Is the universe dark and cold and how far the light of our sun goes?

Light travels INFINITELY FAR...it just gets less intense and less obvious.

The second nearest night sky star is similar to the sun, Alpha Centauri A, and it has a binary companion Alpha Centauri B (also similar to the sun). The two also have a vague connection with our actual nearest night sky star (Proxima Centauri), a red dwarf much dimmer.

The brightest night sky star is Sirius. For the sun to only appear as bright as Sirius, an observer would need to be located about 1.7 light years from the sun.

From a quick estimate, it is reasonable to say that the official boundary of the solar system would be 1 light year from the sun. After this, gravity from other stars starts to become important.

Is the universe dark and cold? As an entirety...yes. If you were to let the entire universe reach thermal equilibrium, the estimated final temperature is 3 Kelvin.

How many stars have been identified and named?

There are about 1500 stars that actually get simple names (and were named in ancient times). By "simple name", I am NOT talking about a cataloging code...I am talking about a 1-word name, as if the star is seen as a character of the ancients that it is worthy of a simple name. For instance: Sirius counts, Polaris counts, Vega counts and Betelgeuse counts. "Epsilon Eridani" does not count...that is using the constellation name and a Greek letter code, rather than the star having a unique name. "55 Cancri" doesn't count, "Gliese 581" doesn't count, "WASP17" doesn't count.

What is the distance between Sun and the nearest star?

4.2 light years from Sol to Proxima Centauri.

Is their darkness in between these two stars?

"Darkness" is NOT a "stuff". "Darkness" doesn't exist, it is just our name for the default image of a lack of light.

The "stuff" between stars is called the interstellar medium, and is really sparse gasses and dust at about a density of a hydrogen atom per cubic centimeter.

1) Yeah on the wholea pretty dark and cold place

2) lots.. heaps. plenty.. here they are: (not all of them but enough to keep you busy)

http://en.wikipedia.org/wiki/Lists_of_stars_by_con...

3) 4.2 light years to Proxima Centauri

4) No.. not complete darkness between Sun and Proxima Centauri. You could see the light from either star while in between them. Inside a Galaxy you will see starlight no matter where you are to some degree or another. Outside a galaxy, maybe not so much.

5) about 2.75 Kelvin which works out to -270 C or -454 F.

Most of the universe is not in a galaxy.

On average even if you figure in the stars and stuff, you have 1 or two gas molecules for every cubic meter of space, and one dust particle for every trillion or so gas molecules.. So space really is pretty spacious, but it not entirely empty. (as you can tell!)

By the time you travel to pluto our sun looks like just another star. I don't know the distances but I'm sure that can be googled. It is incredibly cold throughout the vacuum of space.

Too many questions! One at a time :-p

Light goes infinitely, but gets weaker with distance.

I love a good documentary about the cosmos. You will be amazed..