Science!
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Well, it's obvioulsy because
L = 356⅔~Sp + 2Fim /250m -
Light years and time are different ways to measure time though arent they?
As in 1 light year is nothing like 1 year for us?
As I said above, I don't know, I can't get my head around it.
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Light year is a distance, not a time. If you are travelling 250mm lights years in 50 years, then you are travelling at 5mm x the speed of light.
Been a while since I've done heavy physics, but I didn't think you could travel faster than light, and as you get closer to it, time slows down.
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@MajorRage exactly, a light year is the distance light travels in one earth year. Now, I’m pretty loathe to tell Brian Cox he’s wrong with his analogy, so come on TSF, someone must be wise enough or confident enough to explain why what he says is true
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@MajorRage exactly, a light year is the distance light travels in one earth year. Now, I’m pretty loathe to tell Brian Cox he’s wrong with his analogy, so come on TSF, someone must be wise enough or confident enough to explain why what he says is true
OK, so I did a bit of physics at Uni. Yep, I"m a nerd. Sue me.
Short answer: he's completely right.
Longer answer: it's complicated, because the speed of light is fixed and relativity is a weird thing. So, as you get closer the speed of light and keep accelerating, from your perspective time outside speeds up; from teh perspective of the outside universe, you slow down (and get heavier).Remember that Einstein guy saying energy and mass were interchangeable? Yep, that kicks in here too.
So, long story short, if you're moving incredibly incredibly quickly and do a return trip to Andromeda, it takes 5million years in earth time, but 100 years in spaceship time.
there's more on this here, but he is correct.
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I mean, I assumed he probably was. But my tiny pea fucking brain cannot for the life of me understand why.
Thank you for replying, I just tried reading the link whilst drunk, got lost at the point it said that if I’m travelling towards you at 60mph and you throw a ball at me at 60mph then the ball is not hitting me at 120mph. But I’m a bit drunk. So whilst I know I’m stupid all the time, I’d like to think I’ll be less stupid when sober in the morning. Fingers crossed
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I'll try and confuse myself and others some more then - good luck to sober @Dodge
So, if you do a thought experiment to see how the fixed speed of light affects things, you start to get weird. Imagine you have a spaceship that can instantaneously go 99.999 percent of the speed of light. You're standing there, it takes off and hits that velocity. They shine a torch out the front.
To you, the spaceship is heading away at 99.999% and the light is verrrry slowly moving away from the front of the ship.
Inside the ship, the light is moving away from you at the speed of light. You see this differnetly because inside the ship, time is massively dilated (ie things outside are happening much much faster than you perceive them).Not sure if that helped or confused you, but good luck. It's complex and hard. I remember our lecturer came in to talk about it, put the thought experiment out there. THen came back the next lecture and said 'oops sorry, actually that wasn't right, here's the right answer'. Then came back the lecture after and said oops I was right originally all along, sorry
It's mind bending stuff. -
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What I've never understood is that sure:
I get that if you move in one direction - away from Earth, for example, at 99.999999% the speed of light - sure... there is "relative" time travel.
But - if you then do a U-turn... and travel back the same distance, at the same speed... then "relatively speaking" - there should be no "time travel" - surely? -
Yeah - but the key is in the name of the theory - Relativity.
"Time Travel" only happens in relation to something else.
Yeah - the torch pointing forwards - in relation to the light from THAT - you're nearly going forward in time.
But a torch pointing BACKWARDS... you're travelling away from THAT at 199.999999 % the speed of light...
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That's how I've always assumed it worked... that it must be more about the Velocity, rather than speed - when it all settles out in the wash.
But if Brian Cox is saying otherwise... I guess I must be wrong, I just can't figure out how.
Stupid. Stupid. Stupid Kruse. Gonna have another beer, kill some more brain cells, they're obviously no good. -
But a torch pointing BACKWARDS... you're travelling away from THAT at 199.999999 % the speed of light...
I think this is right. If you are on earth, you see Kruse in a spaceship going away at 99.9999% and the light coming towards you at 100%. I think (fingers crossed) you'd see some serious blueshift - maybe to make shit balance.
Kruse sees light going away in front and behind at 100%. I think.
Also I think you've confused me
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@nzzp yes I’ve tried to get my head around this before, I just fundamentally can’t understand relativity. The first bit, watching a train go by from far away vs close up, watching someone bouncing a ball on that train, to them goes up and down in a vertical line, to the observer outside goes up and down at angles (and therefore travels further) - I get.
Then my mind frazzles when you get to the consequences…
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Further complicated by the fact that they reckon at the time of the big bang stars travelled faster than the speed of light and some continue to do so but we can't see them because travelling faster than light etc. (Partly) explaining why there is less observable matter than there theoretically should be.
Also theoretically would allow us to also travel faster than light by creating a warp bubble around our FTL ship with time distilled around the bubble - or something like that
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What I've never understood is that sure:
I get that if you move in one direction - away from Earth, for example, at 99.999999% the speed of light - sure... there is "relative" time travel.
But - if you then do a U-turn... and travel back the same distance, at the same speed... then "relatively speaking" - there should be no "time travel" - surely?It still takes time for the journey to take place, in either direction. And the closer you get to the speed of light time travels at a different rate for the observer on earth.
So 10 years each way could be 100 years on earth, so 200 years will have passed on earth. It's not a measure of the distance travelled, but the rate at what time passes for you.
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But a torch pointing BACKWARDS... you're travelling away from THAT at 199.999999 % the speed of light...
Late to the party ...
... I thought no. The light is travelling away from you, relative to you, at the speed of light.
It's not Newtonian physics where you add one to the other. The speed of light is absolute.
I thought.
