Post: #1

This is the clearest description of time dilation I have seen.

The concept never felt as clear as this until I saw the video.

Post: #2

This has always blown my mind. An astronaut goes to the international space station for a few months, and he can come back "younger" than when he left. This shit fucks with my head. A guy tried to explain quantum mechanics to me, and he did a good job because I understood it, but it gave me a slight headache. Thanks for posting.

Post: #3

(12-24-2013 10:08 PM)vinman Wrote:  A guy tried to explain quantum mechanics to me, and he did a good job because I understood it,

This actually means he probably did a pretty bad job

Post: #4

I told to explain it to me like he would a 5 year old.

Post: #5

"If you think you understand quantum mechanics, you don't understand quantum mechanics." - Richard Feynman

Post: #6

No offense but what is the purpose of this thread?
I have to take a lot of physics and math classes in college, and ive never seen anyone enjoy quantum physics, other than the poser "oh look at me im so smart".
This concept is so basic that i dont think it even counts as studying quantum physics, plus the video seems it was designed for special ed kids.

Post: #7

I don't think anyone is discussing quantum mechanics on the thread here.

As for time dilation. Yeah - the video is simple (and for me that is a good thing). And the reason I like it is because the geometry involved in the increased path the light takes when the ship is moving is alot clearer and more vivid than just looking at a couple of diagrams explaining the same thing. I studied philosophy at university - and therefore am fascinated by time dilation. Since it gives us more of an insight into the nature of time than the past 3000 years of philosophy put together. I always felt it is a shame that relativity is not discussed much more in philosophy.

Still - I must be slow - since I remember seeing those diagrams (about the path that light takes in a moving ship) about 15 years ago in a physics book. And the simple idea being expressed never popped in my head in the way it did until I saw the cartoon above. So the video was small revelation to me since it lies at the crux of how time dilation occurs. And I am annoyed that I didn't pay more attention when reading books that touched on this in the past.

I have nothing but respect for physicists. I dislike poseurs - and am one of the few philosophy students who admits he would still be studying physics if I was smart enough to handle the maths! :-)

Post: #8

Just to keep things tidy.

I had an interesting (at least I think so!) post on time dilation in a previous thread. For those interested it might be useful since it details a way of visualising time dilation which I have never seen discussed before.

/thread-20880-...#pid374867

/thread-20880-...#pid401244

Post: #9

I have a PhD in physics and used to do practical experiments in this area.

This is the classic twin 'paradox'... and the explanation in the video is wrong. Specifically the only reason the twins are of different ages is because the traveling twin turned around (e.g. changed his reference frame). Up until that point the time dilation would be symmetrical - both twins would think time was traveling more slowly for the other twin.

Also time dilation still occurs during acceleration. Wikipedia's write up in quite good:
http://en.wikipedia.org/wiki/Twin_paradox

Relativity is pretty straightforward and not too difficult to understand. Quantum mechanics is an entirely separate thing. They do intersect in strange and observable ways - like the lifetime of high energy particles.

(Edit: Also time dilation definitely happens during acceleration)

Post: #10

Annnnnnnddd, the headache is back.

Post: #11

I can't believe there's no mention to Judith, of Two and a Half Men. Shit, dude, that's some misandric bitch.

Post: #12

(12-24-2013 08:34 PM)cardguy Wrote:  This is the clearest description of time dilation I have seen.

The concept never felt as clear as this until I saw the video.

yeah, time's relative to the observer - while inhabiting the same physical reality, elephants perceive time quite differently than flies - so do we. it's impossible to exceed the speed of light because as an object accelerates its mass increases which in turn requires more energy to propel it until we require an infinite amount of energy to propel an object of infinite mass. as mass increases ones perception of time slows - so even if a star is 5 light years away, it might only appear to take days to the astronaut traveling close to the speed of light. I suppose before long interstellar exploration will be just another technological advance we all take for granted.

Post: #13

(01-14-2014 08:11 PM)600 Wrote:  I suppose before long interstellar exploration will be just another technological advance we all take for granted.

Probably not. We're gonna spend all that space exploration money on some green energy projects instead. Fuck the galaxy, we have to stay on Earth and worship an idea of a stable climate (that never existed) instead. It's like Zhong Le and the Ming all over again.

Post: #14

Yep, headache, and it's only 9:46 am..

My mind is just not physics friendly.

Post: #15

I always thought the Big Bang was the collapsing of a 4-dimensional star into a black hole (which would create a 3D event horizon).

If you read books like 'Flatland' by Edwin Abbott Abbott or 'Surfing Through Hyperspace' by Clifford A. Pickover it really helps you to visualise higher dimensions - and how a 4D object mught appear when passing through a 3D world - and so on.

Anyway - I just came across a recent physics paper proposing the same thing:

http://www.popsci.com/science/article/20...-after-all

Really interesting stuff. But a bit depressing - since I sense alot of important physcis will be forever unknowable to us since it will involve higher dimensions which we have no way of experiencing.

And also - for those looking for an interesting physics book - the Clifford Pickover book above is really worth checking out.

Post: #16

(12-24-2013 10:08 PM)vinman Wrote:  This has always blown my mind. An astronaut goes to the international space station for a few months, and he can come back "younger" than when he left. This shit fucks with my head. A guy tried to explain quantum mechanics to me, and he did a good job because I understood it, but it gave me a slight headache. Thanks for posting.

Naw, not younger than when he left, but rather younger than he would have been had he just stayed home.