- Other bodies
- Basic Definitions
Mars has two irregularly-shaped small moons namely Phobos and Deimos. Each of the two moons is only a few kilometers wide. The larger moon is named Phobos (“fear”) and the smaller is Deimos (“terror”), named for attributes personified in Greek mythology as sons of the God of War.
Mars Mars Phobos Mars
The Martian atmosphere comprises of a number of contrasting features. The atmosphere of Mars is composed of Carbon dioxide (95%), Nitrogen (3%), Argon (1.6%) and rest oxygen & water.
In March 2004, the Mars Express Orbiter confirmed the presence of methane in patches in the atmosphere of Mars. The discovery of methane has also given rise to various questions regarding the existence of life in Mars in the form of microorganisms (methanogens).
At the surface of Mars, winds up to 40 meters per second (80 miles per hour) accompanied by dust storms and whirlwinds called dust devils can be felt. The average surface temperature of Mars measures -5 degrees C (-64 F). The highest point on Mars is Olympus Mons, a huge shield volcano about 6 kilometers (16 miles) high and 600 kilometers (70 miles) across.
Views of Mars
At the poles, the surface temperature dips to such an extent in the winter months that nearly 25% of the atmosphere condenses into a thick slab of carbon-dioxide ice. When the poles are again exposed to sunlight the CO2 ice de-condenses.
Missions to Mars
The United States, Soviet Union, Europe and Japan have sent several successful missions to Mars including the Mariner, Mars Reconnaissance Orbiter, Mars Global Surveyor, Mars Odyssey, Mars Pathfinder etc.
NASA launched the Mars Exploration Rovers (MER) named Spirit (MER-A) and Opportunity (MER-B) in 2003. Both MER’s landed on Mars in January 2004. Initially, a 90-day mission was planned for both the rovers, but their missions were extended for twice the period. Although the rovers have had some mechanical faults, they have continued sending important data from the planet.
NASA’s Mars Reconnaissance Orbiter arrived at Mars on March 10, 2006. The orbiter has the most powerful telescopic camera ever taken to another planet along with five other scientific instruments. Some of the first radar and imaging results from Orbiter show layers of ice-rich deposits near the poles. It has also photographed various cliffs that are the clearest evidence of sand-dunes on the surface of Mars.
Spirit recently found water-altered minerals in disturbed soils and granular rocks which have evolved as a result of continuous volcanic eruptions.
Mars and Earth
After a time span of about 60,000 years, Mars was closest to the Earth on August 27, 2003 at a distance of 55,758,006 km (approx. 35 million miles). The last time it came so close to the Earth is estimated to have been on September 12, 57,617 BC. Astronomers have forecast an even closer approach by Mars to Earth in the year 2287.
A tiny Sun setting
During a Transit of Earth as seen from Mars, Earth can be seen as a small black disc moving across the face of the Sun.
The view of the event from Mars would be particularly interesting because both the Earth and the Moon can be seen together in a transit. However, sometimes one finishes transiting before the other begins.
The next transit of Earth from Mars will take place on November 10, 2084. The last transit of Earth as seen from Mars took place on May 11, 1984.