Why is the sky dark at night?

Question

If there's really all these quadrillions of stars out there, why doesn't their light brighten the night sky?

Answer 1

Because the distribution of stars is uneven, meaning that some of the stars and galaxies block each other. In addition, many stars are so distant from us that their light has not reached Earth. This is a heavily studied question in astronomy, and it is known as Olbers' paradox, after the German astronomer Heinrich Wilhelm Olbers.

Answer 2

This is a great question and often overlooked as having a simple/basic answer. The easy answer is that the sun is on the other 'side' of the earth,but it poses interesting questions about cosmology. If the universe is infinite in size and age (Steady State Thm), and it can be assumed that the universe is homogeneous over larger scales, then light from all the stars in the universe would have had plenty (infinite) of time to reach earth. Because the universe is infinite, with thereby infinite stars, then earth's 'night' should be just as bright (if not brighter) than during the day. This is because all the light from stars would be hitting the earth, illuminating the night sky. One way to think of this is imagine you are standing in the middle of a huge forest. Looking in any direction, eventually a tree will pass between your line of sight, so you won't be able to see outside of the forest: a tree will always be in your way at some point. Just like the stars, you would always being seeing a starlight in any direction. So the consequence of this is that the universe cannot be infinite in size and age, since it is apparent the light from stars very far away haven't reached us yet. So we can learn a great deal about the cosmology of our universe just by looking up at night! This is known as Olber's Paradox and is an amazing thing to contemplate.

Answer 3

The sky is dark in the night because we have no light source of sun on us.. half of the world is facing opposite. and the stars.. once of the most greatest thing to talk about, a star is the sun.. but lucky for us that sun is the young star in our galaxy. So the other stars that we see are Mireille not in our galaxy ( the milky way galaxy ) The stars that we see in the night.. are light years away from us, looking a star with naked eyes is like looking at very very very small things with a microscope. And the light that the stars can be really really bright much much more bright than out sun.. and this is what helped humans discover black holes, caused by a dieing star.
Sorry i dint want to go too deep just wrote a bit more so u get more interested. das all.. hope i answered ur question.

Answer 4

It is dark outside because the Earth is rotating on its axis while also rotating around the sun and the moon rotates around Earth. So it is night for you when the part of Earth that you are on is tilted away from the sun. Meanwhile on the side of the Earth that is facing towards the sun it is day and on the sides of the Earth it is morning and evening. There are tons of stars in the universe, but they don't actually light up. That is why they don't brighten the sky. Also, you have the moon to brighten the sky. Hope I helped. :)

Answer 5

Because of the recession of the distant galaxies. If the stars were at a static distance from us the night sky would be a single blaze of starlight and life could not possibly exist on earth! This was known as Olber's Paradox and was not explained easily until Edwin Hubble proved the expanding universe was a reality in the early 1920's. He's probably more famous for the space telescope that was named after him.

Answer 6

this question is called "olber's paradox"...and the answer (in reality, a theory) is amazing to me. the universe is expanding. due to the doppler effect, if two objects (the earth and a star, for example) are moving apart then the wavelength of the star's light increases. stars are light years away from us, meaning that their light has a lot of time and distance to gain increased wavelength. so, the visible light from the star is converted to other forms of light, such as microwaves and radio waves, as the wavelength increases. we may not be able to visibly see these stars, but we can certainly pick up on their microwaves and radio waves. i hope this helps.

Answer 7

Because the sun is on the other side of the Earth.
As for all of the stars-yes, they are there and they do emit light. However, they are too far away. Think of it this way: When you are in a football stadium at night with the lights on, it is very bright. However, the lights in that football stadium do not provide you with light if you are two miles away.

Answer 8

because the sun is on the opposite side of the Earth and the other stars are light years away....like really far,so its not enough to provide light for the Earth

Answer 9

There is also a vast amount of dust and grit in space. This mops up visible wavelengths of EM radiation and converts it into infra-red, at which frequency the night sky looks very bright.

Answer 10

The earth rotates all the time, and the sun stays still, so when the earth spins then the sun will be on one side, giving it light. So on one side of the world it will be day and on the other it would be night.
Hope that helped!