Conceptual illustration showing the scale of outer space and our location within it. Our most immediate home in space is the Solar System (top right), a series of planets, minor planets, dwarf planets and comets orbiting a star known as the Sun. The Earth is 150,000,000 km from the Sun, a distance known as an astronomical unit (AU). The 2nd balloon shows nearby interstellar space. The next nearest star is Proxima Centauri, a red dwarf 4.2 light-years from the Sun. Zooming out even more we see our Milky Way galaxy, a spiral of hundreds of billions of stars some 100,000 light-years across. In the fourth balloon we see how the Milky Way lies in relation to local intergalactic space. It is just one of dozens of galaxies in the Local Group. Even these vast distances are puny compared to those of the farthest known galaxies, which are thousands of times more distant still (final balloon).