperatures". American Chemical Society. 18 July 2013. Archived from the original on 27 January 2023. Retrieved 3 January 2023.
  16. ^ a b c "Mars Exploration Rover Mission: Spotlight". Marsrover.nasa.gov. 12 June 2007. Archived from the original on 2 November 2013. Retrieved 14 August 2012. Public Domain This article incorporates text from this source, which is in the public domain.
  17. ^ Sharp T, Gordon J, Tillman N (31 January 2022). "What is the Temperature of Mars?". Space.com. Archived from the original on 22 April 2020. Retrieved 14 March 2022.
  18. ^ a b Hassler DM, Zeitlin C, Wimmer-Schweingruber RF, et al. (24 January 2014). "Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover". Science. 343 (6169). Tables 1 and 2. Bibcode:2014Sci...343D.386H. doi:10.1126/science.1244797. hdl:1874/309142. PMID 24324275. S2CID 33661472.
  19. ^ a b c d Mallama A, Hilton JL (October 2018). "Computing apparent planetary magnitudes for The Astronomical Almanac". Astronomy and Computing. 25: 10–24. arXiv:1808.01973. Bibcode:2018A&C....25...10M. doi:10.1016/j.ascom.2018.08.002. S2CID 69912809.
  20. ^ "Encyclopedia - the brightest bodies". IMCCE. Archived from the original on 24 July 2023. Retrieved 29 May 2023.
  21. ^ a b Barlow NG (2008). Mars: an introduction to its interior, surface and atmosphere. Cambridge planetary science. Vol. 8. Cambridge University Press. p. 21. ISBN 978-0-521-85226-5.
  22. ^ a b Rees MJ, ed. (October 2012). Universe: The Definitive Visual Guide. New York: Dorling Kindersley. pp. 160–161. ISBN 978-0-7566-9841-6.
  23. ^ "The Lure of Hematite". Science@NASA. NASA. 28 March 2001. Archived from the original on 14 January 2010. Retrieved 24 December 2009.
  24. ^ Halliday, A. N., Wänke, H., Birck, J.-L., et al. (2001). "The Accretion, Composition and Early Differentiation of Mars". Space Science Reviews. 96 (1/4): 197–230. Bibcode:2001SSRv...96..197H. doi:10.1023/A:1011997206080. S2CID 55559040.
  25. ^ Zharkov VN (1993). "The role of Jupiter in the formation of planets". Evolution of the Earth and Planets. Washington DC American Geophysical Union Geophysical Monograph Series. Vol. 74. pp. 7–17. Bibcode:1993GMS....74....7Z. doi:10.1029/GM074p0007. ISBN 978-1-118-66669-2.
  26. ^ Lunine JI, Chambers J, Morbidelli A, et al. (2003). "The origin of water on Mars". Icarus. 165 (1): 1–8. Bibcode:2003Icar..165....1L. doi:10.1016/S0019-1035(03)00172-6.
  27. ^ Barlow NG (5–7 October 1988). H. Frey (ed.). Conditions on Early Mars: Constraints from the Cratering Record. MEVTV Workshop on Early Tectonic and Volcanic Evolution of Mars. LPI Technical Report 89-04. Easton, Maryland: Lunar and Planetary Institute. p. 15. Bibcode:1989eamd.work...15B.
  28. ^ Nesvorný D (June 2018). "Dynamical Evolution of the Early Solar System". Annual Review of Astronomy and Astrophysics. 56: 137–174. arXiv:1807.06647. Bibcode:2018ARA&A..56..137N. doi:10.1146/annurev-astro-081817-052028.
  29. ^ Yeager A (19 July 2008). "Impact May Have Transformed Mars". ScienceNews.org. Archived from the original on 14 September 2012. Retrieved 12 August 2008.
  30. ^ Minkel JR (26 June 2008). "Giant Asteroid Flattened Half of Mars, Studies Suggest". Scientific American. Archived from the original on 4 September 2014. Retrieved 1 April 2022.
  31. ^ Chang K (26 June 2008). "Huge Meteor Strike Explains Mars's Shape, Reports Say". The New York Times. Archived from the original on 1 July 2017. Retrieved 27 June 2008.
  32. ^ Ćuk M, Minton DA, Pouplin JL, et al. (16 June 2020). "Evidence for a Past Martian Ring from the Orbital Inclination of Deimos". The Astrophysical Journal. 896 (2): L28. arXiv:2006.00645. Bibcode:2020ApJ...896L..28C. doi:10.3847/2041-8213/ab974f. ISSN 2041-8213.
  33. ^ News Staff (4 June 2020). "Researchers Find New Evidence that Mars Once Had Massive Ring | Sci.News". Sci.News: Breaking Science News. Archived from the original on 7 November 2023. Retrieved 7 November 2023.
  34. ^ "Did ancient Mars have rings?". Earthsky | Updates on Your Cosmos and World. 5 June 2020. Archived from the original on 7 November 2023. Retrieved 7 November 2023.
  35. ^ Tanaka KL (1986). "The Stratigraphy of Mars". Journal of Geophysical Research. 91 (B13): E139–E158. Bibcode:1986JGR....91E.139T. doi:10.1029/JB091iB13p0E139. Archived from the original on 16 December 2021. Retrieved 17 July 2019.
  36. ^ Hartmann, William K., Neukum, Gerhard (2001). "Cratering Chronology and the Evolution of Mars". Space Science Reviews. 96 (1/4): 165–194. Bibcode:2001SSRv...96..165H. doi:10.1023/A:1011945222010. S2CID 7216371.
  37. ^ a b c "ESA Science & Technology - The Ages of Mars". sci.esa.int. Archived from the original on 29 August 2023. Retrieved 7 December 2021.
  38. ^ Mitchell, Karl L., Wilson, Lionel (2003). "Mars: recent geological activity : Mars: a geologically active planet". Astronomy & Geophysics. 44 (4): 4.16–4.20. Bibcode:2003A&G....44d..16M. doi:10.1046/j.1468-4004.2003.44416.x.
  39. ^ Russell P (3 March 2008). "Caught in Action: Avalanches on North Polar Scarps". HiRISE Operations Center. Archived from the original on 7 April 2022. Retrieved 28 March 2022.
  40. ^ "HiRISE Catches an Avalanche on Mars". NASA Jet Propulsion Laboratory (JPL). 12 August 2020. Archived from the original on 1 March 2022. Retrieved 28 March 2022.
  41. ^ Peplow M (6 May 2004). "How Mars got its rust". Nature: news040503–6. doi:10.1038/news040503-6. Archived from the original on 28 November 2022. Retrieved 10 March 2007.
  42. ^ a b NASA – Mars in a Minute: Is Mars Really Red? Archived 20 July 2014 at the Wayback Machine (Transcript Archived 6 November 2015 at the Wayback Machine) Public Domain This article incorporates text from this source, which is in the public domain.
  43. ^ a b Stähler SC, Khan A, Banerdt WB, et al. (23 July 2021). "Seismic detection of the martian core". Science. 373 (6553): 443–448. Bibcode:2021Sci...373..443S. doi:10.1126/science.abi7730. hdl:20.500.11850/498074. PMID 34437118. S2CID 236179579. Archived from the original on 1 March 2024. Retrieved 17 October 2021.
  44. ^ a b c Samuel H, Drilleau, Mélanie, Rivoldini, Attilio, et al. (October 2023). "Geophysical evidence for an enriched molten silicate layer above Mars's core". Nature. 622 (7984): 712–717. Bibcode:2023Natur.622..712S. doi:10.1038/s41586-023-06601-8. hdl:20.500.11850/639623. ISSN 1476-4687. PMC 10600000. PMID 37880437.
  45. ^ Nimmo F, Tanaka K (2005). "Early Crustal Evolution of Mars". Annual Review of Earth and Planetary Sciences. 33 (1): 133–161. Bibcode:2005AREPS..33..133N. doi:10.1146/annurev.earth.33.092203.122637. S2CID 45843366.
  46. ^ a b "In Depth | Mars". NASA Solar System Exploration. Archived from the original on 21 December 2021. Retrieved 15 January 2022.
  47. ^ Kim D, Duran C, Giardini D, et al. (June 2023). "Global Crustal Thickness Revealed by Surface Waves Orbiting Mars". Geophysical Research Letters. 50 (12). Bibcode:2023GeoRL..5003482K. doi:10.1029/2023GL103482. hdl:20.500.11850/621318.
