Mars, the ‘Red Planet‘ is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war. The red color of the planet comes from the effect of the iron oxide prevalent on Mars’ surface, which gives it a reddish appearance distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial planet (Rocky planet) with a thin atmosphere. The Surface features of Mars are reminiscent of a hybrid between Earth and Mars. Mars has impact craters like Moon. Mars also has valleys, deserts, volcanos, and polar ice caps similar to Planet Earth.
| EARTH | MARS | |
|---|---|---|
| Average Distance from Sun | 93 million miles | 142 million miles |
| Average Speed in Orbiting Sun | 18.5 miles per second | 14.5 miles per second |
| Diameter | 7,926 miles | 4,220 miles |
| Tilt of Axis | 23.5 degrees | 25 degrees |
| Length of Year | 365.25 Days | 687 Earth Days |
| Length of Day | 23 hours 56 minutes | 24 hours 37 minutes |
| Gravity | 2.66 times that of Mars | 0.375 that of Earth |
| Temperature | Average 57 degrees F | Average -81 degrees F |
| Atmosphere | nitrogen, oxygen, argon, others | mostly carbon dioxide, some water vapor |
| Number of Moons | 1 | 2 |
Credit: WestEastSpace We did the scientific notation on purpose to better show the relationship of mass. The mass of Mars is roughly 10% of Earth, and the Mass of the Moon is roughly 10% of Mars.
Mars Topography
Credit NASA — MARS ORBITER LASER ALTIMETER (MOLA) MAP OF MARS
The Mars Orbiter Laser Altimeter aboard Mars Global Surveyor produced the first global map of the topography of Mars. MOLA operated by shining a laser at the planet and timing its reflection. The highly detailed along-orbit topographic profiles were resampled into this gridded map. The map is in Mercator projection to 70 degrees North and South, and Polar Stereographic projection for the south (left) and north (right) poles. The most obvious feature of this map is the major contrast in elevation between the southern highlands (mostly orange) and northern lowlands (blue). The highest elevations are found in the Tharsis volcanic province at about 250°E, while the lowest elevations are in the Hellas basin at about 60°E.
Mars magnetic fields
We first learned about Mars’ magnetic fields from the way they interacted with the solar wind.
In 1965 Mariner 4, one of America’s first interplanetary probes, passed within 8,000 kilometers (4,971 miles) of Mars’ surface. At that distance, it failed to detect any magnetic field. Earth has a planet-wide field can be detected by magnetometers within 60,000 kilometers (37,282 miles). What Mariner did note was that the solar wind was being bent around the planet, widely in some places.
Credit NASA — At one time, Mars had a magnetic field similar to Earth, which prevented its atmosphere from being stripped away.
In 2001, NASA’s Mars Global Surveyor confirmed the presence of remnant magnetic fields, but not from the core. Rather the weak magnetic field on Mars is believed to be concentrated exclusively in ancient crust. The portions of the crust that are magnetized likely became magnetic before the cooling of the Martian core.
Credit NASA –The global map of Mars is built up from many thousands of orbits of the The Mars Global Surveyor at constant altitude (mapping orbit), and uses colors to represent the strength and direction of the field caused by crustal magnetization.
