Is our univese still expanding?

Answer 1

Universe was always the same, it was just that we didn't knew enough about it.

Answer 2

Yes, easily seen by astronomers as "redshift". The light of distant galaxies is almost always redder than it should be, because they are moving away from us fast and the light is "stretched".

Another question is will it continue to expand, or will it all be pulled back together by gravity?

Our universe is expanding now, pushed out by the big bang.

Gravity is trying to slow the expansion and pull it all back together.

Which will win? The force from the big bang or gravity? Astronomers have been asking this question for a long time. The answer is stated simply as a number called Omega. They try to measure Omega. If Omega is less than one the universe will expand forever. If it's greater than one the universe will collapse back. If it's exactly one, the universe will expand forever, but the rate of expansion will always be slowing down. After a long while it will almost stop.

More info:

Omega is really really hard to measure. It depends on questions like "How much dark matter is there?" The current best value is somewhere around 1/3. But the measurement is so uncertain that could well be one. In fact scientists think that might be the case. They think that if Omega wasn't one we should get an answer like .00006, or 75,000,000. 1/3 is close to one compared to those numbers.

The reason they think that, if it wasn't one, Omega should be far from one, is that the theories of the big bang say that omega was set very early in the bang. And that, unless it was exactly one, it should keep changing over time. They used to be puzzled why it should be anywhere near to one. It was like Omega was balanced on one in a very unlikely way.

Then someone invented a slight modification of the big bang theory called "inflation". One reason people like inflation so much is that it says omega would have been set as exactly one by inflation, where it would stay.

So presently, astronomers think that Omega is exactly one, the universe will expand forever, but that the rate of expansion will always be slowing down.

Answer 3

Yes, our universe is still expanding. Assuming that:

a) Universe = space and not space-time

b) The density of the universe does not change.

c) The universe is NOT infinite

However, if the density of the universe changes we can find out whether it expands or not.

If the density of the universe over the critical density is greater than 1 then our universe will stop expanding.

If the density of the universe over the critical density is less than 1 then it will expand forever.

If the density of the universe over the critical density is equal to 1 then the universe will not expand and will remain as it is now.

If u want to know how did they find the value of the critical density go here:

http://www.physlink.com/education/AskExperts/ae252.cfm

Answer 4

Our universe is infinite, which means it has no boundary or edge. It goes on for ever. When people say the expanding universe, they are talking about the contents of the universe, galaxies, stars, and planets. Our Moon is moving away from the Earth at a rate of 4" per year.

Answer 5

Yes, the universe is still expanding. And what's baffling scientists is that the expansion is accelerating! The Universe is currently 156 billion light years across!

Answer 6

Hi. One theory says so. But the measurements are based on the 'stretching out' of light which may still have another explanation. (A good scientist ALWAYS doubts!)

Answer 7

Yes.

Answer 8

according to observations yes it is still expanding.

Answer 9

Yes, it will expand forever.

Answer 10

yep expanding and expanding till it bursts

Answer 11

yes