why is the universe completley black when there is so much light out there?

Question

There are stars, sun, galaxies, all of these thigns that emit light but the universe is still completley dark.....why is that?

Answer 1

Two problems.

a) light travels at a finite speed of 300,000km per second while celestial bodies are light-years apart

b) light needs something to bounce off of or be absorbed by something in order for it to be observed. A photon (package of light) is just energy and can only be observed if there's something to use it.

Answer 2

Ari was very close, with Olber's Paradox. Olber considered an infinite universe filled to a constant density of stars. If this is true, he stated, then the sky should be filled with sun-bright light at all times; a distant star's light would be dimmer, but there would be more of them, and so forth. Of course the sky is not bright at night, so he knew there was a flaw.

And there are several flaws. First, there is a large amount of dust in the cosmos. That dust obscures distant, faint objects, so their light doesn't come unabated to the earth's sky (if it gets here at all). Second, there is the recession of galaxies due to the expansion of the universe. At a distance (from us) of around 15 billion light years (or so) no light can get to the earth, because at that distance light hasn't had time to get here (in effect, we are looking at the point in time when the universe was formed). Finally, although there are a lot of galaxies and stars, there is not an infinite number (mainly due to the 15 billion light year boundary), so the light would not be sun-bright everywhere.

I hope this helps, and I hope I have my facts straight about the Olber's Paradox. I'm gratified that someone out there besides me has heard of it. Good going, Ari!

Answer 3

AKA the Olbers Paradox.

If the universe is infinite in age and in size, then every line of sight should hit a star. And the night sky should NOT be black, but it is. Why?

Because the universe is finite and size and age and is expanding; there is a horizon 15 billion-ish light-years away (the edge of the observable universe) that we can not see past.

Answer 4

The Universe does not need to be lit in order to say it exists. If we had sense that would deteect magnetic field than we would se the Universe in terms of the field.
And since no one has really given an exact explanation of what light is.We dont really know how light roams around. There may be a lot of light, but we just dont see it in space, except in the space of our sun and earth. And the speck of light that comes to us from stars may be a different phenomena than we understand it to be. They say light is a wavy photon. But I never saw the wave of a photon. Maybe the wave is too small to see. Or maybe its not a wave at all. Maybe its just a lump of something and lumps are not visible unless they colide with something.

Answer 5

To further the previous answer, even though the photons are flying around everywhere, the universe is still black because there's nothing for them to bounce off of. For the same reason you can't see a flashlight's beam in a dark room (only the wall that the beam hits), the universe looks black because you don't see light until you're either looking at its source, or something reflecting it.

Answer 6

That's Obler's paradox. It's because the light sources are so far away that our eyes don't register the few photons an hour we get from most of them. If you train a powerful telescope like Hubble on a small dark spot, you get thousands and millions of galaxies - after a few weeks of catching photons.

Answer 7

Its simple...there's no air in space, therefore there is nothing for the light to reflect off of. Of course light reflects off of objects in space such as asteroids, comets and other planets because they are composed of matter. And stars and nebulaes are the source of light so obviously we'll see those too. Dark matter on the other hand composes the majority of the universe, but like its name suggests, its dark. And as a result can't see it.

Answer 8

this is Universe, my dear!
no room, no city, not country & not even a galaxy
where you customized or Just put them some Satellites
or is not like the Candle-light in the room
if anything exist, if anything happens..
whether The heaven! or TheHELL!
is in this..

UniVerSe {you we us}

called TheUNIVERSE

Answer 9

I would say because there is not enough objects to reflect the light.

Answer 10

because the light has to have something to reflect off of, in space there's nothing.