Does light experience time?

Does light (photon) experience time? The most common answer to this is, no. Light does not experience time. But, that's not accurate. So, in this video, let's explore what physics really has to say about this

Chapters
00:00 Intro
00:44 Visualising time dilation
02:28 Time dilation at speed of light
03:12 The problem with this logic
03:46 Ground news is awesome (really)
05:20 Does light reference frame exist?
07:06 So, does photon experience time?
07:40 But what if light reference frame existed?
09:40 But what if we consider ALMOST light speed?
11:48 Summarising
12:48 Bonus question (Speed of light with respect to light?)

P.S. - The illustration for the cart and the photon clock were inspired by the book 'Relativity Visualized' by Lewis Caroll Epstein.

This episode was sponsored by Ground News.

[kyo_.]

man your topics are always so interesting i just have to watch

[mmicoski]

If an object travels almost at c, from its reference frame the universe is traveling at almost c and is extremely contracted in the direction of the movement. So, from its perspective, it would traverse the entire universe almost instantaneously. I think looking this way we could say this object experiences almost no time, meaning it does not see the universe evolve in the very short time (from its perpective) it took to traverse the universe. If you think regular objects do not traverse the entire universe, but a smaller distance between object creation and destruction, for this object it existed during almost no time and was almost instantly destroyed

[armaan]

Oh god I recognize your voice from khan academy

[vyvianalcott]

I'm two minutes in and you are already blowing my mind about concepts I thought I understood. I absolutely love your videos, you are by FAR the best physics presenter and explainer since Feynman. Keep up the great work, I'm hanging on your every word now!

[Pranav_pundir]

Hypothetically, if I make a phone call to my friend who is near the sun, than he would recieve it after more than 8 mins 16 secs and we will have conversation at each interval of more than 8 mins 16 secs?

[kriiistofel]

I read somewhere how we could imagine photon 'perspective'. From it's 'point of view' there is only act of creation and then instantaneous act of annihilation (when it interacts with some object). There is nothing in between for photon, it does not 'experience' time.

[luciddreamworks]

I have a masters in Math, and your videos have allowed me to appreciate axioms, postulates, and modeling so much more.

[manishnamdeo]

That's why i stopped watching your videos... Because you're blindly follow einstein... " No question is meaningless, i just unimaginable to answer but there is an answer"

[AS-zcmr]

I followed your recommendation in a party, and the dude telling the story punched me in the face!!!

[Jupiter]

And you might say, mahesh - i always wondered if we could have a beer together. But einstein says yes, of course you can have a beer with mahesh.

[PTGaonkar]

What a video! I think this series is one of the greatest assistant to understand special theory of relativity

[sophiasalleythedawnofsadie]

Does Time experience Light? is the question i get asked the most. Right behind Do you know what time it is? And How are you doing? Thank the good Lord i have the answer now.

[jensphiliphohmann]

05:40 f
_Looking from s.o.'s perspective basically means looking from s.o.'s reference frame._
I'd put it differently: By "looking from s.o.'s perspective" physicists mean *describing the scenario from a rest frame of her/ his.*
▪︎A frame in this context is a coordinate system which basically maps all of spacetime, so you can't really looking _out of_ it. Rather you express physical quantities in those coordinates.
▪︎Everything kind of has infinitely many rest frames with different orientations or origins.
▪︎Your reference frame is the frame you use to describe a scenario. This _might_ be a rest frame of yours but it _doesn't have to._ And in everyday life, it seldom is. Mostly we implicitly use a frame bound to Earth; otherwise, if I went to Cologne by train, I'd have to say "the train has come to rest (a very active rest like that of someone running on a treadmill) and lets Cologne approach it".

[michaelzoran]

BOTTOM LINE: An object moving at "Nearly" the "Speed of Light" is experiencing "Proper Time" in its own "Frame of Reference, " which measures "Time" when the object is "At Rest." An object "Constantly" (c) moving at the "Speed of Light" is not "At Rest" and therefore has no "Reference Frame" at all to measure "Time."

[sgiri]

Mahesh sir please cover quantum mechanics stuff

[lantonovbg]

Emphatically NO. The velocity of light is ... zero.

[effectingcause]

"There comes a point in every man, woman, and child's life that they wonder - Does light experience time?" See, that's the mindset of a great theoretical physicist..

[florincoter]

Does light experience anything? Humans experience.

[siddhant]

I was literally looking for a person who could explain things that comprehensively. The way you crack things, like the scientists who are much more eager to break apart the subatomic particles in the Large Hadron Collider to understand the behavior or laws of this Universe. The power of visualization and the interpretation you have mastered is just Astonishing. I don't have words for you, you are just limitless.
Keep continuing the series I am learning a lot by opening different ways to visualize things for Better interpretation.
My regards to you.

[michaeljorgensen]

You left out the the thought experiment most people want an answer to.
A spaceship already accellerated close to C and moving past earth and then past the nearest star 4.3 light year away at close to C. Would the astronauts experience less time than 4.3 years?
If so, then did the distance get length contracted for them? Isn't the entire universe smaller for something traveling at close to C.?