· How can we see galaxies if their stars are so faint?

Answer 1

Hiya

Firstly, the stars only appear faint because they are so far away; many of them are actually brighter than our own Sun. This, of course, does ot actually answer your question. So here goes.....

A galaxy has billions of stars, and - although they are (almost) all light years away from each other - it appears that they are all together in the sky because our eyes aren't sufficiently powerful to separate them. Because of this, their light all seems to add together at one point - and so they all reinforce each other. Consequently, a distant galaxy looks like a star (sometimes a fuzzy one if it's one of the nearest ones, like M31 in Andromeda) and will thus appear to be billions of times as bright as one single star.

If you put all this together, you should now realise how we can see these galaxies. It's rather like looking at a single star which is super-bright rather than billions which appear to be super-faint.

Please feel free to drop me a line if you would like to take this further.

Answer 2

Well, the galaxies themselves are actually fairly faint. If you've ever tried to find them in an amateur telescope, you know why they are typically called 'fuzzies'.

Most professional photos are actually taken over fairly long time periods. This allows the light to build up and so more detailed pictures are obtained. Of course, since a galaxy typically has hundreds of billions of stars (or more), the light from all of these stars does add up so you can see the galaxy even thoguh you might not be able to see the individual stars.

Answer 3

The "light" that travels to here from there is not electromagnetic.
If it were light, it can be shown that the lumens (intensity) to be expressed by the stars in those way-distant galaxies would have to be so large, they could not exist. Worse, the spectra we perceive from those distant stars in those far away galaxies match normal-sized and configured stars - they aren't that big. Period.
Worse, IF the light from those stars were ACTUALLY light, then the planets from nearer stars should be visable by the same criteria of detection. They ain't directly detectable, and the best part is that the method we can use to detect planets around nearby stars clearly supports my viewpoint.
The problem is perception: you and the rest of the world have been told for the last six thousand years - that's six millennia of prejuduce, that the spectra from those stars is light, traveling to your eye or telescope. Until now, there hasn't been an alternative, so it has just been ignored. You should read the blather needed to justify this perspective: your grandchildren will study it as we read about those who believed the Sun and stars rotated around the Earth.
Bunk! Flat Earth understanding (the world was once known to be flat)!
There are two fundamental demonstrations that light does not travel betwen stars as coherent spectra, and one reason why it is impossible.
Sooo, if you can set your ego and your education aside - like a true scientist, then read this heretical article, and see if you can look at stars again in the same manner. Start with any chapter that suits you, then read the rest.

Answer 4

Wow, you drug up some dingalings and some fairly neato replies. To be honest, distant galaxies are made up of many, many stars. Our Galaxy, The Milky Way,for example, has more than 200 Billion stars.

So it is not unreasonable to assume that distant galaxies have billions of stars also. Now at distances of 100 to 1000 Light Years it would never be possible to see all of the stars in one of those distant galaxies. You might see some of the brightest individuals, or clumps of bright individuals. But on average, your eye will merely collect all the light in that area and send a message to your brain that there is XYZ amount of light right over there.

Telescopes give us better definition and help somewhat. They also "see" more stars than you did with your naked eye, and in the process, they add to the confusion - sometimes.

If you put a billion weak stars together into a clump, you will see the combined light of them all...that is why you see them in the first place.

Answer 5

If your question was asked in the context of optics, then, as someone said . . . with a good telescope. . . and long exposure (as when taking a photo in the dark).

Others mentioned a telescope isn't necessary. This is true too. We can see the milky way and andromeda galaxies with the naked eye.

But back to optics . . .

You have a large telescope to magnify the light. The light is a constant. the longer you leave the telescope on it the more light you gather. Doing this would make the pinpoints brighter and therefore more visible.

Answer 6

It's true that if your eyes were good enough to resolve the individual stars in the Large Magellanic Cloud, then none of them would be bright enough for you to see because they are so far away. Lucky for you, though, your vision isn't perfect! Your eye is actually made up of tiny "pixels" (rods and cones, they're called), each of which takes in the light from a small region within your field of view. Each "pixel" records how much light is coming in from the region it's looking at, but it can't tell anything about how that light is distributed within the region. (This is one of the reasons that things start to look blurry when you get far away from them - all the individual details start to become smaller than the angular size of a "pixel".)

Anyway, galaxies are extremely far away, so the stars within them appear so close together that each "pixel" in your eye is looking at many different stars. The "pixel" simply adds up the light from all those stars and records that, so even though each star isn't bright enough to see on its own, you are still able to see the galaxy.

It is interesting to note, by the way, that even if you move a galaxy farther away, it won't appear fainter. The light you detect from each individual star will go down, but the stars will also become more bunched together, so each pixel in your eye will have more stars in it. These two effects cancel out, and what we refer to as the galaxy's "surface brightness" (which is basically what you are detecting with your eye) remains constant.

This may seem surprising, but it actually shouldn't be - you experience it in everyday life! For example, imagine a room with big white walls. As you get closer or farther away from each wall, its brightness doesn't appear to change, right? This is the same phenomenon as above - the wall gets fainter as you move away from it, but each pixel in your eye sees more of the wall, and the effects cancel out.

Answer 7

Buncha morons answering this one. What you see is the combined light of billions of stars. It's the same effect of you being able to see the cloud of the Milky Way at night without being able to see the individual stars.

And, no, idiots above me, powerful telescopes can see more stars than you can with your eye, but they still cannot resolve every star of distant galaxies. But as you may not be able to see a single firefly from a thousand yards away, you would see a diffuse cloud of light from ten thousand fireflies.

Answer 8

I like Nicole's answer. Basically, it's because of the accumulation of light. Think of it this way : people on the spae shuttle can see the light from big cities because of the accumulation of light in one area, but they couldn't see you if you were standing in field with a flashlight. It doesn't hurt that the Hubble telescope is outside the earth's atmosphere, which greatly reduces light pollution and interference from the atmosphere as well.

Answer 9

Nebula A faint, cloud like, self-luminous mass of count number located previous the image voltaic device between the celebrities. actual nebulae are gaseous; yet very distant megastar clusters frequently appear like them interior the telescope.

Answer 10

Hello, its not that their so faint, its just that by the time we are receiving their light they are probably gone. I mean they have allready burnt out and were just getting the residual gasses and viewable light from quasiars that are six to 12.5 billion light years away. "remember light traveles 186,000 mps"
Have starrrrrrrey nights

David or charged--------------------Later