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Initial post: Apr 23, 2012 8:32:29 AM PDT
George says:
I am first time poster, didn't know where else to go found this site in a google search. Hope somebody can answer my question.

Was watching a documentary the other night on Einstein and time. I found it kind of intersting and surprising, but not sure I understood it. They had a quote from him saying "life in an illusion....a stubborn one...but an illusion."

What they were talking about is time not being constant like it was long thought but relative to the viewer. Time passes different for everybody. Events that have happened are not really in the past just in past relative to me. Same as events in the future they have already happened. For example my death has already happened, even though it is probably 30 years in the future to me. Doesn't make much sense could somebody put it in layman's terms?

They were saying if we are in motion time will pass slower than if we standed still. They said an experiment was done in early '70s where 2 atomic clocks set at same time, one was stationary while the other was put on jet plane and flown around the world. When it got back there was 2 or 3 seconds different in the time. Which should be impossible as atomic clocks are precise. This got me to thinking...is it possible our motion in the universe is responsible for our time? If motion can decrease the passage of time, makes sense with universe expanding, galaxy moving, sun moving in galaxy and earth orbiting the sun we are under a great amount of motion? The little amount of motion in a jet plane can only change time by 2 or 3 seconds.

They also said things came from great order at the point of the big bang and keeps going to disorder. Things had to be just precise for universe to end up as it is now. Is it possible the future was determined by amount of energy and heat at point of big bang?

In reply to an earlier post on Apr 23, 2012 10:39:47 AM PDT
Last edited by the author on Apr 23, 2012 10:41:00 AM PDT
Don't know what to tell you about events in the future supposedly already having happened. That would seem to suggest that the universe is completely deterministic, i.e., that knowing the present state of affairs and the physical laws governing them, we can predict with perfect accuracy what will happen in the future. That was the claim of Newtonian physics, but I believe quantum physics has discarded this notion.

Regarding the relativity of time, Einstein's original paper on the subject of special relativity in 1905 showed that if we have 2 individuals (called "observers"), each moving at constant velocity (i.e., in a straight line at constant speed) with respect to each other, then each one will observe the other observer's clock to be running more slowly than his own. This is called relativistic time dilation. Another way of saying it is "moving clocks run slow".

This has nothing to do with how precise the clocks are. It is a direct result of the two fundamental premises which underlie the special theory of relativity: 1) the physical laws governing the universe are the same for all observers regardless of their relative motion (another way of saying this is that there are no "privileged" frames of reference); and 2) the speed of light in empty space is the same for all observers regardless of the velocity of the source emitting the light (i.e., light doesn't travel any faster if it's emitted from a source on a supersonic jet than if it's emitted from an object at rest).

I don't think it's true to say that our motion in the universe is responsible for our time. What is true is that if a body is in motion, this motion requires 4 dimensions, 3 of space (length, width, and heighth) and one of time, to be described.

What is also true is that the relative motion of two observers can affect the times of each relative to the other. A famous example is the so-called "twin paradox", where one twin stays home on earth and the other takes a fast rocket (here fast means at least 10% of the speed of light) around the universe. When this twin returns to earth, he's only a few years older but his stay-at-home twin lived to a ripe old age and then died hundreds or even thousands of years ago.

In reply to an earlier post on Apr 23, 2012 1:44:28 PM PDT
Jeff Marzano says:
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In reply to an earlier post on Apr 23, 2012 2:03:58 PM PDT
George you ask some very good questions.

This got me to thinking...is it possible our motion in the universe is responsible for our time? If motion can decrease the passage of time, makes sense with universe expanding, galaxy moving, sun moving in galaxy and earth orbiting the sun we are under a great amount of motion?

Time is a really interesting concept. there are many things that affect time predominantly gravity and velocity. In many ways they are kind of the same thing. as you move faster your mass technically increases. as mass increases time dilation increases. if you were able to sit just outside the event horizon of a black hole you would be experiencing time at about half the rate an observer outside of the hole would feel it.

For example my death has already happened, even though it is probably 30 years in the future to me. Doesn't make much sense could somebody put it in layman's terms?

this is only sort of true. is we were able to observe every particle in the universe, know both its direction and location simultaneously then technically we can predict the future, and technically you are guaranteed to die at a certain time and place. however as long as we arent observing the universe a multitude of wave functions exist all indicating a multidue of velocities and positions. as such your fate isn't technically sealed its more likely part of a probability distribution.

In reply to an earlier post on Apr 23, 2012 2:23:39 PM PDT
Jeff Marzano says:
Steven Burnett says:

[This got me to thinking...is it possible our motion in the universe is responsible for our time ?]

