Time Relativity
20 Dec 2006 6:40:01 UTC
Topic 192213
(moderation:
Ok, I am possibly not correct on this matter. But, with the previously substantial dilemna on relative time, or constant time. I feel the Einstein@Home project, could possibly assist in narrowing the facts. For instance, in Einsteins Theory Of Relativity. Einstein dictates, that time is only relative to a particular position in space opposed to others. But in the theory of constant time, time is identically passing in all reference points in space.
Spinning neutron stars (Pulsars), are a relatively large and accurate means of time calculation. With the increased knowledge of locations of pulsars. We will have a much broad range view of how time passes throughout the universe. With a more broad range of data and locational information. We can possibly calculate the natural spinning speed of neutron stars. And if we can calculate the speed at which they travel through the universe relative to Earth. We may be able to more accuratly prove or disprove the theory of relative time.
Crude example: If under the same circumstances, and environment, five pulsars spin at a rate of 4 revolutions per minute, and one, traveling faster through the universe, is spinning at a different rate from our perspective, but has the same characteristics, and environment as the other five (Other than traveling faster). We may be able to determine, time is relatively different for that pulsar than the others. Food for thought I suppose...
d3xt3r.net
Time Relativity
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Instead of 5 pulsars, what about 5 muons? Muons are unstable and will decay soon after they're formed (about 2 microseconds, or 2 millionths of a second). Many more than 5 have been created and measured in the lab. They're created with a certain amount of energy, and have a velocity proportional to that energy. Hence they travel a certain distance before decaying, not much more than several hundred meters.
But muons are also created in the upper atmosphere, when high energy cosmic rays collide with particles up there, several kilometers above sea level. None of them should ever reach the ground, should they? But many of them do. How can this be? If you say they're moving at 99% the speed of light, but you don't use the equations of Special Relativity, then you get an answer of (300 million meters/second) times (0.000002 seconds) = 600 meters. How in the world can a muon possibly travel a distance of several kilometers, and be detected at ground (sea) level?
To understand how it happens requires understanding of Special Relativity. When considering different inertial frames, as in the case with the muon and the Earth, the proper way to compare the different frames employs a (mathematically derived) factor known as 'gamma', a constant of proportionality, the 'time dilation factor', and it's equal to one over the square-root of one minus the velocity squared over the speed of light squared. Here's one of many pages offering an explanation: Time Dilation
So an observer on Earth sees a muon (created with the high energy cosmic ray) living longer than the muon created with less energy in the lab. The only difference between them is their velocity. The muons created by the cosmic rays have a velocity of about 99% of the speed of light, and using Special Relativity, that yields a value for gamma of about 7, which results in an observed time dilation of the muon's lifetime, meaning that instead of seeing it travel only 600 meters, it will appear to last 7 times longer, traveling 7 times farther, or about 4200 meters, plenty of time/distance to make it from the upper atmosphere all the way to the ground.
An even better understanding of Special Relativity, and gamma, shows that from the inertial frame of the muon, it appears that the length of the Earth's atmosphere has contracted by a factor of about 7. According the muon's time, it still lives only 0.000002 seconds, but the 4200 meters of atmosphere (as seen from the inertial frame of the Earth) appears to the muon as a contracted distance of only about 600 meters...
That is a very god argument
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That is a very god argument for special relativity... I personally believe in relative time. But, I have had many discussions with others about the contraversy of constant or relative time....
d3xt3r.net
There was a terrific
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There was a terrific validation of time variations in steep gravity gradients recently. See this thread, in particular this post, showing a curve correlating General Relativity predictions vs measured signal delays. Agreement was to within one twentieth of one percent. No other theory ( yet ) offers that level of concordance with reality for that scenario.
The gut-level 'trouble' with Relativity is that it tends to contradict everyday intuition - which is born of our low speed, low energy existence. It does match predictions at low speeds/energies with say Newtonian physics - which assumes a constant rate clock tick regardless of circumstances - however it diverges from that in more extreme situations. But it does work and gives the right numbers to predict experiments.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal