10 Things You Should Know Before You Go into Space

President Bush has unveiled a plan to return astronauts to the Moon by 2015; after training there, the astronauts would head for Mars sometime later. But space is a tricky place to travel, even for astronauts who know what they're up against. Here are ten useful facts for the aspiring space traveler. The more you know, the further you'll go.
1. The gravitational pull of a black hole is so strong that everything that comes near it is ripped apart. The exact behavior of a black hole is not fully understood, but no known object or substance can escape from it. Not even light can escape. That's why a black hole is black, or rather, has a complete absence of color.
2. Major storms are common on Jupiter. Its most famous storm, the Great Red Spot, has been raging since telescopes were first aimed at the planet centuries ago.
3. Mars is home to the largest known volcano in the solar system, Olympus Mons. It is 26 km (16 mi) high (almost twice as high as Earth's Mount Everest) and covers an area about as large as the state of Arizona.
4. The surface temperature on Venus is extremely hot--about 462°C (864°F); hot enough to melt lead. To put this in perspective: lead melts at 328°C (662°F).
5. To reach outer space, you need to travel at least 80 km (50 mi) beyond Earth's surface.
6. The Voyager probes (launched in 1977) yielded some surprising information about Jupiter's moons. The most surprising discovery was that Io is covered with active volcanoes spewing ice and sulfur compounds into space. Io was the first celestial body other than Earth found to be geologically active.
7. Comets are icy wanderers that populate the solar system's outermost reaches. These "dirty snowballs" are chunks of ice and dust. When a comet ventures into the inner solar system, some of its ice evaporates.
8. In the vacuum of space, objects become intensely hot when exposed to the Sun and extremely cold when in the shadow of Earth or some other body.
9. The brightest star in the sky is Sirius. It is 51 trillion miles away from Earth, and is one of the closest stars to Earth. Another name for Sirius is Dog Star.
10. Neptune has the fastest winds in the solar system, reaching speeds of 2,000 km/hr (1,200 mi/hr).
For more information about space travel, read Encarta's article on Space Exploration.