What is the relationship between Space & Time?
475057
Space time is the total of all demsions.  They as you may know are height, length, depth, and time.  Time is the fouth demsions because things take time to move.  However time an dspace are theorized to be somehow related.  In this case they would have similar measuremants becuase of that relation.  We can't truly define time, or space.  Space could be infinite and that the universe just sits in it.  Time could also be inifite and yet everything we know as time could just be an event in it.  Humans set a try finite number to infinity sometimes, hence it's given the name the name the "limit".  There's always more to find in this vast, endless world of ours, but all those things will definitely not be found in our liftime.  Maybe, if you believe in this, we'll see the human race find the answers while the rest of us are in heaven.
719023
well i've been wondering for a long time about the nature of time. It seems that since time is the fourth dimension and we are living in 3 dimensions we may never actually understand the nature of time. Physicists say that time and space doesnt exist as such but a combined entity called spacetime exists. Philosophers may have better answers.
290592
*Edit*\nSorry for editing again!\nTo answer your questions. Yes the past still exists! But objects in the past have a fixed (p,q,r,s,u,v,w,x,y,z,t) location (where each letter represents another dimension in space, t = time). To realise this, think about where you were last Friday at exactly 4:00pm. You're position at that time will never change again. Wherever you were, that's where you'll always have been last Friday at 4:00pm. The rest of this post explains why you cannot go back to that time without dramatic changes in your string physiology, but that time travel may be possible for some types of matter (possibly supersymmetric matter?). Unless matter has moved backward along the time dimension, it cannot move forward, because the time dimension is expanding along with the rest of the universe.\n\nI had this discussion on a drive up to play hockey in Edmonton the other day. Here's my idea but I don't know if it is true:\n\nYes, time travel is possible. Time is just like the three other open dimensions we are used to - you can travel back and forth along the 3 space dimensions and it is possible that things (notice I don't say people, keep reading to find out why) can move back along time. But as far as I know, the four dimensions of space and time do not have radii like the 5-11 compactified dimensions of M-Theory do. Therefore something travelling in time cannot loop back to the same place in time that it was before. Thus you could not go back in time and have yourself arrive at the same place in spacetime that you are today. The dimension is linear.\n\nThe MOST important part of this is the idea of symmetry breaking. In my mind, symmetry breaking accounts for why something traveling back along the time dimension will not encounter the same events that originally occurred when it started it's motion along time. Symmetry breaking is a time dependent event. The easiest way to explain it is to reference the poem "The Road Not Taken" by Robert Frost. Events in time diverge at critical points (usually at critical values for state variables like temperature). Travelling back in time would cause disorder of various aspects of energy and matter in the universe, and different bifurcation paths, or "decisions", might occur, effectively changing the future in ways imperceptible to things that are made up of baryonic matter, which leads me to my final point.\n\nThe only objects that could time travel are those made up of closed, unattached strings. The strings of ordinary matter, like that which we are made up with, are open ended and attached to dimensions. This is why the mass that makes up us and objects like the sun distort spacetime. Time actually travels slower as you approach mass, and this is what causes masses to move toward each other. Time gets warped and masses fall towards spacetime that is in a lower transient state. What makes us up is effectively 'attached' to time, so unless we could change ourselves to be made up of matter of closed loop strings, we cannot attach ourselves from time. This also means we cannot leave our universe either, but that's another story.
265661
A theoretical distortion of space-time in a region of the universe that would link one location or time with another, through a path that is shorter in distance or duration than would otherwise be expected.
575355
Time refers only here on Earth. Where there is 24 hours in a day. In space, time does not exist. If you travel millions of light years away and then come back, you'll find out that people you know are way older than the last time you saw them.
187337
how can something without a boundary, like the universe,  have a center?\nand yes, time is subjective. basically i think it's only a measurement of life.
1186741
Time is called a dimension because in Einstein's theory of relativity it makes mathematical sense to do so. Events happen in spacetime, 3 spatial and 1 time dimension. But their orientation in space and time relative to each other, depends on the observer and the relative speeds of the events.\n\nIn Einstein's formulas these dimensions are mixed by transformations depending on the velocities. This works only if we add time as a dimension.    \n\nTo give the *position* of an event in four dimensional space-time you need to give a reference observer first, another event, relative to which you measure.  And the answer will depend on your speed and the speed of the observer. And that is just what relativity means: the resulting coordinates or not the same for everybody but depend on the relative speeds.
569838
Time is a forth dimension.
128617
length, width, depth. Time and space
612415
Time is currently one of the few fundamental quantities. These are quantities which can not be defined via other quantities because there is nothing more fundamental known at present. Thus, similar to definition of other fundamental quantities (like space and mass), time is defined via measurement. Currently, the standard time interval (called conventional second, or simply second) is defined as 9 192 631 770 oscillations of a hyperfine transition in the 133caesium (Cs) atom.\n\nThis definition of time coupled to the current definition of space in physics makes our space-time to be Minkowski space-time - and thus makes special relativity absolutely correct simply by definition.\n\nPrior to Albert Einstein's relativistic physics, time and space had been treated as distinct dimensions; Einstein linked time and space into spacetime. He said that time was basically what a clock reads; the clock can be any action or change, like the movement of the sun. Einstein showed that people traveling at different speeds will measure different times for events and different distances between objects, though these differences are minute unless one is traveling at a speed close to that of light. Many subatomic particles exist for only a fixed fraction of a second in a lab relatively at rest, but some that travel close to the speed of light can be measured to travel further and survive longer than expected (a muon is one example). According to the special theory of relativity, in the high-speed particle's frame of reference, it exists for the same amount of time as usual, and the distance it travels in that time is what would be expected for that velocity. Relative to a frame of reference at rest, time seems to "slow down" for the particle. Relative to the high-speed particle, distances seems to shorten. Even in Newtonian terms time may be considered the fourth dimension of motion; but Einstein showed how both temporal and spatial dimensions can be altered (or "warped") by high-speed motion.\n\nEinstein (The Meaning Of Relativity): "Two events taking place at the points A and B of a system K are simultaneous if they appear at the same instant when observed from the middle point, M, of the interval AB. Time is then defined as the ensemble of the indications of similar clocks, at rest relatively to K, which register the same simultaneously."
