The speed of light isn't even really a speed, it's a property of space itself.
But it's also a speed
And also my furniture is a property of space itself
Mine isn't. I got it at Bed, Bath, and Infinitely Beyond.
Your one furniture can do my favorite things but not my favorite amount
I get to know either where the favourite things the furniture is doing is happening, or when the favourite things the furniture is doing happen, but not both. It seems like a big enough flaw to throw the furniture out into the skip.
If your furniture is a property of space, is keeping it in a small apartment an act of theft?
"Property is theft"
It's like it's both space and time.
A bit late to the party, but I'll try anyway!
So, first, speed is distance over time. Miles per second, kilometers per hour, whatever.
Consider a person rocketing by a planet in a little spaceship at a good fraction of the speed of light. To amuse themselves, they're bouncing a ball between two paddles on opposite walls of their craft. The ball describes a path like:
O--------O
--O----O
-----O
Of course, to a person on a planet they're blasting past, the path looks different - the ship moves a long way between each bounce, so they see:
O----------------------------------O
-------O------------------O
----------------O
The thing is, both of these are correct from each point of view - from each reference frame. For the shipboard person, the ball moves the width of the ship, and for the planetside person, it covers the distance the ship traveled in the bounce (plus some for the width).
Now, swap the ball for a photon, which always moves at the same speed. The distance the photon travels from the two points of view - the two reference frames - is different, so the time component of the photon's measured speed must change as well because the photon's speed remains the same! Each side sees the photon moving at the same speed, despite the difference in distance traversed each pov sees - which means each must also have a different measurement of the time involved!
So, time is compressed on the spaceship relative to the planet - from the ship, the planetside observer is moving very fast, while to the planetside observer, the space pilot is moving in slow motion. The speed of the photon is universal - it's the distance it travels between bounces, and therefore how long it takes to bounce, that differs between their perspectives.
I want to know why it works that way. I'm pretty sure we don't actually know why that is a law of nature, just that it is. Some of these things I learned in physics I was frustrated that we can't explain the why. We just kind of know this is what experiments tell us, and the math.
If you mean the relativity part, to my understanding space and time are basically a shared dimension, so the faster something is moving in space the slower it's moving in time. Why it's shared, I have no clue.
And that is what is meant by time dilation, and why Matthew Mcconaughey was younger than his grandkids. His balls took longer to bounce......
Alright alright alright
And remember, a photon of light does not experience time. Time only applies to mass. When a photon is emitted traveling at the speed of light, it is eventually absorbed by something, eglight from the sun hitting your eye. The photon of ligjt, from the photon POV is emitted and absorbed in the same instance.
But some of the photon is absorbed by the material it passes through called spectroscopy. I guess then it’s good it’s also a wave, as per the Light Slot Experiment.
It wasn't a wave when I checked.
😂😂😂
No fair, you changed the outcome by measuring it.
Keep the faith. Don't collapse the wave.
If you were on a train that was travelling at 60 mph and you threw a ball (inside the train) and the ball was travelling at 10 mph (inside the train), then the ball would objectively be travelling at 70 mph. Any observer (outside the train) would be able to understand why it looks like 10 mph inside the train and 70 mph outside the train.
Are you with me?
Okay, so the same thing does not happen with light! If you turn on a flashlight (inside the train), the light would be travelling at 670,616,629 mph regardless of whether the train was stationary or moving. So an observer outside the train would see the light travelling at the same speed as an observer inside the train. Even if the train was some supersonic invention from the future, the light inside the train would still be travelling at 670,616,629 mph - not 670,616,629 mph plus the speed of the train. And both inside and outside the train, observers would see the light as travelling at that speed. That's the big thing to get hold of!
How can this possibly be the case?
The answer is that time itself actually slows down when we are in motion. At low speeds, the effect is negligible, but the closer we get to the speed of light, the more the effect becomes observeable, until, when we are travelling at the speed of light, time stands still. If we were able to go faster than the speed of light, we would be travelling backwards through time.
Thanks for fucking up my mind so I can't get anything done at work for the rest of the day lol
Oh it gets even weirder than that.
One observer can see two events happen simultaneously while another sees them happen at different times.
And EVEN WORSE than that, thanks to length contraction at relativistic speeds, you could have one observer think that a train is contained entirely within a tunnel, but another observer sees the train sticking out both ends of the tunnel at the same time without ever fitting entirely within it.
and/or: One observer objectively masures that object A is longer than object B, while another observer objectively measures that object B is longer than object A.
The two observers are not just hanging out together, of course. They are moving ridiculously fast relative to one another.
The speed of causality is a hell of a drug.
I finally feel (kinda) confident with time dilation, and now everyone's talking about length dilation 😭
Wonder if that applies to my dih
Honey, I'm gonna run real fast, look at how long my digling gets
Ok, firstly I'm not very smart. Secondly I don't understand the meme AND don't understand the explanations in the comments.
Can anyone actually dumb it down so a stupid person like me can understand it?
I suggest watching these videos from Float Head Physics. They're just some of the clearest and most intuitive explanations of relativity I've seen, and any other explanation I give here would just be me attempting to paraphrase him.
https://www.youtube.com/watch?v=Zkv8sW6y3sY https://www.youtube.com/watch?v=Vitf8YaVXhc
He has a whole playlist on special relativity which is really insightful if you want an even deeper dive, as well as playlists on other things like general relativity and quantum mechanics, all of which are based on building intuition instead of starting with complicated math equations.
Thank you for this.
When sailing boats pushed for speed they ended up hitting an unexpected speed barrier. As you increase velocity the break wave created by the bow of the ship elongates until the length of the ship is at 1 wavelength, then the hull drag prevents further acceleration. For a 50 meter ship it's about 17 knots. You can get much faster lifting the boat from the water as you gain speed with an underwater wing, the current max speed was set 47 years ago at ~276 knots. But that's only because they can remove the hull from the high drag environment and is extremely dangerous to attempt to break. The speed of light is nothing like that because spacetime itself can stretch and squish, I just wanted to talk about boats for a bit.
I love this because this feels like something the 10th doctor would say to confused daleks while stalling
I don't like being deceived John! Tell me more about boats!
So you're saying, we need to jump the spaceship out from space/time. With a wing.
I'm not even mad because now I get why and how these competition multihull boats basically fly above water while keeping like 1% of the boat in water
Those ones are reaching a new speed limit as well, the cavitation around the hydrofoil starts at a certain speed/angle and stalls the foil, which then abruptly drops the hull back into the water.
I’ve been wondering how long before the equivalent of variable swept wings will be added to the cup boats.
Still very interesting
You have two observers, moving directly opposite each other.
Each has a flashlight pointing back at the other.
The speed of the light from those torched is the same for both observers.
(Instead the light would be red-shifted.)
Add a third observer, stationary to one and moving towards the other. As the third observer passes that observer, the speed of light from their flashlight never changes, and it’s the same speed as from the other two. (Instead it would go from being blue shifted to red shifted.)
This adds substantially more questions than it answers.
It's complicated (and don't trust me too much, I'm not qualified), but if you've heard of time dilation and whatnot, if you start traveling at speeds comparable to the speed of light, spacetime distorts in such a way that from your point of view all light coming from any direction travels at the same speed.
This is also why (or one of the reasons) according to science you cannot travel faster than the speed of light, since light would still need to be traveling away from you at the speed of light and you'd need to occupy negative space in that direction, or something like that.
-Scientists after discovering General Relativity
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