Would you choose invisibility or teleportation?
Would you choose invisibility or teleportation?
You could turn invisibility on and off as you like and there would be no time limit. Your clothes would turn invisible too, and you could decide whether the items you are holding would be visible or not.
There would be no limits on how many times or where you could teleport. The items you hold while teleporting would be teleported too. You would also have the ability to know if the place would be safe to teleport to, so you wouldn't teleport and get impaled by an icicle or teleport inside a wall and get your insides filled with concrete or something.
Personally, I don't know which one would I pick. Invisibility would be awesome for pranks and stuff, but teleportation probably would be more useful for everyday life.
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Me being able to teleport would prove that FTL is possible so I think I'd have to take it for that alone. Invisibility in comparison is tricky but very grounded in existing physics.
Why would teleportation necessarily be faster than light?
Some assumptions are common with teleporting.
If it takes the same time to travel 10 meters or 10000 kilometers that kinda implies faster than light.
To light, there's no difference in those times, as I understand. A light particle doesn't experience traveling at all. From its own perspective, it exists where it is created, then immediately where it is absorbed, in the same instance. So you could say it doesn't experience time at all. All of its energy exists in its velocity, and none of it in its movement through time.
Don't ask me to prove or explain this, because I don't remember where I heard it or if I even remember it correctly. 😅
Actually light does experience time in its own frame of reference. For somebody observing(us in this example) the light or any object that moves at the speed of light in vacuum, it would seem that object is not experiencing time at all, that is, if there was clock on the object and we tried to measure the time that clock reads, it would give the same number as the result of the reading irrespective of when or where we measure it in our frame of reference.
By what you're saying, it sounds like you're confirming what I said, just in a different way. A photon experiences time, but in its own frame of reference, the time experienced is zero. From its perspective, the time it takes to travel from one destination to the next, is zero. Just like the clock following it would show, from our perspective. Or am I misunderstanding?
First of all, talking about a photon's experience is weird because when moving at the the speed of light, the transformation equations associated with changing the frame of reference start having infinities appearing within them which makes it impossible to mathematically define things like time elapsed or distance travelled.
Secondly it is a little confusing to talk about of frames of reference but I will try my best to explain.
Assume there are two balls(A and B) in an empty region of spacing moving away from each other at speed of 1m/s. Since there are refrences in the background, we have no idea of both the balls are moving or ball A is the only one moving or ball B is the only one moving. From ball A's perspective, it would seem like ball B is moving away from it while it is stationary. Vice versa for ball B which thinks A is moving while it is stationary. Now let us say that the balls have a way to measure the time elapsed and distance travelled. Now when ball A sees that 10 seconds have passed and that ball B has travelled 10m. To verify this it measures the reading shown by ball B. To its surprise it finds out the reading from B's instruments show that only 8 seconds have and that B travelled only 8m. This is the time dialation and length contraction that happens in special relativity. Till now everything is fine but interesting things start to happen when you switch perspectives. In the frame of reference of B, it measures that 10 seconds has passed and that A has moved 10m in that duration. When it tries to verify these measurements from A's instruments, it finds out that they show that only 8sec have passed and that A has only travelled 8m. Now we are in trouble as these measurements seem incompatible. Not only are the instruments not agreeing with each, other, the instruments don't even agree with themselves depending on the frame. This is eventually resolved by the realisation that the order of events is not the same for all frames. In A's, frame, it seems to B that started measuring late by 2s while from B's frame it seems A started measurements later. Adding this 2 second delay in both frames solves all the measurement inconsistency issues.(The numbers used are random. If you actually calculate the difference in measurements coming from a relative velocity of 1m/s, the differences will be exceeding small)
Now that a basic understanding is out of the way, let us discuss the case of the photon. From our frame of reference, the photon is moving at the speed of light, we can measure with our instruments for how long the photon moved and what was the distance it moved but when we measure using the photon's instruments we see that the clock always shows the same time and no time has lapsed. From the photon's frame, it seems like it is stationary and everything else is moving at the speed of(which is obviously not true. Weird things happen when we try talk of moving at the speed of light beacuse of the infinities I aluded to before) and so while it clock is ticking, the clocks of the world around it seem stopped. So in conclusion while it valid to say that photons experience no time, it is only because we can't go to the photon's frame of reference because physics and math fail us that point.
Sorry for the incredibly long reply.
It was my understanding that light does not experience time.
And yes it does experience time from our dimension because the speed of light is finite, making the lifetime of a photon as observed from a different frame of reference, non-zero.
I think the point I was trying to make was that the lifetime of the photon is nonzero to us, from our perspective, but zero to the photon, from its perspective. All of its energy is in its velocity.
Remember in Interstellar when they slingshot around the black hole and it cost them like 80 years or whatever? The time around them went by faster as a result. Well a photon going at c would see time around it going by at max time speed as well, so it would arrive at its destination immediately after it departed. (From its perspective.)
That's how I understand it.
Are you referring to dark matter? What kind of invisibility is grounded in physics?
It would require matter (including the inter-particle interactions) involving no absorption or emission of photons.
According to some models, subatomic particles exert action at a distance by exchanging photons.
This is what bothered me about the notion of a “black domain” in the Three Body series
You're wayyy over complicating it, invisibility is just a matter of taking the light that hits you, bending it around you and putting it back in place. We can already do this on a small scale with fixed stationary setups.
Even simpler is just a very accurate and fast camera/display system that records and displays the background onto itself.