  48. ^ Wieczorek MA, Broquet A, McLennan SM, et al. (May 2022). "InSight Constraints on the Global Character of the Martian Crust". Journal of Geophysical Research: Planets. 127 (5). Bibcode:2022JGRE..12707298W. doi:10.1029/2022JE007298. hdl:10919/110830.
  49. ^ Huang Y, Chubakov V, Mantovani F, et al. (June 2013). "A reference Earth model for the heat-producing elements and associated geoneutrino flux". Geochemistry, Geophysics, Geosystems. 14 (6): 2003–2029. arXiv:1301.0365. Bibcode:2013GGG....14.2003H. doi:10.1002/ggge.20129.
  50. ^ Fernando B, Daubar IJ, Charalambous C, et al. (October 2023). "A Tectonic Origin for the Largest Marsquake Observed by InSight". Geophysical Research Letters. 50 (20). Bibcode:2023GeoRL..5003619F. doi:10.1029/2023GL103619. hdl:20.500.11850/639018.
  51. ^ Golombek M, Warner NH, Grant JA, et al. (24 February 2020). "Geology of the InSight landing site on Mars". Nature Geoscience. 11 (1014): 1014. Bibcode:2020NatCo..11.1014G. doi:10.1038/s41467-020-14679-1. PMC 7039939. PMID 32094337.
  52. ^ Banerdt WB, Smrekar SE, Banfield D, et al. (2020). "Initial results from the InSight mission on Mars". Nature Geoscience. 13 (3): 183–189. Bibcode:2020NatGe..13..183B. doi:10.1038/s41561-020-0544-y.
  53. ^ Khan A, Ceylan S, van Driel M, et al. (23 July 2021). "Upper mantle structure of Mars from InSight seismic data" (PDF). Science. 373 (6553): 434–438. Bibcode:2021Sci...373..434K. doi:10.1126/science.abf2966. PMID 34437116. S2CID 236179554. Archived (PDF) from the original on 20 January 2022. Retrieved 27 November 2021.
  54. ^ Khan A, Huang, D., Durán, C., et al. (October 2023). "Evidence for a liquid silicate layer atop the Martian core". Nature. 622 (7984): 718–723. Bibcode:2023Natur.622..718K. doi:10.1038/s41586-023-06586-4. hdl:20.500.11850/639367. PMC 10600012. PMID 37880439.
  55. ^ Le Maistre S, Rivoldini A, Caldiero A, et al. (14 June 2023). "Spin state and deep interior structure of Mars from InSight radio tracking". Nature. 619 (7971): 733–737. Bibcode:2023Natur.619..733L. doi:10.1038/s41586-023-06150-0. ISSN 1476-4687. PMID 37316663. S2CID 259162975. Archived from the original on 12 October 2023. Retrieved 3 July 2023.
  56. ^ Rayne E (2 July 2023). "Mars has liquid guts and strange insides, InSight suggests". Ars Technica. Archived from the original on 3 July 2023. Retrieved 3 July 2023.
  57. ^ van der Lee S (25 October 2023). "Deep Mars is surprisingly soft". Nature. 622 (7984): 699–700. Bibcode:2023Natur.622..699V. doi:10.1038/d41586-023-03151-x. PMID 37880433. Archived from the original on 6 December 2023. Retrieved 12 March 2024.
  58. ^ Witze A (25 October 2023). "Mars has a surprise layer of molten rock inside". Nature. 623 (7985): 20. Bibcode:2023Natur.623...20W. doi:10.1038/d41586-023-03271-4. PMID 37880531. Archived from the original on 9 January 2024. Retrieved 12 March 2024.
  59. ^ McSween HY, Taylor GJ, Wyatt MB (May 2009). "Elemental Composition of the Martian Crust". Science. 324 (5928): 736–739. Bibcode:2009Sci...324..736M. CiteSeerX 10.1.1.654.4713. doi:10.1126/science.1165871. PMID 19423810. S2CID 12443584.
  60. ^ Bandfield JL (June 2002). "Global mineral distributions on Mars". Journal of Geophysical Research: Planets. 107 (E6): 9–1–9–20. Bibcode:2002JGRE..107.5042B. CiteSeerX 10.1.1.456.2934. doi:10.1029/2001JE001510.
  61. ^ Christensen PR (27 June 2003). "Morphology and Composition of the Surface of Mars: Mars Odyssey THEMIS Results" (PDF). Science. 300 (5628): 2056–2061. Bibcode:2003Sci...300.2056C. doi:10.1126/science.1080885. PMID 12791998. S2CID 25091239. Archived (PDF) from the original on 23 July 2018. Retrieved 17 December 2018.
  62. ^ Valentine, Theresa, Amde, Lishan (9 November 2006). "Magnetic Fields and Mars". Mars Global Surveyor @ NASA. Archived from the original on 14 September 2012. Retrieved 17 July 2009. Public Domain This article incorporates text from this source, which is in the public domain.
  63. ^ Neal-Jones N, O'Carroll C. "New Map Provides More Evidence Mars Once Like Earth". NASA/Goddard Space Flight Center. Archived from the original on 14 September 2012. Retrieved 4 December 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  64. ^ "Martian soil 'could support life'". BBC News. 27 June 2008. Archived from the original on 13 August 2011. Retrieved 7 August 2008.
  65. ^ Kounaves SP (2010). "Wet Chemistry Experiments on the 2007 Phoenix Mars Scout Lander: Data Analysis and Results". J. Geophys. Res. 115 (E3): E00–E10. Bibcode:2009JGRE..114.0A19K. doi:10.1029/2008JE003084. S2CID 39418301.
  66. ^ Kounaves SP (2010). "Soluble Sulfate in the Martian Soil at the Phoenix Landing Site". Geophysical Research Letters. 37 (9): L09201. Bibcode:2010GeoRL..37.9201K. doi:10.1029/2010GL042613. S2CID 12914422.
  67. ^ David L (13 June 2013). "Toxic Mars: Astronauts Must Deal with Perchlorate on the Red Planet". Space.com. Archived from the original on 20 November 2020. Retrieved 26 November 2018.
  68. ^ Sample I (6 July 2017). "Mars covered in toxic chemicals that can wipe out living organisms, tests reveal". The Guardian. Archived from the original on 18 February 2021. Retrieved 26 November 2018.
  69. ^ Verba C (2 July 2009). "Dust Devil Etch-A-Sketch (ESP_013751_1115)". HiRISE Operations Center. University of Arizona. Archived from the original on 1 February 2012. Retrieved 30 March 2022.
  70. ^ Schorghofer, Norbert, Aharonson, Oded, Khatiwala, Samar (2002). "Slope streaks on Mars: Correlations with surface properties and the potential role of water" (PDF). Geophysical Research Letters. 29 (23): 41–1. Bibcode:2002GeoRL..29.2126S. doi:10.1029/2002GL015889. Archived (PDF) from the original on 3 August 2020. Retrieved 25 August 2019.
  71. ^ Gánti, Tibor (2003). "Dark Dune Spots: Possible Biomarkers on Mars?". Origins of Life and Evolution of the Biosphere. 33 (4): 515–557. Bibcode:2003OLEB...33..515G. doi:10.1023/A:1025705828948. PMID 14604189. S2CID 23727267.
  72. ^ Williams M (21 November 2016). "How bad is the radiation on Mars?". Phys.org. Archived from the original on 4 April 2023. Retrieved 9 April 2023.
  73. ^ Wall M (9 December 2013). "Radiation on Mars 'Manageable' for Manned Mission, Curiosity Rover Reveals". Space.com. Archived from the original on 15 December 2020. Retrieved 9 April 2023.
  74. ^ "Comparison of Martian Radiation Environment with International Space Station". NASA Jet Propulsion Laboratory (JPL). 13 March 2003. Archived from the original on 9 April 2023. Retrieved 9 April 2023.
  75. ^ Paris A, Davies E, Tognetti L, et al. (27 April 2020). "Prospective Lava Tubes at Hellas Planitia". arXiv:2004.13156v1 [astro-ph.EP].
  76. ^ "What Mars Maps Got Right (and Wrong) Through Time". National Geographic. 19 October 2016. Archived from the original on 21 February 2021. Retrieved 15 January 2022.
