Hypothetically if the earth were infinite in size then how far away would the edge of the known world be?
108420
Well I would think if it were infinite in size then you would never be able to find an edge since, it would also be infinitly high :)  I think. . .
321995
If you consider the edge of the universe to be the furthest anything visible has traveled since the beginning then it would be where light has gone the furthest, and since light traveles at 299,792,458 metres per second, then the universe would be expanding in any one direction at 299,792,458 metres per second.
594695
The universe cannot have an end, it has to be infinite and completely symetrical. This leads to three possible scenarios for its shape a saddle shape, a spheroid, and a flat plane. Different experiments have led scientists to believe that space is an infintie flat plane. The main reason why we know that if there were edges to space then we would have to me moving towards some objects and away from others. This is not the case as all observed entities are moving away from us. This leads to the assumption of a infinite expanding universe. \n\nAs far as our perception is concerned we are not inside of anything since the universe occupies all of the space that we can observe so the universe is everything. But if somehow you could step out of our universe into a higher dimension you dont know what you would see. There are some theorists who believe our universe is one of many universe. But since there is no way to see out of the universe we may never be able to answer this question. I agree that if you start thinking in this manner it can get quite perplexing\n\nTo the person who said space must have an edge to expand think of a baloon. If we go down a dimension imagine that our galaxy is a penny glued on the surface of a baloon. To us the baloon has no edges at all since we cannot see out into the third dimension, yet the baloon is expanding. So from our vantage point we live on an infinite surface that is expanding and causing nearby pennies to all travel away from us.
789663
well, it does not have to be INFINTE, it can just be UNLIMITED.\n\nwhat's the difference?\n\nwell, on the surface of say, Mars, you or I, in a rover, could walk forever and never hit a limit.  But Mars is clearly not infinite.
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.
14387
"There is disagreement over whether the Universe is finite or infinite in spatial extent and volume.\n\n"However, the observable Universe, consisting of all locations that could have affected us since the Big Bang given the finite speed of light, is certainly finite. The edge of the cosmic light horizon is 13.7 billion light years (4.19 gpc) distant. The present distance (comoving distance) to the edge of the observable Universe is larger, since the Universe has been expanding; it is estimated to be about 78 billion light years (7.8 × 1010 light years, or 7.4 × 1023 km). This would make the comoving volume, of the known Universe, equal to 1.9 × 1033 cubic light years (assuming this region is perfectly spherical). The observable Universe contains about 7 × 1022 stars, organized in about 100 billion galaxies, which themselves form clusters and superclusters. The number of galaxies may be even larger, based on the Hubble Deep Field observed with the Hubble Space Telescope. The Hubble Space Telescope discovered galaxies such as Abell 1835 IR1916, which are over 13 billion light years from Earth.\n\n"Both popular and professional research articles in cosmology often use the term "Universe" when they really mean "observable Universe". This is because unobservable physical phenomena are scientifically irrelevant; that is, they cannot affect any events that we can perceive. See also Causality (physics).\n\nWe live in the centre of the Universe that we observe, in apparent contradiction to the Copernican principle which says that the Universe is more or less uniform and it has no distinguished centre. This is simply because light does not travel infinitely fast, and we make observations of the past. As we look further and further away, we see things from epochs (times) closer and closer to the limit of time, which equals zero, according to the Big bang model. Since light travels at the same speed in any direction towards us, it is reasonable to suggest that we live at the center of our observable Universe."
235823
I would say that there is no edge. The matter in our solar system is constantly being pulled and shifted by gravity fluxes, and if you were to drift further out you would run into another solar system similar in design to ours, just varying in scale. Because as humans we can only fully understand information that has a start and finish does not mean that there are borders to all things.
1092455
Yes.  Infinity goes in both directions.  Space is space, large or small.  IMHO  ;-)
659476
"...What are the dimensions (length, width, and height or thickness) of the physical universe (in light years)?..."\nThe universe can't be measured in terms of length, width, and height. Such parameters require some reference point from which measurements can be made, along with some distant boundary where the measurement would end. You simply can't do that with the universe because the universe is isotropic, meaning it's the same in all directions from any observing point. From Earth we can look outward in any direction and 'see' about 13.7-billion light years. From Earth that represents a boundary. Here comes the tricky part: if some alien in a galaxy 13.7-billion light years away from Earth looked outward in all directions (including back towards Earth) they'd 'see' a universe that appeared to be 13.7-billion light years in scope. In other words, the universe has no boundary. To have one it would have to be inside some "thing" else, and there's absolutely no evidence that such is the case.\n\nTo confuse the issue even more, if we had the ultimate telescope with limitless viewing power we still will never be able to see into the universe beyond a certain range. That's because at almost the same instant of the Big Bang the universe briefly expanded faster than light (this doesn't violate relativity because it was the space of the universe that did the expanding). In our 'normal' universe the speed of light is the speed limit which prevents us from ever seeing any of that inflation because it's moving away faster than the speed of light.\n-----------------------------------------------------------\n"...I've read that the universe is thought to be "saddle shaped..."\nMore recent observations point more towards the universe being geometrically "flat." This simply means that the universe appears to be infinite, that its space will expand forever while cooling more and more over the eons.\n------------------------------------------------------------\n"...What does it mean for example, to say that the universe is expanding at a rate of 70 kilometers per second per (x number of light years)?..."\nYou've described the so-called Hubble Constant. (70 km/sec/Mpc) It means if galaxy 'A' is 1 Mpc (1-million ly) away from us it's recessional velocity will be 70 km/sec. If galaxy 'B' is 2 Mpc away then it's velocity will be 140 km/sec It's important to keep in mind though that it's space that's expanding like that, not the galaxies moving THROUGH space; they just get carried along.\n------------------------------------------------------------\n"...I was not able to find a rate of acceleration of expansion..."\nI've been looking for a figure too. So far the only thing I've come up with is -3.15^36 /sec/sec  Darned if I know what the units of measurement are though. Maybe someone else on Yahoo can help us out with that.
