3. The Hubble Space Telescope has been racing around Earth for 19 years. Over that time, it has collected a lot of important data and changed our understanding of space.
“In recent months, the historic telescope has been suffering from technical difficulties. These problems are not all that surprising,” says Frank Summers, an astronomer in Baltimore. “The Hubble has already lived longer than it was originally expected to,” he says.
When scientists first designed the Hubble Space Telescope, they expected it to last for 15 years. In 2010, it will reach twenty years. The spacecraft recently completed its 100,000th orbit (绕轨道飞行) around Earth. The reason the Hubble has lasted so long is that people have been able to go up and fix it when parts break. Repairs are common on ground telescopes, but the Hubble is the only space telescope that receives these kinds of visits.
Hubble’s problems also show how important the telescope has been to astronomy in the last twenty years. Scientists have used the telescope to watch moons around planets and planets around stars. It has taught scientists about black holes and dark matter. And it has taken images of exploding stars, dust storms and more. “It is the best telescope in history,” Frank Summers says. “There are things we can do with the Hubble that we can’t do with anything else. It provides us with a bird’s eye view of the universe.”
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