  77. ^ "Planetary Names: Categories for Naming Features on Planets and Satellites". International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). USGS Astrogeology Science Center. Archived from the original on 5 December 2017. Retrieved 18 April 2022.
  78. ^ "Viking and the Resources of Mars" (PDF). Humans to Mars: Fifty Years of Mission Planning, 1950–2000. Archived from the original (PDF) on 14 July 2019. Retrieved 10 March 2007. Public Domain This article incorporates text from this source, which is in the public domain.
  79. ^ Tanaka KL, Coles KS, Christensen PR, eds. (2019), "Syrtis Major (MC-13)", The Atlas of Mars: Mapping its Geography and Geology, Cambridge: Cambridge University Press, pp. 136–139, doi:10.1017/9781139567428.018, ISBN 978-1-139-56742-8, S2CID 240843698, archived from the original on 1 March 2024, retrieved 18 January 2022
  80. ^ "Polar Caps". Mars Education at Arizona State University. Archived from the original on 28 May 2021. Retrieved 7 December 2021.
  81. ^ Davies ME, Berg RA (10 January 1971). "A preliminary control net of Mars". Journal of Geophysical Research. 76 (2): 373–393. Bibcode:1971JGR....76..373D. doi:10.1029/JB076i002p00373. Archived from the original on 1 March 2024. Retrieved 22 March 2022.
  82. ^ Archinal, B. A., Caplinger, M. (Fall 2002). "Mars, the Meridian, and Mert: The Quest for Martian Longitude". American Geophysical Union, Fall Meeting 2002. 22: P22D–06. Bibcode:2002AGUFM.P22D..06A.
  83. ^ de Vaucouleurs G, Davies ME, Sturms FM Jr (1973), "Mariner 9 Areographic Coordinate System", Journal of Geophysical Research, 78 (20): 4395–4404, Bibcode:1973JGR....78.4395D, doi:10.1029/JB078i020p04395
  84. ^ NASA (19 April 2007). "Mars Global Surveyor: MOLA MEGDRs". geo.pds.nasa.gov. Archived from the original on 13 November 2011. Retrieved 24 June 2011.
  85. ^ Ardalan AA, Karimi R, Grafarend EW (2009). "A New Reference Equipotential Surface, and Reference Ellipsoid for the Planet Mars". Earth, Moon, and Planets. 106 (1): 1–13. doi:10.1007/s11038-009-9342-7. ISSN 0167-9295. S2CID 119952798.
  86. ^ Zeitler, W., Ohlhof, T., Ebner, H. (2000). "Recomputation of the global Mars control-point network". Photogrammetric Engineering & Remote Sensing. 66 (2): 155–161. CiteSeerX 10.1.1.372.5691.
  87. ^ Lunine CJ (1999). Earth: evolution of a habitable world. Cambridge University Press. p. 183. ISBN 978-0-521-64423-5.
  88. ^ "ESA Science & Technology - Using iMars: Viewing Mars Express data of the MC11 quadrangle". sci.esa.int. Archived from the original on 29 December 2021. Retrieved 29 December 2021.
  89. ^ Chang K (15 April 2023). "New Mars Map Lets You 'See the Whole Planet at Once' - Scientists assembled 3,000 images from an Emirati orbiter to create the prettiest atlas yet of the red planet". The New York Times. Archived from the original on 16 May 2023. Retrieved 15 April 2023.
  90. ^ Staff (16 April 2023). "Welcome to Mars! Caltech's Jaw-Dropping, 5.7 Terapixel Virtual Expedition Across the Red Planet". SciTech. Archived from the original on 16 April 2023. Retrieved 6 April 2023.
  91. ^ "Mars Atlas: Olympus Mons". NASA's Mars Exploration Program. Archived from the original on 29 March 2023. Retrieved 30 March 2022.
  92. ^ a b Plescia JB (2004). "Morphometric Properties of Martian Volcanoes". J. Geophys. Res. 109 (E3): E03003. Bibcode:2004JGRE..109.3003P. doi:10.1029/2002JE002031.
  93. ^ Comins NF (2012). Discovering the Essential Universe. W. H. Freeman. p. 148. ISBN 978-1-4292-5519-6.
  94. ^ Schenk P (2012). "The Geologically Recent Giant Impact Basins at Vesta's South Pole". Science. 336 (6082): 694–697. Bibcode:2012Sci...336..694S. doi:10.1126/science.1223272. PMID 22582256. S2CID 206541950.
  95. ^ Andrews-Hanna JC, Zuber MT, Banerdt WB (2008). "The Borealis basin and the origin of the Martian crustal dichotomy". Nature. 453 (7199): 1212–1215. Bibcode:2008Natur.453.1212A. doi:10.1038/nature07011. PMID 18580944. S2CID 1981671.
  96. ^ a b Choi C (1 October 2021). "Mars: What We Know About the Red Planet". Space.com. Archived from the original on 6 January 2022. Retrieved 6 January 2022.
  97. ^ Moskowitz C (25 June 2008). "Huge Impact Created Mars' Split Personality". Space.com. Archived from the original on 6 January 2022. Retrieved 6 January 2022.
  98. ^ Wright S (4 April 2003). "Infrared Analyses of Small Impact Craters on Earth and Mars". University of Pittsburgh. Archived from the original on 12 June 2007. Retrieved 26 February 2007.
  99. ^ Vogt GL (2008). Landscapes of Mars (PDF). New York, NY: Springer. p. 44. doi:10.1007/978-0-387-75468-0. ISBN 978-0-387-75467-3. Archived from the original on 1 March 2024. Retrieved 31 March 2022.
  100. ^ "ESA Science & Technology - Craters within the Hellas Basin". sci.esa.int. Archived from the original on 2 January 2022. Retrieved 2 January 2022.
  101. ^ Rodrigue CM. "The Geography of Mars". Home.csulb.edu. Archived from the original on 30 January 2022. Retrieved 20 February 2022.
  102. ^ "41st Lunar and Planetary Science Conference (2010)" (PDF). Archived (PDF) from the original on 30 January 2022. Retrieved 31 January 2022.
  103. ^ Wetherill GW (1999). "Problems Associated with Estimating the Relative Impact Rates on Mars and the Moon". Earth, Moon, and Planets. 9 (1–2): 227–231. Bibcode:1974Moon....9..227W. doi:10.1007/BF00565406. S2CID 120233258.
  104. ^ Costard FM (1989). "The spatial distribution of volatiles in the Martian hydrolithosphere". Earth, Moon, and Planets. 45 (3): 265–290. Bibcode:1989EM&P...45..265C. doi:10.1007/BF00057747. S2CID 120662027.
  105. ^ Sagan C, Fox P (August 1975). "The canals of Mars: An assessment after Mariner 9". Icarus. 25 (4): 602–612. Bibcode:1975Icar...25..602S. doi:10.1016/0019-1035(75)90042-1. Archived from the original on 26 March 2023. Retrieved 22 March 2022.
  106. ^ Wolpert, Stuart (9 August 2012). "UCLA scientist discovers plate tectonics on Mars". UCLA. Archived from the original on 12 August 2012. Retrieved 13 August 2012.
  107. ^ Lin A (4 June 2012). "Structural analysis of the Valles Marineris fault zone: Possible evidence for large-scale strike-slip faulting on Mars". Lithosphere. 4 (4): 286–330. Bibcode:2012Lsphe...4..286Y. doi:10.1130/L192.1.
  108. ^ Cushing, G. E., Titus, T. N., Wynne, J. J., et al. (2007). "Themis Observes Possible Cave Skylights on Mars" (PDF). Lunar and Planetary Science XXXVIII. Archived (PDF) from the original on 15 September 2011. Retrieved 2 August 2007.
  109. ^ "NAU researchers find possible caves on Mars". Inside NAU. Vol. 4, no. 12. Northern Arizona University. 28 March 2007. Archived from the original on 28 August 2007. Retrieved 28 May 2007.
  110. ^ Rincon P (17 March 2007). "'Cave entrances' spotted on Mars". BBC News. Archived from the original on 30 September 2009. Retrieved 28 May 2007.
  111. ^ "The Caves of Mars | U.S. Geological Survey". USGS. Archived from the original on 31 December 2021. Retrieved 12 January 2022.
