Universal time constant

[Moontanman]

I'm sure this will be cleared up fast but I have to ask, Is it possible there is a universal time that is same everywhere and what we see and measure as time is just a local distortion caused by mass and or speed?

[freeztar]

Originally Posted by Moontanman

I'm sure this will be cleared up fast but I have to ask, Is it possible there is a universal time that is same everywhere and what we see and measure as time is just a local distortion caused by mass and or speed?

Mass 'bends' spacetime. Time is relative between two inertial frames. This is Einstein's GR.

[Overdog]

Here's a way to think about it:

Consider twin physicists Al and Bert who devise a new method (far better than measuring cosmic microwave background) to determine the age of the universe. They do so to an extraordinarily high degree of precision – stating it in seconds to many, many decimal places. Having done so, they synchronize two clocks to the determined age of the universe and allow them to continue ticking off time from that point on.

After winning the Nobel prize for this work, Al uses his prize money to build a near light speed space ship and he heads off, with his clock, to travel the cosmos at high speed, accelerating and changing directions along the way, coming in close proximity to black holes and other high gravity bodies, and eventually returning to earth. Of course, the time elapsed for Al will be less than the time elapsed for the earthbound Bert, so when they compare clocks they show different times.

So, how old is the universe?

Age of the universe -- absolute or relative? Text - Physics Forums Library

[Moontanman]

I understand that time is relative, that is where my question comes from. Since all times are relevant to each observer then that would mean that time is nothing but a concept that is meaningless when applied to the entire universe. but if time has a constant that is the same everywhere but the places where it is distorted by speed or mass. some places are more distorted than others but what if there was a greater "time" separate from everything? Would relativity still work as different observers living in different distorted areas see each relative to the amount of distortion they are experiencing? I guess you would have to be able to step out side the universe to see this overall time constant. Or maybe a higher level time like a fifth dimension. (assuming that time as we see it is a the fourth.)

[freeztar]

Originally Posted by Moontanman

I understand that time is relative, that is where my question comes from. Since all times are relevant to each observer then that would mean that time is nothing but a concept that is meaningless when applied to the entire universe. but if time has a constant that is the same everywhere but the places where it is distorted by speed or mass. some places are more distorted than others but what if there was a greater "time" separate from everything? Would relativity still work as different observers living in different distorted areas see each relative to the amount of distortion they are experiencing? I guess you would have to be able to step out side the universe to see this overall time constant. Or maybe a higher level time like a fifth dimension. (assuming that time as we see it is a the fourth.)

Ah, ok, I see what you are saying.

The problem here is that it is not just about a place (ie space). You could theoretically have two observers, at rest, separated by a great deal of space without any gravitational influence. I suppose this would be what you are calling the universal time constant. But as soon as one observer starts moving, it's relative again. Since things in the universe don't tend to sit still, I think the concept of the universal time constant is not very meaningful, except as a thought experiment.

[modest]

Originally Posted by freeztar

Since things in the universe don't tend to sit still, I think the concept of the universal time constant is not very meaningful, except as a thought experiment.

It can be useful though, especially in cosmological models. If the universe is treated as homogeneous which is a good approximation then the model can be solved with constant proper time. While this is a useful convention I'd agree that it doesn't reflect the reality of a particular observer where proper time is dilated by either motion or topology. Hubble time is then only constant for comoving observers ignoring variations in local gravity. It's a useful approximation and most normal in cosmology, but I think you're quite right; it's only an approximation.

-modest

[REASON]

I wonder if your wondering the same thing I have considered before. It can be difficult to express. The notion and experience of time is very particular to the observer.

When you look out at the stars in the night sky, you are at one instant observing a myriad of differing time frames since each star is at a different proximity and the light eminating from each has taken a different amount of time to reach your eyes. What is seen in any instance is not a true representation of reality at that moment.

Even looking at an image of a galaxy is a distortion, particularly if it is askew, because the light eminating from the far edge of the galaxy has taken significantly longer to reach the eye than the light from the near edge. It is virtually impossible to see an accurate representation of a spiral galaxy at any moment in time from our point of view.




I read your question as: Is there a universal time that exists for all matter and energy at any given moment that is independent of any observer?

I think the answer is yes, but, it cannot be observed.

Say for instance you are looking at a super red giant star that appears to be on the verge of going supernova. It is 1,000 years from exploding from your point of view, but 2,000 light years away in distance. As you look at the star, it has already exploded in reality. If you could traverse the stream of light from your eye all the way to the star, you would approach real time the closer you came to the star, and half way there, you would witness the explosion occurring.

It is our perception of time that distorts reality, and our perception is limited by the speed of light. But all of the objects in the universe exist in some condition simultaneously at any given moment in time, even as we are unable to perceive of it. That condition is what is relative to universal time as I see it.