Time is based on the vibration of the atomic structure I think.

In a black hole the gravitational forces are so intense that the atoms cannot vibrate. As a result time does not exist inside a black hole.

So if you fall into a black hole I guess time would start to either speed up or slow down. You see stars form, shine, and burn out in just a few minutes for example.

I guess your watch would stop also.

Jeff Marzano

Posted on Apr 23, 2012 6:24:11 PM PDT
George says:
Yup, show said gravity had an affect on time. Forgot to mention that. It has only a small affect thought it said.

Events in the future already have happened makes sense thru. If a viewer from a distance galaxy can see our future it must already have happened. They couldn't see it if not. Events in the past seem long ago to me or you but to viewer on a plane of reference they are happening now. Freaky stuff when you stop to think of it

Show also said nothing in law of physics stopping time travel. But were puzzled why never no visitors from the future? They said even if person from the future goes back in time cannot change events. What has happened happened cannot be changed. Maybe that's why no visitors from the future? No sense them going back in time.

In reply to an earlier post on Apr 23, 2012 6:55:01 PM PDT
Doctor Who says:
"Yup, show said gravity had an affect on time. Forgot to mention that. It has only a small affect thought it said."
That depends on the mass. At the event horizon of a black hole, time stands still.

"If a viewer from a distance galaxy can see our future it must already have happened. They couldn't see it if not. Events in the past seem long ago to me or you but to viewer on a plane of reference they are happening now."

Its one way to make sense of the math. I think it might be valid. It is rather hard to say without knowing what time is.

"Show also said nothing in law of physics stopping time travel. But were puzzled why never no visitors from the future? They said even if person from the future goes back in time cannot change events. What has happened happened cannot be changed."

So far there is nothing in the laws of physics that would prevent time travel. But yes, if Marty goes back in time and stops his parents from getting together, then how would he be born and who stopped his parents from getting together? There are several resolutions to this paradox, none of which is simple. The many worlds interpretation of quantum mechanics suggests that you went back in time to a parallel world and did not affect your original world at all. A second idea states that everything that happened is unchangeable, ie, you could go back in time, but your actions would be required to construct the future (your past) as you know it. For example, if you go back in time and terminate the person who you think was responsible for creating powerful robots before they actually do it, it must have really been someone else.

These ideas are actually explained fairly well by Brian Green in the Nova program The Fabric of the Cosmos. If you are interested, you can watch it online free at the following website (and completely legally!):

http://www.pbs.org/wgbh/nova/physics/fabric-of-cosmos.html#fabric-of-cosmos

In reply to an earlier post on Apr 23, 2012 8:03:53 PM PDT
Jeff Marzano says:
George says:

Maybe that's why no visitors from the future ?]

Well that's another conspiracy theory. Sometimes when people see flying saucers those are our ancestors from Atlantis traveling through time.

Jeff Marzano

In reply to an earlier post on Apr 23, 2012 8:30:51 PM PDT
tom kriske says:
george, you said - If a viewer from a distance galaxy can see our future it must already have happened. They couldn't see it if not.

this is complete fiction george, nobody in a distant galaxy is viewing our future. never have, never will. they can, however, see our past.

In reply to an earlier post on Apr 23, 2012 8:51:14 PM PDT
Re original post: You have brought up two basic issues: our perception of time, and time as measured by instrumentation. We have no means of comparing any two person's individual conception of time, but we assume that it does not differ substantially among people. And that is all that anyone can really say about the subject.

But time as measured by instrumentation is another matter. Clocks on any two systems which are moving with respect to each other will each be perceived by an observer on the other system to be running slow; this is a consequence of special relativity. GPS satellites must deal with this, and also with the reduced gravitational potential where they orbit, which causes an additional effect (in the other direction) due to general relativity. The effects are very small (on the order of nanoseconds), but when you are trying to measure position with GPS, every nanosecond is a foot of error.

