how many planets in the milky way solar system
Milky Way The Milky Way is a barred spiral galaxy with a diameter between 100,000[30] and 180,000 light-years.[31] The Milky Way is estimated to contain 100–400 billion stars.[32][33] There are probably at least 100 billion planets in the Milky Way.[34][35] The Solar System is located within the disk, about 26,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.
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 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.
Milky Way The Sun is 25,000–28,000 ly (7.7–8.6 kpc) from the Galactic Center. This value is estimated using geometric-based methods or by measuring selected astronomical objects that serve as standard candles, with different techniques yielding various values within this approximate range.[15][16][17][90][91][92] In the inner few kpc (around 10,000 light-years radius) is a dense concentration of mostly old stars in a roughly spheroidal shape called the bulge.[93] It has been proposed that the Milky Way lacks a bulge formed due to a collision and merger between previous galaxies, and that instead it has a pseudobulge formed by its central bar.[94]