Bővebb ismertető
^ Introducing In the Beginning
Our Place in
Space
Space is really big! The planet we live on, Earth, is just one in a family of eight planets in our Solar System. Earth orbits a yellow dwarf star-the Sun. Though important to us, our Sun is just one of billions of other suns that make up a spiral-shaped galaxy called the Milky Way. We see our Sun in the day; our galaxy's other suns appear as the stars of the night sky. As big as our galaxy is, it is just one member of a local group of several dozen galaxies that, in turn, are just a small part of a vast network of billions of other galaxies. All these planets, stars, and galaxies make up what we call the universe.
The cosmic neighborhood
Our nearest neighbors in space are the worlds of our Solar System. They are close enough for people and robot probes to visit them. But beyond our neighborhood, the vast distances of space make it impossible for us to travel to other stars and galaxies.
The Solar System Zoom out. and Earth is just one planet in a system of worlds, which includes seven other major planets and seveml dwarf planets. It takes about six hours for light to travel from the Sun to the dwarf planet Pluto.
The blue marble
Astronauts who visited the Moon saw the distant Earth as a blue marble floating In the blackness of space, above the gray, lifeless landscape of the Moon.
Earth Our home is a small, watery, blue planet that orbits about eight light-minutes from the warmth and light of an ordinary yellow star, the Sun. So far. Earth is the only place in the universe where we know life exists.