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Looking for composite picture of Milky-way from outside galaxy

by jackmell
Tags: composite, galaxy, milkyway, picture
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jackmell
#1
Aug15-13, 03:14 PM
P: 1,666
Hi,

I recall some years ago seeing a composite picture of what our galaxy would look like from outside the galaxy, for example from Andromeda but was not able to find one or even how to search for it on the web. I was wondering if anyone here is familiar with it and perhaps even if we've improved the picture.

Oh by the way if you're interested, can anyone here tell me the name of the galaxy in the quote below without looking it up? Whirlpool? Not sure.

Quote Quote by MathJakob View Post




Credit for the photo belongs to Nick Risinger. Website credits in the bottom left hand side of the picture.

Thanks,
Jack
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phyzguy
#2
Aug15-13, 03:50 PM
P: 2,179
I think what Nick Risinger did was take this map of the Milky Way galaxy and somehow combine it with a photo of M51 (Whirlpool galaxy) so that it looks more like an actual photograph. The photo on this site references those two images.
jackmell
#3
Aug15-13, 04:07 PM
P: 1,666
Quote Quote by phyzguy View Post
I think what Nick Risinger did was take this map of the Milky Way galaxy and somehow combine it with a photo of M51 (Whirlpool galaxy) so that it looks more like an actual photograph. The photo on this site references those two images.
So that map you cited is an accurate picture of how the Milky-way actually looks like? I suppose it is since the arms are labeled. Also, may I ask a dumb question: so then I assume the Milky-way is really barred? Didn't know that. I guess I though that picture was just a picture of another galaxy and not really representative of the Milky-way.

phyzguy
#4
Aug15-13, 04:49 PM
P: 2,179
Looking for composite picture of Milky-way from outside galaxy

Yes, it's believed to be a two-armed barred spiral. It's hard to make maps of the Milky Way, since we're sitting inside it and the plane of the Milky Way is filled with dust that obscures our view of distant objects. So most of the map was made using radio and infrared (Spitzer) observations that can penetrate the dust. I'm not sure how accurate it really is, but I think it's the best map we have. This article talks more about who made the map and how they did it.
jackmell
#5
Aug15-13, 05:35 PM
P: 1,666
Ok. I looked at the references. So that picture of a two armed barred-spiral galaxy is qualitatively, an accurate illustration of what we believe the milky-way looks like from outside the galaxy.

So we actually cannot determine accurately the distance to a good distribution of stars in the Milky-way in order to construct a nice 3D model of the galaxy right? I did review methods of computing stellar distances:

http://en.wikipedia.org/wiki/Stellar_distance

but I assume there are problems even with IR in determining relatively accurate distances inside our Milky-way beyond what looks like 4000 light years and we know the Milky-way is 100,000 light years across (although I realize we can measure distances relatively accurately outside our galaxy).

Guess I didn't realize that.

Thanks for the help phyzguy. :)


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