The Planet Mars: Mars
Mars is closest to the Earth than during the past 11
years, and this summer's opposition of Mars (directly 180 degrees
from the sun) provides all star gazers with a wonderful opportunity
to view this most interesting planet.
Mars will appear as a reddish disk with a few light
and dark regions and prominent white polar caps. Mars' rotation
axis is tilted 24 degrees from its orbital plane, therefore it
undergoes seasonal changes like the Earth. The polar caps grow
and shrink with the seasons. The permanent polar caps are made
of frozen water ice. The changing caps are mostly frozen carbon
dioxide (dry ice) which settles in from the thin
Martian atmosphere, which consists of 95 percent carbon dioxide.
Planet-wide dust storms occur on Mars. The planet's
northern surface is mostly rolling volcanic plains formed from
lava flows while the southern hemisphere is heavily cratered highlands
lying several kilometers above the lower northern plains. Mars
hosts the largest canyon in the solar system and the largest volcano.
Olympus Mons (Mt. Olympus) is larger than the state of Wyoming,
rising some 25 km (15 miles) above the surface. Olympus Mons is
nearly two and a half times higher than Mt. Everest is from sea
level.
Vallis Marineris, the largest canyon in the solar system,
runs nearly 5000 km long and would extend the entire length of
the United States. Its maximum width is 500 km, so Arizona's Grand
Canyon would be only a small tributary.
Have an enjoyable time gazing at this wonderful red
planet during our pleasant summer season.
You can get more details on the evening skies and a monthly star
chart via the Wyoming
Skies: Sky Charts For more information, send questions
and comments by e-mail to: Dr.
Ron Canterna (canterna@uwyo.edu).
Return to Wyoming Skies: Monthly Interests