why is the universe so vast?
450787
When talking about the universe, asking "why" something is the way it is usually has no absolute, 100% answer.\nThe best answer to your question is that the universe somehow began over 13.7-billion years ago and immediately began expanding. The expansion has gone on, steadily increasing the size of the cosmos until we observe its vastness today.\n\nGod should be spelled B-I-G B-A-N-G\nPBrax@netscape.com
127551
Because the universe is a vacuum and there's nothing to stop it from expanding. This is assuming that the big bang theory is correct and it's expanding because of the explosion .
400480
Olliehunt has the right idea, but the expansion of the Universe during the first second (although probably less than that), was so incredibly fast, millions and millions of times faster than the speed of light, that the final figure he came up with is much smaller than what could be the actual size of the Universe.\n\nThe simple answer is, we don't know.  It's vast!
984793
Space is not empty nor is it mostly empty.  Just because you don't see what is between one galaxy and another does not make space empty.  Most of the matter that makes up the universe is not visible.  Therefore the apperant emptiness of space.
1159722
Well - the universe is infinite in so far as it can have an infinite distance.  However, if you take the classical approach, you can assume that the universe is at LEAST twice as wide as the distance light has travelled in the billions of years since the Big Bang, or moment of creation.  The reason is that the Universe contains all things, and it's width can be measured as the point between the two things at greatest distance from eachother.  The greatest distance between any two points is the distance between the first two photons that headed off in opposite directions at the time of the Big Bang.  Those photons still exist, and are still making their lonely trek through the unimaginable black nothingness at close to two hundred thousand miles per second.  So yes, I do believe the universe is that big.  At some point, you can view the positions of those photons more as a variable in some giant computer.  Their distance from everything else is actually pretty much irrelevant, since there is nothing out there for them to interact with.
1076114
Odds are that the universe IS teeming with life.  We haven't been to the universe -- it's very big and most of it is too far away.
145870
This is a common source of confusion. There is a lot about this on the internet and I would direct you to those resources. However it is like we are ants on the surface of an expanding balloon. To ants, living in a 2 dimensional world, they cannot percieve the third dimension that the balloon is expanding into. \n\nThe attached link gives a very detailed, clear and complete discussion about misconceptions about the universe and its expansion. There are many other less difficult explanations available on the internet, however.
1106252
speaking in all logic terms all religon aside.  The universe always was it and it always will be here in one way or another.  But before the "big bang" the universe was smaller, much smaller infact than it was before this catastrophic event.  After the big bang everything that was once very very dense and all close together, is now moving apart from eachother at a considerable rate, leaving more and more area of what we call "space".
962950
This sort of question generates the highest percentage of false and meaningless responses of any other I know of in A&S forum. Here's the real poop. According to the BB model of the universe, the universe is expanding, but there is no boundary beyond which there is only empty space into which stars and galaxies are expanding into. This is a common misinterpretation due to a widespread inability to grasp the concept of curved space. On a large scale, every can consistently be presumed to be pretty much the same as it is in our neighborhood, although any conclusions about what lies beyond the observable universe are impossible. However, the volume of the universe may be either finite or infinite. This is simply not known. In General Relativity, finite *and* unbounded is not a contradiction.
21164
4 In recent centuries astronomers who scanned the heavens with early telescopes noticed some fuzzy, cloudlike formations. They assumed that these were nearby clouds of gases. But in the 1920’s, as larger, more powerful telescopes came into use, these “gases” were found to be something far more immense and significant: galaxies.\n\n5 A galaxy is a vast group of stars, gas and other material rotating around a central nucleus. Galaxies have been called island universes, for each one of them is in itself like a universe. For example, consider the galaxy we live in, which is called the Milky Way. Our solar system, that is the sun and the earth and other planets with their moons, is part of this galaxy. But it is only a very tiny part, for our Milky Way galaxy contains over 100 billion stars! Some scientists estimate at least 200 to 400 billion. And one science editor even stated: “There could be as many as five to ten trillion stars in the Milky Way galaxy.”2\n\n6 The diameter of our galaxy spans so vast a distance that if you could travel as fast as the speed of light (186,282 miles a second) it would take you 100,000 years to cross it! How many miles is that? Well, since light travels about six trillion (6,000,000,000,000) miles in a year, multiply that by 100,000 and you have the answer: our Milky Way galaxy is about 600 quadrillion (600,000,000,000,000,000) miles in diameter! The average distance between stars within the galaxy is said to be about six light-years, or about 36 trillion miles.\n\n7 It is almost impossible for the human mind to comprehend such size and distance. And yet, our galaxy is just the beginning of what is in outer space! There is something even more staggering. It is this: So many galaxies have now been detected that it has been said they “are as common as blades of grass in a meadow.”3 About ten billion galaxies are in the observable universe! But there are many more beyond the range of today’s telescopes. Some astronomers estimate that there are 100 billion galaxies in the universe! And each galaxy may contain hundreds of billions of stars! I don't think there's an end in sight.
104718
well... the universe is not infinite or so say today's scientists. according to the parallel universe theory,there are various universes and our's is one of 'em . well one cannot really define the *length* of a universe because it is almost impossible to percieve something that big for the human mind.
10073
The size of the universe in terms of length, width, height, time is in a state of flux. At any instant it may be expanding or contracting. The universe is generally accepted to be currently expanding. \n\nM Theory (the conglomeration of the 5 superstring theories) tells us that the universe is the result of, so called, “membranes” colliding in such a way that create a pocket of space which we call the universe. If M Theory is accurate, it is probable that there are many universes just as there are many planets, solar systems, and galaxies. \n\nFor more information:\nhttp://en.wikipedia.org/wiki/M_theory
1033786
this is actually a common misconception about the big bang.  the universe may be something like the two dimensional surface of a sphere.  it is finite yet has no boundary and no center.  nothing exists "outside" the universe.  to quote a dead writer, "there is no there, there".\n\nread this:\nhttp://www.sciam.com/print_version.cfm?articleID=0009F0CA-C523-1213-852383414B7F0147
398088
I asked that question to Dr. Brian Greene, author of "The Elegant Universe".  His answer was "the Universe is continually expanding", and therefore, you can't put a size on it.  The Universe, in a sense, CREATES the space it's expanding into.  It is all-encompassing.
828819
Thats a question that physics is still trying to answer.  \nThere are 3 types of theories on how big the universe is and the shape of it.  It is either flat, meaning it will always be this large and continue forever.  There is the closed ellipse type, meaning the universe started from something, but unfortunatly will end after its reaches its max capacity and starts to shrink again.  There is still the hyperbola theory meaning that the universe started at a finite point and is always expanding.
36543
As I understand it, the universe is in fact finite.  However, it's expansion is continuous and progresses at such a rate that we can not, with current technology, move beyond to see the end.
328729
Well, if you want to break it down even more, the universe only consists of minscule, vibrating strings.  At least, that's the most widely accepted theory in fundamental physics right now.\n\nThe beauty of it all is how much complexity can arise from such simple fundamentals.