Physicist: One of the most profound insights ever made by peoplekind is that time is relative. This isn’t some abstract idea, mistake, or mathematical artifact. If you have two identically functioning clocks, you can start them together, move them to different locations or along different paths, then when you physically bring them back together to compare, they will literally have registered different amounts of time.
You may be inclined to say, “sure, it’s weird… but which clock is right?”. The existentially terrifying answer is: there is no such thing as a “correct clock”. Every clock measures its own time and there is no such thing as a universal time. And yet, cosmologists are always talking about the age of the universe (a mere 13.80±0.02 billion years young). When talking about the age of the universe we’re talking about the age of everything in it. But how can we possibly talk about the age of the universe if everything in it has its own personal time?
The short answer is: almost everything is about the same age. The biggest time discrepancy is between things deep inside of galaxies and things well outside of galaxies, amounting to a couple parts per million (or one or two seconds per week). Matter that has been in the middle of large galaxies since early in the universe’s history should be no more than on the order of 50,000 years younger than matter that has managed to remain in intergalactic space. Considering that our best estimates for the age of the universe are only accurate to within 20 million years or so (0.1% relative error), a few dozen millennia here and there doesn’t make any difference.
There are two ways to get clocks to disagree: the twin paradox and gravitational time dilation. The twin paradox a bizarre consequence of the difference between ordinary geometry and spacetime geometry. In ordinary geometry, the shortest distance between two points is a straight line. In spacetime geometry, the longest time between two points is a straight line. A “straight line” in spacetime includes sitting still, so if you start with two clocks in the same place and take one on a trip that eventually brings it back to its stationary partner, then the traveling clock will have fallen behind its sedentary twin.
The Twin Paradox: The straighter the path taken between two locations, the more time is experienced. Gravitational Time Dilation: Things farther from mass experience more time.
Assuming that the traveling clock travels at a more-or-less constant speed, you can figure out how much less time it experiences pretty easily. If the traveling clock experiences 
Gravitational time dilation is caused by the warping of spacetime caused by the presence of energy and matter (mostly matter) which is a shockingly difficult thing to figure out. When Einstein initially wrote down the equations that describe the relationship between mass/energy and spacetime he didn’t really expect them to be solved (other than the trivial empty-space solution); it took Schwarzschild to figure out the shape of spacetime around spherical objects (which is useful, considering how much round stuff there is to be found in space). He did such a good job that the event horizon of a black hole, the boundary beyond which nothing escapes, is known in fancy science circles as the “schwarzschild radius”.
Fortunately, for reasonable situations (not-black-hole situations), you can calculate the time dilation between different altitudes by figuring out how fast a thing would be falling if it made the trip from the top height to the bottom height. Once you’ve got that speed, v, you plug it into 
By and large, the effect from the twin paradox is smaller than the effect from gravity, because if something is traveling faster than the local escape velocity, then it escapes. So the velocity you plug into gamma for the twin paradox (the physical velocity) is lower than the velocity you’d plug in for gravitational dilation (the escape velocity). If you have some stars swirling about in a galaxy, then you can be pretty sure that they’re moving well below the escape velocity.
The escape velocity from the surface of the Earth is 11km/s, which yields a gamma of 
Point is, it doesn’t make too much difference where you are in the universe: time is time.
Now admittedly, there are examples of things either trapped in black holes or screaming across the universe at near the speed of light, but the good news for us (on both counts) is that such stuff is rare. The only things that move anywhere close to the speed of light is light itself (no surprise) and occasionally individual particles of matter. Light literally experiences zero time, so the “oldest” photons are still newborns; they have a very different notion of how old the universe is. No one is entirely sure how much of the matter in the universe is presently tied up in black holes, but it’s generally assumed to be a small fraction of the total.
Long story short: when someone says that the universe is 13.8 billion years old, they’re talking about the age of the matter in the universe, almost all of which is effectively the same age.
The situation is that though time is relative everything near us in the universe has experienced similar movement to give a consistent perspective on the universe’s origin, about 14 billion years.
What I find fascinating is that time has speed limits. Time can go up to, but never reach the speed of light.
