Does Light Experience Time?

Have you ever noticed that time flies when you're having fun? Well, not for light. In fact, photons don't experience any time at all. Here's a mind-bending concept that should shatter your brain into pieces.

[beepboopgpt]

On a double slit experiment a photon already knows where it's gonna end up before it could happen. Is it because photons experience Past, Present, Future at the same time? It's so mind blowing!

[ammusionist]

OK - I get this. I really do. I've been trying to conceptualise gravity for some time. I get that if a particle moves through a region of space-time that's affected by a large mass that it's trajectory gets observably altered. The thing that set me on this path was trying to work out - if an object is at rest relative to the large mass it starts moving towards it. Where does the kinetic energy come from to achieve this?

The mind numbing answer seems to be that all matter is moving through time-space at a total velocity of C, but mostly through time. When we are near a curved region of space some of our movement through time is bent in the direction of space and we start moving. Mass doesn't just bend space, it distorts the relationship between space and time. We don't gain energy it's just redirected and we loose a little time to space.

What's really got me at the moment is the concept of how fast we are actually moving through time. What vast quantities of time are we skipping over for every tick of a second hand!

I'm going to go to bed and stare at the ceiling now. How could I not?

[PurpleAvenue]

I'm not positive, but I think someone may have filmed you from a distance and uploaded it to youtube as a bigfoot video

[Curious]

As I understand it, even particles with mass travel at the speed of light at microscopic scales. Its only by their interaction with the higgs field that they appear, at larger scales, to travel slower than the speed of light. So if that's true then everything is really moving at the speed of light, which means none of our fundamental particles ever experience any space or time. So then it would seem that space and time is some sort of emergent phenomenon.

I'd be very interested to see you make a video that could explain how space and time emerges, and what does it mean to have no space and no time. Does that mean in some sense the whole universe, past and future, exists with in a single point? Are we still living within the singularity, and the big bang is just part of the illusion?

[karlnicholas]

Maybe someone asked already: If a photon is never absorbed, does it travel forever? If so, isn't that a paradox? How can something travel both for forever and for no time at all?

[dnrob]

This is the first time I have seen anyone bring this up. Very good.

[HASONRAZ]

electron, photon etc. - these r just names we have given to describe 'something'. Actually what r these we may never know.

[GreyFang]

This *_IS_* my favorite mind altering fact.

Another is related to the concept of infinite that you spoke of recently. By definition, there are/can/should be an infinite number of exact copies of me typing this very comment, along with infinite copies of every other possible variation as well. Analogous to sitting between to facing parallel mirrors.

[adamoleeee]

Fraser, normally I find myself nodding along and enjoying the glorious wisdom, today I had to pause 3 times to let my brain catch up, i'm still wrapping my head around this, You Sir, are magnificent, Thank you :P

[RussellCatchpole]

I'm no scientist but this kind of fits with a theory I have been bouncing around for a while. Light doesn't travel through time, time travels through light. That is to say, a photon exists in all of it's locations but only the 'now' location is relevant as time passes.

[lynchmob]

Quarks are amazing, there can never be a single quark. They come in pairs. They are special in that, if you tried to pull them apart, the force between them gets stronger. The harder you pull, the more difficult it becomes. Once you have put in so much energy (enough to pull them apart), That energy instantaneously becomes another pair of quarks at the point of separation. Mass = Energy, Energy = Mass  E=MC squared. 

[IRONMANAustralia]

What I find interesting here is that you could calculate how long you can travel at x speed before you would run into the end of the universe. A Big Crunch would limit your ability to exist and therefore travel time from your own perspective, as would a Big Rip. A Big Freeze you could survive for a while even after the last proton decay, so you slam on the brakes and your ship still exists in cold, dark, void.

So if you could likewise accelerate an entire galaxy to near the speed of light, you could place it in the future and move there to live after the rest are gone. In this manner you could distribute galaxies across time and extend the functional life of the universe by billions of times.  Suck it entropy.

[gaetanodaloia]

Dear Fraser, I've already heard something like that. There’s a consistent number of physical scientist saying that at light speed, time wouldn’t exists anymore. Everything would just be there at once at the same time – or what we would call “same time”.
Everything would be there. From the beginning to the end of the “once supposed” times. Say from the big bang to the big crunch for that matters. At luminal speed you could move across the otherwise so called “time” just as if you were moving between different points in space.

So. Imagine an existence in that situation, out of time. It is not eternal or infinite or timeless, it is just outside the dimension of time.
Well then it has to be a superconscious existence able to get everything, every event ever existed or ever happened at once, simultaneously, in this unique same domain, or how we would still say: at the same time.

