Back Mars Afrikaans Mars (Planet) ALS ማርስ Amharic Marte (planeta) AN Tiw (tungol) ANG Maas ANN मंगल ग्रह ANP المريخ Arabic لمريخ ARY مريخ ARZ
 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 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Adjectives |
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| Symbol | .svg){kind=small} | ||||||||
| Orbital characteristics[1] | |||||||||
| Epoch J2000 | |||||||||
| Aphelion | 249261000 km (1.66621 AU)[2] | ||||||||
| Perihelion | 206650000 km (1.3814 AU)[2] | ||||||||
| 227939366 km (1.52368055 AU)[3] | |||||||||
| Eccentricity | 0.0934[2] | ||||||||
| 686.980 d (1.88085 yr; 668.5991 sols)[2] | |||||||||
| 779.94 d (2.1354 yr)[3] | |||||||||
Average orbital speed | 24.07 km/s[2] | ||||||||
| 19.412°[2] | |||||||||
| Inclination |
| ||||||||
| 49.57854°[2] | |||||||||
| 2022-Jun-21[5] | |||||||||
| 286.5°[3] | |||||||||
| Satellites | 2 (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) | ||||||||
| Flattening | 0.00589±0.00015[5][6] | ||||||||
| 1.4437×108 km2[7] (0.284 Earths) | |||||||||
| Volume | 1.63118×1011 km3[8] (0.151 Earths) | ||||||||
| Mass | 6.4171×1023 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 | |||||||||
| Temperature | 209 K (−64 °C) (blackbody temperature)[15] | ||||||||
| |||||||||
| Surface absorbed dose rate | 8.8 μGy/h[18] | ||||||||
| Surface equivalent dose rate | 27 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 |
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Mars is the fourth planet from the Sun. It is also known as "the Red Planet", because of its orange-red appearance.[22][23] Mars is a desert-like rocky planet with a tenuous carbon dioxide (CO2) atmosphere. At the average surface level the atmospheric pressure is a few thousands of Earth's, atmospheric temperature ranges from −153 °C (−243 °F) to 20 °C (68 °F)[24] and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half as wide as Earth or twice the Moon, with a diameter of 6,779 km (4,212 mi), and has a surface area the size of all the dry land of Earth.
Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south divide, the Martian dichotomy, with the northern hemisphere mainly consisting of relatively flat, low lying plains, and the southern hemisphere of cratered highlands. Geologically, the planet is fairly active with marsquakes trembling underneath the ground, but also 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). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos. With a significant axial tilt of 25 degrees Mars experiences seasons, like Earth (which has an axial tilt of 23.5 degrees). A Martian solar year is equal to 1.88 Earth years (687 Earth days), a Martian solar day (sol) is equal to 24.6 hours.
Mars was formed approximately 4.5 billion years ago. During the Noachian period (4.5 to 3.5 billion years ago), its surface was marked by meteor impacts, valley formation, erosion, the possible presence of water oceans and the loss of its magnetosphere. 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 is the currently dominating and remaining influence on geological processes. Due to Mars's geological history, the possibility of past or present life on Mars remains an area of active scientific investigation.
Mars has been observed throughout history and has been an element in many cultures with different associations, being readily visible in Earth's sky as a red wandering star. In 1963 the first flight to Mars took place with the en-route lost Mars 1. The first successful exploration of Mars came about in 1965 with Mariner 4. 1971 saw the very first orbit around Mars and anywhere beyond the Moon (Mariner 9), as well as the first (uncontrolled) impact (Mars 2) and landing (Mars 3) on Mars. As of 2023, there are at least 11 active probes orbiting Mars or on the Martian surface. Mars is an often proposed target for future human exploration missions, though no such mission is planned yet.
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