Astronomers have known for decades that our Milky Way Galaxy and the neighboring Andromeda Galaxy are approaching each other. What we haven’t known is just how close the encounter will be. Recent Hubble measurements have been able to pin down the trajectory with a smashing conclusion: in about four billion years the two galaxies will crash together in a nearly head-on collision. Further, the spiral galaxies will have completely merged and transformed to create a single elliptical galaxy around six billion years in the future.

“Hubble’s Universe Unfiltered” is a recurring broadcast from HubbleSite.org, online home of the Hubble Space Telescope. Astrophysicist Frank Summers takes viewers on an in-depth tour of the latest Hubble discoveries. Find more episodes at HubbleSite.org.

HubbleSite page: http://hubblesite.org/explore_astronomy/hubbles_universe_unfiltered/episodes/17

* Notes

NASA’s Hubble Shows Milky Way is Destined for Head-on Collision with Andromeda Galaxy:
http://hubblesite.org/newscenter/archive/releases/2012/20/

Milky Way drawing
Credit: NASA, JPL-Caltech, R. Hurt (SSC-Caltech)
http://www.spitzer.caltech.edu/images/1923-ssc2008-10a-A-Roadmap-to-the-Milky-Way

Milky Way panorama
Copyright: Axel Mellinger (used with permission)
http://home.arcor-online.de/axel.mellinger/

Large Magellanic Cloud
Credit: David Malin
Copyright: Australian Astronomical Observatory (used with permission)
http://www.aao.gov.au/images/captions/uks014.html

Small Magellanic Cloud
Credit: NOAO/AURA/NSF
http://www.noao.edu/image_gallery/html/im0563.html

Andromeda Galaxy
Credit: Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF
http://www.noao.edu/image_gallery/html/im0424.html

Triangulum Galaxy
Credit: T.A.Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and M.Hanna (NOAO/AURA/NSF)
http://www.noao.edu/image_gallery/html/im0775.html

Local Group Schematic
Credit: Christine Godfrey

Visible Light Spectrum
Credit: Wikimedia Commons user Philip Roman
http://commons.wikimedia.org/wiki/File:EM_spectrum.svg

Neon Pizza Sign
http://free-images-etc.rb-d.com/wp-content/uploads/IMG_9043.jpg

Neon Spectral Lines
Credit: Wikimedia Commons user Jan Homann
http://commons.wikimedia.org/wiki/File:Hydrogen_Emission_Spectrum.svg

Hydrogen Spectral Lines
Credit: Wikimedia Commons user Jkasd
http://commons.wikimedia.org/wiki/File:Hydrogen_Emission_Spectrum.svg

Interacting Galaxies UGC 8835
Credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)
http://hubblesite.org/newscenter/archive/releases/2008/16/image/ah/

Barnard’s Star Proper Motion
Credit: Steve Quirk
http://commons.wikimedia.org/wiki/File:Barnard2005.gif

Stellar Deep Field
Credit: NASA, ESA and T.M. Brown (STScI)
http://hubblesite.org/newscenter/archive/releases/2003/15/image/a/

Milky Way and Andromeda Collision Scenario
Credit: NASA, ESA, and A. Feild and R. van der Marel (STScI)
http://hubblesite.org/newscenter/archive/releases/2012/20/image/m/

Milky Way, Andromeda, Triangulum Encounter Visualization
Visualization Credit: NASA, ESA, and F. Summers (STScI)
Simulation Credit: NASA, ESA, G. Besla (Columbia University), and R. van der Marel (STScI)
http://hubblesite.org/newscenter/archive/releases/2012/20/video/j/

Music “Stars”
Credit: Shamil Elvenheim (CC-BY-NC-SA 3.0)
http://freemusicarchive.org/music/Shamil_Elvenheim/strolling_through_electronic_spaces/13_-_Shamil_Elvenheim_-_Stars

Earth in Hammer-Aitoff Projection
Credit: Wikimedia Commons user Strebe
http://commons.wikimedia.org/wiki/File:Aitoff_projection_SW.jpg

Milky Way, Andromeda, Triangulum Encounter Visualization – Hammer-Aitoff Projection
Visualization Credit: F. Summers (STScI)
Simulation Credit: G. Besla (Columbia University), and R. van der Marel (STScI)

Illustrative Sky Views of the Milky Way-Andromeda Collision
Credit: NASA, ESA, Z. Levay, R. van der Marel, and G. Bacon (STScI), T. Hallas, and A. Mellinger
http://hubblesite.org/newscenter/archive/releases/2012/20/video/d/

Andromeda Constellation
Credit: A. Fujii (used with permission)
http://www.davidmalin.com/fujii/fujii_index.html