It’s weird. Light has a null interval traveling from the Sun to the earth. We see 8 minutes. Light travels timelessly since it goes at the speed of light.
I don’t think we do “see 8 minutes”. To see the 8 minutes we would have to travel to the Sun instantly, watch a photon being emitted by the Sun, and then travel instantly back to Earth to await the photon’s arrival.
This is not possible. We fool ourselves into thinking it takes 8 minutes only because we can *imagine* being on the Sun and then immediately imagine being back on Earth. So we infer that the photon took 8 minutes from the point of emission, but it’s not really true; from the photon’s frame of reference it took no time. My understanding is that every point in space has its own clock effectively disconnected from every other.
I have struggled with this idea because respected physicists frequently make similar statements.
That is silly. We measure the distance to the sun by methods like triangulation and we have measured the speed of light and can therefor calculate how long it takes for light to travel to the earth. If we wanted to we could calculate how long it would take for a space-alien traveling at near light speed, but for us on earth relativistic corrections are not significant.
Measuring it would be difficult but could in principle be done. It’s tricky but we could use Compton scattering to detect when a photon passed it. Picking one headed toward are detector on earth we could measure it on arrival.
There would be problems such as the wrong photon hit our detector (noiese), but in the time peak would be be sharp. There are obvious practical difficulties with doing this experiment, but no conceptual ones.
We do in effect measure ‘speed of light’ in radio wavelengths when we detect signals sent from satellites near and far.
Summary, photons are outside of time and distance.
Therefore all photons are in a dimensionless point.
There is no distance between any photons.
Because photons are outside of time they are eternal.
This leads to a possible paradigm shift in physics.
This is explained well from this quote:
The special theory of relativity predicts that for an observer moving at the speed of light distance traveled shrinks to zero while time slows to standstill. Thus as far as light itself is concerned it does not travel any distance, and takes no time to do so. As Gilbert Lewis showed back in 1926, from lights point of view the Universe is so bent that there is no separation between the point of emission of light and its point of absorption…
If light does not experience itself to have traveled any distance, it does not need a vehicle or mechanism by which to travel … it’s only in our frame of reference, the frame of observers with mass who move at sub light speeds, that light appears to travel through space and time; and only in that frame does the question of whether it is a wave or particle or both arise.
Peter Russell’s from Mad About Modern Physics.
Much more to follow.
Time has speed limits that goes from zero to approaching the speed of light. That means that TIME AND THE SPEED OF LIGHT ARE TWO DIFFERENT AND SEPARATE ENTITIES, which in turn opens up a modern door into physics. TWO UNIVERSES!
But that’s just the first step. The above suggests TWO UNIVERSES. The one of time , matter, etc. And the other a universe of speed of light photons.
Next the eternal photon universe was the first singularity that created all, through photons create electron positron pairs… next …
The fallacy of measuring the age of the universe through light speed measurements is now becoming well known. Veritasium has even made a video now that quite well describes the problem of using the speed of light to measure the age of the universe. Emphasizing the fact that the one way speed of light is a convention derived from Einstein’s synchronization c͟o͟n͟v͟e͟n͟t͟i͟o͟n͟
https://youtu.be/pTn6Ewhb27k?t=702
The discoveries of Einstein didn’t upset physicists enough!!!
There’s more to his discoveries, a lot more.
FACT: photons don’t experience distance or time. So;
If you have 2 photons with one 32 billion light years away and the other when you strike a match here and now: how far apart art they? ZERO!
There is no distance between these two or any other two photons.
Photons are outside of distance.
If you have 2 photons with one released soon after the Big Bang, and one after you stuck a match here and now: how much time is there between the two events? ZERO!
There is no distance between these two or any two photons. Photons are outside of time.
This means every photon ever is outside distance and time OR is in a single eternal dimensionless point!!! I shorten this to Dimp meaning DIM(ensionless) P(oint).
This opens up new discoveries left and right!!!
Photons don’t experiency anything. They do move in all reference frames and thus become separated from each other.
See November 9th quote. Thanks.