# "origins of time"

1. Apr 22, 2015

I was asked what do i think what is time.I scratched my head a little bit and thought to myself.

Time must be a physical thing just in a different form much like energy and matter.Also relativity views time as " space-time" that alone tellsme they are related.This is sort of a statement from me yet a question at the same time in the case if it's wrong.

So I conclude that matter has energy as can be seen from the smallest parts of atoms , elementary particles up to bigger things like molecules and organisms fluids and solids everything changes so we can see that time ahs passed and then we decided so that it is easier for us we somehow would calibrate these changes into what we now know as seconds , minutes, etc.

Also I thought about can one stop time, and judging by my previous wording I guess it should imply to stop all the vibrations , movement down till the smallest particles in all of universe correct? So one more question comes to mind , would a heat death of the universe cause time to stop ,or would there still be leftover even small rate of change in parts of the universe?

2. Apr 22, 2015

### rumborak

The discussion about the origin and nature of time is rather deep and involved.
My personal understanding of the matter is that while time in the physical sense is simply another dimension and part of the 4-dimensional spacetime, the directionality of time and its passage is mostly due to the increasing entropy of the universe.

3. Apr 22, 2015

### DaveC426913

Not like matter or energy, no.

Time is a dimension. A degree of freedom though which matter and energy can move (with certain notable constraints on that movement.)

Even if all the atoms in the universe reached the same temperature, that does not mean they would stop moving about. Nor would they stop vibrating.
The universe would contain the same amount of energy, it's just that it wouldn't be in any usable form. So, there no reason to think time would stop.

4. Apr 22, 2015

### phinds

No more than length is a physical thing. As has already been pointed out, time is a dimension, just like length.

5. Apr 23, 2015

I would call length a property of something much like color , form etc.

Ok phinds , if time is a dimension much like the other three ones of space, then would there be any time in a space where there is no matter ? I assume no.
But then again I'm almoust certain that there cannot be simply empty space can there ? Also I read the same elsewhere on university sites etc that space cannot exist without matter.

This question does not directly come from my original ones but then I wonder , is the expansion of space a matter driven thing ? Because if not then what else would make the space to expand, I guess since we haven't figured out the exact cause we call the cause " dark" energy.

6. Apr 23, 2015

### phinds

It's hard to think of time as a property of something the way length is, but it is, just a different kind of something.

I'm an engineer. This is too philosophical for me. Time is what a clock measures. No matter means no clocks, but beyond that I'm no willing to go. You'll find dozens of threads on this forum discussing all that.

Again, too philosophical for me, and there are lots of threads discussing it.

Right. We don't know. It doesn't seem to be a "matter driven thing", but since we don't know WHAT "dark energy" is, it's not a good idea to rule anything out.