The concept of time cannot exist without a universe in which it can act, so it is generally considered that time began with the beginning of space in the big bang. There are two books that address this issue in far more detail than I can post here, and I recommend both:

Stenger, The Fallacy of Fine-Tuning: Why the Universe Is Not Designed for Us.
Krauss, A Universe from Nothing: Why There Is Something Rather than Nothing

In reply to an earlier post on Apr 24, 2012 11:41:44 AM PDT
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In reply to an earlier post on Apr 24, 2012 11:42:57 AM PDT
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In reply to an earlier post on Apr 24, 2012 2:51:39 PM PDT
noman says:
Automatic time perception in the human brain for intervals ranging from milliseconds to seconds.
Authors:
Näätänen, Risto
Syssoeva, Olga
Takegata, Rika
Source:
Psychophysiology; Jul2004, Vol. 41 Issue 4, p660-663

Abstract:
Time perception in everyday life deals with various intervals. Here we investigated whether an automatic duration-discrimination mechanism in audition operates even for intervals of an order of seconds, by using the mismatch negativity (MMN), an index of automatic change detection in audition. In Experiment 1, occasional decrements of the duration of a repetitive "standard" tone elicited an MMN in subjects ignoring auditory stimulation, even with the standard-stimulus durations over a second. Nevertheless, the MMN amplitude was significantly diminished with standard-stimulus durations of 800 ms and above, despite the fact that a constant deviant versus standard duration ratio was used. Complementary experiments varying the interstimulus interval (Experiment 2) and the magnitude of duration change (Experiment 3) yielded corroborating results. The present results suggest that automatic duration discrimination in audition operates even for durations of the order of seconds; yet its optimum time scale might be of the order of milliseconds.

Posted on Apr 24, 2012 2:51:43 PM PDT
roundaboutte says:
As it has been stated by several posters.(two observers moving at a constant speed on a line parallel with one another will will view the others clock to be be running slower than their own).This is true ,Depending on how far away they are from each other.1-mile=1/186,000th of one second.93,000 miles .05 seconds and if they were 186,000 away from the others clock it would look to be one second slower than their own clock. Roundaboutte.

In reply to an earlier post on Apr 24, 2012 2:56:39 PM PDT
No, it has nothing to do with how far apart they are. If they were 5 billion light years apart but at rest with respect to each other (and assuming neither are in a strong gravitational field) they will each observe the other's clock to be running at the same rate as their own.

What causes relativistic time dilation is not distance but relative velocity.

It's true that if one clock was a light-second away from another, each clock would receive the time the other is keeping one second later (assuming the information was moving at the speed of light), but this would not affect the rate, assuming the clocks were at rest with respect to each other. In other words, each clock would be ticking at the same rate.

In reply to an earlier post on Apr 24, 2012 3:10:43 PM PDT
roundaboutte says:
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In reply to an earlier post on Apr 24, 2012 3:16:38 PM PDT
No, you're confusing the time with the rate time is passing. If two clocks at rest with respect to each other were 5 billion light-years apart, each would read the other as showing a time 5 billion years earlier, but advancing at the same rate as their own.

What relativity says is that if these clocks were moving at a constant velocity (straight line, constant speed) with respect to each other, each would see the other ticking at a slower rate, by a factor (1-v^2/c^2)^(1/2), where v is the relative velocity, and c is the speed of light. This factor is miniscule for ordinary velocities we experience in everyday life, which is why we don't notice relativity.

In reply to an earlier post on Apr 24, 2012 3:27:31 PM PDT
Last edited by the author on Apr 24, 2012 3:29:53 PM PDT
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In reply to an earlier post on Apr 24, 2012 3:41:19 PM PDT
The twin paradox falls outside of special relativity. In fact each twin can tell their case apart from the other because the one travelling and coming back ages much more slowly than the twin which stays put.

The explanation of the paradox is that the travelling twin undergoes acceleration, which is outside the realm of special relativity. (Special relativity deals only with non-accelerating frames of reference). When the travelling twin's rocket turns around, his frame of reference shifts in such a way as to break the symmetry. If the travelling twin is travelling at a substantial fraction of the speed of light for a few years, when he returns his twin will have lived to a ripe old age (or possibly been run over by a car) and died hundreds or even thousands of years ago.

There is no one clock underlying the universe. Time is relative.

In reply to an earlier post on Apr 24, 2012 3:41:42 PM PDT
Exactly.

In reply to an earlier post on Apr 24, 2012 3:52:27 PM PDT
Last edited by the author on Apr 24, 2012 3:53:26 PM PDT
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In reply to an earlier post on Apr 24, 2012 3:54:21 PM PDT
No, it doesn't. The clock of every observer is equally valid. So saith Einstein, first for all inertial observers (special relativity) then for all observers regardless of their motion (general relativity).

In reply to an earlier post on Apr 24, 2012 4:03:34 PM PDT
tom kriske says:
whomper, is there some hidden motive behind your endless, babbling stream of mind-numbing misinformation?
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Discussion in:  Science forum
Participants:  20
Total posts:  143
Initial post:  Apr 23, 2012
Latest post:  Dec 18, 2012

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