Whats Bigger Space or Time?

[Universally_thinking]

Whats Bigger Space or Time?

[moonlord]

You can't compare them. Time is measured in seconds, space in meters. It's like asking whether a crocodile is more green than it's long.

[jinydu]

Well, not exactly moonlord. Once one goes a little deeper into relativity, one finds that it is natural to set c = 1 (yes, the dimensionless 1). When this is done, many things become much more elegant: Space and time are measured in the same units, electric and magnetic fields are measured in the same units, etc.

Even so, Universally_thinking's question isn't really that well-defined. Could you rephrase it more precisely, Universally_thinking?

[Nick]

Which has more mass and which is larger?

[pat]

Even so, Universally_thinking's question isn't really that well-defined. Could you rephrase it more precisely, Universally_thinking?

Yes, even given that time and space are directly comparable, the original question then is equivalent to: What's Bigger Length or Width?

Of course, there are more degrees of freedom in space than in time (assuming you confine yourself to one or the other). But, if I understand the Big Bang, then the Length of the Universe is twice the Time (read: Age) of the Universe. (Though, part of me thinks that relativity might make the Length and Time equal rather than letting Length be twice the Time.)

[jinydu]

Also, another problem with the comparison is that space and time can intermingle under changes of coordinate system. Look up "Lorentz transformation".

[Universally_thinking]

k, thanks my other friend said this "space is expanding and time is continuing so i guess theyre the same" is that true?

[jinydu]

k, thanks my other friend said this "space is expanding and time is continuing so i guess theyre the same" is that true?

I recommend you study general relativity (which I have not done yet) if you want an accurate answer to such questions.

[batmanmg]

i'll take a stab at it. i've got a 50 50 chance of being right. but i think im 100 percent sure that space is bigger. time only has 2 directions. forward and backward. 3d space, the space you know and love, has 6 directions. so its bigger.

[Universally_thinking]

wow thats interesting! maybe space is one layer on top of time and they constantly grow...

[batmanmg]

grow? i don't think space grows. and im not sure that time does either. i used to think that one moved through time. but now i think that one instead has internal timeline, and it extends from it at rates relative to its motion. so time might grow. but not space.

[Universally_thinking]

argh i was getting mixed up with universe and space. sorry guys

[gerren]

Isnt the Universe basically made of space that is expanding outwards until what scientist's theory of the Big Crunch comes into play?

[PWrong]

Isnt the Universe basically made of space that is expanding outwards until what scientist's theory of the Big Crunch comes into play?

Pretty much, except the big crunch is looking unlikely now.

[XVX]

The number of directions is irrelevant. A 2D square can have a larger area than a 3D box.


As far as space and time, they are exactly the same.


Otherwise, we would experience time without space, or space without time.

Without both those quantities, it would be impossible to move.

[papernuke]

As far as space and time, they are exactly the same.

no its not. can you go up down left or right in time? no. you only can go back and forewards. also, how can you measure time the same way as space? in space you use meters, feet, inches, etc. but with time you measure it with seconds, hours, days, years, etc.

[gerren]

you only can go back and forewards

Actually, no, you cant go back in time. Only God has that ability due to his abiltiy to possibly exist in many other dimensions

[PWrong]

Space and time have different units. There is a concept of "distance" in spacetime, but it doesn't follow Pythagoras' theorem.
s^2 = x^2 + y^2 + z^2 - t^2
One difference between space and time is this minus sign.

Another difference is that time is not symmetric, because entropy increases with time.

[XVX]

Space and time have different units. There is a concept of "distance" in spacetime, but it doesn't follow Pythagoras' theorem.
s^2 = x^2 + y^2 + z^2 - t^2

Notice that its t squared and not (ct) squared. By unit analysis, t must have units of length in your equation, which is correct in "God given units" which jinydu already stated.

These quantities have the same unit. The speed of light is set to one, the reason being that it appears so much throughout relativity that it seemed natural to absorb it into the units.

The minus sign is the crucial difference that makes relativity relativity and not just some adding of one more dimension. If you just added a 4th dimension in the spirit of Pythagoras, you would not have time dilation, length contraction, black holes or light cones. Relativity IS something different that is not just the addition of another dimension......all because of that minus sign.


An attempt was made with entropy to define time, but it was pointed out that while the Universe must increase in entropy, individual systems are allowed to decrease in entropy. For instance, the evolution of a human was a non-equilibrium process. A magnet is the alignment of electrons that has almost the lowest number of states, ie, the lowest entropy. When you stretch a rubber band, its entropy decreases, but yours increased.



But alas, I think this is the best answer. Based on PWrong's equation there, if the time component is greater than the space component, then s^2 is negative! These are called timelike events, which is what we exist in. If s^2 is positive, then the space component is greater and these spacelike events have motion faster than the speed of light.

Here's something for you people who think they can imagine the 4th dimension, try and imagine this. If s^2 is zero, then there is zero displacement. Massless particles that travel at the speed of light have s^2 = 0. So the light you see, that travels so incredibly fast in 3D, has no displacement in this "4th dimension." It just sits at zero displacement in 4D spacetime, independent of what its displacement or time of travel is in 3D. A motionless point, that travels only in time, is the light you see in relativity.

In conclusion, since we live in a Universe that must have s^2 negative upto and including zero and since zero is the ultimate limit, then we must have as much space as there is time to get that zero result.