Am I anywhere close to what you were getting at?

[Moontanman]

Originally Posted by REASON

I wonder if your wondering the same thing I have considered before. It can be difficult to express. The notion and experience of time is very particular to the observer.

When you look out at the stars in the night sky, you are at one instant observing a myriad of differing time frames since each star is at a different proximity and the light eminating from each has taken a different amount of time to reach your eyes. What is seen in any instance is not a true representation of reality at that moment.

Even looking at an image of a galaxy is a distortion, particularly if it is askew, because the light eminating from the far edge of the galaxy has taken significantly longer to reach the eye than the light from the near edge. It is virtually impossible to see an accurate representation of a spiral galaxy at any moment in time from our point of view.




I read your question as: Is there a universal time that exists for all matter and energy at any given moment that is independent of any observer?

I think the answer is yes, but, it cannot be observed.

Say for instance you are looking at a super red giant star that appears to be on the verge of going supernova. It is 1,000 years from exploding from your point of view, but 2,000 light years away in distance. As you look at the star, it has already exploded in reality. If you could traverse the stream of light from your eye all the way to the star, you would approach real time the closer you came to the star, and half way there, you would witness the explosion occurring.

It is our perception of time that distorts reality, and our perception is limited by the speed of light. But all of the objects in the universe exist in some condition simultaneously at any given moment in time, even as we are unable to perceive of it. That condition is what is relative to universal time as I see it.

Am I anywhere close to what you were getting at?

Yes, that is what i had in mind.

[modest]

Originally Posted by REASON

I read your question as: Is there a universal time that exists for all matter and energy at any given moment that is independent of any observer?

I think the answer is yes, but, it cannot be observed.

I'm not sure I can agree with you there REASON. If it can't be observed, why would we say it exists?

Originally Posted by REASON

It is our perception of time that distorts reality, and our perception is limited by the speed of light. But all of the objects in the universe exist in some condition simultaneously at any given moment in time, even as we are unable to perceive of it. That condition is what is relative to universal time as I see it.

According to relativity the laws of physics are the same in all inertial frames of reference. If the speed of light is constant in all those frames then time is not. It is therefore a pretty basic tenet of relativity to say there is no privileged or constant or universal time.

Perhaps (as Moontanman said) if we could see time from outside the universe or from some other dimension where we could see time itself as more than one dimension... then perhaps. But, as I understand things this doesn't fit with current physics.

[REASON]

Originally Posted by modest

I'm not sure I can agree with you there REASON. If it can't be observed, why would we say it exists?

I knew this would be difficult to explain, particularly for me since I am not a physicist and have studied very little physics. I am likely to defer to experts on this subject, and will easily conceed if I am challenged to provide calculations to back up my statements. I don't have a problem with conceeding my point in this instance.

My view of this is strictly philosophical. I don't personally know of any way to mathematically support this.

As we observe the universe in all it's splendor and glory, we can understand that there is matter and energy all around us. We can see it for one, and we have learned to use tools to see the universe in ways that we are unable to with our naked eyes, such as x-ray and infrared observations.

Let's just consider the Sun. It takes approximately eight minutes for the light from the sun to reach the Earth. So when we observe the sun, we are observing it from our perspective as it actually appeared eight minutes ago. We are literally looking back in time as we are experiencing it in our current time. This is simply due to the delay caused by the light covering the distance. I know you understand this.

But we can also understand that the sun actually exists in a particular state concurrently with our time frame, we just have to wait eight minutes to observe it. This is what I mean when I say that we and the sun exist at the same time, but we can't observe both at the same time because of the distance between us.

What I suggested, which may be improper, is that just like the Earth and the Sun can exist at the same time even though we are not able to observe both of them simultaneously in the same time frame, so it is with all matter and energy in the universe. Everything exists in a particular condition at any given moment. If you could imagine that everything froze at some moment except you, and you had the ability to traverse the universe, you could observe everything as it existed at that moment in time. But because of the limitations of light and distance, one can never observe all matter and energy as it actually exists at any given moment in time from a particular location.

What I suggested relative to Moontanman's question, is that universal time might be the time relative to all matter and energy as it exists, independent of the limitations created by an observer at any particular location. But this time would be impossible to observe because it is impossible to be all places at once.

I still don't know if I have explained these ideas very well and I'm sure there are things I'm missing. But it's interesting to ponder.

Originally Posted by modest

According to relativity the laws of physics are the same in all inertial frames of reference. If the speed of light is constant in all those frames then time is not. It is therefore a pretty basic tenet of relativity to say there is no privileged or constant or universal time.

This may be true, but it may also simply be indicative of our inability to quantify time universally.