(February 21, 2017 at 2:08 pm)Alasdair Ham Wrote: You're missing my point. Therefore time travel isn't possible because the future doesn't exist to visit yet.

There is no time travel involved in this thread.

It's the entire subject of the thread. Are you on the right thread? No wonder you're confused.

Nope.
The OP assumed that that cartoon was talking about time travel. It is not.

"Time travelling is just full of crap, innit?"

That's what I'm addressing. My answer is "Yes".

The problem with that then, is that the cartoon that was used was misleading, because it has nothing to do with time travel.
Sure, maybe time travel is complete crap.

Yeah. And I think you pointed out already that no one would actually age differently.

The cartoon is a joke because it's, well, a cartoon.

No one would age differently, relative to their time frame.
And technically, no the cartoon isn't a joke, it's pretty accurate.
But again, we're off topic. Time travel and time relativity are two different things.

Time doesn't really pass or travel at all. Only the measuring of it changes.

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(February 21, 2017 at 2:21 pm)LostLocke Wrote: No one would age differently, relative to their time frame.
And technically, no the cartoon isn't a joke, it's pretty accurate.
But again, we're off topic. Time travel and time relativity are two different things.

It may seem to be 5 years from one point of reference and 50 years for another due to the way our measuring of time works.... but it's objectively the same amount of time that's passed if time even passes at all. Time doesn't need an observer. So relative to 'their time frame' doesn't apply to objective time.

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(February 21, 2017 at 2:21 pm)LostLocke Wrote: Time travel and time relativity are two different things.

Exactly.

Again, science can only measure what seems to be the case, not what's actually the case. It can only measure any particular observer's perspective it can't measure actual time.

(February 21, 2017 at 2:10 pm)Alasdair Ham Wrote: It's the entire subject of the thread. Are you on the right thread? No wonder you're confused.

If you took my advice to study more physics, because it is what we are talking about, as an insult, then I feel sorry for you.

Seeing your replies to me on this matter just showcase that, I am not going to bother in schooling you, given your youtube grade philosobable and logic. You may crow victory now, IDGAF about your ignorance. Its your problem, not mine.

*over and out*

(February 19, 2017 at 11:27 pm)Alex K Wrote: There is another layer of subtlety to this that is barely ever discussed in popular treatments: travel speed itself is not an absolute observer-independent quantity in relativity, so there's no unique objective way to say who is faster and who is slower. This is why in two space ships passing each other, each could claim to be at rest while the other is fast, hence both could equally claim that their time runs faster. This seems paradoxical. The way the paradox is avoided in nature is very interesting: there is no way to compare the "time speed" of two observers unless 1. the two observers meet twice, or 2. if one observer prepares several synchronized clocks set up a distance apart, which are passed in succession by the other observer.

In the first case, the paradox is avoided bc one observer has to turn around and go back, breaking the symmetry of the situation. In the second case likewise, there is no paradox because the synchronicity of spatially separated clocks is not observer-independent either and the observer in the passing space ship will simply see the two clocks as not synchronous in the first place, explaining why they seemingly show more time passing even though they are the ones who are moving from his vantage point .

With regards to the first case, what happens if the two spaceships are traveling in huge circular routes, next to each other, but in opposite directions? Then they would technically pass each other multiple times without actually turning back?

Did I, or did I not just break the universe?