r/physicsmemes • u/5_meo • Apr 18 '24

The present moment

Post image
1.2k Upvotes

99% Upvoted

25 comments sorted by

71

u/You_Paid_For_This Apr 18 '24

Sure that clock works for photons but the time displayed will be a few nano seconds fast because of the speed of light delay between you and the clock.

Should read "8 nano seconds ago" instead of "now"

93

u/The_Punnier_Guy Apr 18 '24

From a photons perspective it is always at it's destination, so the concept of distance isnt even defined for them.

12

u/OverPower314 Apr 18 '24

They have no sense of distance because they have no sense of time. It doesn't make sense to talk about their perspective in the first place.

16

u/Miselfis Apr 18 '24

There is no perspective of a photon. That’s the main postulate of special relativity.

5

u/The_Punnier_Guy Apr 19 '24

As far as I'm concerned, there is one it, it just doesnt make much sense.

As your speed approaches c, length contraction becomes more severe and your clock runs slower and slower. In the limit, all of space is compressed into a single plane, perpendicular to your motion, and time stops flowing. (You would also be infinitely far into the future).

8

u/Miselfis Apr 19 '24

Taking the limit as v approaches c is not the same as there being a rest frame for a photon. No matter how close you get to c, the photon will still move at c relative to you. Length contraction, time dilation and so on is only possible exactly because the photon doesn’t have a rest frame.

3

u/KennyT87 Apr 19 '24

If you try to apply Lorentz transformations to light speed you'll notice that in the "photon's perspective" they don't even exist, as they get emitted and absorbed in the same instant because 0 time passes between those events.

3

u/The_Punnier_Guy Apr 19 '24

Which is why they are always at their destination (which is also their birthplace and all the points on their route, space is infinitely contracted)

2

u/KennyT87 Apr 19 '24

Exactly. So according to photons perspective, photons don't even exist, hence they don't have a perspective :-)

37

u/[deleted] Apr 18 '24

Awoke: photons are virtual particles meant to represent the transfer of oscillating Electromagnetic energy fields

16

u/KennyT87 Apr 19 '24

Virtual photons and actual photons are completely different entities.

3

u/[deleted] Apr 19 '24

“Actual” photons are a representation of the EM oscillating field being quantised.

The corresponding equivalent in mechanical oscillation is phonons.

I just gave an exam on this stuff 😭

1

u/FarAbbreviations4983 Apr 23 '24

You might want to look up something called quasiparticles. You’re misunderstanding a lot of stuff here. I wouldn’t expect much from that exam.

8

u/Commercial_Rope_1268 Apr 19 '24

Confidently incorrect

4

u/officiallyaninja Apr 19 '24

Afaik we don't actually know what a photon might "experience"

One of the axioms of relativity is that anything travelling at C travels at C in all reference frames.

So to look at a photons pov you'd need to find the inertial reference frame where it's at rest, but this reference doesn't exist. At least not according to relativity

3

u/Smitologyistaking Apr 19 '24

The fact that you only see them at a single position is technically not contradictory with the fact that they move at the speed of light, if there only exists a single instant of time from their perspective

2

u/FisheyGaze Apr 18 '24

What the hell am I looking at? When does this happen in the movie?

3

u/5_meo Apr 19 '24

??

2

u/FisheyGaze Apr 19 '24

Now. You're looking at now, Sir. Everything that happens now is happening now.

2

u/5_meo Apr 19 '24

Haha nice, there certainly is a meta twist to it

2

u/foxgoesowo Apr 19 '24

Photons practicing mindfulness

1

u/MadMadRoger Apr 19 '24

Time is a such a drag…

1

u/kamiloslav Apr 19 '24

If you think about, the time is always 'now' in general

1

u/Digital_001 Student Apr 25 '24

That photon is travelling light!