ghwellsjr said:
abrogard said:
Nope. It is not clear to me. And I did not 'read and understand' post #4. I read it.
It is hard to understand Special Relativity with just words. Diagrams help a lot. I will quote some of my comments from post #4 and illustrate them with spacetime diagrams to see if that will help you to understand.
ghwellsjr said:
In their own rest frames, atoms vibrate at their 'normal' frequencies. In other frames where they are moving, their vibrations are slowed but this doesn't make them different material atoms or atoms in a different state.
Let's assume that we have a particular species of atom that emits pulses of light at a rate of a billion times a second which is one pulse every nanosecond.
ghwellsjr said:
For example, if two atoms moving away from each other at some speed give off a frequency of light that can be observed by the other atom, they will each see the same Doppler shifted frequency of light, or a slowing of the frequency. But this is not Time Dilation. If they are moving towards each other at the same speed, they will each see a speeding up of the frequency but in both cases, the same Time Dilation is in effect.
Here is a spacetime diagram showing two of these atoms, one red and one blue, starting off separated from each other but approaching and passing at 0.8c:
Please note that this is the rest frame of the blue atom and the red atom is the one that is moving at 0.8c and so it is the one that is Time Dilated by the factor of 1.667. The dots mark off one-nanosecond increments of time for each atom.
At the bottom of the diagram, the red atom is moving toward the blue atom and during this time, the blue atom sees the frequency of the light pulses coming from the red atom Doppler shifted by a factor of 3 as you can see by the 3 thin red lines compressed into the one-nanosecond interval of time just before the red atom reaches the blue atom. Once the red atom passes the blue atom, the Doppler shift changes to a factor of 1/3 so it takes three nanoseconds of blue's time to see each one-nanosecond pulse coming from the red atom.
The first lesson to be learned here is that the blue atom cannot see the Time Dilation factor (1.667) of the red atom, it can only see the Doppler shift factors of 3 and 1/3.
Now let's look at another diagram showing what the red atom sees of the blue atom's pulses:
Note that this is the same IRF as the first diagram, the rest frame of the blue atom. However, the Doppler shift factors that the blue atom saw of the red atom's pulses are identical to the Doppler shift factors that the red atom sees of the blue atom's pulses.
ghwellsjr said:
Time Dilation is not observable, it is the result of assigning an IRF to both atoms which will determine the speeds of both atoms and that establishes the Time Dilation of each atom, the faster it is moving the more its Time Dilation. You can make one atom at rest in one IRF which makes the second atom have all the speed so only the second atom is Time Dilated. Or you can have a different IRF in which the second atom is at rest and the first atom has all the speed making it the only one with Time Dilation. Or you can have an IRF in which both atoms are moving in opposite directions at some intermediate speed which will make them both have the same intermediate Time Dilation. But in all cases, they both see the same Doppler shift in the observed frequency of light.
As stated, we can have an IRF in which both atoms are moving in opposite directions at the same speed, in this case 0.5c:
The Time Dilation factor for both atoms is 1.1547 and I show the pulses going from each atom to the other atom. Again, they each observe the Doppler shift factor of 3 while they are approaching and 1/3 while they are departing.
Finally, we look at the same situation but in the rest frame of the red atom:
Once again, the Doppler shift factors are the same as in the other IRF's. And as I stated, the red atom vibrates "normally" in its own rest frame.
Does this help you to understand post #4? Any questions?