  112. ^ a b Philips T (31 January 2001). "The Solar Wind at Mars". Science@NASA. Archived from the original on 18 August 2011. Retrieved 22 April 2022. Public Domain This article incorporates text from this source, which is in the public domain.
  113. ^ Grossman L (20 January 2011). "Multiple Asteroid Strikes May Have Killed Mars's Magnetic Field". Wired. Archived from the original on 30 December 2013. Retrieved 30 March 2022.
  114. ^ a b Jakosky BM (1 April 2022). "How did Mars lose its atmosphere and water?". Physics Today. 75 (4): 62–63. Bibcode:2022PhT....75d..62J. doi:10.1063/PT.3.4988. ISSN 0031-9228. S2CID 247882540.
  115. ^ Lundin, R (2004). "Solar Wind-Induced Atmospheric Erosion at Mars: First Results from ASPERA-3 on Mars Express". Science. 305 (5692): 1933–1936. Bibcode:2004Sci...305.1933L. doi:10.1126/science.1101860. PMID 15448263. S2CID 28142296.
  116. ^ Bolonkin AA (2009). Artificial Environments on Mars. Berlin Heidelberg: Springer. pp. 599–625. ISBN 978-3-642-03629-3.
  117. ^ Atkinson, Nancy (17 July 2007). "The Mars Landing Approach: Getting Large Payloads to the Surface of the Red Planet". Archived from the original on 5 August 2010. Retrieved 18 September 2007.
  118. ^ Carr MH (2006). The surface of Mars. Vol. 6. Cambridge University Press. p. 16. ISBN 978-0-521-87201-0.
  119. ^ "Mars Facts | All About Mars". NASA's Mars Exploration Program. Archived from the original on 10 October 2023. Retrieved 27 December 2021.
  120. ^ Mahaffy PR (19 July 2013). "Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover". Science. 341 (6143): 263–266. Bibcode:2013Sci...341..263M. doi:10.1126/science.1237966. PMID 23869014. S2CID 206548973.
  121. ^ Lemmon MT (2004). "Atmospheric Imaging Results from Mars Rovers". Science. 306 (5702): 1753–1756. Bibcode:2004Sci...306.1753L. doi:10.1126/science.1104474. PMID 15576613. S2CID 5645412.
  122. ^ Sample I (7 June 2018). "Nasa Mars rover finds organic matter in ancient lake bed". The Guardian. Archived from the original on 18 June 2018. Retrieved 12 June 2018.
  123. ^ Mumma MJ (20 February 2009). "Strong Release of Methane on Mars in Northern Summer 2003" (PDF). Science. 323 (5917): 1041–1045. Bibcode:2009Sci...323.1041M. doi:10.1126/science.1165243. PMID 19150811. S2CID 25083438. Archived (PDF) from the original on 13 March 2012. Retrieved 1 November 2009.
  124. ^ Franck L, Forget F (6 August 2009). "Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics". Nature. 460 (7256): 720–723. Bibcode:2009Natur.460..720L. doi:10.1038/nature08228. PMID 19661912. S2CID 4355576.
  125. ^ a b Oze, C., Sharma, M. (2005). "Have olivine, will gas: Serpentinization and the abiogenic production of methane on Mars". Geophysical Research Letters. 32 (10): L10203. Bibcode:2005GeoRL..3210203O. doi:10.1029/2005GL022691. S2CID 28981740.
  126. ^ Webster CR, Mahaffy PR, Pla-Garcia J, et al. (June 2021). "Day-night differences in Mars methane suggest nighttime containment at Gale crater". Astronomy & Astrophysics. 650: A166. Bibcode:2021A&A...650A.166W. doi:10.1051/0004-6361/202040030. ISSN 0004-6361. S2CID 236365559.
  127. ^ Jones N, Steigerwald B, Brown D, et al. (14 October 2014). "NASA Mission Provides Its First Look at Martian Upper Atmosphere". NASA. Archived from the original on 19 October 2014. Retrieved 15 October 2014. Public Domain This article incorporates text from this source, which is in the public domain.
  128. ^ Wright K (22 March 2022). "Sound Speed Measured on Mars". Physics. 15: 43. Bibcode:2022PhyOJ..15...43W. doi:10.1103/Physics.15.43. S2CID 247720720. Archived from the original on 12 April 2022. Retrieved 6 April 2022.
  129. ^ Maurice S, Chide B, Murdoch N, et al. (1 April 2022). "In situ recording of Mars soundscape". Nature. 605 (7911): 653–658. Bibcode:2022Natur.605..653M. doi:10.1038/s41586-022-04679-0. ISSN 0028-0836. PMC 9132769. PMID 35364602. S2CID 247865804.
  130. ^ Chow D (7 December 2021). "In an ultraviolet glow, auroras on Mars spotted by UAE orbiter". NBC News. Archived from the original on 7 December 2021. Retrieved 7 December 2021.
  131. ^ "Auroras on Mars – NASA Science". science.nasa.gov. Archived from the original on 14 May 2015. Retrieved 12 May 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  132. ^ Brown D, Neal-Jones N, Steigerwald B, et al. (18 March 2015). "NASA Spacecraft Detects Aurora and Mysterious Dust Cloud around Mars". NASA. Release 15-045. Archived from the original on 19 March 2015. Retrieved 18 March 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  133. ^ Deighan J, Jain SK, Chaffin MS, et al. (October 2018). "Discovery of a proton aurora at Mars". Nature Astronomy. 2 (10): 802–807. Bibcode:2018NatAs...2..802D. doi:10.1038/s41550-018-0538-5. ISSN 2397-3366. S2CID 105560692. Archived from the original on 22 May 2022. Retrieved 5 April 2022.
  134. ^ a b Schneider NM, Jain SK, Deighan J, et al. (16 August 2018). "Global Aurora on Mars During the September 2017 Space Weather Event". Geophysical Research Letters. 45 (15): 7391–7398. Bibcode:2018GeoRL..45.7391S. doi:10.1029/2018GL077772. hdl:10150/631256. S2CID 115149852.
  135. ^ Webster G, Neal-Jones N, Scott J, et al. (29 September 2017). "Large Solar Storm Sparks Global Aurora and Doubles Radiation Levels on the Martian Surface". NASA. Archived from the original on 1 October 2017. Retrieved 9 January 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  136. ^ Goodman JC (22 September 1997). "The Past, Present, and Possible Future of Martian Climate". MIT. Archived from the original on 10 November 2010. Retrieved 26 February 2007.
  137. ^ "Mars' desert surface..." MGCM Press release. NASA. Archived from the original on 7 July 2007. Retrieved 25 February 2007. Public Domain This article incorporates text from this source, which is in the public domain.
  138. ^ Kluger J (1 September 1992). "Mars, in Earth's Image". Discover Magazine. 13 (9): 70. Bibcode:1992Disc...13...70K. Archived from the original on 27 April 2012. Retrieved 3 November 2009.
  139. ^ Hille K (18 September 2015). "The Fact and Fiction of Martian Dust Storms". NASA. Archived from the original on 2 March 2016. Retrieved 25 December 2021.
  140. ^ Philips T (16 July 2001). "Planet Gobbling Dust Storms". Science @ NASA. Archived from the original on 13 June 2006. Retrieved 7 June 2006. Public Domain This article incorporates text from this source, which is in the public domain.
  141. ^ "Water ice in crater at Martian north pole". ESA. 28 July 2005. Archived from the original on 9 February 2010. Retrieved 19 March 2010.
  142. ^ Whitehouse D (24 January 2004). "Long history of water and Mars". BBC News. Archived from the original on 11 January 2009. Retrieved 20 March 2010.
  143. ^ Holt JW, Safaeinili A, Plaut JJ, et al. (21 November 2008). "Radar Sounding Evidence for Buried Glaciers in the Southern Mid-Latitudes of Mars". Science. 322 (5905): 1235–1238. Bibcode:2008Sci...322.1235H. doi:10.1126/science.1164246. hdl:11573/67950. ISSN 0036-8075. JSTOR 20145331. PMID 19023078. S2CID 36614186. Archived from the original on 22 April 2022. Retrieved 22 April 2022.
  144. ^ Byrne, Shane, Ingersoll, Andrew P. (2003). "A Sublimation Model for Martian South Polar Ice Features". Science. 299 (5609): 1051–1053. Bibcode:2003Sci...299.1051B. doi:10.1126/science.1080148. PMID 12586939. S2CID 7819614.
