Astrophysics (Index)About

Mars

(well-explored planet in the solar system)

Mars is the fourth solar system planet from the Sun and the second smallest. Characteristics:

It has two small moons, Phobos and Deimos both smaller than 25 km in diameter. There has been interest in whether Mars might harbor life, and the fact that it is within the Sun's habitable zone makes the idea plausible. But the average surface temperature is on the order of -70 centigrade, well below water's triple point making surface liquid water unlikely, and water in Martian ground is generally locked in permafrost, making a location suitable for life unlikely. There is evidence that Mars's surface once had water, such as apparent shorelines and river beds, and it is generally accepted that Mars once had considerable water, though that may not have lasted very long compared to the age of the solar system. To have had water, Mars necessarily once had a considerably higher temperature, presumably requiring a greenhouse effect, which in turn would require a thicker atmosphere in the past, including sufficient greenhouse gas(es).

Mars's axial tilt cycles over a wider range than Earth's, largely due to its lack of such influence as the Moon has on Earth's. This results in Mars's more pronounced climate changes over the long term.

Far more space missions have been sent to Mars than to any other planet, more than 40, beginning in the 1960s with the NASA Mariner and Viking programs and the Soviet Mars program. Recent years have had orbiters (e.g., NASA's Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO)), landers (e.g., NASA's Phoenix), rovers (e.g., NASA's Mars Exploration Rover and Curiosity), and other missions swinging by. From the orbiting and landing probes much of Mars' geography and geology has been mapped and investigated: the huge volcano, Olympus Mons, taller than any mountain on Earth, and the Medusae Fossae Formation (MFF), a large region of flat lowlands that appears to be a lava deposit.

Future missions and proposals include missions from numerous countries: Mars 2020 from NASA, and others by the EU, Japan, Russia, China, and other countries, including an ExoMars rover mission by the European Space Agency and Russia.


(planet,solar system)
Further reading:
http://en.wikipedia.org/wiki/Mars
http://en.wikipedia.org/wiki/Exploration_of_Mars
RedshiftParsecs
/Distance
Lightyears
/Lookback Years
  
~00.4AU~0lynearestMars
~02.7AU~0lyfurthestMars

Referenced by pages:
albedo
asteroid belt
astrobiology
astronomical symbol
biosignature
Ceres
methane (CH4)
carbon dioxide (CO2)
comet
crustal magnetism
Earth analog
equilibrium temperature (Teq)
ExoMars
Goddard gravity model (GGM)
habitable zone (HZ)
impact
isolation mass
J2
Kelvin-Helmholtz instability (KHI)
late heavy bombardment (LHB)
magnetic field
magnitude
Mars 2020
Mars crosser (MC)
Mars Express
Mars Observer (MO)
MarsWRF
MAVEN
Mars Exploration Rover (MER)
Mars Global Surveyor (MGS)
MMRTG
MMX
moment of inertia factor
moon
Moon formation
Mars Pathfinder (MPF)
Mars Polar Lander (MPL)
Mars Reconnaissance Orbiter (MRO)
Mars Science Laboratory (MSL)
neutron scattering
obliquity
Phoenix
Planet Nine
planetary embryo
Pluto
polygonal ground
radar
regolith
rocky planet
Rosalind Franklin
rotation period
SpeX
stratigraphy
Trace Gas Orbiter (TGO)
Titius-Bode law
twinkling
water activity (aw)

Index