how many planets in our milky way galaxy
Milky Way The Milky Way is a barred spiral galaxy with a diameter between 150,000 and 200,000 light-years (ly).[24][25][26] It is estimated to contain 100–400 billion stars.[27][28] There are probably at least 100 billion planets in the Milky Way.[29][30] The Solar System is located within the disk, 26,490 (± 100) light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The stars in the innermost 10,000 light-years form a bulge and one or more bars that radiate from the bulge. The galactic center is an intense radio source known as Sagittarius A*, likely a supermassive black hole of 4.100 (± 0.034) million solar masses.
Milky Way The Milky Way is the galaxy[21][22][23][nb 1] that contains our Solar System.[24] The descriptive "milky" is derived from the appearance from Earth of the galaxy – a band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle").[25][26][27] From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe.[28] Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis,[29] observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.
Planet Planets are generally divided into two main types: large low-density giant planets, and smaller rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites.
Milky Way Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 14,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a stream of neutral hydrogen gas extending from these two small galaxies across 100Â° of the sky. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way.[176] Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest dwarf galaxies of the Milky Way are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies that are dynamically bound to the Milky Way, which is supported by the detection of nine new satellites of the Milky Way in a relatively small patch of the night sky in 2015.[177] There are also some dwarf galaxies that have already been absorbed by the Milky Way, such as Omega Centauri.[178]