  145. ^ "Polar Caps". Mars Education at Arizona State University. Archived from the original on 28 May 2021. Retrieved 6 January 2022.
  146. ^ "Mars' South Pole Ice Deep and Wide". NASA. 15 March 2007. Archived from the original on 20 April 2009. Retrieved 16 March 2007. Public Domain This article incorporates text from this source, which is in the public domain.
  147. ^ "NASA – NASA Rover Finds Clues to Changes in Mars' Atmosphere". NASA. Archived from the original on 26 December 2018. Retrieved 19 October 2014. Public Domain This article incorporates text from this source, which is in the public domain.
  148. ^ Heldmann JL (7 May 2005). "Formation of Martian gullies by the action of liquid water flowing under current Martian environmental conditions" (PDF). Journal of Geophysical Research. 110 (E5): Eo5004. Bibcode:2005JGRE..110.5004H. CiteSeerX 10.1.1.596.4087. doi:10.1029/2004JE002261. hdl:2060/20050169988. S2CID 1578727. Archived from the original (PDF) on 1 October 2008. Retrieved 17 September 2008. 'conditions such as now occur on Mars, outside of the temperature-pressure stability regime of liquid water'... 'Liquid water is typically stable at the lowest elevations and at low latitudes on the planet because the atmospheric pressure is greater than the vapor pressure of water and surface temperatures in equatorial regions can reach 273 K for parts of the day [Haberle et al.., 2001]'
  149. ^ Kerr RA (4 March 2005). "Ice or Lava Sea on Mars? A Transatlantic Debate Erupts". Science. 307 (5714): 1390–1391. doi:10.1126/science.307.5714.1390a. PMID 15746395. S2CID 38239541.
  150. ^ Jaeger WL (21 September 2007). "Athabasca Valles, Mars: A Lava-Draped Channel System". Science. 317 (5845): 1709–1711. Bibcode:2007Sci...317.1709J. doi:10.1126/science.1143315. PMID 17885126. S2CID 128890460.
  151. ^ Lucchitta, B. K., Rosanova, C. E. (26 August 2003). "Valles Marineris; The Grand Canyon of Mars". USGS. Archived from the original on 11 June 2011. Retrieved 11 March 2007. Public Domain This article incorporates text from this source, which is in the public domain.
  152. ^ Murray JB (17 March 2005). "Evidence from the Mars Express High Resolution Stereo Camera for a frozen sea close to Mars' equator". Nature. 434 (703): 352–356. Bibcode:2005Natur.434..352M. doi:10.1038/nature03379. PMID 15772653. S2CID 4373323.
  153. ^ Craddock, R.A., Howard, A.D. (2002). "The case for rainfall on a warm, wet early Mars". Journal of Geophysical Research. 107 (E11): 21–1. Bibcode:2002JGRE..107.5111C. CiteSeerX 10.1.1.485.7566. doi:10.1029/2001JE001505.
  154. ^ Malin MC, Edgett KS (30 June 2000). "Evidence for Recent Groundwater Seepage and Surface Runoff on Mars". Science. 288 (5475): 2330–2335. Bibcode:2000Sci...288.2330M. doi:10.1126/science.288.5475.2330. PMID 10875910. S2CID 14232446.
  155. ^ a b "NASA Images Suggest Water Still Flows in Brief Spurts on Mars". NASA. 6 December 2006. Archived from the original on 7 August 2011. Retrieved 6 December 2006. Public Domain This article incorporates text from this source, which is in the public domain.
  156. ^ "Water flowed recently on Mars". BBC. 6 December 2006. Archived from the original on 30 August 2011. Retrieved 6 December 2006.
  157. ^ "Water May Still Flow on Mars, NASA Photo Suggests". NASA. 6 December 2006. Archived from the original on 2 January 2007. Retrieved 30 April 2006. Public Domain This article incorporates text from this source, which is in the public domain.
  158. ^ Lewis, K.W., Aharonson, O. (2006). "Stratigraphic analysis of the distributary fan in Eberswalde crater using stereo imagery" (PDF). Journal of Geophysical Research. 111 (E06001): E06001. Bibcode:2006JGRE..111.6001L. doi:10.1029/2005JE002558. Archived (PDF) from the original on 3 August 2020. Retrieved 25 August 2019.
  159. ^ Matsubara, Y., Howard, A.D., Drummond, S.A. (2011). "Hydrology of early Mars: Lake basins". Journal of Geophysical Research. 116 (E04001): E04001. Bibcode:2011JGRE..116.4001M. doi:10.1029/2010JE003739.
  160. ^ "Mineral in Mars 'Berries' Adds to Water Story" (Press release). NASA. 3 March 2004. Archived from the original on 9 November 2007. Retrieved 13 June 2006. Public Domain This article incorporates text from this source, which is in the public domain.
  161. ^ "Mars Exploration Rover Mission: Science". NASA. 12 July 2007. Archived from the original on 28 May 2010. Retrieved 10 January 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  162. ^ Elwood Madden ME, Bodnar RJ, Rimstidt JD (October 2004). "Jarosite as an indicator of water-limited chemical weathering on Mars". Nature. 431 (7010): 821–823. doi:10.1038/nature02971. ISSN 0028-0836. PMID 15483605. S2CID 10965423. Archived from the original on 3 March 2022. Retrieved 22 April 2022.
  163. ^ "Mars Rover Investigates Signs of Steamy Martian Past". NASA Jet Propulsion Laboratory (JPL). 10 December 2007. Archived from the original on 6 July 2022. Retrieved 5 April 2022.
  164. ^ "NASA – NASA Mars Rover Finds Mineral Vein Deposited by Water". NASA. 7 December 2011. Archived from the original on 15 June 2017. Retrieved 14 August 2012. Public Domain This article incorporates text from this source, which is in the public domain.
  165. ^ Lovett RA (8 December 2011). "Rover Finds "Bulletproof" Evidence of Water on Early Mars". National Geographic. Archived from the original on 1 May 2021. Retrieved 31 March 2022.
  166. ^ Lovett RA (26 June 2012). "Mars Has "Oceans" of Water Inside?". National Geographic. Archived from the original on 28 April 2021. Retrieved 31 March 2022.
  167. ^ McCubbin FM, Hauri EH, Elardo SM, et al. (August 2012). "Hydrous melting of the martian mantle produced both depleted and enriched shergottites". Geology. 40 (8): 683–686. Bibcode:2012Geo....40..683M. doi:10.1130/G33242.1. ISSN 1943-2682.
  168. ^ a b Webster G, Brown D (18 March 2013). "Curiosity Mars Rover Sees Trend in Water Presence". NASA. Archived from the original on 24 April 2013. Retrieved 20 March 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  169. ^ Rincon P (19 March 2013). "Curiosity breaks rock to reveal dazzling white interior". BBC News. BBC. Archived from the original on 8 March 2021. Retrieved 19 March 2013.
  170. ^ "NASA Confirms Evidence That Liquid Water Flows on Today's Mars". NASA. 28 September 2015. Archived from the original on 28 September 2015. Retrieved 28 September 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  171. ^ Drake N (28 September 2015). "NASA Finds 'Definitive' Liquid Water on Mars". National Geographic News. Archived from the original on 30 September 2015. Retrieved 29 September 2015.
  172. ^ Ojha L, Wilhelm MB, Murchie SL, et al. (2015). "Spectral evidence for hydrated salts in recurring slope lineae on Mars". Nature Geoscience. 8 (11): 829–832. Bibcode:2015NatGe...8..829O. doi:10.1038/ngeo2546. S2CID 59152931.
  173. ^ Moskowitz C. "Water Flows on Mars Today, NASA Announces". Scientific American. Archived from the original on 15 May 2021. Retrieved 29 September 2015.
  174. ^ McEwen A, Lujendra O, Dundas C, et al. (5 August 2011). "Seasonal Flows on Warm Martian Slopes". Science. 333 (6043): 740–743. Bibcode:2011Sci...333..740M. doi:10.1126/science.1204816. PMID 21817049. S2CID 10460581. Archived from the original on 29 September 2015. Retrieved 28 September 2015.
