Time: A Scientific Exploration

[elosin]

What is time??

 

[Dale]

It is the thing referred to by the "t" in many physics formulas.

 

[PAllen]

Read all about it:

http://fqxi.org/community/essay/winners/2008.1

 

[Naty1]

try here:
http://en.wikipedia.org/wiki/Time

"Time is how nature keeps everything from happening simultaneously."

 

[juanrga]

What is time??

An evolution parameter.

 

[Joel_GMG]

Time is a value we use to chronicle changes in matter.

 

[Phrak]

It's the same stuff as space, but different.

 

[N468989]

Time is the rate at which things change. Some perceive it as fast others slow. It is said that if we were capable of traveling at the speed of light time would stop.

 

[Phrak]

Time is the rate at which things change. Some perceive it as fast others slow. It is said that if we were capable of traveling at the speed of light time would stop.

So you think time has a relative velocity. Care to clarify this-- you know, as the ratio of one thing compared to another. What are you comparing?

 

[med17k]

time is another dimension of space in which all particles in the universe move in one direction only .but because all particles around us move in time with approximately the same velocity we find it hard to visualize time as a dimension of our universe.

 

[N468989]

So you think time has a relative velocity. Care to clarify this-- you know, as the ratio of one thing compared to another. What are you comparing?

The time as we perceive is relative to the observer. The biological time is constant, which is the rate at which we live. If we where to go outer space and travel at speed near the speed of light we would age less compared to people on earth, thus "travelling into the future". When we came back everyone would of aged much more.

Gravity also influences time, it is well known that due to the gravity force or field that satelites "time" is slower than Earth time. That is why the GPS (Global Positioning System) time has to be adjusted.

 

[elosin]

Whao, all of this are new information. thanks they help alot=D
But one more question, if time is (space ,other dimensions that things travel to one direction.), What is before time? If time is what is mention, anything that happen before that should not even happen. Hence if that did not happen how does time even start?

 

[N468989]

Whao, all of this are new information. thanks they help alot=D
But one more question, if time is (space ,other dimensions that things travel to one direction.), What is before time? If time is what is mention, anything that happen before that should not even happen. Hence if that did not happen how does time even start?

Nobody knows, if anyone states anything it is only a theory. In my opinion we will never know, but we will eventually get closer...

I believe everything has always existed, we are just newcomers to this reality.

 

[Dale]

What is before time?

The question is nonsensical. Time defines before and after, so it doesn't make sense to ask what is before time. That is like asking "what is north of lattitude".

 

[N468989]

The question is nonsensical. Time defines before and after, so it doesn't make sense to ask what is before time. That is like asking "what is north of lattitude".

I think that what he means is what happened before the big bang which is our time reference (13.7 billion years ago).

 

[Phrak]

The time as we perceive is relative to the observer. The biological time is constant, which is the rate at which we live. If we where to go outer space and travel at speed near the speed of light we would age less compared to people on earth, thus "travelling into the future". When we came back everyone would of aged much more.

Gravity also influences time, it is well known that due to the gravity force or field that satelites "time" is slower than Earth time. That is why the GPS (Global Positioning System) time has to be adjusted.

You didn't get my point. Time, as you use the word, is not a rate, nor is there something like a "biological time constant" that measures elasped time.

Anyway, sure: elapsed time differs for different observers.

 

[cbd1]

Time is separation in space-like points in spacetime. The more separation the space-like points (i.e. the less dense the spacetime), the faster the relative rate of time. (This is seen with gravitational time dilation.) If there is no separation between space-like points--like at a singularity of a black hole--time does not pass.

Thus, before the Big Bang came out of singularity, there was no separation in space-like points, so time was not passing.

Only if there was an event preceding the big bang, in which there was separation (i.e. a contracting cycle, or 'big crunch') time didn't ever pass prior to the instant the big bang came out of singularity.

 

[Dale]

I think that what he means is what happened before the big bang which is our time reference (13.7 billion years ago).

To our current understanding that is like asking "what is north of the north pole."

 

[nitsuj]

To our current understanding that is like asking "what is north of the north pole."

Easy, south pole.

Maybe the question "what was before time?" implied a frame of reference different from the one without time. i.e. looking at a black hole from Earth. (your statement regarding north of north pole implies same thing, otherwise south pole is right)

 

[Dale]

Easy, south pole.

In what way is the south pole north of the north pole? The south pole is, by definition, not north of anything.

 

[nitsuj]

In what way is the south pole north of the north pole?

When the Earth is upside down. (the perspective of the observer standing on Earth facing the south pole)

 

[elosin]

The question is nonsensical. Time defines before and after, so it doesn't make sense to ask what is before time. That is like asking "what is north of lattitude".

What I meant is, if you don't even have a time yet or time has not been created. How can you have a before and after if you do not even have a time line? Time is what we human define but is does it even really exist something call time?

 

[Dale]

How can you have a before and after if you do not even have a time line?

Exactly. That is why the question is nonsensical.

 

[Dale]

When the Earth is upside down. (the perspective of the observer standing on Earth facing the south pole)

Nonsense. The location of the poles has nothing to do with the perspective of any observer. Similarly, at any location on the globe, which direction is north and which is south is unrelated to the perspective of any observer.

