visual distortion of distant galaxies

Sjoerd · Post by **Sjoerd** » Fri Jul 08, 2005 9:00 am

I saw the picture today of the neelde galaxy (NGC 4565 ) (july 8 2005) and started wondering about any visual distortions that might be there. galaxies are rotating and always on the move, it occourd to me that although the needle galaxy is 30 million light-years distant, it is also 100.000 across. That probably means that the light from the edge closed to us is younger then the light from the center or the left and right edges of the needle galaxy. Does this result in any visual distortions? or does that galaxy move so slowly that any distortions are negligable?

William Roeder · Post by **William Roeder** » Fri Jul 15, 2005 6:22 pm

I'm surprised no one has tried to answer this. I would think that the visual distortions would be very noticable.

If the 100.000 diameter galaxy rotates every 200.000 years, (our galaxy takes 220.000,) then by the time the light from the outer edge becomes parallel to the front of the galaxy (50.000 years) the stars would have rotated 1/4th revolution and would be in front. We would be seeing the star as a blur.

christopher antonsen · Post by **christopher antonsen** » Sat Jul 16, 2005 7:33 am

c'mon guys - we're talking about 1/3 of 1% here. my eyes aren't that good - are your's?

William Roeder · Post by **William Roeder** » Mon Jul 18, 2005 5:39 pm

1/3 of 1% of WHAT?

My simple thought experiment predicts that half of the visible portion of a galaxy should be blured.

makc · Post by **makc** » Tue Jul 19, 2005 6:55 am

William Roeder wrote:1/3 of 1% of WHAT?

Isn't that my fault, per chance? I was talking about distortions of star trails there.

Why do you expect things to be blurred? I think stars simply would be in wrong positions, and appear to be moving slightly slower/faster along the edge. We can't see stars on the other side anyway.

William Roeder · Post by **William Roeder** » Tue Jul 19, 2005 1:21 pm

If we are seeing the same star at the edge and in the middle at the same time wouldn't it be a blur?

This is not valid, and not because you've missed a coulpe of zeroes. To see anything in two places would require it to move faster than light.

EDIT: Oops

I am so sorry for accidentially

-ing this post instead of

-ing it. Most of it survived in a quote. Makc.

mwhidden · Post by **mwhidden** » Tue Jul 19, 2005 5:42 pm

William Roeder wrote:If the 100.000 diameter galaxy rotates every 200.000 years, (our galaxy takes 220.000,) .

I think you meant 220,000,000 years.

William Roeder · Post by **William Roeder** » Tue Jul 19, 2005 6:29 pm

Doh! What's a factor of 1000 among friends. I knew I had something wrong - Yes, it is 220 million.

So the blur would be 1/4000 of the radius.

S. Bilderback · Post by **S. Bilderback** » Wed Jul 20, 2005 12:47 pm

You would see the increased blurring of the outer stars only if you has an exposure of a million years or so.

William Roeder · Post by **William Roeder** » Wed Jul 20, 2005 1:37 pm

That would be the Hubble 4000 and later models

makc · Post by **makc** » Thu Jul 21, 2005 7:32 am

I've been a bad boy today.