# Opposite of FTL Barrier?

• January 11th, 2022, 01:47 PM
zinjanthropos
Opposite of FTL Barrier?
Simply... is it possible for all motion in the universe to slow to zero? If c is the ultimate high speed barrier for particles, then is zero the ultimate low speed barrier? I assume that zero is not a speed therefore not attainable, something like that. Makes me wonder about not quite reaching c. Is it such that nothing can achieve zero or c? Just curious, no expert here.
• January 11th, 2022, 02:39 PM
PhDemon
Anything with a temperature above absolute zero will have some motion as temperature is caused by atoms and molecules vibrating. Even at absolute zero there is zero point energy so at the level of molecules there is always motion. The average of all these movements may average out to zero though.
• January 11th, 2022, 02:52 PM
zinjanthropos
Quote:

Originally Posted by PhDemon
Anything with a temperature above absolute zero will have some motion as temperature is caused by atoms and molecules vibrating. Even at absolute zero there is zero point energy so at the level of molecules there is always motion. The average of all these movements may average out to zero though.

Yes I understand that much. Maybe I'm asking a more philosophical question, idk. If c or zero cant be reached by a particle then do they both compare similarly? Light consists of photons, even massless it's still a particle, and I assume that no photon can reach a speed higher than c. c then would not be a barrier but the highest speed a photon can attain. Anything beyond that just can't be achieved in this universe. Would it be more correct to say nothing we know of is faster than a photon?

Edit: When a photon is created it must be emitted from an object in motion since everything's moving. However it instantaneously goes from zero to c. The moment a photon is created, is that judged to be from a stationary position, absolutely zero movement at that instant? Or does every photon possess even the most minute motion at the time of its creation? Ditto for when absorbed.
• January 11th, 2022, 04:22 PM
PhDemon
Too "philosophical" for me! Photons always travel at c so your idea of "zero to c" is not correct. Either there is no photon or there is a photon travelling at c, there is nothing in between these two states.
• January 11th, 2022, 04:45 PM
geordief
Ph ,Do photons actually "travel"

Is it the wave that travels and the photon that is detected ?Anything like that?
• January 11th, 2022, 05:10 PM
zinjanthropos
Quote:

Originally Posted by PhDemon
Too "philosophical" for me! Photons always travel at c so your idea of "zero to c" is not correct. Either there is no photon or there is a photon travelling at c, there is nothing in between these two states.

That would make sense if no particle can reach zero speed. Wouldn’t be able to start or should I say exist at zero speed either I think. Still no discounting it’s a particle or wave (particle/wave duality). Almost appears as if no emitter motion, no photon. It’s like unless there is motion a photon can’t exist…. BUT IVE BEEN WRONG BEFORE:smile: Seems other than a photon, there’s nothing that can stake claim to being the slowest particle that can exist:shock:
• January 11th, 2022, 05:38 PM
mathman
Since motion has both speed and direction, speed less than 0 simply means going in the opposite direction.
• January 12th, 2022, 12:28 PM
zinjanthropos
Quote:

Originally Posted by mathman
Since motion has both speed and direction, speed less than 0 simply means going in the opposite direction.

Don't think I'm same page with you there.

Just realized that the speed a photon travels at (do I say in a vacuum?) is not only its fastest but its slowest also. Would that be a fair statement?
• January 12th, 2022, 08:42 PM
mathman
Quote:

Originally Posted by zinjanthropos
Quote:

Originally Posted by mathman
Since motion has both speed and direction, speed less than 0 simply means going in the opposite direction.

Don't think I'm same page with you there.

Just realized that the speed a photon travels at (do I say in a vacuum?) is not only its fastest but its slowest also. Would that be a fair statement?

I don't get your point. My definition of speed is the magnitude of a velocity vector. The speed of light (vacuum) is c no matter what direction it's going.
• January 19th, 2022, 04:03 AM
The Raven
Another way to ask the question would be: can any two objects be traveling at exactly the same speed, and in exactly the same direction?

The speed of light is the maximum difference in speed that any two objects can achieve. The maximum identicalness of speed seems like what the op is asking.

I'm tempted to try and invoke the Heisenberg uncertainty principle, which places a limit on the accuracy with which you can measure any object's speed and velocity (if you want to know both.) If you can't get a perfect measurement of the two objects' relative speeds and locations, then even if their relative speed were zero, you wouldn't be able to know it was.