To get a better sense of Earth’s place in the universe, imagine you can fly straight up. After about four miles, you’ve left the part of the atmosphere where you can breathe. Flip on the oxygen, and keep going.
You’ll pass the Moon, which helps control our tides. Go farther and you get to the Sun, the source of our energy. Go even farther, and you see that our Sun is just one of billions of stars in the Milky Way galaxy. But even the Milky Way is like a grain of sand, and the universe is like a beach.
