An artist's picture of the Dawn spacecraft in space.
Asteroids are pieces of rock that orbit the sun. They sometimes are called planetoids, or small planets.
Dawn was sent to the asteroid belt in search of information that may help scientists better understand how our solar system was formed. Marc Rayman says Vesta was chosen as Dawn’s first stop because of its special qualities.
MARC RAYMAN: “Many people think of asteroids as sort of little chips of rock, right? That’s how they’re depicted in movies, maybe the size of a building or a mountain or something like that. But Vesta is not like that. This is a very big place. It’s more than three hundred thirty miles, or five hundred thirty kilometers in diameter and it’s got twice the surface area of California.”
MARIO RITTER: Vesta is the second largest asteroid in the asteroid belt. Many scientists believe asteroids are space objects that never combined with other material to form a planet. More than seven thousand asteroids have now been identified. Most are less than one hundred kilometers wide.
Marc Rayman says Vesta appears to have a layered structure, one that is similar to planets like Earth, Mars and Venus.
Scientists have repeatedly studied Vesta since its discovery more than two hundred years ago. Most of what is known about it was learned through telescopic images. NASA hopes that Dawn’s year long orbit around Vesta will help scientists learn more about the development of the solar system, and how asteroids and other space objects were created.
最新
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25