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The Andromeda Galaxy is approaching the Milky Way at about 110 kilometres per second (68 mi/s). What is the velocity that Milky way is approaching M87 ?

Mateus
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1 Answers1

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The Milky Way and M87 are moving apart at 1231 km/s.

http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=M+87&img_stamp=yes&extend=no

DavePhD
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  • i read this : "the entire Virgo Cluster recedes from us at an average of about 1000 km/sec. But while all the other galaxies in the Cluster recede from us at somewhere around that speed, Messier 86 approaches us at some speed between 244 and 419 km/sec" Is this correct? M87 is blue-shifted? – Mateus Jun 02 '14 at 19:33
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    M86 is approaching and blue shifted http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=m86&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES M87 is receding and red-shifted – DavePhD Jun 02 '14 at 19:36
  • by the size of M86 and its gravitational pull, the milky way is traveling at 244 km/s toward M86. But M86 is not going toward Milky way at this speed, right? i think it is going towards mk in just a fraction of this velocity, am i right? – Mateus Jun 02 '14 at 19:41
  • M86 is approaching the Milky Way galactic center at 278 km/s. That is the actual velocity, with an uncertainty of 6km/s. – DavePhD Jun 02 '14 at 19:46
  • I understand but my point is : MW is static in space and M86 is approaching us at 278km/s OR M86 is static and MV is approaching M86 at 278km/s OR MW and M68 are approaching each other at 139km/s each ? Sorry for my astrophysics ignorance, can we know this ? – Mateus Jun 02 '14 at 19:51
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    you would have to pick a frame of reference that you consider static. For example, M86 is moving about 106 km/s relative to the CMB rest frame and the Milky Way is moving about 370 km/s relative to the CMB rest frame http://mnras.oxfordjournals.org/content/386/4/2221.full – DavePhD Jun 02 '14 at 20:09
  • What if my frame of reference is the ship in this image: http://i.imgur.com/CF60bCV.jpg – Mateus Jun 02 '14 at 21:14
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    It's undefined, because there is nothing to which the ship is stationary. There is no such thing as "absolutely stationary". Motion relative to the Cosmic Microwave Background (CMB) is the closest thing to an absolute frame. See http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from – DavePhD Jun 02 '14 at 21:25