If time was literally going slower or faster, and not in just the sense of light, all particles, nuerons, everything would move slower or faster. How could one possibly slow time down or speed it up? Is the dimension of time like the tracking bar of windows media player while playing a song or movie? If one could "pull" the bar of time back or forward they could reverse, slow down, and fast forward all the other dimensions. Right now it seems like there aren't even any theories on how we can grasp the dimension of time though. I've read on these forums that time is real because it's a dimension and I've also heard people say its not real and it's all in our head. Which is it?

BTW First time poster here, Hola!

if time were slowed down, not only would everything move more slowly, you would also see more slowly, and think more slowly. it would take longer for a second to pass, but you would not notice this, since your brain would also be processing more slowly during that second. the length of the second would seem the same to you.

the only person who would notice the longer second would be an outside observer, watching you think slowly. and of course this is exactly what happens in relativity theory. someone watching a moving system sees all processes in the moving frame move more slowly, as well as all comoving people watching that moving system think more slowly.

so yes, not only is this scenario possible, it is required by the geometry of spacetime.

Hello Gatzzu and lethe.

This might be off the topic a little.

Picture an electron moving through space and time. Suddenly it hits a photon. We will call this an interaction. The electron changes direction then emits a photon and changes it direction yet again.

Lets stop there for a second and talk about that photon. Photon's are carriers of the electric field. However Dirac showed that a sufficiently energetic photon could produce an electron-positron pair out of the blue by converting its own energy into the masses of the two particles. The positron will soon meet an electron and get annihilated and release a single burst of energy as a photon.

So a photon happily travelling through time and space all of a sudden gets the urge to create an electron-positron pair. The electron continues, the positron gets annihilated and we have a photon again.

Now back the the question at hand. In 1949 Dr Feynman said that a positron moving forward in time is equivalent to an electron moving backward in time. And apparently this is mathematically provable.

The idea I want to raise here is the issue of that lone photon. We know that the anti-particle of an electron is a positron. But a photon is it's own anti-particle. A very important concept I would like to make clear here is that if a photon is its own antiparticle and its movement through space and forward through time is exactly the same as the same photon moving through the same length of space but in the reverse direction of time. Hence time is not relative to the photon.

We have all been shown in high-school physics that if we were a photon then time is irrelevent because we would experience the start and the end of the existence of the universe at the same time. To a high-school observer watching a photon this is because it travels at the speed of light. But shouldn't we be taught that the reason is because it is it's own anti-particle?

Back to our demonstration of the electron and positron. Lets follow our electron through time and space. It meets an energetic photon and absorbs it. Then it is scattered backwards in time until it emits a photon and then moves forward in time again. Isn't this an amazing concept??

My question to you is: When an atom of, say, Hyrogen is energized with energy, the electron in the valence band absorbs some of that energy and jumps up a quantum level into a higher energy state. The atom is said to be 'excited' and sooner or later the electron will release a quanta of energy and fall to a lower energy level. This is all well but couldn't we equally say the following: An electromagnetic wave travelling backward in time arrives at the atom and causes the electron to jump?

What do people think about this?

hmmm.... i m not sure that it is correct to say this about the photon. but i m not sure. it is interesting, and i have never thought about it that way.

you see, the dirac equation that the electron obeys has positive and negative frequency solutions, and this is why we interpret the positron as an electron moving backwards through time. i don t think the same thing happens with maxwell s equation for the photon.

i m gonna fool around with the equations a bit. lemme see.

Not all particles that are their own anti-particles are travelling a the speed of light because theY are not all with zero mass.

For example, the Z⁰ is its own antiparticle. When a Z⁰ is created and then anihilated, in its own frame of reference, the time at which it is created and then anihilated are different.