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#1
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Looking at Galaxy NGC 891
Have a picture of this galaxy(I like pictures) This galaxy shows itself
as a parrel plane in our line of view(horizontal) The picture is shown in visible light. The first thought that comes to mind looking at the picture is "what is that very dark area?" This dark area seems to slice the galaxy into an upper and lower parts. It looks like a long black cloud blocking out the stars that are in back of it. Would all galaxies have this feature when their line of view is edge on ? Bert |
#2
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The dark lane is composed of dust and gas---basically the same thing as
nebulae. Within our own Milky Way, we're able to see some of them (the Orion Nebula, Lagoon, Eagle, etc.) when newly formed hot stars are close enough to excite the atoms in them. But there are many more that remain dark and unilluminated. Compare the image of NGC 891 with a wide field time exposure of the Milky Way (like the one below) and you'll see a striking similarity. Dust lanes are a feature of most edge-on spiral galaxies, but absent in ellipticals, which tend to be dust poor. http://www.davidmalin.com/fujii/source/af3-21_72.html "G=EMC^2 Glazier" wrote in message ... Have a picture of this galaxy(I like pictures) This galaxy shows itself as a parrel plane in our line of view(horizontal) The picture is shown in visible light. The first thought that comes to mind looking at the picture is "what is that very dark area?" This dark area seems to slice the galaxy into an upper and lower parts. It looks like a long black cloud blocking out the stars that are in back of it. Would all galaxies have this feature when their line of view is edge on ? Bert |
#3
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Bill thanks for that picture. I think I should have said "Do all "spiral
galaxies" that are seen edge on have this horizontal dark area running through. A spiral galaxy looks like a pizza edge on. It is compressed top to bottom. It spreads out east and west(sideways). Well in the middle it has a meat ball. Bert |
#4
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"G=EMC^2 Glazier" wrote in message...
... Have a picture of this galaxy(I like pictures) This galaxy shows itself as a parrel plane in our line of view(horizontal) The picture is shown in visible light. The first thought that comes to mind looking at the picture is "what is that very dark area?" This dark area seems to slice the galaxy into an upper and lower parts. It looks like a long black cloud blocking out the stars that are in back of it. Would all galaxies have this feature when their line of view is edge on ? Bert That's a beauty, Bert! Your first thought is a dust lane that spans the circumference of the disk. The intriguiging thing for scientists is that in high-res photos of NGC-891, there are sprays of material (gas and dust) that are being accelerated perpendicular to the disk. This effect is not well-understood... http://www.noao.edu/outreach/aop/obs...891blocks3.jpg And no, not all edge-on galaxies exhibit such a dust lane. Here are more pics of edge-ons. You'll also find that dust lanes, when they *are* present, can vary widely in size and shape... http://www.curtisnet.co.uk/~acurtis/edge.html In your studies, try to find images of NGC-891 in the infrared. These are the best images for penetration of the dust lane. happy days and... starry starry nights! -- The Flow! The Flow! The Flow ain't goin' slow, The Flow is goin' faster than I really want to go. The Flow! the Flow! I must go with The Flow, The Flow is where I want to be-- NOT on the sandy sho'. NObody wants to feel... ALL WASHED UP Paine Ellsworth |
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Hi Painius Nice pictures.Thank you. Never heard that edge on spiral
galaxies don't radiate as much photons in our line of view. That has to be true. Having lots of gas and dust that seem to be at the rim of the disc blocks out photons. Is it possible Painius even the Hubble could not see these edge on galaxies say at distances 5 billion LY That could make for some interesting thinking. I can see why infrared photons are better for going through dust. That is proven here on earth with every sun set,and sun rise. Bert |
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