How fast are galaxies moving?

[finaldeathh]

Since the universe is expanding because the galaxies are moving away from each other, how fast are the galaxies moving, or expanding, in space? And because galaxies are moving, wouldn't light from other glaxies reach us slower because light is trying to chase us?

 

[mott]

i may be wrong on this but i belive thats the doppler effect where light shifts from blue to red. im not sure how fast the actual speed is.

 

[nacnud]

Be prepare to be confused <img src="/images/icons/smile.gif" /><br /><br />The galaxyes arn't moving away from each other. Space is expanding between the galaxies.<br /><br />There is a difference, try looking up the big bang on wikipedia to see what I mean.

 

[newtonian]

finaldeathh- I'll try to answer in the order you posted those good questions:<br /><br />1. Not all galaxies are moving away from each other. Some are gravitationally bound. We are heading towards Andromeda and will merge with it. The entire local group of galaxies, including Andromeda and Milky Way, are heading for the Great Attractor.<br /><br />2. Light speed is independent of the speed of the galaxy emitting light. The light still reaches us at 186,000 miles per second. However, galaxies like Andromeda have their light spectrum blue-shifted because of heading towards us.<br /><br />Very distant galaxies are all moving away from us and their light spectrum is red-shifted.<br /><br />3. However, there may be galaxies near our visibility horizon which are now moving away from us faster than light speed- though we see them as they were billions of years ago when they were receding from us slower than light speed.<br />4. Yes, as nacnud noted, there is a difference between motion on/in the fabric of space which has a speed limit of 186,000 miles per second, and the expansion of the fabric of space which apparently has no speed limit or at least can stretch out much faster than light speed.

 

[newtonian]

finaldeathh - I do not know how fast galaxies are moving- may I ask in reference to what reference point? <br /><br />I have the same question, to be more detailed:<br /><br />How fast is Milky Way moving towards the Great Attractor?<br /><br />How fast is Milky Way moving towards Andromeda?<br /><br />How fast are the other galaxies in our super-cluster moving towards the Great Attractor, e.g. Andromeda?<br /><br />Are we receeding from the other attractor in Perseus?

 

[xmo1]

Guess this page is for you Newtonian:<br /><br />http://www.dennisys.com/physical_science/astrophysics.htm <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>