Eli5 how does a photon not experience time when zooming toward point b? Wouldn’t other photons from point b passing it appear as time happening very quickly?
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Because photons aren’t “things”. It’s not a unit of mass like a basketball. It’s just energy. I’m not a physicist, but I know radio. As it turns out, light is just a different frequency of radio (electromagnetic) waves. They’re not that special or unique and by studying these lower frequencies used for radio we can learn some things.
A radio wave (low frequency light) is just two intersecting waves. One magnetic, the other electrical (hence the term “electromagnetic” 🤔)
So we all know that a magnetic change creates an electric current. That electric current happens to be perpendicular. So radio and light are just that – magnetic energy causing electric current, causing magnetic energy, causing electric current, etc. this is basically just energy, so it propagates at the speed of information oscillating back and forth until something absorbs the energy.
Now what’s a “photon”? Well, I dunno. But this electromagnetic wave sure has a lot of energy at the high frequencies that make light. If that energy hits something, the energy doesn’t disappear. Most of that energy creates heat, but what if some of it turned into mass – as mass and energy are interchangeable at the quantum level – and that mass would have momentum.
I can’t back up that last sentence, but y’all are welcome to write a thesis paper proving it as long as you reference “some rando on the internet” in the paper.
Light clocks… You build yourself one, and then look at it while traveling at c. It won’t tick once!!!
Don’t think of the speed of light as a speed. Think of it as the *relationship* or *conversion factor* between space and time. While you’re still, you’re ticking forward through time at full speed (*c*). When you start moving, in a sense you’re trading some of that speed in *time* in order to give you speed in *space*. This means from the perspective of everyone else, time moves more slowly for you. The faster you go in space, the more you “rotate” out of the time dimension and the slower and slower your clock ticks from everyone else’s perspective. Once you reach the speed of light, your speed is rotated completely out of the time dimension and you’re *not moving through time anymore*. Photons simply don’t experience time; in a sense, they’re at a stand-still in the time dimension, and from their reference frame (if you could call it that), the start and end of their life is instantaneous regardless of physical distance.
Were you listening to The Dude’s story? You have no frame of reference here.
Photons don’t “experience” anything. Obviously, from a philosophical standpoint, they aren’t people and don’t have experiences. But a rock experiences time, in the sense that it experiences erosion, and maybe its atoms undergo radioactive decay and stuff. A photon doesn’t do any of that. It just has its wavelength and its direction of travel and its angular momentum, and that’s all. There’s nothing “inside” a photon that can change. If a photon hits another particle and has its direction or angular momentum changed, then… well, the question of “is it still the same photon or a new photon?” is another one of those philosophical questions.
It’s not a little pellet, it’s a ripple. It’s very hard to use material metaphors because they often don’t hold up. For instance, you think your speed is currently 0 but it’s actually 300MM m/s slower than light. Light is 0. Time is the condition of moving slower than light, the more slowly the motion the more time it endures.
So then you say, but light isn’t instant. It takes time for it to move. But that’s only for you, because you’re so slow. For it, everything is instantaneous and simultaneous.
It’s kind of like magic, but it’s actually science. The answer is that it happens with 3D space and time in our physical reality.
Light its self feels 0 time relative to us. To imagine this, its created and hits what ever is absorbing it the other end. This happens instantly from its perspective. Thus, we see light because we are an outside observer only. But basically loght shouldnt exaist but because time is non zero for us we see the light
I keep seeing this statements coming up about how a “photon doesn’t experience time”.
Usually what follows immediately is some kind of statement that basically assigns a reference frame to the photon, such as “If I travel at the speed of light then…”
The moment you do this, your question exits the realm of physics. It’s a nonsense statement. You’re asking a theory that tells you that you can’t ask that, what happens if you ask it. Even the idea “photons don’t experience time” comes from a tenuous interpretation of a mathematical artifact, not a LITERAL application of physical reality. It’s like the Alcubierre drive, it’s a mathematical construction not a literal thing in physics.
Imagine you calculated the time it takes a police car to catch up to your speeding vehicle. If you do this you get two values: a negative number and a positive number. Normally we throw the negative number in the trash, but in General Relativity instead people stare at it in amazement.
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