Is universe has a finite size?if yes then wat is beyond universe?is it not also called universe?and if it is finite then why physics books tel the size of universe.sounds puzzling

it's expanding

that would imply a limit to me

I would agree with Quite.

Based on the Big Bang theory, it would seem that it must have a finite size.

But that's only if the Big Bang theory is correct.

As to "what's on the outside"?

I'm not even sure that question can have a sensible meaning. If space is finite, then there really is no such thing as "outside", since outside and inside are relative to some "divider". But the concept of a "divider implies space on both sides of the divider. So the concept of "outside the univers" is really a pretty meaningless concept - at least in terms of what we know about spactime.

It's always expanding and it's us that helps it do do so...

I was reading Scientific American on a plane flight to Florida a while back and there was a good article. They have measured different rates of expansion in different areas of the universe and take that as proof of dark matter. I didnt have the math for most of it but I kinda got the conceptual gist of it

Some believe that the energy behind our thoughts help the expansion. So we are in a time where the thoughts are well...playing catch up, so to speak. We and the universe(s) are benefiting from our ancestors energetic thoughts. It was an interesting show.
Like you Qman, I didn't have the math to keep up..but stayed with it as best I could and found it fascinating.

Yes - the universe is expanding - but what is it expanding into?

Perhaps we are hung up on a definition in regards to this OP.

So what defines universe? Think about it...

What defines space - must matter exist in all space?

I keep trying to imagine space devoid of any reference point (i.e matter) and I find that I cannot. Intuitively, I can't see either matter or space existing independently the other.

But on the other hand, if I think about something "at the edge of space", I can imagine myself moving "away from it". (Although, there would be no difference between me moving away from it, and it moving away from me.) But really, that just makes me one of the reference points, so again, I cannot imagine looking "out" from an object at the edge of the universe.

But on an even other hand, I can imagine a "massless first-person viewpoint" moving away from the edge.

Which kinda leads to the intersting idea that it is "the action of viewing" that creates space.

Just some ruminations.

anybody who gives you a concrete answer to these questions ........., well they've been sniffing too much model airplane glue. it's all theory.

What would interest me is does the universe or space end anywhere? Is their a cliff?

Wow, great questions and great answers. I agree with jrbroglie that 'we don't know'; but as far as the dominant theory goes...

One question is: If space is finite, does it have an edge?

It would seem at first that it must - if its not infinite, then it must end, right? and if it ends, it has an edge, right?

But consider the surface of a balloon. The surface of a balloon is finite, and (within the two dimension of that surface) has no 'edge'. (The surface itself is the edge of the three dimensional balloon... but lets set that aside.)

This idea also helps us visualize the expansion; the 2D balloon surface can increase in size, as the 3D balloon structure expands in three dimensions.

This idea also helps us to understand 'curvature of space'. While trapped within the 2D balloon surface, it would be difficult or impossible for many to imagine their world being curved, but its obvious to us 3D creatures that a balloon is curved.

Our three dimensional space might be similarly curved.

Space is infinite but the universe is finite. Because the universe encompasses everything that exists (all matter) and beyond that is just space.

There are various density levels,and sometimes this universe will communicate with a human through the language of synchronicity.

Because I do not understand at all can you clarify some things please.

Density is a scaler (unite of measurement). Can you explain how it has levels?

How can inorganic matter communicate?

Define the language of synchronicity please.

About different Density: On earth....

Although it is hard to imagine it, space without matter is a moot point, even if it does exist.

One of my first questions when I was a child was, "How high is the sky?"

I soon learned that the earth's atmosphere (that we depend on for our lives and air) is very very thin. Go up one mile and you are at the edge of outer space.

Just traveling from the Colorado to Florida will cause a pressure change because of altitude. I noticed that bottles of lotion in my suitcase had collapsed (or imploded) from the pressure and a car we had in tow required a new radiator because the pressure damaged it. It had been sealed up tight.

Imagine what the change in altitude and pressure does to deep sea fish that are brought up from the sea. They also collapse. How does that fish survive in that much pressure? It survives because its body adapted to it, but it could not survive the change when it was taken up into our atmosphere.

Our physical bodies have adapted to the pressure here on earth and they can also adapt to changes of altitude because of their density.

Does anyone know what causes these changes of pressure and altitude?
I don't know the scientific study behind them. I am only speaking from what I have experienced.

I know when deep diving under the ocean, if you come up too fast and don't give your body time to de-pressurize it can kill you.

Yes I know what you are speaking about.

Me too.

The changes of pressure are a result of gravity. Air and water have substance (matter). That matter is affected by gravity just as a large rock is. When there is air or water above you it is pressing down on you creating pressure. The more air or water the greater the pressure. because water is denser than air we feel the pressure changes more as we move up and down a water column.

A sealed container is equalized to the pressure that it was sealed in. If it experiences more pressure by going under water or to a lower elevation it has a tendency to collapse inward as a result of the pressure. On the other hand if it was sealed under high pressure and moved to an area of lower pressure it has a tendency to expand or explode.