Ask Lemmy

Uhh, relativity, fun. This gets a lot more mind boggling, imagine 3 people, A and B are in a train and C is an observer outside. From C point of view, B will pass him first, then A. This train is going at 50% the speed of light and it's very long, A and B are 1 second light apart, i.e the distance that light takes 1 second to travel.

If A shines a flashlight B will see it 1 second later. However from C point of view since the light was shone the train moved forward 0.5 light seconds. So the light has to travel 1.5 light seconds distance, and it does so in exactly 1.5 seconds. So the observers disagree on the distance the light travel, but also disagree on the time it took, but they agree on the speed of light.

This makes things weird, because both A and B say that 1 second passed, but C says that 1.5 seconds passed. This means that people moving faster experience time slower. Which means that if you take two twins, put one on a fast moving ship, e.g. 80% speed of light, by the time he comes back only a few minutes would have passed for him, but years would pass for the other.

The back of my brain is fizzing.

I had the Relativity conversation with my 16 year old this past weekend, as he is taking AP Physics.

Yeah, he couldn't wrap his mind around it. Honestly, I can't say I understand it very well. I get that C (speed of light) is C in all reference frames. What I do not understand is for a spaceship traveling at C, the forces being transmitted between the atoms from stern to bow are unable to catch up to the next forward atoms. Hence time dilation, at least for those forces being transmitted "forward" in the ship's reference frame.

However, what happens to those forces being transmitted bow to stern or "backward" in the ship's reference frame? Would those forces be "dead stopped" in an external reference frame? Yet travel at C from bow to stern in the ship's reference frame? What does that mean for the ship if those forces are only being transmitted one way?

Or, as I very much suspect, do I just not have a clue as to how it really works. I always thought that "time dilation" was simply the inability of forces being transmitted from atom to atom. As those forces are limited to C and they are attempting to catch up to another atom also traveling at C. With that said, those forces are transmitted in multiple directions, not just the vector the ship is on.

Ok, another one of my very few brain cells just committed suicide and I'm not drinking anything, so I'll stop now.

If you’re on a truck traveling at 60mph, and throw a ball forward at 60mph, that ball is moving at 120mph.

Technically it would be moving at something like 119.99999999km/h and that discrepancy slowly increases the closer you get to the speed of light

Is that fucking garbage still going ahead!??

Sheeeeit

Same with people who complain qbout facebook and use facebook.

Yeah, but it's from Apple! /s

I think I've read before that our eyes are most sensitive to the color green out of any other color, something about it that wavelength of light is absorbed more readily by the cones in our eyes. Being exposed to it daily and maybe having their survival dependent on it probably helps them develop that ability.

Do you have a source? There is a common myth that innuits have 100+ words for snow, which is stretch beyond any reasonable sense, I'm afraid this might be similar.

To boldly go... where few men have gone before.

What happened exactly today that boggled your mind?

Where in the world did you get that number and what were the specific parameters?

Because "2.3 billion people — 29.6% of the global population — don’t have adequate access to food" and "9 million people die from hunger-related causes every year"

Perhaps. But infinite universes is still just a theory. So why let such a astronomical 'what if,' get you down?

Yep, if there's an infinite number of parallel universes then there's an infinite number where nothing is different. Maybe the only difference between the universes was the position of a mote of dust on an uninhabited planet in a galaxy on the other side of the universe.

If the many worlds interpretation is correct, that would mean that there's not really an infinite number of discrete realities, but more of a continuum. So there are infinite other realities in the same way that there are infinite points on a line, but this exact reality is still unique.

That's not right at all by my thinking.

Infinite multiverse means infinite exact same universe as ours, yes. But it also means there are also infinite different universes. But you can use comparisons to see that there would likely be more universes that are different than ours because of small permutations in history causing larger effects in the future. So I like to think there are both many exact universes, and many very different universes.