Time in a vacuum sphere?
969401
Time is a thing invented by man.  Planets and such like don't care about time, they just keep on going forever which is a really long time.
830585
Y'know, I've been trying to get a handle on that for a long time, but so far I understand it to mean that post-Einstein, once you  include time as a fourth axis to the 3 spatial ones, the universe makes sense in terms of our physical laws working everywhere and everytime.  That is a neccessity of a good physical law - it must always work no matter where in the universe you test it or how fast you're travelling.  In other words, translations and rotations of objects or fields or whatever must have no effect on the validity of the law.  If you do not include time as an axis perpendicular to the 3 spatial ones (mathematically, of couse), what we predict won't agree with what we see, especially in such cases as high relative velocities (as in approacing the speed of light), and strong gravitational fields.  Amoung the oddest result of this view is that, in truth, all time actually exists simultaneously, and there is some not-quite-understood mechanism that only lets us see one instant at a time.\n\nAnyway, to answer your question, "How does spacetime work?", the answer is, much better than space or time alone and separate.  They are, in fact, as inseparable as the pair of poles of a magnet.\n\nThis all might be not quite accurate, especially since I'm so far just an "armchair physicist" with no formal education in the area, (tho I'm looking forward to taking physics, including the higher levels, if I can ever get thru these friggin' calculus classes).  Anybody else have something to contribute or set me straight on??
270366
In a sense, time may be relative to size.  If you look at a time dilation equation, t' = t*(1/(1-(v^2)/(c^2))^(1/2)) you can see that time is related to velocity.  The larger (i.e. more massive) an object it, the more space it displaces and the greater the gavitational (velocity) effect.\n\n---EDIT---\n\nThe more massive an object the greater it's gravitational force.  From experimental fact, the speed of gravity is much faster than light. (Yes, I know, this contradicts Special Relativity, but that's another discussion.)\n\nAdditionally, the mass-square of the electron neutrino, measured from tritium beta decay experiments, has been found to be negative. (Yes, this too contradicts Special Relativity.)\n\nSo, from one extreme to the other, time is only relevent for a object that is moving, not for a stationary object.\n\nThat being said, there is nothing that tells us how time flows for a "moving" observer, only for a "fixed" observer.  Therefore, time must actually a constant.
1102952
Gravitational time dilation caused by a spherically symmetric, nonrotating massive body can be computed exactly by using the Schwarzschild solution to the Einstein field equations. This is also a good approximation to a slowly rotating, roughly spherical body like the Earth. The time dilation given is:\n\nt0=t1√(1-2GM/(rc²)) where:\n\nt0 is the time between two events for an observer within the gravitational field\nt1 is the time between those same events for an observer well outside the gravitational field\nG is Newton's  gravitational constant\nM is the mass of the object creating the gravitational field\nr is the distance of the observer in the gravitational field from the center of said field\nc is the speed of light
85344
Based on the relativity theory, there are many studies that are taking place to look into the possibility of traversing the time-space continuum.  As far as I know, we're not quite there yet.  But if and when we are, we should be able to tap into the theoritical "worm-holes" to go into different points in space without having to exume too much time.
333310
As was said above, the space-time interval between two events (3 space coordinates, 1 time coordinate) is the analogue to the distance between two points in R^3 when one adds a time axis. In flat spacetime, the interval is the dI that satisfies (dI)^2 = (dx)^2 + (dy)^2 + (dz)^2 - (cdt)^2. Invariants of this form are called metrics. You can derive this metric from the postulates of special relativity, specifically that the speed of light in vacuum is an invariant.\nCurved manifolds will have different metrics; just like the distance between two points on a sphere (as measured on the sphere) does not follow the Pythagorean theorem. The Schwarzschild metric is a metric for the spacetime around a massive body. See http://en.wikipedia.org/wiki/Schwarzschild_metric .
1005667
http://en.wikipedia.org/wiki/black_hole\nTry the link.\nBlack holes do excel time but as black holes are 7 dimensional objects they aren't given a large description alot as we don't know alot about them.\nTime is true as all 4 dimensions 0d, 1d, 2d. 3d and 4d are expelled as time is a dimension. Time will go too.\nThe 7th dimension has or doesn't have it's own time as it belongs to subspace.\nMacro and Micro dimensional time is stopped at a black hole as a black hole destroys spacetime dimensions on entrance. s dimensions are removed the object would no longer be.\nBlack holes have a plug hole gravitation effect for 4d dimensional objects.\n\nThe person who enters the black hole would be stuck in time before he/her actually dies.\nThe person who is watching sees his eternity there in less than 0.001 seconds.
1163741
time is a relative thing....it's a measure that isn't even the same  in normal situations.as an example:u are sitting on a bench, you hae your clock with u,someone else ifs flying in a supersonic, he has his clock with him,in a hundred years or so his clock will show less than yours.time travel...well that's another complex thing...you see if somone were to travel at light speed it would gain a lot of time comparing to someone travelling at sublight speeds.there is a theory that if someone were to orbit the earth let's say , in it's oposite spining direction at a faster than light speed it would reach it's start position...BEFORE the actual start time, thus travelling in the past , but faster then light speeds can't be reached .other temporal anomalies apear in wormholes.
855043
It's all theory, we don't know if (something) can exceed the speed of light. I would argue that time would be void at that moment, but again it's my theory. Interesting thought though.
