<P> The Solar System's location in the Milky Way is a factor in the evolutionary history of life on Earth . Its orbit is close to circular, and orbits near the Sun are at roughly the same speed as that of the spiral arms . Therefore, the Sun passes through arms only rarely . Because spiral arms are home to a far larger concentration of supernovae, gravitational instabilities, and radiation that could disrupt the Solar System, this has given Earth long periods of stability for life to evolve . The Solar System also lies well outside the star - crowded environs of the galactic centre . Near the centre, gravitational tugs from nearby stars could perturb bodies in the Oort cloud and send many comets into the inner Solar System, producing collisions with potentially catastrophic implications for life on Earth . The intense radiation of the galactic centre could also interfere with the development of complex life . Even at the Solar System's current location, some scientists have speculated that recent supernovae may have adversely affected life in the last 35,000 years, by flinging pieces of expelled stellar core towards the Sun, as radioactive dust grains and larger, comet - like bodies . </P> <P> The Solar System is in the Local Interstellar Cloud or Local Fluff . It is thought to be near the neighbouring G - Cloud but it is not known if the Solar System is embedded in the Local Interstellar Cloud, or if it is in the region where the Local Interstellar Cloud and G - Cloud are interacting . The Local Interstellar Cloud is an area of denser cloud in an otherwise sparse region known as the Local Bubble, an hourglass - shaped cavity in the interstellar medium roughly 300 light - years (ly) across . The bubble is suffused with high - temperature plasma, that suggests it is the product of several recent supernovae . </P> <P> There are relatively few stars within ten light - years of the Sun . The closest is the triple star system Alpha Centauri, which is about 4.4 light - years away . Alpha Centauri A and B are a closely tied pair of Sun - like stars, whereas the small red dwarf, Proxima Centauri, orbits the pair at a distance of 0.2 light - year . In 2016, a potentially habitable exoplanet was confirmed to be orbiting Proxima Centauri, called Proxima Centauri b, the closest confirmed exoplanet to the Sun . The stars next closest to the Sun are the red dwarfs Barnard's Star (at 5.9 ly), Wolf 359 (7.8 ly), and Lalande 21185 (8.3 ly). </P> <P> The largest nearby star is Sirius, a bright main - sequence star roughly 8.6 light - years away and roughly twice the Sun's mass and that is orbited by a white dwarf, Sirius B . The nearest brown dwarfs are the binary Luhman 16 system at 6.6 light - years . Other systems within ten light - years are the binary red - dwarf system Luyten 726 - 8 (8.7 ly) and the solitary red dwarf Ross 154 (9.7 ly). The closest solitary Sun - like star to the Solar System is Tau Ceti at 11.9 light - years . It has roughly 80% of the Sun's mass but only 60% of its luminosity . The closest known free - floating planetary - mass object to the Sun is WISE 0855 − 0714, an object with a mass less than 10 Jupiter masses roughly 7 light - years away . </P>

The composition of the planets in our solar system