orbit of Mars is nearly circular,
it is somewhat more eccentric than the orbits of the other
planets. Mars is more than 30 million miles farther, from
the Sun, during some parts of it's year, than it is at
others. Mars takes 687 of our days (that's slightly less than 2 of our years) to make one circuit around the Sun,
traveling at about 54,000 miles per hour. Mars rotates at
about the same speed as Earth - 24 hours and 37 minutes.
Mars' average distance from the Sun has been calculated at
141 million miles, so the temperature on Mars would be much
lower than on Earth even if the atmosphere were the same as
ours. Mars does not have a magnetic field as Earth does, and
because of this Mars is continually exposed to an influx of
cosmic radiation 100 times as intense as on Earth, even
though Mars is farther from the Sun than Earth. Where the atmosphere is well
mixed by turbulence (below an altitude of 125 km [78 miles]), 95.3 percent of
the atmosphere by weight is carbon dioxide. This is a comparatively large amount
of carbon dioxide, nine times the quantity now in the Earth's much more massive
atmosphere. However, much of the Earth's carbon dioxide is chemically locked in
sedimentary rocks; Martian carbon dioxide is less than 1/1,000 the terrestrial
total. The balance of the Martian atmosphere consists of molecular nitrogen
(N2), argon (Ar), water vapor (H2O), and rare gases. In addition to these
molecules, there are also trace amounts of gases that have been produced from
the primary constituents by photochemical reactions, generally high in the
atmosphere; this component includes molecular oxygen (O2), carbon monoxide (CO),
nitric oxide (NO), and small amounts of ozone (O3). Mars axis of
rotation is inclined 25 degrees, therefore Mars has seasons
as does the Earth, except that the Martian seasons are
longer because the year is longer on Mars. White caps
increase at the polar regions during the winter season and
then shrink during the summer periods. These polar caps are
believed to be both ice and carbon dioxide. It is the carbon
dioxide that is seen to come and go with the seasons. This
carbon dioxide is the same as "Dry Ice" here on
Earth. When you cool carbon dioxide gas down to 110 degrees
below zero "Dry Ice" begins to form. You may Clik
on the Planet's image (above) to see the Martian surface.
The Canals of Mars
have become a greater mystery than they were before the
voyage of Mariner4. Mariner 9 was placed in an orbit above
Mars and has transmitted over 10,000 photos covering 100% of
the planets surface. One of the volcanic features is
"Olympus Mons", a volcano whose caldera is over 50
miles wide, with the outer slopes measuring 300 miles in
diameter. This volcano stands 90,000 feet above the
surrounding plain. Flowing water, non-existent on Mars at
the present time, carved great canyons on the surface, one
10 times longer and 3 times deeper than the "Grand
Canyon".
You can follow the
Mars "Rover" mission at this link >http://www.mars.jpl.nasa.gov/mer/
Mars has two satellites. The outer satellite, "Deimos", revolves around Mars in about 31 hours. "Deimos" is about 5 by 7.5 miles in size. The inner satellite, "Phobos", whips around Mars in 7+ hours, making 3 trips around the planet each Martian day. "Phobos" measures about 8 by 12 miles in size.
You may clik on The Star Cruiser to see an alternate image of the Martian surface.
