Spiral Galaxies (APOD 24 July 2007)

[tvkrys]

While looking at today's APOD (Spiral Galaxy M83), I wondered ... do all galaxies appear to rotate clockwise, or are there some that rotate counter-clockwise? If both ways, what are the percentages? If both ways, is that simply because of our vantage point, or is there a physics reason for the difference?

Thanks,
K-

[Qev]

Galaxies appear (to us) to rotate in pretty much any direction, clockwise or counter-clockwise. The Galaxy Zoo project is, in part, studying the distribution of spiral galaxies in either direction, to see if that can tell us anything about how the local universe has evolved over time.

[harry]

Hello Qev

Nice link.

My son loves it.

[Cambridge2007]

Sorry if its been mentioned already as I am new to forums (fora?).
On the Southern Pinwheel image there are several apparent pairs of images suggesting gravitational lensing though if so surprisingly this was not mentioned in the notes - at 3.30 (o'clock) a pair of similar looking spirals edge on, close by a pair of 'stars' in same orientation, 5 o'clock another pair of stars - similar orientation....

[BMAONE23]

http://antwrp.gsfc.nasa.gov/apod/image/ ... er_big.jpg

While the two Blue stars @ 3:30 and the two Yellow stars @ 5 appear to have the same apparent luminosity as their opposed twins the two galaxies at 3:30 arent from lensing, the upper one is slightly larger and is rotating clockwise to our perspective while the lower one is smaller and is rotating anti-clockwise. I didn't notice them though my first time looking at the image.

[bystander]

As the stars are in the foreground, they can't very well be an effect of lensing.