Universe Expansion?

Question

If the universe is constantly expanding....what is it expaning into?

Answer 1

There is no edge.

The distance between points is getting longer.

If you go far enough in one direction, you come back from the other side.. but expanding means that it takes longer and longer at constant speed to get back where you started.. the path length is expanding.

Why does it have to expand into something? That idea requires finite net volume, and two internal compartments. The universe expanding only means that the definition of distance between internal points is changing, not that there is any such thing as the "outside" or "surface" and that the "surface" is "expanding" too.

Answer 2

This question is based on the ever popular misconception that the Universe is some curved object embedded in a higher dimensional space, and that the Universe is expanding into this space. This misconception is probably fostered by the balloon analogy which shows a 2-D spherical model of the Universe expanding in a 3-D space. While it is possible to think of the Universe this way, it is not necessary, and there is nothing whatsoever that we have measured or can measure that will show us anything about the larger space. Everything that we measure is within the Universe, and we see no edge or boundary or center of expansion. Thus the Universe is not expanding into anything that we can see, and this is not a profitable thing to think about. Just as Dali's Corpus Hypercubicus is just a 2-D picture of a 3-D object that represents the surface of a 4-D cube, remember that the balloon analogy is just a 2-D picture of a 3-D situation that is supposed to help you think about a curved 3-D space, but it does not mean that there is really a 4-D space that the Universe is expanding into.

Answer 3

For thousands of years, astronomers wrestled with basic questions about the size and age of the universe. Does the universe go on forever, or does it have an edge somewhere? Has it always existed, or did it come to being some time in the past? In 1929, Edwin Hubble, an astronomer at Caltech, made a critical discovery that soon led to scientific answers for these questions: he discovered that the universe is expanding.

The ancient Greeks recognized that it was difficult to imagine what an infinite universe might look like. But they also wondered that if the universe were finite, and you stuck out your hand at the edge, where would your hand go? The Greeks' two problems with the universe represented a paradox - the universe had to be either finite or infinite, and both alternatives presented problems.

After the rise of modern astronomy, another paradox began to puzzle astronomers. In the early 1800s, German astronomer Heinrich Olbers argued that the universe must be finite. If the Universe were infinite and contained stars throughout, Olbers said, then if you looked in any particular direction, your line-of-sight would eventually fall on the surface of a star. Although the apparent size of a star in the sky becomes smaller as the distance to the star increases, the brightness of this smaller surface remains a constant. Therefore, if the Universe were infinite, the whole surface of the night sky should be as bright as a star. Obviously, there are dark areas in the sky, so the universe must be finite.

But, when Isaac Newton discovered the law of gravity, he realized that gravity is always attractive. Every object in the universe attracts every other object. If the universe truly were finite, the attractive forces of all the objects in the universe should have caused the entire universe to collapse on itself. This clearly had not happened, and so astronomers were presented with a paradox.

When Einstein developed his theory of gravity in the General Theory of Relativity, he thought he ran into the same problem that Newton did: his equations said that the universe should be either expanding or collapsing, yet he assumed that the universe was static. His original solution contained a constant term, called the cosmological constant, which cancelled the effects of gravity on very large scales, and led to a static universe. After Hubble discovered that the universe was expanding, Einstein called the cosmological constant his "greatest blunder."

At around the same time, larger telescopes were being built that were able to accurately measure the spectra, or the intensity of light as a function of wavelength, of faint objects. Using these new data, astronomers tried to understand the plethora of faint, nebulous objects they were observing. Between 1912 and 1922, astronomer Vesto Slipher at the Lowell Observatory in Arizona discovered that the spectra of light from many of these objects was systematically shifted to longer wavelengths, or redshifted. A short time later, other astronomers showed that these nebulous objects were distant galaxies.

The Discovery of the Expanding Universe
Meanwhile, other physicists and mathematicians working on Einstein's theory of gravity discovered the equations had some solutions that described an expanding universe. In these solutions, the light coming from distant objects would be redshifted as it traveled through the expanding universe. The redshift would increase with increasing distance to the object.

