The Heliosphere
At last we arrive at the very edge of the solar system where the heliosphere lies, a teardrop-shaped region of space containing electrically charged particles given off by the sun. Many astronomers think that the limit of the heliosphere, known as the heliopause, lies about 9 billion miles (15 billion kilometers) from the sun. And that completes our tour of the solar system. Welcome to interstellar space!