Mars

Mars

Pictured in natural color in 2007
Designations
Pronunciation	/ˈmɑːrz/ (listen)
Adjectives	Martian
Orbital characteristics
Epoch J2000
Aphelion	249200000 km (154800000 mi; 1.666 AU)
Perihelion	206700000 km (128400000 mi; 1.382 AU)
Semi-major axis	227939200 km (141634900 mi; 1.523679 AU)
Eccentricity	0.0934
Orbital period	686.971 d (1.88082 yr; 668.5991 sols)
Synodic period	779.96 d (2.1354 yr)
Average orbital speed	24.007 km/s (86430 km/h; 53700 mph)
Inclination	1.850° to ecliptic; 5.65° the Sun's equator; 1.67° to invariable plane
Longitude of ascending node	49.558°
Argument of perihelion	286.502°
Satellites	2
Physical characteristics
Mean radius	3389.5 ± 0.2 km  (2106.1 ± 0.1 mi)
Equatorial radius	3396.2 ± 0.1 km  (2110.3 ± 0.1 mi; 0.533 Earths)
Polar radius	3376.2 ± 0.1 km  (2097.9 ± 0.1 mi; 0.531 Earths)
Flattening	0.00589±0.00015
Surface area	144798500 km2[1] (55907000 sq mi; 0.284 Earths)
Volume	1.6318×1011 km3 (0.151 Earths)
Mass	6.4171×1023 kg (0.107 Earths)
Mean density	3.9335 g/cm3 (0.1421 lb/cu in)
Surface gravity	3.72076 m/s2[2] (12.2072 ft/s2; 0.3794 g)
Moment of inertia factor	0.3662±0.0017
Escape velocity	5.027 km/s (18100 km/h; 11250 mph)
Sidereal rotation period	1.025957 d  24h 37m 22s
Equatorial rotation velocity	241.17 m/s (868.22 km/h; 539.49 mph)
Axial tilt	25.19° to its orbital plane
North pole right ascension	317.68143°  21h 10m 44s
North pole declination	52.88650°
Albedo	0.170 geometric 0.25 Bond
Surface temp. min mean max Kelvin 130 K 210 K 308 K Celsius −143 °C[3] −63 °C 35 °C[4] Fahrenheit −226 °F[3] −82 °F 95 °F[4]
Apparent magnitude	−2.94 to +1.86
Angular diameter	3.5–25.1″
Atmosphere
Surface pressure	0.636 (0.4–0.87) kPa 0.00628 atm
Composition by volume	95.97% carbon dioxide 1.93% argon 1.89% nitrogen 0.146% oxygen 0.0557% carbon monoxide

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, nicknamed The Red Planet.

Mars is a terrestrial planet with caps of water and carbon dioxide.^[5][6] It has the largest volcano in the Solar System, and some very large impact craters.^[5]

Mars is named after the mythological Roman god of war because it appears of red color. Anything that has to do with Mars is called "Martian".

Space probes, such as the Viking program landers, are the main tools for the exploration of Mars.

1. ↑ Grego, Peter (2012). Mars and how to observe it. Springer Science+Business Media. ISBN 978-1-4614-2302-7. Retrieved 2019-04-26 – via Google Books.
2. ↑ Hirt, C.; Claessens, S. J.; Kuhn, M.; Featherstone, W. E. (July 2012). "Kilometer-resolution gravity field of Mars: MGM2011". 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.
3. ↑ ^{3.0 3.1} Cite error: The named reference cold was used but no text was provided for refs named (see the help page).
4. ↑ ^{4.0 4.1} Cite error: The named reference hot was used but no text was provided for refs named (see the help page).
5. ↑ ^{5.0 5.1} "Mars: Extreme Planet". NASA. Archived from the original on 2011-10-26. Retrieved 2011-10-25.
6. ↑ Cite error: The named reference nasa070315 was used but no text was provided for refs named (see the help page).