To the eye alone, the Milky Way is simply a hazy band of light — a glowing archway in a dark night sky. In fact, it vaults high overhead this evening, from southwest to northeast. But seen through a telescope, the Milky Way is a dazzling tapestry of individual stars — millions upon millions of them. They outline the disk of our home galaxy.
A new European space telescope will measure the distances to many of those stars with unprecedented accuracy. That effort will provide by far the best 3D map of our region of the galaxy. What’s more, the craft will measure each star’s temperature, brightness, and its motion through space. Astronomers will use that information to understand more about the evolution of the entire galaxy.
Gaia is scheduled for launch as early as this month. It’ll orbit the Sun about a million miles away from Earth, providing an unobstructed view of the heavens.
Over the next five years, it’ll look at a billion stars about 70 times each. That will allow the craft to compile a dossier on each of those stars, and measure each star’s distance with far greater accuracy than ever before — a thousandth of a percent for the closest stars.
Gaia also will discover new objects. Mission scientists expect it to find thousands of planets in other star systems, tens of thousands of the failed stars known as brown dwarfs, and hundreds of thousands of asteroids in our own solar system — all while compiling its map of our galactic home.
Script by Damond Benningfield, Copyright 2013
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