Galactic year - wikipedia Galactic year File : Milky Way Arms ssc2008 - 10. svg Approximate orbit of the Sun ( yellow circle ) around the Galactic Centre The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy. Estimates of the length of one orbit range from 225 to 250 million terrestrial years. The Solar System is traveling at an average speed of 828,000 km / h ( 230 km / s ) or 514,000 mph ( 143 mi / s ) within its trajectory around the galactic center, a speed at which an object could circumnavigate the Earth 's equator in 2 minutes and 54 seconds ; that speed corresponds to approximately one 1300th of the speed of light. The galactic year provides a conveniently usable unit for depicting cosmic and geological time periods together. By contrast, a `` billion - year '' scale does not allow for useful discrimination between geologic events, and a `` million - year '' scale requires some rather large numbers. Timeline of the universe and Earth 's history in galactic years Main articles : Timeline of the formation of the Universe, Timeline of natural history, and Timeline of the far future The following list assumes that 1 galactic year is 225 million years. About 61.32 galactic years ago Big Bang About 54 galactic years ago Birth of the Milky Way 20.44 galactic years ago Birth of the Sun 17 -- 18 galactic years ago Oceans appear on Earth 16.889 galactic years ago Life begins on Earth 15.555 galactic years ago Prokaryotes appear 12 galactic years ago Bacteria appear 10 galactic years ago Stable continents appear 6.666 galactic years ago Eukaryotes appear 6.8 galactic years ago Multicellular organisms appear 2.4 galactic years ago Cambrian explosion occurs 2 galactic years ago The first brain structure appeared in worms 1.11 galactic year ago Permian -- Triassic extinction event 0.2935 galactic years ago Cretaceous -- Paleogene extinction event 0.001 galactic years ago Appearance of modern humans Present day 1 galactic year from now All the continents on Earth may fuse into a supercontinent. Three potential arrangements of this configuration have been dubbed Amasia, Novopangaea, and Pangaea Ultima 2 -- 3 galactic years from now Tidal acceleration moves the Moon far enough from Earth that total solar eclipses are no longer possible 4 galactic years from now Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible. Multicellular life dies out 12 galactic years from now The Earth 's magnetic field shuts down and charged particles emanating from the Sun gradually deplete the atmosphere 15 galactic years from now Surface conditions on Earth are comparable to those on Venus today 22 galactic years from now The Milky Way and Andromeda Galaxy begin to collide 25 galactic years from now Sun ejects a planetary nebula, leaving behind a white dwarf 30 galactic years from now The Milky Way and Andromeda will complete their merger into a giant elliptical galaxy called Milkomeda or Milkdromeda 500 galactic years from now The Universe 's expansion causes all galaxies beyond the Milky Way 's Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe 2000 galactic years from now Median Point of the Local Group of 47 galaxies will coalesce into a single large galaxy File : Sun_in_orbit_around_Galactic_Centre. gif Visualisation of the orbit of the Sun ( yellow dot and white curve ) around the Galactic Centre ( GC ) in the last galactic year. The red dots correspond to the positions of the stars studied by the European Southern Observatory in a monitoring programme. References Jump up ^ Cosmic Year, Fact Guru, University of Ottawa Jump up ^ Leong, Stacy ( 2002 ). `` Period of the Sun 's Orbit around the Galaxy ( Cosmic Year ) ''. The Physics Factbook. Jump up ^ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question18.html NASA -- StarChild Question of the Month for February 2000 Jump up ^ Geologic Time Scale -- as 18 galactic rotations Jump up ^ Williams, Caroline ; Nield, Ted ( 20 October 2007 ). `` Pangaea, the comeback ''. New Scientist. Retrieved 2 January 2014. Jump up ^ Franck, S. ; Bounama, C. ; Von Bloh, W. ( November 2005 ). `` Causes and timing of future biosphere extinction '' ( PDF ). Biogeosciences Discussions 2 ( 6 ) : 1665 -- 1679. Bibcode : 2005BGD... 2.1665 F. doi : 10.5194 / bgd - 2 - 1665 - 2005. Retrieved 19 October 2011. Jump up ^ Luhmann, J.G. ; Johnson, R.E. ; Zhang, M.H.G. ( 1992 ). `` Evolutionary impact of sputtering of the Martian atmosphere by O+ pickup ions ''. Geophysical Research Letters 19 ( 21 ) : 2151 -- 2154. Bibcode : 1992GeoRL... 19.2151 L. doi : 10.1029 / 92GL02485. Jump up ^ Quirin Shlermeler ( 3 March 2005 ). `` Solar wind hammers the ozone layer ''. nature news. doi : 10.1038 / news050228 - 12. Jump up ^ Cox, J.T. ; Loeb, Abraham ( 2007 ). `` The Collision Between The Milky Way And Andromeda ''. Monthly Notices of the Royal Astronomical Society 386 ( 1 ) : 461. arXiv : arXiv : 0705.1170. Bibcode : 2008MNRAS. tmp... 333C. doi : 10.1111 / j. 1365 - 2966.2008. 