The Red Planet
Mars, the fourth planet from the Sun, is the last of the inner,
terrestrial planets. Its surface is covered with an iron-rich clay,
giving the planet a reddish color. Even with the unaided eye, Mars
appears redder than the other planets and stars in the night sky.
Mars has two moons: Phobos, which is about 13 miles wide, and Deimos,
which is about 7 miles wide. These moons are so small that some
scientists believe they are asteroids that were captured by Marss
Courtesy of NASA JPL
When spacecraft began photographing Mars in the 1960s and 1970s,
astronomers didnt find the Martian people that many science
fiction writers had predicted. They did find mountains that are
three times higher than Mount Everest, a canyon that is as long
as the United States is wide, a bulge that is bigger than Alaska
and over six miles high, and a crater that is almost four miles
deep. Images have also shown signs of erosion in many places, indicating
that Mars may have had flowing rivers or oceans in the distant past.
In 1997, the Mars Pathfinder landed on the planet surface, and
sent the rover Sojourner to study the area around its landing site.
The mission proved that relatively low-cost missions to Mars were
possible, and provided a great deal of information on the geology,
chemistry, and atmospherics of the planet.
In early 2004, the Spirit and Opportunity rovers landed in two
different locations on the surface of Mars. Like robotic geologists,
Spirit and Opportunity are currently exploring the Martian surface,
taking samples of the soil and rocks and sending back many incredible
images. The Odyssey and Mars Global Surveyor continue to orbit the
planet, studying its geology, weather, and climate from above. They
also perform an important role in the rover missions, relaying commands
from Earth to the rovers, and data from the rovers to Earth.
Mars is in the evening sky through winter and spring in 2004,
in Taurus, setting at sunset by June. Look for the red planet in
the eastern morning sky beginning in mid-October and through the
end of the year.