If the Universe is infinite there must be a star in every direction you look. So why is the night sky dark?

Question

Does this prove the Universe is not infinite? (There is an answer.)

Remember, even if just one or two photons per second were reaching us from any star, because there is one in every direction the sky would be light. It is not enough to say they are a long way away or there is dirt in the way unless you can block EVERY photon this way.

None of the explanations saying dust etc gets in the way makes sense, because the dust would eventually heat up and re-readiate light, and the night sky would still be bright.

And we do not know if the Universe is infinite in space or not.

But we do know that it is not infinite in time, becuase its started at the Big Bang.

Answer 1

The expansion of the universe is the main reason. Yes, there are certainly stars in every direction, most of them contained within other galaxies. At extreme ranges (about 13.7-billion light years) those galaxies are moving away from us so fast that their light is effectively red-shifted out of sight.

Answer 2

The night sky is dark (not saturated with stars) for many reasons.

First off, light pollution limits the number of stars you can see. If the brightness of the night sky is brighter than a star as it appears from Earth, then you will not see the star.

Second, not every point ihe universe contains a star. There are vast voids between stars and galaxies alike. Even if there is a star if you go far enough, the human eye has a limit on the magnitude of light it can detect, and the absolute visual magnitude decreases following an inverse square law.

Third, just because a portion of space is dark doesn't mean nothing is there. Space is full of dust which blocks out stars. Dust is responsible for the dark patches in the band of the Milky Way that is visible in the night sky during part of the year.

Answer 3

First of all, Universe is not infinite. It is a boundary less finite thing. Stars are present in the universe in every direction but the Human sight is limited till in certain directions. Also there is pollution. You cannot overlook the pollution these days. Stars that are far away are not visible because light from them may have not reached us till now (not even a single photon).
Also a major reason in the cities is the Light Pollution. You may not have read about this anywhere, but this a result of excessive lightning in the cities. As an example, I live in Delhi, India. The place where I live is close to the one of the busiest crossings in asia. There are malls, shops, festivities, lasershows, traffic, metro rail evry thing and so the sky is orange colour even in the darkest hour of night and hardly any stars are visible.

Answer 4

When I look at the sky in my part of the world I see stars in every direction. But the sky isn't a solid plane of stars, and some are too far away to be seen, especially with the naked eye. Clouds, air pollution and light pollution also effect how many, if any, stars you see on any given night. If you've ever been in a big city, and then went out into the country, you'll notice there seem to be more stars in the country because there isn't as much ambient light to mix with that of the stars.

Answer 5

Universe is big, but not infinite!

But that doesn;t mean there's not a star in every direction... the problem is the light is often blocked, by a physical body or another inteaction... some stars are very pale and don't really carry much light to us, but I recommend you look at the Hubble Space Telescope and the pictures it took of that "dark sky"

Answer 6

The Universe is not infinite!

There are not an infinite amount of stars!

There are a lot of stellar clouds, which are dense collections of gas and dust. This will block a lot of the light as well.

Answer 7

The most easy to explain way is that there is almost no air in the space,that is why there is no dust or dust particle in the space which can scatter & absorb or radiate light. That is why we see the night sky dark. just for the opposite reason we see the sky blue from the earth in morning.

Answer 8

There are, the thing is many directions you look in, the stars are too far away to even see the light from them - or we are so far from there that the first light from that star has not yet reached us.

Answer 9

Yes,the space is infinite and there is star in every direction but some are close to us and some are far and as we can't see distant star so it seems as there is no star in all direction.

Answer 10

There are stars in every direction you look.Isn't it?May be sometimes due to clouds you may see the sky dark.