please answer?important question.?

Question

if there is a star everywhere,then why in the space not bright with the light as well as the heat of the stars.what happens to all the energy emitted from the stars.it can't be lost because energy is niether produced not destroyed.

so my question is-
why is the universe not bright?
why is the universe so cold?
where does the energy of heat and light go?

Answer 1

Ok lets take these one by one:

1. The brightness of a star depends on the distance between two fixed points (The star and you). Since some stars are so far away.. millions of light years.. the star is not visible to the human eye.
2. The energy that a star gives off is disapated throughout the universe so in order to make the universe warm, there would need to be a star the size of 3/4th the universe.
3. The energy of heat and light are evenly distrubuted throughout the universe.

Answer 2

Who said stars are everywhere?

I don't believe stars are everywhere. There is a finite number of stars in our universe, and the stars that do exist are not evenly distributed. In addition, the light from some stars is probably blocked from reaching the Earth. Black holes can also bend or absorb light from other stars.

If there were an infinite number of stars, and they were randomly distributed throughout the sky, then I agree the night sky should appear bright, unless something was blocking or absorbing the light before it reached the Earth.

I believe the universe is cold because of the vastness of space. While it might seem like the universe should heat up, the universe is so vast that the energy ejected into space is diluted until it is cold.

Pure speculation ... I suspect that someday mankind is going to find that what we call "the" universe, is actually a small speck in a much larger super-universe. Although there is no proof that I am aware of that shows there is anything beyond what we know as "the" universe, I don't think we know enough to be certain that there isn't.

Answer 3

Space is mostly empty. There are stars everywhere but the space between them is much greater than the space the occupy.
Energy, be it light or heat (of course heat doesn't travel through a vacuum at all) varies inversely with the distance from the source. Which is to say the farther away froma source of energy you are, the less energy there is that reaches you. Check out this link:

http://video.google.com/videoplay?docid=8095482682672703968

Might help answer some of your questions.


Also, light does not need a medium to be seen. Light is neither a wave nor a particle but somewhere in between. Heat does not travel through space. The heat we get from stars is the energy from the light (infared and otherwise).

Answer 4

That's a very interesting question the answer is that the light hasn't reached us yet. Anything beyond about 13 billion light years hasn't reached us yet.

The universe is so cold because the density of energy is very low, stars are hot but stars are small bodies compared to the great void of space, so their heat and light is being diluted by the empty space, hence the cold.

THe energy of heat and light go in every direction and fills the entire universe, but the universe is SO BIG AND LARGE that energy and head is being spread up to a point where it is almost zero.

Answer 5

Yes, the space is filled with stars - billions and billions of them. Many of them are millions time more powerful as our Sun, too.

So why is the universe so cold, and why is it not bright?

Think of the space - the HUGE space... Now, scale the each star into the right size so the propotions are right in this HUGE space.

Now, what you get is a HUGE space with tiny dots everywhere.

The amount of energy and light produced by each of the star is insignificant in respect of the HUGE space, thus not enough to heat up or light up.

By the way, the heat and the light is reaching the earth. That's how you see them. (as a tiny dots)

Answer 6

A little illustration is needed here. I would like you to picture a golf ball, a softball, a beach ball and a large balloon about 6' in diameter.

Say the golf ball is the sun. In relative size the softball is about 3 and one half times the diameter of the golf ball. but the surface area of the sphere of the softball is many times that of the surface area of the sphere of the golfball. When we look at the beach ball it has an even greater surface area of the sphere of the beah ball. And of course if we go to the 6' dia balloon then the surface area is still greater.

Now picture that these balls are made of clear plastic and are set one inside the other. The clear golf ball now represents 100 percent of the output of the sun. At the clear softball the output remains the same but it is spread thinner over the surface of the softball. At the beach ball the out put is still 100 percent but again it is spread even thinner over even more surface. And of course the 6' dia balloon the output is spread even thinner.

What this means in direct terms is that if we were to take a small diameter piece of steel rod and went from the golf ball to the balloon each place that the steel rod intersects the softball, the beach ball and the balloon the amount of heat and light energy at those points is reduce in direct relation to the distance from the golf ball.

I hope I didn't get to simplistic but this is how I explained it to my 12 year old granddaughter and she understood almost immediately.

Answer 7

Well, you're looking at -369 F on pluto, lets say our sun heats pluto (well, it is the closest). By the time the suns rays hit pluto, it would be lucky to be -100 F, if not, colder. That hitting a temp of -369 more or less snap freezes the heat, the heat is gone.

The next closest sun is Proxima Centauri in Alpha Centauri C, about 4.36 light-years away, meaning light requires 4.36 years to travel from the stars to Earth, that's just light, heat takes longer. And after traveling that far, its no wonder its cold.

This disperse over time, that's all thats happening here, you have to remember, its a big universe!

Answer 8

Even though there are billions upon billions of stars in the universe,there still is a lot of empty space in between,also billions of these stars are too far away,that the light they emit we won't get to see in our own life times,as to the universe being cold,again,the space in between stars is so inmense that the heat from the stars is not enough to warm up or light up the vast universe

Answer 9

oh my goodness... someone who thinks the same exact way as me. I used to ask that same question to myself. But then I started to realize that they are very far away from each other and that there is alot of space(universe) out there. Also I don't know if this has to do with anything but I think also because there is really no air out there either so i guess that there is no medium for the light to travel through.Also stars that we see now might not still be there because there light takes light years to travel to our galaxy so ther might not be as many stars out there as you think.

Hey I am just glad that there is someone who thinks like me and likes to ask questions about this stuff!!!

Answer 10

To much distance. Is similar to the light of a distance town at night. Some areas of the night sky are brighter than others like the Milky Way or Orion Nebula.