Mars

Mars' Moons | "Life" on Mars

Overview

Mars is about half the size of our planet, Earth. It's thin atmosphere is slowly being blown away by the sun's solar wind. However, its atmosphere forms clouds, and sometimes supports planet-wide dust storms.

The red planet has many features that are visible to the backyard observer with a powerful enough telescope. First of all, Mars has a reddish color due to the iron oxide - commonly known as rust - that is in the soil.

The first feature that most can see on Mars are the polar ice caps. These huge caps of water and carbon dioxide ice expand and shrink due to seasonal changes on Mars.

Second, "canals" and "seas" cover the entire planet. The canals may have been waterways many millions or billions of years ago, but they are now dry, as are the seas. The seas were probably oceans that covered parts of Mars.

Third, the largest volcano in our solar system, Olympus Mons, lies on Mars. It is 24 km (15 miles) high, and the top of it is 70 km (40 miles) wide; the base is about 600 km (375 miles) wide. This volcano is now dormant, but was active millions of years ago.

Mars is also home to one of the longest (more than 4,000 km (2500 miles long)) canyon systems in the solar system called Valles Marineris ("Mariner Valley"). The canyon system ranges from 5 to 8 km (3-5 miles) deep. If placed on Earth, this would stretch from New York to Los Angeles.

You can find the current weather of Mars, as well as its position relative to Earth at the Mars Today home page, sponsored by NASA.

Atmosphere

As can be seen in the table below, Mars' atmosphere is much less than Earth's and Venus', and it exerts a pressure of only 0.000636 bars at the surface. Its composition is nearly all CO₂; the rest is approximately:

• CO₂: 95.32%
• N₂: 2.7%
• Ar: 1.6%
• O₂: 0.13%
• CO: 0.08%
• H₂O: 0.021%
• NO: 0.01%
• Ne: 0.00025%
• HDO: 0.000085%
• Kr: 0.00003%
• Xe: 0.000008%

The surface density is 20 g/m³. Below 30° latitude, wind speeds range up to 150 m/s, and above that only 40 m/s. The scale height of the Jovian atmosphere is about 11.1 km.

It is not yet clear how Mars' atmosphere evolved. It is assumed that its original composition was as the other planets - mostly hydrogen and helium. It probably evolved in a slightly similar fashion to Venus and Earth.

Unique Characteristics

Mars is the most Earth-like planet in the solar system (except for in size and therefore surface gravity; Venus takes the cake for that characteristic). Because of this, several scientists believe that, if done correctly, Mars can be terra formed into a planet inhabitable by humans.

Mars has some unique characteristics:

• First off, Mars has the largest volcano in the solar system, Olympus Mons.
• It also has the largest canyon system in the solar system called Valles Marineris. This is pictured to the right.
• Third, Mars is the only other planet besides Earth to posses frozen water at its poles, which scientists have seen grow and shrink as the Mars seasons change.
• Fourth, Mars is the only other planet (that we know of) that has the capability of supporting life, past or present (see "Life" on Mars).

Spacecraft that Have Visited or Will Visit

1. Marsnik 1 (Mars 1960A) - attempted Mars flyby (launch failure) in 1960
2. Marsnik 2 (Mars 1960B) - attempted Mars flyby (launch failure) in 1960
3. Sputnik 22 - attempted Mars flyby in 1962
4. Mars 1 - Mars flyby (contact lost) in 1962
5. Sputnik 24 - attempted Mars lander in 1962
6. Mariner 3 - attempted Mars flyby in 1964
7. Mariner 4 - 1 flyby in 1964
8. Zond 2 - Mars flyby (contact lost) in 1964
9. Mariner 6 - 1 flyby in 1969
10. Mariner 7 - 1 flyby in 1969
11. Mars 1969A - attempted Mars orbiter (launch failure) in 1969
12. Mars 1969B - attempted Mars orbiter (launch failure) in 1969
13. Mariner 8 - attempted Mars flyby (launch failure) in 1971
14. Cosmos 419 - attempted Mars orbiter and lander in 1971
15. Mars 2 - Mars orbiter and attempted lander in 1971
16. Mars 3 - Mars orbiter and lander in 1971
17. Mariner 9 - 1 flyby in 1971
18. Mars 4 - Mars flyby and attempted Mars orbiter in 1973
19. Mars 5 - Mars orbiter in 1973
20. Mars 6 - Mars lander (contact lost) in 1973
21. Mars 7 - Mars flyby and attempted Mars lander) in 1973
22. Viking 1 - Mars orbiter and lander in 1976
23. Viking 2 - Mars orbiter and lander in 1976
24. Phobos 1 - attempted Mars orbiter and Phobos landers in 1988
25. Phobos 2 - Mars orbiter and attempted Phobos landers in 1988
26. Mars Observer - attempted Mars orbiter (contact lost) in 1992
27. Mars Global Surveyor - Mars orbiter from 1996-Present
28. Mars 96 - attempted Mars orbiters/landers
29. Mars Pathfinder - Mars lander in 1997
30. Nazomi (Planet-B) - ISAS Mars orbiter in 1998
31. Mars Climate Orbiter - attempted Mars orbiter in 1998
32. Mars Polar Lander - attempted Mars lander in 1999
33. Deep Space 2 (DS2) - attempted Mars penetrators in 1999
34. 2001 Mars Odyssey - Mars orbiter from 2001-Present
35. Mars Express - Mars orbiter from 2003-Present and attempted lander
36. Spirit (MERA) - Mars lander from 2004-Present
37. Opportunity (MERB) - Mars lander from 2004-Present
38. Mars Reconnaisance Orbiter - Mars orbiter with a planned launch in 2005
39. Phoenix - Mars scout lander with a planned launch in 2007
40. Netlanders - Mars netlanders with a planned launch in 2007
41. Mars 2009 - Mars science laboratory rover with a planned launch in 2009
42. Mars 2011 - Mars scout mission with a planned launch in 2011

Mythology

Mars obtained its name due to its deep, war-like red color. The Romans named the planet after their god of war, Mars. Olympus Mons, the largest volcano in the solar system is named after Mount Olympus, the home of the Greek / Roman gods and goddesses. Mars' two moons, Phobos and Deimos, are named after Fear and Panic, the two lackeys of Mars.

Data for the Planets