Interstellar space is the term given to the space between stars within the galaxy. The sun's nearest known stellar neighbor is a red dwarf star called Proxima Centauri, at a distance of about 4.2 light years. We are beginning to find that many stars besides the sun harbor their own solar systems with planets, which are being called extrasolar planets, or exoplanets.The first exoplanet was discovered in 1992, and the milestone of 500 exoplanets known came in early 2011. Most are relatively nearby, within 5,000 light years, although one candidate was discovered in September 2005 via "microlensing" at a distance of 17,000 light years.
Our whole solar system, along with all the local stars you can see on a clear dark night, reside in one of our galaxy's spiral arms, known as the Orion arm, as they orbit the supermassive black hole in the dense star cluster at the center of our galaxy some 26,000 (±1400) light-years distant from us. At this great distance, we go around once about every 250 million years. Stars very close to the central mass are observed in keplerian orbits with periods as short as 15.2 years. This spiral disk that we call the Milky Way includes some 200 billion stars, thousands of gigantic clouds of gas and dust, and enormous quantities of mysterious dark matter.
The Milky Way has two small galaxies orbiting it nearby, which are visible from Earth's southern hemisphere. They are called the Large Magellanic Cloud and the Small Magellanic Cloud.
Our galaxy, one of billions of galaxies known, is traveling through intergalactic space. On a cosmic scale, all galaxies are generally receding from each other, although those relatively close together may exhibit additional local motion toward or away from each other as well.