1.what is meant by "Universe is expanding"?

Question

modern & latest theory on the Universe.

Answer 1

This is a great article about it that explains it really well that I enjoyed reading.
http://www.sciam.com/print_version.cfm?articleID=0009F0CA-C523-1213-852383414B7F0147

Answer 2

The galaxies are all moving away from each other, because of this process, we say the universe is expanding.Big Bang theory supports this and with the help of Big Bang we say Universe is expanding.

What Big Bang theroy says....
According to the Big Bang theory, the universe originated in an extremely dense and hot state. Then a kind of 'explosion' which happened some 15 billion years ago made the space itself has expanded with the passage of time, carrying the galaxies with it.Hence universe is expanding.

Regards
Diwakar

Answer 3

This is a literal term. The universe started as a single point and then through processes that aren't really understood expanded into everything that can be seen today through telescopes. The universe is very big but it isn't infinite, it has a leading edge moving outward in every direction, expanding.

Answer 4

Many of the answers are correct when they say because of the Big Bang, all matter is moving outward in all directions. Here is an example of what's happening in our world of size and velocity that might help you understand how all matter is also moving away from eachother. Imagine you are on a highway and going 60 mph and a car in front of you is going 70 mph and a car behind you is going 50 mph. The three cars are all moning the same direction but moving away from each other at the same time. The lead car is moving away from you at a difference of 10 mph and you are moving away from the car behind youat a rate of 10 mph. Its all in the difference in velocities. Matter that left first in the Big Bang is moving faster than the matter that left behind it. Add this idea to the matter is moving in all direction. You have an expanding universe that all thing are also moving away from eachother.

Answer 5

according to Big Bang Theory all the matter in the Universe is rushing away from each other
Thus Universe is expanding

Answer 6

If one accepts the "big bang" theory, that the universe started from a single point and is now moving outward in all directions from that point, then it is like a balloon that is being continually inflated. Therefore, it is continually expanding.

Answer 7

Concept of the expanding universe is derived from the fact that all the planets and heavenly bodies are moving away from each other at a constant rate. Researches say that in the past millions of years the the planets 'ave moved away from their respective positions.

Answer 8

That is called the expansion theory. It states that the universe will continue to move outward following the residual energy from the big bang.

Answer 9

Let me take u back to yhe Big Bang. At that time our universe was extremely hot having infinite temp. and havinf a point size.
Now, at the time of big bang, the heat energy got converted into matter( by Einstein's relation, e=mc^2), so the temperature of universe was decreased. But as this decreasing temperature means decreasing heat energy, so according to secod law of thermodynamics:-entropy of unoverse is always incresing, something else had to increase, that something else was the size of the universe which is continuously incresing. This increase in size is called as expansion of universe. As universe is expanding in size, its temperature is decreasing at a rate proportional to that of its expansion.

Answer 10

The velocity with which the other galaxies are rushing away from
the earth increases from the earth.The motion of other galaxies
away from the earth gives rise to the idea of "expanding universe".

Answer 11

well it is considered that the universe is expanding at the rate of 1billion square km every minute.that is quite a big space.the galaxies are actually moving around the universe when we think they r stationery