13048. x. Jump up ^ Loeb, Abraham ( 2011 ). `` Cosmology with Hypervelocity Stars ''. Harvard University. arXiv : 1102.0007. Jump up ^ `` The Local Group of Galaxies ''. University of Arizona. Students for the Exploration and Development of Space. Retrieved 2 October 2009. Jump up ^ Adams, Fred C. ; Laughlin, Gregory ( April 1997 ). `` A dying universe : the long - term fate and evolution of astrophysical objects ''. Reviews of Modern Physics 69 ( 2 ) : 337 -- 372. arXiv : astro - ph / 9701131. Bibcode : 1997RvMP... 69... 337A. doi : 10.1103 / RevModPhys. 69.337. Jump up ^ `` Milky Way Past Was More Turbulent Than Previously Known ''. ESO News. European Southern Observatory. 2004 - 04 - 06. After more than 1,000 nights of observations spread over 15 years, they have determined the spatial motions of more than 14,000 solar - like stars residing in the neighbourhood of the Sun. Star Formation Accretion Molecular cloud Bok globule Young stellar object Protostar Pre-main - sequence star Herbig Ae / Be Orion T Tauri FU Orionis Herbig -- Haro object Hayashi track Henyey track Evolution Main sequence Red giant branch Horizontal branch Red clump Asymptotic giant branch Protoplanetary nebula Planetary nebula PG1159 star Dredge - up Instability strip Luminous blue variable Blue straggler Stellar population Supernova Supernova impostor Hypernova Hertzsprung -- Russell diagram Color -- color diagram Luminosity class Subdwarf Dwarf Blue Red White Yellow Brown Subgiant Giant Blue Red Bright giant Supergiant Blue Red Yellow Hypergiant Yellow Spectral classification WR Be OB Subdwarf O Subdwarf B Late - type Chemically peculiar Am Ap / Bp Barium Carbon CH CN Extreme helium Lambda Boötis Lead HgMn Technetium Shell Remnants White dwarf Helium planet Neutron star Radio - quiet Pulsar Binary X-ray Magnetar Stellar black hole X-ray binary Burster Theoretical stars Black dwarf Exotic Quark Strange Preon Planck Electroweak star Dark - matter star Dark - energy star Black star Gravastar Frozen star Q star Quasi-star Thorne -- Żytkow object Iron star Blitzar Nucleosynthesis Deuterium burning Lithium burning Proton -- proton chain CNO cycle Helium flash Triple - alpha process Alpha process Carbon burning Neon burning Oxygen burning Silicon burning S - process R - process Fusor Nova Symbiotic Remnant Luminous red nova Structure Core Convection zone Microturbulence Oscillations Radiation zone Atmosphere Photosphere Starspot Chromosphere Corona Stellar wind Bubble Bipolar outflow Accretion disk Asteroseismology Helioseismology Eddington luminosity Kelvin -- Helmholtz mechanism Properties Designation Dynamics Effective temperature Kinematics Magnetic field Absolute magnitude Mass Metallicity Rotation UBV color Variable star Mira variable Star systems Binary Contact Common envelope Eclipsing Multiple Star cluster Open cluster Globular cluster Super star cluster Planetary system Earth 's Solar System Earth - centric observation of Pole star Circumpolar star Constellation Asterism Magnitude Apparent Extinction Photographic Radial velocity Proper motion Parallax Photometric - standard star Lists Star names Arabic Chinese Extremes Most massive Highest temperature Largest volume Smallest volume Brightest Historical Most luminous Nearest Nearest bright Stars with exoplanets Brown dwarfs White dwarfs Milky Way novae Notable supernovae Supernova candidates Supernova remnants Planetary nebulae Timeline of stellar astronomy Related articles Substellar object Brown dwarf Sub-brown dwarf Planet Galactic year Galaxy Supercluster Guest star Gravity Intergalactic star Infrared dark cloud Starfield Category : Stars Star portal Time measurement and standards Chronometry Orders of magnitude Metrology International standards Coordinated Universal Time offset UT ΔT DUT1 International Earth Rotation and Reference Systems Service ISO 31 - 1 ISO 8601 International Atomic Time 6 - hour clock 12 - hour clock 24 - hour clock Barycentric Coordinate Time Barycentric Dynamical Time Civil time Daylight saving time Geocentric Coordinate Time International Date Line Leap second Solar time Terrestrial Time Time zone 180th meridian Obsolete standards Ephemeris time Greenwich Mean Time Prime meridian Time in physics Absolute time and space Spacetime Chronon Continuous signal Coordinate time Cosmological decade Discrete time and continuous time Planck time Proper time Theory of relativity Time dilation Gravitational time dilation Time domain Time translation symmetry T - 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Question: how long does it take for the milky way to rotate
Answer: galactic year