Let's look broadly at how Mars compares
to earth. Frst Mars is 49 million miles
further away from the Sun than the Earth is.  Mars is moving slower than the Earth
and has a longer orbital path. The earth
is revolving or traveling around the Sun
at over 66,000 miles per hour and
completes one orbit in about three
hundred and sixty five and one quarter
days. Mars is revolving around the Sun at
about 54,000 miles per hour and travels
a much longer path. As a result
Mars takes 687 days to complete one
orbit. Mars and Earth have similar tilts.
This means that both Earth and Mars
experience winter, spring, summer, and fall.
But since Mars is further from the Sun
its seasons are all much colder than
those on Earth. Mars turns or rotates
slightly slower on its axis than the
Earth does. As a result, one day on mars
is 24 hours and 40 minutes. The diameter
of Mars is about half that of Earth. It
is the second smallest planet in the
Solar System.  Mars has 63 percent less
gravity than earth. This means that you
weigh sixty-three percent less on Mars.
For example, if you weigh 250 pounds
on earth, on Mars you would
weigh only 156 pounds. It also means it
will be easier to jump higher.
Mars is much colder than earth with an
average temperature of minus 81°F.
That's over 100° Fahrenheit below freezing.  Mars is, on average,
colder than the Antarctic and
drier than the Sahara. Humans could not
survive breathing in the Martian
atmosphere because it is 96% carbon
dioxide. Earth's atmosphere is 78%
nitrogen and 21% oxygen. In the past
century we have learned much about
Earth's interior but we have little
direct evidence for what's inside Mars.
In the future,
geophysical monitoring instruments will
be deployed to Mars. This instrumentation
will provide evidence to answer the many
questions we have about what lies
beneath the surface of the red planet.