1056226
The Universe cannot be infinite, because it is expanding, which points to its origin where everything began at the same point, namely the singularity of the Big Bang.  Therefore, if it is expanding, it is bounded.\n\nHowever, it is thought that it probably doesn't have an edge, much like the Earth doesn't have an edge.  If you started in a spaceship and went in a straight line, you would eventually end up where you started, much like if you started at the North Pole and went in a straight line, you would end up back the North Pole.\n\nThe reason: although you would be going in a straight line on the 2-D surface of the Earth, that line is curved in the 3rd dimension.  So, if spacetime is curved in the 4th dimension, you could be going in a straight line 3 dimensionally, but it would be curved 4th dimensionally.
1056452
It is partly a matter of scale, and partly because of local relief in the landscape. \n If you were to stand on a perfectly flat plain or on the surface of an ocean, the farthest point you could see would be approximately 30 miles distant.  \n Also, because of changes in elevation over smaller distances, and/or obstructions to our field of vision, we tend to see even smaller 'chunks' of curvature, which our brains interpret to be flat.
596706
scientist believe the universe is infinite which means no boundries, no edges- going on forever
281372
No.\n\n\nUPDATE:\n\nSome of your here don't understand the concept of infinity. You don't ever reach, approach or ever come near infinity. A googleplex raised to the power of a googleplex is as far away from infinity as is the number 1. There is also an infinity between any two numbers. For instance, there's an infinity between the numbers 1 and 2, and so on and so on.
921651
I don't think so. Does earth have an end? Nope, not in 2D. So universe may not have an end in 3D, but can be multidimensional
38951
The universe has no center, but it is not infinite.  It is finite but unbounded, like the surface of a golf ball.  The surface does not have a center nor a boundary, but it is not infinite.
1060678
Imagine a situation where you would come back to your starting place no matter which direction you go as long as you kept going far enough. This is true, for example, on the surface of a sphere. But it turns out that there are analogs of this for going any direction in three dimensions. In this case, the universe would be finite (like the surface of a sphere), but would have no boundary (again like the surface itself). This is actually a simplified version of the models used by physicists for describing a finite universe. In reality, the evidence suggests that the universe is infinite.
134220
We believe the universe to be infinite in size.  In some ways, we know how small the universe is not.\n\nThe universe is atleast 13 billion light years in radius from the earth. The furthest galaxy seen to date dates from 13 billion years ago.  This means that the light from that galaxy took 13 billion years to reach us and so, at the speed of ... uh ... light, it was 13 billion light years away from earth.  This is 76,424,219,300,000,000,000,000 miles away or 76 sextillion miles away.\n\nThe problem is seeing past that distance because Hubble discovered that light keeps shifting toward the red part of the spectrum and beyond as the universe continues to expand.  There could be stuff past where we can see but we don't know because we can't see it.\n\nAnother reason I say minimum is because after the light left that galaxy 13 billion years ago, we believe that the galaxy continued to move away from us during that 13 billion year period due to the expansion of the universe.  So, it is over 13 billion light years away from us today and the light from that galaxy "today" would take over 13 billion years to reach us.\n\nBut in reediting this just now, I realized that there might actually be a stretching effect for the distance due to the time that has passed.  In otherwords, the distance that the light travelled in the first year (13 billion years ago) has since expanded (causing the redshift) and so will be more miles in distance than the light year travelled in the most recent year till now.  Which may be why articles on the oldest galaxies seen never mention distance but only mention time or age.  They never say the observed galaxy is 13B light years away, they say that it is 13B years old and leave it at that. Let's just ignore this plausible issue for the moment.  \n\nWith out extrapolating, you might calculate the volume of a sphere that is 13 billion light years in radius and use that as a lower bound for the size of the universe:\n\n4/3 radius^3 => 5.9*10^68 cubic miles.  Don't know about you but I can't even comprehend how big that is.\n\nAs for who or what created it, well, that depends on what you believe and what evidence you allow to modify that belief.\n\nI liked the article in March 2005 Scientific American on the "Misconceptions of the Big Bang".