If the universe is expanding, where is it going?

Question

My Geology 102 textbook makes some basic statements about the formation of the universe and the solar system. One of these statements is that the universe is constantly expanding. My question is, expanding into what? Expanding relative to what? Another statement is that the universe started from a "big bang." I have heard of this theory before but have never understood it. What caused the "big bang?"

Answer 1

The universe is expanding in all directions, but length and witdth wise. Think of something like blowing up a balloon. It is relative to the growing amount of matter, the number of stars being born, new solar systems, etc. The big bang was supposedly caused by a single force that separated into different forces: gravity, electromagnetism, the strong nuclear force and the weak nuclear force.

There is another theory called inflation. The universe is said to have expanded ten to the fiftieth power times its original size in ten to the negative 32 seconds, then slowed its expansion. The universe can be either opened (meaning it will expand forever) or closed (meaning it is limited) depending on the density of its matter. 90% or more of the matter is Dark Matter, which is basically Nothing...in my opinion there is no way Nothing can be very dense at all, which leads to the conclusion that the universe is infinate.

On the other hand it has been expanding more and more slowly since the beginning. Maybe it will slow down to a complete stop someday and stay suspended, or maybe it will start going backwards. There is a situation I've heard called Zeno's Paradox. In this hypothetical situation a runner has to run a certain distance...say, 100 feet. And he keeps running half the distance he has left. He starts with 50, then 25, then 12.5, then 6.25 and son on, but it never completely adds up to the goal. A similar rule might apply to the universe as well.

About a million years after the big bang the universe cooled down to 5000 f and protons and electrons fused to form hyrdogen. The formation of hydrogen atoms allowed wavelengths of light to appear, which is how color probably started.

Answer 2

I'll answer the second part first.

The Big Bang was a massive explosion. All of the matter and energy that makes up our current universe was compressed into a very small point called a singularity. Singularities are very dense, meaning they have a lot of mass for the amount of space they take up. In fact, the point that forms a black hole, the thing that actually sucks up all of the dust and light and planets that happen to come too close, is a singularity. But the singularity that formed the Universe was much, much, much, much heavier.

As for what an explosion is and isn't - the Big Bang did not require oxygen. It was basically a very very tightly packed ball of subatomic particles and energy that somehow released - this was at a very high temperature and in a very short period of time. This wasn't an explosion like dynamite - this was like a supernova on the strongest steroids you can imagine.

Nobody knows WHY the singularity exploded. There are lots of explanations, but nothing is really known for a fact.

The fact that it DID explode, though, is a very strongly-tested and evidence-backed statement. There was almost without a doubt a Big Bang.

As an aside, because of how singularities affect gravity, space, and time, there was no "before" the Big Bang. Time stands still when you get really massive and really dense. So no time = no "before."

As to what the Universe is expanding into - that's a bit easier to explain.

The Universe is expanding into nothingness. Absolute, total nothingness. There are no physical laws beyond the boundary of the Universe, because there is nothing for those laws to apply TO.

The Universe is expanding relative to itself. Last week, the Unvierse had a smaller diameter than it does this week. Next week, it will have an ever larger diameter.

The best way to think about the Universe is to imagine it as a basketball. We are inside the basketball somewhere. Where we are, we can move in any one of the six directions - left, right, up, down, forward, or backward, if we wanted to. But if we go all the way to the boundary, then we'd have to stop. We could only go in five directions, because the sixth direction is blocked by the boundary of the Universe.

Answer 3

some other people have answered the first two questions here I'll attempt to answer the 3rd one what cause the big bang? well from what I've learned over the years the universe will expand until it reach a certain point and then it will contract in what has come to be called the big crunch. now there are some who say that this isn't so but there are many mathematical models that say that we are indeed leaning in that direction. if this is so then this is probably not the first time this particular universe has gone though the cycle that would be created, and in the end the big bag could be seen in the same way that a sun goes supernova once it reaches a certain mass where the heat and pressure can no longer be sustained and it explodes, spewing matter back into the universe. mind you this is a simplified version of the process, but hopefully you get what I'm saying. also be mind full that this is merely speculation and supposition based on what is known and what models are available, as well as some logical leaps. i.e. in the end it's just a theory.

Answer 4

Well, what did happen before the big bang?
Few schoolchildren have failed to frustrate their parents with questions of this sort. It often starts with puzzlement over whether space "goes on forever," or where humans came from, or how the planet Earth formed. In the end, the line of questioning always seems to get back to the ultimate origin of things: the big bang. "But what caused that?"


