the universe expanding?

Question

o.k. my teacher said that scientists are baffled that the universe is expanding instead of decreasing but i was thinking if the big bang theory was suppose to be the biggest explotion in history cant the expanding be just the left over shock wave from the explotion.

what do you think?

Answer 1

I thought the universe was infinate, they can't see very many light years away, and are discovering new planets everyday.

Maybe they mean it like new planets are being found. But not in a literal sense of expanding, your teacher needs to be more clear on what they mean.

Answer 2

The Big Bang starts off the universe on a rapid expansion. With time, the expansion should slow down under the effect of the gravity of all the mass the universe contains.

For a time, the big question was whether or not there was enough mass so that the expansion would eventually stop. However, everyone agreed that if the universe contains mass, then the expansion must slow down.

And it did for a dozen billion years. Expansion continued but at a slower and slower pace.

But now (i.e., in the last one or two billion years), it looks like the expansion is picking up again. That is the baffling part (what is causing it to accelerate again?).

Answer 3

Scientists aren't baffled, they just don't have all the pieces of the puzzle (from the split-split nanosecond after the BB) to work out the detailed physics and math.

The problem with the idea you've stated is that the Big Bang wasn't an explosion (like a bomb going off).
It was the sudden inflation of space and everything in it - in a tiny fraction of a second space expanded from a zero point to the size of a proton, and then kept expanding.
Its the momentum left over from that inflation moment that is partly due to the expansion.
Since it appears that the expansion of the universe is actually accelerating, the theory is that dark energy is has an "anti-gravity-like" effect and is actually causing the expansion to speed up.

Answer 4

According to inflationary cosmology, the universe is expanding at a faster rate because of negative gravity, which is what caused the big bang in the first place. For the first 7 billion years or so, the universe expanded but decelerated, because the positive gravity of the concentrated mass was greater than the force of the expansive gravity. Once the universe reached a critical size, the expansive gravitational force took over and muscled the universe to expand at a faster rate. The universe has been accelerating since then, and will continue to accelerate faster. I'm not sure on the details on what causes inflationary gravity, it has to do with the universal constant and the early universe getting stuck on a higher energy level, for more information you could google inflationary cosmology, or read Brian Greene's book.

Answer 5

I think you are referring to the fact that the universe is apparently expanding *faster* now than in the past. This was a very unexpected observation but it seems to be the case. There must be some other force at work than the Big Bang, because most scientists thought the mass of the universe would either slow the expansion or cause it to reverse and everything would come back together (what was called the Big Crunch). As it is expanding faster now than in the past, scientists proposed theorectical things like "dark energy" to try and account for it.

Answer 6

The universe IS expanding..not in the sense that it is getting wider or longer like hair grows or something..but kinda like baking dough. Everything is expanding..even space between objects. They know this because Astronomers have mapped and calculated the distances.etc. or nearby objects and have noticed that everything is getting farther apart from everything else. For example..you might think that because something get's farther from a certain point..it must get closer to another point..but no...everything is expanding..space is expanding. This is how we have calculated the age of the universe..by the consistent speed at which the universe is growing. Another special point...there is no center and there is no edge of the universe.

It is greatly theorized that it will keep on expanding forever..but there are some other conclusions that lean toward the universe/space expanding and collapsing in on itself..what after that? Well, there is also a notion out there that questions the occurances of Big Bang(s) and that it is a continuous process...but that gets into stuff I have yet to learn..String Theory..etc

Answer 7

The universe expanding is the biggest theory supporting the Big Bang, since there is not gravity to stop the universe. Newtons law says "an object will remain in action until and equal and opposite force acts upon it."
I feel that there will never be a way to know for sure how it really happen, all current theories are just that, theories. They cannot be proven completely or disproved.

Answer 8

Well, you are partly correct, but there is not a shock wave but rather inertia that would be in play there. Shock waves require contiguous matter contact, and there is mostly nothing (a vacuum) in space. The paradox for scientists is that the summation of the masses of all matter in the universe should cause a center of gravity toward which objects decelerate and eventually lose all their outward velocity. At that point in time, matter would "fall" back toward that center of gravity and the universe would begin to collapse. Thus far we have not been able to determine that any such effect is occurring, so we still have a lot to learn.

Answer 9

the fast answer is annoying to hold close. Supposedly the universe is starting to be its very own area because it expands swifter than gentle. extra possibly is that scientists have not have been given any theory what's certainly happening obtainable in deep area, around 14 billion gentle years away, and got here up with that theory. i'm confident it consists of distinctive techniques blowing mathematical formulation and a brilliant number of darkish count number.

Answer 10

You are looking at it the wrong way there was no explosion. more a creation of matter, light, and time all at once.
Example picture a loaf of unbaked raisen bread. the raisens are the galaxies, and the bread is the universe. As the bread bakes the yeast rises and becomes larger the raisens do not go anywhere, but the bread or space between the raisens expands makeing the distance between the raisens become larger. Hence the expansion of the universe.

Answer 11

The universe is clearly expanding. We know that from the redshift of light from distant galaxies. That red shift is a Doppler shift. The exact same kind of Doppler shift that the police use to measure the speed of a car with radar. There is no mystery there.

But new measurements of bright supernova combined with theories about how bright they should be seem to indicate that it is expanding faster and faster every year instead of slower and slower. That is what has them confused, not the fact that it is expanding. The expansion is not mysterious at all. It is only the increasing speed of the expansion that is mysterious.