  175. ^ Dundas CM, McEwen AS, Chojnacki M, et al. (December 2017). "Granular flows at recurring slope lineae on Mars indicate a limited role for liquid water". Nature Geoscience. 10 (12): 903–907. Bibcode:2017NatGe..10..903D. doi:10.1038/s41561-017-0012-5. hdl:10150/627918. ISSN 1752-0908. S2CID 24606098. Archived from the original on 22 November 2017. Retrieved 3 April 2022.
  176. ^ Schorghofer N (12 February 2020). "Mars: Quantitative Evaluation of Crocus Melting behind Boulders". The Astrophysical Journal. 890 (1): 49. Bibcode:2020ApJ...890...49S. doi:10.3847/1538-4357/ab612f. ISSN 1538-4357. S2CID 213701664.
  177. ^ Wray JJ (30 May 2021). "Contemporary Liquid Water on Mars?". Annual Review of Earth and Planetary Sciences. 49 (1): 141–171. Bibcode:2021AREPS..49..141W. doi:10.1146/annurev-earth-072420-071823. ISSN 0084-6597. S2CID 229425641. Archived from the original on 3 May 2021. Retrieved 3 April 2022.
  178. ^ Head, J.W. (1999). "Possible Ancient Oceans on Mars: Evidence from Mars Orbiter Laser Altimeter Data". Science. 286 (5447): 2134–7. Bibcode:1999Sci...286.2134H. doi:10.1126/science.286.5447.2134. PMID 10591640. S2CID 35233339.
  179. ^ Kaufman M (5 March 2015). "Mars Had an Ocean, Scientists Say, Pointing to New Data". The New York Times. Archived from the original on 7 March 2020. Retrieved 5 March 2015.
  180. ^ Sample I (21 December 2018). "Mars Express beams back images of ice-filled Korolev crater". The Guardian. Archived from the original on 8 February 2020. Retrieved 21 December 2018.
  181. ^ "EPA; Great Lakes; Physical Facts". 29 October 2010. Archived from the original on 29 October 2010. Retrieved 15 February 2023.
  182. ^ "Mars Ice Deposit Holds as Much Water as Lake Superior". NASA. 22 November 2016. Archived from the original on 26 December 2018. Retrieved 23 November 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  183. ^ Staff (22 November 2016). "Scalloped Terrain Led to Finding of Buried Ice on Mars". NASA. Archived from the original on 26 December 2018. Retrieved 23 November 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  184. ^ Mitrofanov I, Malakhov A, Djachkova M, et al. (March 2022). "The evidence for unusually high hydrogen abundances in the central part of Valles Marineris on Mars". Icarus. 374: 114805. Bibcode:2022Icar..37414805M. doi:10.1016/j.icarus.2021.114805. S2CID 244449654.
  185. ^ Badescu V (2009). Mars: Prospective Energy and Material Resources (illustrated ed.). Springer Science & Business Media. p. 600. ISBN 978-3-642-03629-3. Archived from the original on 4 March 2023. Retrieved 20 May 2016.
  186. ^ Petropoulos AE, Longuski JM, Bonfiglio EP (2000). "Trajectories to Jupiter via Gravity Assists from Venus, Earth, and Mars". Journal of Spacecraft and Rockets. 37 (6). American Institute of Aeronautics and Astronautics (AIAA): 776–783. Bibcode:2000JSpRo..37..776P. doi:10.2514/2.3650. ISSN 0022-4650.
  187. ^ Taylor C (9 July 2020). "Welcome to Cloud City: The case for going to Venus, not Mars". Mashable. Archived from the original on 21 October 2022. Retrieved 21 October 2022.
  188. ^ Vitagliano A (2003). "Mars' Orbital eccentricity over time". Solex. Universita' degli Studi di Napoli Federico II. Archived from the original on 7 September 2007. Retrieved 20 July 2007.
  189. ^ a b Meeus J (March 2003). "When Was Mars Last This Close?". International Planetarium Society. Archived from the original on 16 May 2011. Retrieved 18 January 2008.
  190. ^ Laskar J (14 August 2003). "Primer on Mars oppositions". IMCCE, Paris Observatory. Archived from the original on 13 November 2011. Retrieved 1 October 2010. (Solex results) Archived 9 August 2012 at the Wayback Machine
  191. ^ Tillman NT, Dobrijevic D (20 January 2022). "How Long Does It Take to Get to Mars?". Space.com. Retrieved 23 August 2024.
  192. ^ a b "Mars Opposition | Mars in our Night Sky". NASA's Mars Exploration Program. Archived from the original on 5 October 2023. Retrieved 7 December 2021.
  193. ^ "EarthSky | Why is Mars sometimes bright and sometimes faint?". earthsky.org. 5 October 2021. Archived from the original on 7 December 2021. Retrieved 7 December 2021.
  194. ^ "Close encounter: Mars at opposition". ESA/Hubble. 3 November 2005. Archived from the original on 10 September 2015. Retrieved 1 April 2022.
  195. ^ Mallama, A. (2011). "Planetary magnitudes". Sky and Telescope. 121 (1): 51–56.
  196. ^ "Mars Close Approach | Mars in our Night Sky". NASA's Mars Exploration Program. Archived from the original on 8 November 2019. Retrieved 18 January 2022.
  197. ^ "Slide 2 Earth Telescope View of Mars". The Red Planet: A Survey of Mars. Lunar and Planetary Institute. Archived from the original on 18 May 2021. Retrieved 28 November 2011.
  198. ^ Zeilik M (2002). Astronomy: the Evolving Universe (9th ed.). Cambridge University Press. p. 14. ISBN 978-0-521-80090-7.
  199. ^ "Close Inspection for Phobos". ESA website. Archived from the original on 14 January 2012. Retrieved 13 June 2006.
  200. ^ "Planetary Names". planetarynames.wr.usgs.gov. Archived from the original on 30 December 2023. Retrieved 30 May 2022.
  201. ^ "Phobos". NASA Solar System Exploration. 19 December 2019. Archived from the original on 12 January 2022. Retrieved 12 January 2022.
  202. ^ "Explaining the Birth of the Martian Moons". AAS Nova. American Astronomical Society. 23 September 2016. Archived from the original on 13 December 2021. Retrieved 13 December 2021.
  203. ^ Adler M, Owen W, Riedel J (June 2012). Use of MRO Optical Navigation Camera to Prepare for Mars Sample Return (PDF). Concepts and Approaches for Mars Exploration. 12–14 June 2012. Houston, Texas. 4337. Bibcode:2012LPICo1679.4337A. Archived from the original on 26 December 2018. Retrieved 28 August 2012.
  204. ^ Andert TP, Rosenblatt, P., Pätzold, M., et al. (7 May 2010). "Precise mass determination and the nature of Phobos". Geophysical Research Letters. 37 (L09202): L09202. Bibcode:2010GeoRL..37.9202A. doi:10.1029/2009GL041829.
  205. ^ a b Giuranna M, Roush, T. L., Duxbury, T., et al. (2010). Compositional Interpretation of PFS/MEx and TES/MGS Thermal Infrared Spectra of Phobos (PDF). European Planetary Science Congress Abstracts, Vol. 5. Archived (PDF) from the original on 12 May 2011. Retrieved 1 October 2010.
  206. ^ Bagheri A, Khan A, Efroimsky M, et al. (22 February 2021). "Dynamical evidence for Phobos and Deimos as remnants of a disrupted common progenitor". Nature Astronomy. 5 (6): 539–543. Bibcode:2021NatAs...5..539B. doi:10.1038/s41550-021-01306-2. S2CID 233924981.
  207. ^ Rabkin ES (2005). Mars: A Tour of the Human Imagination. Westport, Connecticut: Praeger. pp. 9–11. ISBN 978-0-275-98719-0.
  208. ^ Thompson HO (1970). Mekal: The God of Beth-Shan. Leiden, Germany: E. J. Brill. p. 125.
  209. ^ Novakovic B (2008). "Senenmut: An Ancient Egyptian Astronomer". Publications of the Astronomical Observatory of Belgrade. 85: 19–23. arXiv:0801.1331. Bibcode:2008POBeo..85...19N.
  210. ^ North JD (2008). Cosmos: an illustrated history of astronomy and cosmology. University of Chicago Press. pp. 48–52. ISBN 978-0-226-59441-5.