One evasive tactic is to claim that the universe didn't have a beginning, that it has existed for all eternity. Unfortunately, there are many scientific reasons why this obvious idea is unsound. For starters, given an infinite amount of time, anything that can happen will already have happened, for if a physical process is likely to occur with a certain nonzero probability-however small-then given an infinite amount of time the process must occur, with probability one. By now, the universe should have reached some sort of final state in which all possible physical processes have run their course. Furthermore, you don't explain the existence of the universe by asserting that it has always existed. That is rather like saying that nobody wrote the Bible: it was. just copied from earlier versions. Quite apart from all this, there is very good evidence that the universe did come into existence in a big bang, about fifteen billion years ago. The effects of that primeval explosion are clearly detectable today-in the fact that the universe is still expanding, and is filled with an afterglow of radiant heat.


So we are faced with the problem of what happened beforehand to trigger the big bang. Journalists love to taunt scientists with this question when they complain about the money being spent on science. Actually, the answer (in my opinion) was spotted a long time ago, by one Augustine of Hippo, a Christian saint who lived in the fifth century. In those days before science, cosmology was a branch of theology, and the taunt came not from journalists, but from pagans: "What was God doing before he made the universe?" they asked. "Busy creating Hell for the likes of you!" was the standard reply.


If the big bang was the beginning of time itself, then any discussion about what happened before the big bang, or what caused it-in the usual sense of physical causation-is simply meaningless. Unfortunately, many children, and adults, too, regard this answer as disingenuous. There must be more to it than that, they object.


Indeed there is. After all, why should time suddenly "switch on"? What explanation can be given for such a singular event? Until recently, it seemed that any explanation of the initial "singularity" that marked the origin of time would have to lie beyond the scope of science. However, it all depends on what is meant by "explanation." As I remarked, all children have a good idea of the notion of cause and effect, and usually an explanation of an event entails finding something that caused it. It turns out, however, that there are physical events which do not have well-defined causes in the manner of the everyday world. These events belong to a weird branch of scientific inquiry called quantum physics.

Answer 5

A) It's expanding relative to itself (there is more and more space in the universe as time goes on)

B) It's not expanding into anything, it's just expanding. Stop trying to picture the universe as something that could exist on a smaller scale, like a balloon.

C) No one could possibly know what caused the Big Bang, because the universe didn't exist before it. Maybe God caused it, does that make you feel better?

Answer 6

Hi, well the universe is expanding yes. How we know is thanks to Edwin Hubble. He based his discovery on red shift. Which is a shift towards the red end of the spectrum in the observed spectral lines of stars and galaxies.

Now we don't know what it is expanding into but there are theories of what will happen if this continues. One is called the Big Crunch. This is the opposite of the Bing Bang.

What caused the Bing Bang is also unknown but it is just a widely ecepted theory. It states that the universe began 10-20 billion years ago in a huge explosion. But for an explosion to happen you much have oxygen, and a source of flame for the combustion reaction to occur.

One theory is that it occured from a black hole. I don't know much about the theory. But anyway the Big Crunch:

This is that that universe will reach its limits and sort of "bounce back" sort of shrinking but very rapidly. So that it "crunches" the things with in it.

I hope this was of some use to you. Sorry my answer is a little late took a bit to write it. Memory not what is use to be.

Answer 7

You ask tough questions that our best and brightest minds can't fully explain.

I like to think of the universe as 'existence'. Observations and measurements have shown that the universe - all that exists - is expanding. What's beyond existence? It's impossible to define because it doesn't exist yet... Tripppy.

As for the big bang - much easier to define. Existence - every bit of matter and energy - had shrunk down to a single point that reached pressures, temperatures and potential energy so great that it literally exploded - expanding outward in all directions.

This doesn't go into much detail but for me it's the best way to describe what's beyond the boundries of our universe and how it began.

Answer 8

The answer is very vely simple. The Universe is here to stay. For the time Being its not going any where.
Things may move inside the Universe's volume but cannot go beyound it. If that wouldnt have been the case we would have had an unstable Universe, where equilibrium would be totally out of quilt.
Usually noise comes out of a Big Bang.The theory was highly publisized and it did make a lot of noise( quite a bit from Fred Hoyle)

Answer 9

This type of question will never be answered by us mortals with our finite mental capacity. We simply cannot understand or deduce concepts of infinity. We must believe them, because it is even less rationale to think that space has boundaries... I mean, if you travel in one direction long enough, doesn't there have to still be something (space) beyond you in the same vector in which you are travelling?

Further, we must also believe that all matter has existed for infinite... if not, then how did it come into being? Even the big bang doesn't explain what happened *before* that singular event, but something must've happened if the matter existed a priori.

However, keep thinking of those questions... to find out the answers to our universe, we must keep thinking about the questions.

Thanks for posing this question, as it does provide some great food for thought!

Answer 10

the universe is expanding relative to itself. the example of a balloon is flawed becauseit has a 2 dimensional surface. space is three dimensional and all the points in it are moving away from each other. its not expanding 'somewhere' because it encompases everything. as for the big bang, you could spend your entire life searching for an answer and never find one, all I can tell you is good luck!

i just wanted to make it clear that space is not being added to the universe, thespace that is already here is streching.