 

[nitsuj]

Nonsense. The location of the poles has nothing to do with the perspective of any observer. Similarly, at any location on the globe, which direction is north and which is south is unrelated to the perspective of any observer.

Cardinal directions have to be coordinated with something, that's always implied and is intuitive. Because you didn't explicitly mention what the cardinal directions were coordinated with I specifically assumed it was with the observer. So a north direction from the north pole is heading towards the south pole.

Saying you can't travel in a north direction when at the north pole is nonsensical.

Saying you can't travel a "north pole" direction when at the north pole is true but a singularity that seems much different than one for time.

 

[ghwellsjr]

You can't travel east or west when at the north pole either. All you can do is stay put or start traveling south.

 

[Joncon]

Cardinal directions have to be coordinated with something

Aren't they coordinated with the Earth's magnetic field?

Saying you can't travel in a north direction when at the north pole is nonsensical.

No it isn't. At the North Pole you can only travel in one direction - South

 

[nitsuj]

No it isn't. At the North Pole you can only travel in one direction - South

I'd guess 360 different directions, one of them being north.

 

[DrGreg]

At the North Pole you can only travel in one direction - South

I'd guess 360 different directions, one of them being north.

There's an infinite number of directions, but every one of them is southwards.

Southwards=towards the South Pole, by definition
Northwards=towards the North Pole, by definition

 

[yoron]

Time is what defines you, from your birth to your death. It is also what 'moves' you, and your measurements into a orderly fashion temporarily. It has only one beat locally, as proven if you measure your heartbeats against your wristwatch. If your 'given' life span is ten million heartbeats then it will be so no matter where you are or how fast you go.

It's not a illusion, and it has a arrow.
To prove it a illusion you better become immortal :)

 

[nitsuj]

There's an infinite number of directions, but every one of them is southwards.

Southwards=towards the South Pole, by definition
Northwards=towards the North Pole, by definition

Yup and nobody said southwards.

 

[Dale]

Cardinal directions have to be coordinated with something, that's always implied and is intuitive. Because you didn't explicitly mention what the cardinal directions were coordinated with I specifically assumed it was with the observer. So a north direction from the north pole is heading towards the south pole.

No, the poles are coordinated with the axis of rotation of the Earth with the north pole being the one where the star Polaris is overhead. North and south have nothing whatsoever to do with an observer.

Saying you can't travel in a north direction when at the north pole is nonsensical.

Huh? I can't believe you actually wrote this. You can only travel south from the north pole.

 

[Dale]

Yup and nobody said southwards.

That is a distinction without a difference. If you are traveling south you are going towards the south, hence southwards.

North and south have nothing to do with observers, the south pole is not north of the north pole, and an observer at the north pole cannot travel north, he can stay put or travel south.

 

[bobc2]

What is time??

I think the biggest problem with grappling with a concept of time is the tendency to try to think of time as some mixture of space and time. I think the biggest source of confusion has arisen from the use of the term, space-time--as though space and time are somehow mixed. The 4th dimension is not time, nor is it some kind of mixture of space and time.

So, one could first imagine the universe as a 4-dimensional space populated by 4-dimensional objects. The whole 4-dimensional universe is just there--all at once. Don't even bring time into the picture initially. This assures that you begin with a distinct separation of space and time into two separate concepts. This concept goes by the name of "Block Universe" and was suggested by Einstein's colleague, Kurt Godel (many physicists feel like Einstein embraced this concept--he just never liked to discuss it openly because of some of the bizarre implications).

Now, after envisioning a static 4-dimensional universe, then put in consciousness moving along the 4th dimension at the speed of light. So, in some sense--at least for us 4-D universe inhabitants/observers--the time comes in with consciousness.

Special relativity directly implies such a 4-dimensional block universe. Thus, the 4th dimension should not be thought of as a time dimension. It is a physical spatial dimension in the same sense as the other three spatial dimensions.

 

[N468989]

I think the biggest problem with grappling with a concept of time is the tendency to try to think of time as some mixture of space and time. I think the biggest source of confusion has arisen from the use of the term, space-time--as though space and time are somehow mixed. The 4th dimension is not time, nor is it some kind of mixture of space and time.

So, one could first imagine the universe as a 4-dimensional space populated by 4-dimensional objects. The whole 4-dimensional universe is just there--all at once. Don't even bring time into the picture initially. This assures that you begin with a distinct separation of space and time into two separate concepts. This concept goes by the name of "Block Universe" and was suggested by Einstein's colleague, Kurt Godel (many physicists feel like Einstein embraced this concept--he just never liked to discuss it openly because of some of the bizarre implications).

Now, after envisioning a static 4-dimensional universe, then put in consciousness moving along the 4th dimension at the speed of light. So, in some sense--at least for us 4-D universe inhabitants/observers--the time comes in with consciousness.

Special relativity directly implies such a 4-dimensional block universe. Thus, the 4th dimension should not be thought of as a time dimension. It is a physical spatial dimension in the same sense as the other three spatial dimensions.

To exist space there must exist time. Time is a consequence of space and vice-versa and they must coexist. For something to change in space there must be a time sequence associated, so we can assume that time is another dimension, sure.

Theoretical physicists suggest that there are parallel universes, I believe that there are other dimensions that we couldn't even begin to imagine. If we lived in a 2D world time would exist also but could we grasp the concept of 3D?