  211. ^ Swerdlow NM (1998). "Periodicity and Variability of Synodic Phenomenon". The Babylonian theory of the planets. Princeton University Press. pp. 34–72. ISBN 978-0-691-01196-7.
  212. ^ Cicero MT (1896). De Natura Deorum [On the Nature of the Gods]. Translated by Francis Brooks. London: Methuen.
  213. ^ NASA (9 October 2022). "All About Mars". mars.nasa.gov. Archived from the original on 10 October 2022. Retrieved 10 October 2022.
  214. ^ Stephenson FR (November 2000). "A Lunar Occultation of Mars Observed by Aristotle". Journal for the History of Astronomy. 31 (4): 342–344. Bibcode:2000JHA....31..342S. doi:10.1177/002182860003100405. ISSN 0021-8286. S2CID 125518456. Archived from the original on 17 April 2023. Retrieved 2 April 2022.
  215. ^ Harland DM (2007). Cassini at Saturn: Huygens results. Springer. p. 1. ISBN 978-0-387-26129-4.
  216. ^ McCluskey SC (1998), Astronomies and Cultures in Early Medieval Europe, Cambridge: Cambridge University Press, pp. 20–21, ISBN 978-0-521-77852-7
  217. ^ Needham J, Ronan CA (1985). The Shorter Science and Civilisation in China: An Abridgement of Joseph Needham's Original Text. Vol. 2 (3rd ed.). Cambridge University Press. p. 187. ISBN 978-0-521-31536-4.
  218. ^ de Groot JJ (1912). "Fung Shui". Religion in China – Universism: A Key to the Study of Taoism and Confucianism. American Lectures on the History of Religions, volume 10. G. P. Putnam's Sons. p. 300. OCLC 491180. Archived from the original on 26 February 2024. Retrieved 5 January 2016.
  219. ^ Crump T (1992). The Japanese Numbers Game: The Use and Understanding of Numbers in Modern Japan. Nissan Institute/Routledge Japanese Studies Series. Routledge. pp. 39–40. ISBN 978-0-415-05609-0.
  220. ^ Hulbert HB (1909) [1906]. The Passing of Korea. Doubleday, Page & Company. p. 426. OCLC 26986808.
  221. ^ Taton R (2003). Taton R, Wilson C, Hoskin M (eds.). Planetary Astronomy from the Renaissance to the Rise of Astrophysics, Part A, Tycho Brahe to Newton. Cambridge University Press. p. 109. ISBN 978-0-521-54205-0.
  222. ^ Frautschi SC, Olenick RP, Apostol TM, et al. (2007). The Mechanical Universe: Mechanics and Heat (Advanced ed.). Cambridge [Cambridgeshire]: Cambridge University Press. ISBN 978-0-521-71590-4. OCLC 227002144.
  223. ^ Hirshfeld A (2001). Parallax: the race to measure the cosmos. Macmillan. pp. 60–61. ISBN 978-0-7167-3711-7.
  224. ^ Breyer S (1979). "Mutual Occultation of Planets". Sky and Telescope. 57 (3): 220. Bibcode:1979S&T....57..220A.
  225. ^ Peters WT (1984). "The Appearance of Venus and Mars in 1610". Journal for the History of Astronomy. 15 (3): 211–214. Bibcode:1984JHA....15..211P. doi:10.1177/002182868401500306. S2CID 118187803.
  226. ^ Sheehan W (1996). "2: Pioneers". The Planet Mars: A History of Observation and Discovery. Tucson: University of Arizona. Bibcode:1996pmho.book.....S. Archived from the original on 26 April 2012. Retrieved 16 January 2010 – via uapress.arizona.edu.
  227. ^ Milner R (6 October 2011). "Tracing the Canals of Mars: An Astronomer's Obsession". Space.com. Archived from the original on 25 December 2021. Retrieved 25 December 2021.
  228. ^ a b Sagan C (1980). Cosmos. New York City: Random House. p. 107. ISBN 978-0-394-50294-6.
  229. ^ Basalla G (2006). "Percival Lowell: Champion of Canals". Civilized Life in the Universe: Scientists on Intelligent Extraterrestrials. Oxford University Press US. pp. 67–88. ISBN 978-0-19-517181-5.
  230. ^ Dunlap DW (1 October 2015). "Life on Mars? You Read It Here First". The New York Times. Archived from the original on 2 October 2015. Retrieved 1 October 2015.
  231. ^ Maria, K., Lane, D. (2005). "Geographers of Mars". Isis. 96 (4): 477–506. doi:10.1086/498590. PMID 16536152. S2CID 33079760.
  232. ^ Perrotin M (1886). "Observations des canaux de Mars". Bulletin Astronomique. Série I (in French). 3: 324–329. Bibcode:1886BuAsI...3..324P. doi:10.3406/bastr.1886.9920. S2CID 128159166.
  233. ^ Zahnle K (2001). "Decline and fall of the Martian empire". Nature. 412 (6843): 209–213. doi:10.1038/35084148. PMID 11449281. S2CID 22725986.
  234. ^ Drake N (29 July 2020). "Why we explore Mars—and what decades of missions have revealed". National Geographic. Archived from the original on 18 February 2021. Retrieved 7 December 2021.
  235. ^ "In Depth | Mariner 04". NASA Solar System Exploration. Archived from the original on 3 August 2020. Retrieved 9 February 2020. The Mariner 4 mission, the second of two Mars flyby attempts launched in 1964 by NASA, was one of the great early successes of the agency, and indeed the Space Age, returning the very first photos of another planet from deep space. Public Domain This article incorporates text from this source, which is in the public domain. "Spacecraft – Details - Mariner 4". NASA – NSSDCA. Archived from the original on 4 September 2018. Retrieved 9 February 2020. Mariner 4...represented the first successful flyby of the planet Mars, returning the first pictures of the martian surface. These represented the first images of another planet ever returned from deep space. Public Domain This article incorporates text from this source, which is in the public domain.
  236. ^ Ward, Peter Douglas, Brownlee, Donald (2000). Rare Earth: Why complex life is uncommon in the universe. Copernicus Series (2nd ed.). Springer. p. 253. ISBN 978-0-387-95289-5.
  237. ^ Bond P (2007). Distant Worlds: Milestones in planetary exploration. Copernicus Series. Springer. p. 119. ISBN 978-0-387-40212-3.
  238. ^ "New Online Tools Bring NASA's Journey to Mars to a New Generation". NASA. 5 August 2015. Archived from the original on 7 August 2015. Retrieved 5 August 2015.
  239. ^ Culpan D (10 July 2015). "Explore the Red Planet with Nasa's Mars Trek". Wired UK. Archived from the original on 31 March 2022. Retrieved 31 March 2022.
  240. ^ Strickland A (12 February 2021). "Meet the orbiters that help rovers on Mars talk to Earth". CNN. Archived from the original on 22 March 2022. Retrieved 22 March 2022.
  241. ^ Hill T (9 February 2021). "As new probes reach Mars, here's what we know so far from trips to the red planet". The Conversation. Archived from the original on 16 February 2022. Retrieved 22 March 2022.
  242. ^ Myers SL, Chang K (14 May 2021). "China's Mars Rover Mission Lands on the Red Planet". The New York Times. Archived from the original on 28 December 2021. Retrieved 15 May 2021.
  243. ^ Davidson J (22 February 2024). "Blue Origin Debuts New Glenn on Our Launch Pad". Retrieved 15 April 2024.
  244. ^ "Second ExoMars mission moves to next launch opportunity in 2020". European Space Agency. 2 May 2016. Archived from the original on 19 March 2022. Retrieved 24 March 2022.
  245. ^ "ExoMars to take off for the Red Planet in 2022". European Space Agency. 12 March 2020. Archived from the original on 19 March 2022. Retrieved 24 March 2022.
  246. ^ Amos J (17 March 2022). "Joint Europe-Russia Mars rover project is parked". BBC News. Archived from the original on 6 April 2022. Retrieved 24 March 2022.
  247. ^ "A saga for Rosalind Franklin – To Mars and back". Retrieved 13 May 2024.
  248. ^ "NASA, ESA Officials Outline Latest Mars Sample Return Plans". planetary.org. 13 August 2019. Archived from the original on 4 August 2020. Retrieved 9 September 2019.
  249. ^ "Mars Sample Return Campaign". mars.nasa.gov. Archived from the original on 15 June 2022. Retrieved 31 January 2022.
