APOD 2004 Feb 21

[makc]

I came there from today's APOD link. Just thought could it be that it's not NGC 4622 rotates clockwise, but it's Milky Way rotates faster, and hence an illusion

[BMAONE23]

Isn't it a matter of perspective though. if you look at a clock face on, the hands rotate clockwise (hence the phrase) but if you look at the clock from the reverse side the hands appear to rotate counter-clockwise. All galaxies may in fact rotate in only one direction but due to our perspective, they appear to rotate differently. It is wierd though that the arms rotate opposite to the direction of their spiral.

[lllbr0kenlll]

i didnt know that...
really,.. they rotate like a saw blade....like digging into space?

[Empeda]

Not usually - this is an unusual example - probably as a result of a galactic collision.