Answer 4

I want to expand a bit on the previous posters answer. The universe is a 4D object with both space and time part of the object. When we say that the universe is expanding, we mean that spatial distances between 'stationary' observers are increasing over time. In other words, when we slice this 4D object, the picture looks larger at later times than at earlier times. The 'object' isn't expanding or contracting, it just is.

An analogy: suppose that latitude represents time on a globe and 'space' is represented by latitude lines. Then, at the south pole, the universe is a point. As you move up, the 'universe' expands until you get to the equator. Then it shrinks again until at the north pole, it is a point again. Now ask yourself 'what is the universe expanding into?'. The only sensible answer is 'into the future'. This is the answer to your question.

Answer 5

How heavy an oject is also have some pull. That pull is gravity. Now some have done some mathematicals and found that all the planets, stars,glalxiesand black holes only come to about a third of the total matter for any gravity to stop this expansion. And since it takes gravity to keep the universe together. thereisn't enough matter to make enough gravity, unless there is dark matter.Which is theoretical, to keep the universe not only to gether but from keeping it from flying apart. But, thereis another Theory., that is dark enery, it is supposed to be making up to 93 or to 95% of the universe and it it responsible for the universe expansion , in it's speeding the expansion up. I hope that's sounds right

Answer 6

How it was determined the universe is constantly expanding I would like to know, but if that is the case then there must be more beyond this universe for it to expand into. Or maybe it just stretches that confining barrier to the point that it ruptures and this universe ceases to exist. All of which takes place on a scale of time that we cannot even begin to comprehend. Some say the universe is infinite, meaning it existed for an infinite amount of time thus it has always existed and will always exist and always expand into that infinite space which would take us infinite time to find.

edit: The next user refers to "stationary observers". What in the universe is stationary? And how do you know it is stationary with no boundaries to measure against?

Answer 7

*shakes head*
You guys ALL have the wrong notion of what the universe REALLY is.

The universe is actually a giant snowglobe full of flecks of snow that humans refer to as stars and planets. Humans are merely the bacteria that live on one of the billions of these snowflakes.

Outside of this snowglobe is "God", the Jolly Green Radioactive Giant who owns this snowglobe (It sits on top of his Jolly Green Desk). When it is bored, it would give the snowglobe a shake, causing the spacetime (liquid that the stars are suspended in) to flow in a whorling current. Since humans are so miniscule and occupy much less than 0.00000000000000000000000000000000000000000000001% of this giant snowglobe, what they observe to be an increase in the distance between two points in their tiny pathetic portion of the snowglobe due to the current that "God" created, they automatically assume, "ah hah, the universe must be constantly increasing in size!"

WRONG! While the universe is "expanding" where the humans live, in another portion of the snowglobe certain snowflakes are moving against the current, and thus to the bacterial inhabitants of those snowflakes, the universe is actually shrinking. A good example would be the blackholes, areas where current and countercurrent clash and spin into a sucking hole.

I hope this shed some light to you ignorant and foolish humans. How do I know all this, you ask? I am Strawberry Shortcake, sister to the Jolly Green Giant and also the proud owner of my own Red Glittery Strawberry Scented Snowglobe.

Answer 8

if the universe is expanding , then it refers to the movement of the galactic mater from one another like the spreading of the dough on a hot plate for making some pan cake or the pouring of the egg on a hot pane for making omelet. so it is referred to a thing that is made of matter . matter alone can expand.what is not a mater can never expand or shrink and it can not even be touched or seen by any scope like electron microscope )anything can expand only in there is some space and what ever matter expands should expand into space - emptiness -void .nothing can expand into anything that is filled in. The void is nothingness . so the universe is expanding into nothing - a space that is vacuum .Though vacuum is nothing - emptiness is nothing - it exists to allow everything to move in it .but for it nothing can move or exist .

Answer 9

If you understand how it can be curved in a higher dimension then you will be able to visualise it doesnt have to be expanding 'in to' anything. I'd go further in to it but I seem to see this question on here about twice a day.

Check out 'brief history of time' 'the fabric of the cosmos' 'universe in a nutshell' 'emperor's new mind' etc.

Answer 10

Think of it as points in the universe growing farther apart. If you try to figure out what it's expanding into, you're wasting your time because there is no answer.