But isn’t this what we use to refer to as God…?

[geistreiches]

if a photon does not experience space and time, that would mean all photons we see are the same and there is just one, it gives me the impression that the universe might be a projection from one point and space and time are just an illusion

[stevegovea]

Photons do not experience time....but that doesnt mean time in it self stops.
Everthing inside our universe is experiencing time differently because we are all traveling at different speeds...whether you are a photon or a turtle....

[spacemankermit]

I'm so glad you answered my question on the other video.  The question of whether or not light experiences time has been bothering me for a very long time... and it get's worse!  If light doesn't experience time, then could light be in the two different places at the same time?  If light can be in more than one place at the same time, could it be possible that all the light in the universe is the same light?  i.e. the singularity?

[kevin_dasilva]

I've been having these crazy ideas like maybe "dimensions" (1D, 2D, 3D) could be grouped into threes (or maybe that is just my bias being in the third)

Think of it like this: 0D is dimensionless, in our reality just a theoretical construct. Place infinite 0D realities "side by side" then we can create a line of points. Line being 1D. Repeat that process of placing infinite 1D realities (lines) parallel to each other (infinite, because they aren't supposed to have width, so you would need infinite) to make a plane. The 2D plane reality has no depth, "stack" infinite of them to create 'our' 3D spatial reality. Now is where our brains trip, but place infinite (because 3D space doesn't innately have that 4th coordinate) 3D spatial realities "side by side" to each other in that 4th coordinate, we call it time. That makes a timeLINE.

Is it too much philosophical extrapolation to imagine that we can place infinite 4D realities (timelines) parallel to each other (infinite, because the timeline just like the original 1D lines aren't supposed to have width, so you would need infinite) to make a 5D "timeplane". The 5D plane reality has no depth, "stack" infinite of them to create some theoretical 6D time-spatial reality. If you want your brain to trip even further, place infinite 6D time-spatial realities "side by side" to each other in some theoretical 7th coordinate.

As far as I can extrapolate, each group of three dimensions have a unifying concept. 1D-3D form space. 4D-6D would "form" time in a way our brains can't comprehend. In theory, 7D-10D would "form" something else, to which I am completely and utterly oblivious to.

But now let's take a step back. If the precursor to the 1D line is a theoretical "dimensionless" point (0D), then you can see how our 3D is also the precursor to the 4D timelines we live through and feel bound to. In other words, every moment is a point on that timeline. Seems obvious enough, but just think about it. We can use seconds and what not, but the concept of a moment can be infinitesimally small, as small as you can count it. The moment is the point. If you're a being in this higher octave of dimensions (3-dimension groupings), most probably you look at a single 3D space as YOUR point.

Maybe I am going too far 😅 But in essence, I am trying to say that this might even be fractal, who knows. Maybe what we call 0D actually houses another "octave" of dimensions below. Or maybe not, and this is all there is, and I am reading too much into it.

[sichudorksteiger]

Sir. One of the best videos of yours. And this topic is twisting my brain since a long time.

[TheCyber]

The most mind-boggling thing about this is Lorentz contraction or "length contraction". That "finite" distances ARE shorter as you're approaching the speed of light. Basically since light has a finite speed in vacuum you can use it as a clock for measuring time between two mirrors. If you mount this vertically inside a spaceship moving close to the speed of light horizontally, you'll have a time measuring device for the person inside the ship. While the spaceship is moving the light only goes vertically in the spaceman's reference frame. If a person then stands outside of the spaceship watching the clock, the light would have to travel farther because it is both moving vertically and horizontally + having a finite speed. This means that time is experienced different being outside or inside the spaceship. IF this is true (it is because c is a constant) and because c is a constant you have "relative time" meaning that measured speeds (distance unit per time unit) can differ. Say moving 100 meters in 2 seconds for the person outside the spaceship and moving 100 meters in 1 second inside the spaceship. Since it would then be possible to measure speeds above the speed of light c which we have already concluded was impossible to do while you had mass, only one thing can be changed -> the distance. So you have relative time AND relative distances because both changes. So if you have to move from point A to point B you'll be able to shorten the distance (physically) by moving quickly in a straight line towards point B.
And our universe does this without having to buffer or calculate.

[omegamaelstrom]

How I think about this is: if we plug in v=c in the Lorentz transform, t becomes infinity. This means that from a photon's perspective, it takes infinite time to get anywhere (although all distances shrink to zero, absurdly). In my opinion, just like the General Theory of Relativity, this is a sign that the theory breaks down at the speed of light, just like General Relativity breaks down at the point of infinite curvature - the point of singularity in a black hole.