  250. ^ Kilicpublished C (28 September 2022). "Mars is littered with 15,694 pounds of human trash from 50 years of robotic exploration". Space.com. Retrieved 4 April 2024.
  251. ^ "Humans have already dumped 7 tonnes of junk on Mars, map reveals". WION. 2 February 2024. Retrieved 4 April 2024.
  252. ^ "NASA Selects Commercial Service Studies to Enable Mars Robotic Science". NASA Jet Propulsion Laboratory (JPL). Retrieved 1 May 2024.
  253. ^ a b c d Wright WH (1947). Biographical Memoir of William Wallace Campbell, 1862–1938 (PDF). Washington, D.C.: National Academy of Sciences. Archived (PDF) from the original on 20 July 2021. Retrieved 22 May 2021.
  254. ^ Salisbury FB (1962). "Martian Biology". Science. 136 (3510): 17–26. Bibcode:1962Sci...136...17S. doi:10.1126/science.136.3510.17. JSTOR 1708777. PMID 17779780. S2CID 39512870.
  255. ^ Kopparapu RK, Ramirez R, Kasting JF, et al. (2013). "Habitable Zones Around Main-Sequence Stars: New Estimates". The Astrophysical Journal. 765 (2): 131. arXiv:1301.6674. Bibcode:2013ApJ...765..131K. doi:10.1088/0004-637X/765/2/131. S2CID 76651902.
  256. ^ Briggs H (15 February 2008). "Early Mars 'too salty' for life". BBC News. Archived from the original on 17 May 2012. Retrieved 16 February 2008.
  257. ^ Hannsson A (1997). Mars and the Development of Life. Wiley. ISBN 978-0-471-96606-7.
  258. ^ Chang K (4 August 2021). "Gilbert V. Levin, Who Said He Found Signs of Life on Mars, Dies at 97". The New York Times. Archived from the original on 4 August 2021. Retrieved 4 August 2021.
  259. ^ Kounaves SP (2014). "Evidence of martian perchlorate, chlorate, and nitrate in Mars meteorite EETA79001: implications for oxidants and organics". Icarus. 229: 206–213. Bibcode:2014Icar..229..206K. doi:10.1016/j.icarus.2013.11.012.
  260. ^ Krasnopolsky, Vladimir A., Maillard, Jean-Pierre, Owen, Tobias C. (2004). "Detection of methane in the Martian atmosphere: evidence for life?". Icarus. 172 (2): 537–547. Bibcode:2004Icar..172..537K. doi:10.1016/j.icarus.2004.07.004.
  261. ^ Peplow M (25 February 2005). "Formaldehyde claim inflames Martian debate". Nature. doi:10.1038/news050221-15. S2CID 128986558.
  262. ^ Nickel M (18 April 2014). "Impact glass stores biodata for millions of years". Brown University. Archived from the original on 17 June 2015. Retrieved 9 June 2015.
  263. ^ Schultz PH, Harris RS, Clemett SJ, et al. (June 2014). "Preserved flora and organics in impact melt breccias". Geology. 42 (6): 515–518. Bibcode:2014Geo....42..515S. doi:10.1130/G35343.1. hdl:2060/20140013110. S2CID 39019154.
  264. ^ Brown D, Webster G, Stacey K (8 June 2015). "NASA Spacecraft Detects Impact Glass on Surface of Mars" (Press release). NASA. Archived from the original on 9 June 2015. Retrieved 9 June 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  265. ^ Stacey K (8 June 2015). "Martian glass: Window into possible past life?". Brown University. Archived from the original on 11 June 2015. Retrieved 9 June 2015.
  266. ^ Temming M (12 June 2015). "Exotic Glass Could Help Unravel Mysteries of Mars". Scientific American. Archived from the original on 15 June 2015. Retrieved 15 June 2015.
  267. ^ "S.442 - National Aeronautics and Space Administration Transition Authorization Act of 2017". congress.gov. 21 March 2017. Archived from the original on 30 March 2022. Retrieved 29 March 2022.
  268. ^ Foust J (18 April 2019). "Independent report concludes 2033 human Mars mission is not feasible". Space News. Archived from the original on 22 August 2020. Retrieved 29 March 2022.
  269. ^ "China plans its first crewed mission to Mars in 2033". Reuters. 23 June 2021. Archived from the original on 21 December 2021. Retrieved 20 December 2021.
  270. ^ Musk E (1 March 2018). "Making Life Multi-Planetary". New Space. 6 (1): 2–11. Bibcode:2018NewSp...6....2M. doi:10.1089/space.2018.29013.emu. ISSN 2168-0256. Archived from the original on 29 June 2019. Retrieved 27 August 2022.
  271. ^ Howell E (13 April 2024). "SpaceX's giant Starship will be 500 feet tall for Mars missions, Elon Musk says (video)". Space.com. Retrieved 20 April 2024.
  272. ^ Weinstein LM (2003). "Space Colonization Using Space-Elevators from Phobos" (PDF). AIP Conference Proceedings. 654. Albuquerque, New Mexico (USA): AIP: 1227–1235. Bibcode:2003AIPC..654.1227W. doi:10.1063/1.1541423. hdl:2060/20030065879. S2CID 1661518. Archived (PDF) from the original on 19 January 2023. Retrieved 6 December 2022.
  273. ^ Bichell RE (6 July 2017). "To Prepare For Mars Settlement, Simulated Missions Explore Utah's Desert". NPR. Archived from the original on 31 December 2022. Retrieved 31 December 2022.
  274. ^ Boyle A (29 September 2015). "Destination Phobos: 'Humans Orbiting Mars' report goes public". GeekWire.
  275. ^ Koch US (1995). Mesopotamian Astrology: An Introduction to Babylonian and Assyrian Celestial Divination. Museum Tusculanum Press. pp. 128–129. ISBN 978-87-7289-287-0.
  276. ^ Cecilia L (6 November 2019). "A Late Composition Dedicated to Nergal". Altorientalische Forschungen. 46 (2): 204–213. doi:10.1515/aofo-2019-0014. hdl:1871.1/f23ff882-1539-4906-bc08-049906f8d505. ISSN 2196-6761. S2CID 208269607. Archived from the original on 22 March 2022. Retrieved 22 March 2022.
  277. ^ Reid J (2011). "An Astronomer's Guide to Holst's The Planets" (PDF). Sky and Telescope. 121 (1): 66. Bibcode:2011S&T...121a..66R. Archived (PDF) from the original on 22 March 2022. Retrieved 22 March 2022.
  278. ^ "Solar System Symbols". NASA Solar System Exploration. Archived from the original on 20 December 2021. Retrieved 7 December 2021.
  279. ^ Jones A (1999). Astronomical papyri from Oxyrhynchus. American Philosophical Society. pp. 62–63. ISBN 978-0-87169-233-7.
  280. ^ Eschner K. "The Bizarre Beliefs of Astronomer Percival Lowell". Smithsonian Magazine. Archived from the original on 25 December 2021. Retrieved 25 December 2021.
  281. ^ Fergus C (2004). "Mars Fever". Research/Penn State. 24 (2). Archived from the original on 31 August 2003. Retrieved 2 August 2007.
  282. ^ Plait PC (2002). Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing 'Hoax'. New York: Wiley. pp. 233–234. ISBN 0-471-40976-6. OCLC 48885221.
  283. ^ Lightman BV (1997). Victorian Science in Context. University of Chicago Press. pp. 268–273. ISBN 978-0-226-48111-1.
  284. ^ Schwartz S (2009). C. S. Lewis on the Final Frontier: Science and the Supernatural in the Space Trilogy. Oxford University Press US. pp. 19–20. ISBN 978-0-19-537472-8.
  285. ^ Buker DM (2002). The science fiction and fantasy readers' advisory: the librarian's guide to cyborgs, aliens, and sorcerers. ALA readers' advisory series. ALA Editions. p. 26. ISBN 978-0-8389-0831-0.
  286. ^ Rabkin ES (2005). Mars: a tour of the human imagination. Greenwood Publishing Group. pp. 141–142. ISBN 978-0-275-98719-0.
  287. ^ Crossley R (3 January 2011). Imagining Mars: A Literary History. Wesleyan University Press. pp. xiii–xiv. ISBN 978-0-8195-7105-2.

Further reading

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