24853
There are many ways to approach this problem. First, a quick and easy way:\n\nLet's agree that Alice is in frame A and Bob is in frame B.\n\nIf they both go on a trip and come back at the same time, as measured by Chuck who stayed home, then based on special relativity we can all agree that whomever was traveling closer to the speed of light on their trip will have a clock that's behind everyone else's (ignore accelerations for simplicity). So, if Alice traveled faster then her clock would be behind even Bob's clock. Based on this you must logically conclude that Alice would have observed Bob's clock ticking FASTER, not slower THAN HER OWN if she somehow viewed him in transit. Of course, Chuck would have seen both their clocks running slowly, but Alice's more slowly than Bob's.\n\nSome things are relative but you have some invariants, namely spacetime and the speed of light. Even if observers don't agree when things happened, the events are still fixed, in one position in spacetime. Einstein said that individually space and time are relative but you still have an absolute from which to measure, and that's spacetime. All entities are moving through spacetime at the speed of light (c). That's right, even you, but most of that velocity is directed through time. If an object were to have a zero velocity in space then its speed through time (the 4th dimension) is c. As you increase your speed through space some of your speed through time is diverted (but the vector total is always c) and thus time appears to slow down for you as observed by someone at rest in space.\nThe point being that there IS an absolute from which to measure so if Bob were traveling slower than Alice then Alice would see Bob's clock ticking faster than hers but slower than the stationary clock.\n\nI didn't quote any sources but most of my current conception of relativity came from an excellent book: "The Fabric of the Cosmos" by Brian Greene.
719425
ya, that one has the same dimension as that of time.see how that eqn is derived.you find distance covered by 'n' seconds then distance covered by (n-1) seconds.subtract.and you get the eqn.... but see wat is the difference b/w the time n and n-1. it is one second..this is the one that appeared in the eqn and confused you.is it clear?
339050
The speed of light in a vacuum is exactly 299,792,458 metres per second (or 1,079,252,848.8  km·h-1, which is approximately 186,282.397 miles per second, or 670,616,629.4 miles per hour). This value is denoted by the letter c, reputedly from the Latin celeritas, "speed". Note that this speed is a definition, not a measurement, since the fundamental SI unit of distance, the metre, has been defined since 1983 in terms of the speed of light—one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. The speed of light through a transparent medium (that is, not in vacuum) is less than c; the ratio of c to this speed is called the refractive index of the medium.
285964
Experiments.\n\nThis has been tested using both subatomic partices and putting super-precise atomic clocks in airplanes and flying them around, as well as with space probes.\n\nWith subatomic particles we know that they have a specific halflife, so the amount of time *we* see particle decay when they are at rest and when they are moving very rapidly can be used to test time dilation.&#92;\n\nAn early test was with muons, which, at rest have a half life of about 2 millisecond. Muons are also created in the upper atmosphere from collisions between atoms with cosmic rays. These muons go flying off at nearly the speed of light. Since we know how fast the muons are going (about the speed of light) and approximately where they are produced, it is possible to determine what the half-life is.\n\nThe result: the nearly speed-of-light muons appear, in our rest frame, to have a longer half-life. Putting it into the Lorentz equation gives just the answer one would expect if there were time dilation.\n\nIn addition to this classic experiment - done in 1941 - the same sort of thing can be done by observing elementary particles in synchrotrons ("atom smashers") and other settings.\n\nAlso, planes have been sent up to fly around to directly measure relativistic effects. These clocks run slightly differently than clocks on the ground due to several relativistic effects including time dilation.\n\nSo, time dilation is definitely NOT fiction. It has been repeatedly tested and verified experimentally.
805625
Time is completely relative.  It bends with the curvature of space.  Space is the absence of matter and is what separates matter from matter and matter from anti-matter.  Anti-matter is the opposite of matter and is responsible for anomalies like black holes and is believed to be the center of galaxies.  Anti-matter and matter form energy when they combine.  So far as we can tell, it looks like a giant flash of light when this occurs.\n\nTo answer your question:\nWhen time is removed from the equation, everything comes to a standstill.  It would be the same if you took away energy.  There would be nothing but stuff standing motionless.  When space is removed from the equation, all matter and anti matter are combined and as a result, pure energy is given off as a byproduct.  If matter is removed from the picture, the only thing that would be left is anti matter, space and energy.  Everything would be dark because there wouldn't be anything to give off light, but there would still be gravitational forces at work.
14306
when u r measuring time from a given inertial time frame every time-frames are relative to it.Standing at that reference frame u can only calculate the precision of individual events but not the absoluteness of the time-frame itself.\n    U don't need to think about the absoluteness ofcourse to describe any property of universe. U do it relative to u.
43761
The speed of light in a vacuum is exactly 299,792,458 metres per second (or 1,079,252,848.8 km/h, which is approximately 186,282.397 miles per second, or 670,616,629.4 miles per hour; sometimes roughly 300,000 km per second). This value is denoted by the letter c, reputedly from the Latin celeritas, "speed", and also known as Einstein's constant. Note that this speed is a definition, not a measurement, in that the fundamental SI unit of distance, the metre, is defined in terms of the speed of light: one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. The speed of light through a transparent medium (that is, not in vacuum) is less than c; the ratio of c to this speed is called the refractive index of the medium.
707260
The virtual particle that mediates electromagnetism is the photon, which is mass-less. therefore, it will not curve the spacetime it lives in.