267029
Yes, time is a relative and would be preceived differently if it could be perceived from all the various perspectives.  Time and space fold in upon each other and we see a result but not the only result.
585685
Time is a dimension we dont understand because is different from our 3 spacial dimensions.. \n\ntime is really the difference of states from one point of the universe to the next, since the universe is expanding time goes on that direction.. the only way to go back would be a way to figure out how to stop the expansion of teh universe.. good luck!\n\nIm hoping for telletransportation, but it's just as hard
1153545
There are a lot of theories about space and time, but I like what a Tom Stoppard character said in the play "Arcadia".  He said one can quickly stir marmalade into porridge, but can NOT stir it back out . \n\nThis is a parable or metaphor for pointing out that time is a framework of process, and most processes-- such as entropy, for example-- move in only one direction.  Although one can run a video backwards, no one in reality can unbake a cake separating it into flour, chocolate, baking powder and other ingredients, nor send the merest slice of chocolate cake "back in time" to co-exist with the flour, chocolate and baking powder of its former existence. \n\n Sending YOU back to live with your ancestors-- you, who, no doubt, have a few atoms and molecules in you from nearly every human being who ever lived-- would be like trying to get a speck of jelly stirred out of the porridge, unbaking a cake:  reversing a process that is complete already!  In time, of course, the process of baking the cake will reverse itself in a way, for the cake, one way or another, will vanish, in the entropy of cakes represented by chewing, digestion, spoiling in the refrigerator, getting stale and being thrown in the garbage for flies and maggots.  But in no sense can a time machine be built to send the least crumb of cake, the least excuse for a man, back in time.\n\n And this is because time is a correlative function of whatever processes occur within a given time frame. Time, whether it speeds up or slows down under certain conditions as claimed in the theory of relativity-- is a process that could not work in reverse! (I don't "know" this, but am convinced-- which, to an old man, is the same thing!) \n\nThink:  If we went back to the time of Alexander, and our 21st century body had one of the atoms in it that formerly had belonged to Alexander, who would get the atom?  If you had "inherited" a patch of skin or a nose from a Native American contemporary of Alexander, who'd get the nose?  Would it, out of courtesy, fly off of his face and snap onto your face, just because you had managed to travel back in time?  There is a rule that is unarguable:  only one person can use a particular atom or a particular molecule of water at a time.  \n\n The other kind of "time travel"--  freezing people and animals into "corpsicles" to be thawed out in ten thousand years-- might seem like time travel to the person surviving the "thaw cycle", but in reality it would not be,  for inducing suspended animation through freezing would not affect "time", it would merely arrest or slow the universal entropy of living things-- aging-- and delay the universal "extreme entropy" experienced ultimately by all who live:  death! \n\n I have been fascinated by suspended animation since, as a child,  I once practiced it: freezing in a block of ice a small fish I caught in a pond, leaving it in the freezer, putting the block of ice back in the pond, and watching the fish swim away.  The fish was swimming at the same rate as he was before I caught him, and, also,  the fish through the entire process "traveled in time" at the same rate as the rest of us, and didn't need a machine-- a Montgomery Ward refrigerator or an Alley Oop time machine-- to do it.  If the freezing didn't hurt its health, the freezing merely delayed its death by the couple of weeks it lay frozen in our freezing compartment.\n\nFish and men, civilizations and stars,  are born, go through certain changes and processes, then they die and can never more be revisited. Elvis sings and leaves the stage, and, no matter how many times  you back to Vegas, you won't find him.
69551
Scientifically, time actually exists as a dimension, but a non-spatial one. Our perception of time may not be necessarily cover the whole concept of what time is. It could be possible that time is some type of "substance" even. But it exists as far as the universe and physics is concerned.\nSince our human experience only covers the present time as a "linear continuum", it's hard to understand time in terms of "existence". It's better to try to define first what "existence" means.\nFor example, for the Taoist, nothing actually exists.\nIn my opinion it's better to come up with a reasonable answer to the question then just put that baby to sleep, because you can throw away your time on a philosophical wild goose chase.\nYou can read "The Elegant Universe" and it'll be so mind-boggling that it might make you not worry about it too much.
943807
The product of space and time is not so much an abstraction as much as an aberrated perception. ( Why, In GR theory, is everyone always going deductively DOWNWARDS into the collapse rather than inductively tracking the event back to original precipitating events?  The answers are THERE.)
514555
Space consists of nothing!\n\nSpace is mostly empty, with a spattering of matter in the form of galaxies, which are drifting further and further away from each other as time moves in the +ve direction.\n\nMatter and energy are mutually convertible.\n\nTime is the fourth dimension, and an important function of entropy or the running down of things.\n\nAs time moves in the +ve direction i.e. forward, entropy increases, things get run down and the energy dissipates over the expanding universe, as does matter, that means that as time goes by, the average density of the universe as we know it reduces, the matter-energy per unit area also reduces.\n\nAs time moves backward, entropy reduces, the space reduces to a point and matter and anti-matter coalesce to nothingness.\n\nst
291057
Time is a human creation used to put a measurable scale to the sequence of events that happen in the universe.