What is the black "ceiling" in space?

Question

What is it exactly? Let me try and compare this. Air is transparent. I can see through it to the items beyond it. There is no air, or anything, obstructing my view in space, so when I see the black "ceiling", I don't think I'm looking at space itself but some black thing. What is it?

Answer 1

It is caused by the expansion of space. Large objects in space visible from Earth through a telescope are generally moving away from us because space is increasing in size. The further away they are, the faster they are moving. Eventually, they are so far away that they are receding faster than light, so light from them can never reach us. This is possible because space itself is expanding, which is the only way objects with positive real mass can move faster than light relative to each other. Since the light can never reach us, space looks black.

The fact that the sky looks black is called Olbers' Paradox.

Answer 2

basically, as light gets further away it gets dimmer, and when it gets so far away you cant see the light any more this is where the sky looks black,. if you live in a city you will not see alot of the stars that are there. go to the countryside on a crisp clear evening and you will see alot more than you have ever seen in your life!! it is really amazing how many more stars you can see when the surrounding area has no light pollution. You mention no air in space, this is true but also in space is alot of dust and rocks which are too far away to see but also block our view. also just as a footnote, the faster a light source travels away or towards you also changes the colour of the light which could explain why some stars are different colours, not to mention they are different gases. good question though :)

Answer 3

"Why is it dark at night?" was the key question which led to the understanding that everything is moving away from us (and from everything else), i.e. the universe is expanding. When light sources are moving away from us, somethiing similar happens to when we hear a siren coming past and away - a change of frequency which in the siren's case means the sound gets lower, and in the case of light means a 'red shift'. This means some of the light out there is no longer in the visible spectrum.

Take a look at http://www.physics.org/facts/sand/dark.html

The problem was identified as Olber's Paradox in the 1950s by Professor Sir Hermann Bondi. You can find plenty about this by entering those terms (Olber's, Bondi, "dark at night" into Google and getting results from books.google.com - the relevant bits can't be cut and pasted, else I'd have given you them here, and you have to read down the various references or search on Bondi on the relevant pages.

Answer 4

Is it not true that most star you look are just a look into the past, as it can take 1000's of light years for the light to reach us.The star you see probably burnt out 1000's of years ago?and if we look deep enough into space we will see the big bang?
in answer to your question, space is not black its just full of colours we can not see, some animals might look at the sky at night and see a wonderful red or blue sky.

Answer 5

It could be the final point in the Earth's atmosphere when there is no longer any light being reflected within it because the atmosphere itself has ceased at that particular height.

It could be a bit like when the sea goes black at a certain depth because light gets absorbed, although it is a very different process taking place in the sea compared to in the atmosphere.

Answer 6

If space and time were infinite, then every direction you look would end in a star. The fact that the night sky is black implies that the universe is not infinite and it has not been here forever. The blackness is the space between stars that is filled only with background radiation - most likely left over from the Big Bang.

ADDED: I agree with A B (and with posters above), at least for the most part. Look up Olber's Paradox.

Answer 7

The sun is light and we can see through air. In space the stars (other suns) are too far away to cast any light to us. There is nothing in space and so it is black. Remember black absorbs light, because it is black.

Answer 8

I think it is a big black lid that is covering half of the Earth.

It is getting old now and is full of little holes that let the light in.

Scientists try to kid us they are stars.

Answer 9

You're not looking at anything. Space is transparent as well. So you see right through it. But for the most part, there isn't anything to see because space is empty. So since you're not looking at anything, there's no light coming from that spot, and you see black.

Answer 10

You are looking at infinity. Mind-boggling to realise it. You are also seeing the far, distant past. Ask yourself something else (a personal ponder of mine): what's beyond our own physical universe? There are more questions than answers!