A Milky Way Question . . .

Question

I once heard that the visible band of light we see in the Milky Way is not its center but one of the galactic arms instead. Is that true?

Answer 1

yes

Answer 2

Absolutely... Try and get a star chart (check your library) and you'll see a pale band drawn across it...

It's hard to make it out in the actual night sky because of light pollution... Anywhere you get street lights, the amount you can see in the sky is much less. You'd have to go somewhere quite remote with little around.

And the reason why you can see the galactic arm rather than the centre is that it's so much closer to us than the centre is... In fact we (our solar system) are IN the arm in question!

I've seen the band myself when I was in the Caribbean last year... it is quite stunning.

Answer 3

Not really one of its arms.  What you are looking at is the "disk" of the Milky Way, through the disk from the near edge toward the far edge.  You can't see the bright center of the Milky Way with the naked eye because there is too much interstellar dust and it blocks the visible light.

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Answer 4

true

We live on a "spur" between two arms.  Almost every single star that can be seen with the naked eye is part of our immediate neighborhood.

The Milky Way is the band of light given off by the stars of two arms.  The stars are individually too small to be seen, but their combined light is just bright enough to be registered by our eyes (unless you live in an over-lit city).

The entire Galaxy is much bigger than these two portions of arms.  Its centre is in the direction of the constellation we call Sagittarius.   As one gets closer to the centre, there is lots of gas and dust, blocking our view.

We use a combination of infra-red telescopes and radio telescopes to get as much information as we can of that region.

But, visually, we can't see the centre, nor the part of the Galaxy that is beyond the centre and the two neighboring arms.

Answer 5

The sun is in a strand of stars called the Orion Spur, which is between the Perseus and Sagittarius Arms. The Perseus Arm is one of the two major arms of our galaxy, but the Perseus Arm is itself a minor feature -- just not as minor as the Orion Spur is. The other major arm of the Milky Way is the Scutum-Centaurus Arm.

The center of the Milky Way is in the direction of Sagittarius, but it's blocked by dust and gas nebulae. It can be observed at infrared and radio frequencies, but not in visible light.

Here's a pretty picture.

http://www.astronomy.com/asy/objects/ima...

Answer 6

Well, sort of..

If you look to the south in the summer toward Sagittarius (assuming you live in the northern hemisphere) you can see the center of the Milky Way Galaxy obscured by some of the dust bands in the next inner arm - the Sagittarius Arm. As you look in this direction, you are looking "upstream" into the unwrapping arm as it comes off the galactic center. ADDED: as shown in this photo:

http://www.astro.uiuc.edu/~kaler/sow/sgr...

If you look to the south in the winter, you are looking "downstream" along our arm of the galaxy, the Orion Arm, toward the constellation Orion.

If you look to the north in autumn, you can see the constellation Perseus. That is in the next outer arm, called the Perseus Arm. You can also look out of the plane of the galaxy, toward Taurus on one side in the fall and toward Virgo on the other side in the spring.

Answer 7

Yep. Earth is on the outer edge of one of the spiral arms, the galaxy center doesn't take up too much of our sky because we're quite far away from it. That band you see stretches right across the sky though and most of it is stars in our arm of the galaxy.

If you want to visualize it, imagine you're an ant standing on the outer edge of a Frisbee. The center would appear quite a long way away, and most of what you see would be the parts of the Frisbee that are nearest to you.