Venus
Venus was the first planet besides Earth to be explored. In 1962, Mariner 2
became the first satellite to fly past a planet, sending back pictures of
a planet hidden by cloud cover. The carbon dioxide clouds create a greenhouse
effect, producing temperatures hot enough to melt lead on the planet's surface.
In 1990 the spacecraft Magellen provided the first detailed pictures of the
surface. The surface is dominated by volcanic activity, including volcanoes
larger than Mount Everest.
Earth
Earth is by far the prettiest planet to look at, with blue oceans, brown-green
land masses, and white clouds. Of course, it need not be stated what is so
special about Earth, but we will do it anyways : It's the only known body
in the universe that harbors life.
Mars
Mars has always been the most likely spot for extraterrestial life, although no
missions have yet to identify any living organisms. Olympus Mons is one of the
largest volcanoes in the solar system, reaching three times as high as Mount
Everest. Iron oxide on Mars surface presents a reddish-brown hue, while white polar
ice caps are visible with small telescopes. Mars has two moons that are most
likely captured asteroids. Jupiter
Jupiter has been in the news a lot latley. First, Comet Showmaker-Levy 9 exploded
into the giant planet in 1994, and currently the Galileo spacecraft is
completing a tour of the Jovian system. Jupiter is the nearest of the
outer gas giants and contains the Great Red Spot, a giant hurricane three
times the size of Earth. Jupiter's four largest moons are easily visible
through binoculers. Io contains active volcanoes, Europa has a fractured
surface, Callisto is heavily cratered, and Ganymede is larger than
Mercury.
Saturn
The great ringed planet has the most extensive and beautiful set of rings in the
solar system. The Cassini mission is currently being built for the trip to Saturn.
Visit What's New in Astronomy for more information about how
you can fly your name to Saturn.
Uranus
While the rest of the planets have a rotational axis perpendicular to the plane of
the Sun, Uranus' is almost parallel. Meaning its poles face directly towards the
Sun during part of its orbit. Uranus has an extensive ring system, but unlike
Saturn's they are made of dark, dull material.
Neptune
The Great Dark Spot is a similar storm in composition to Jupiter's Great Red Spot.
Uranus' moon Triton is a curiousity becuase it travels in an opposite direction of
the other Neptunian moons. Triton was most likely once a separate minor planet,
but was sucked in by Neptune's gravity.
Pluto
Very little is known about Pluto, other than it has a large moon, Chiron, and
the surface may be covered with methane ice. Because of its odd orbit, Pluto is
actually closer to the Sun than Neptune from 1979 to 1999.
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