Stephen Hawkins Universe - Time Travel

[Castiel]

Isn't time relative to gravity? I'm sure I read somewhere that the space shuttle 'time travels' as the digital clocks on there are calibrated to run ever so slightly slower due to the time difference between up there and down here....

....or am I missing the point entirely

Airline pilots lose around 2 seconds during their lifetime due to time dilation effects.

 

[Castiel]

To explain the principle better look at the Twin Paradox, this explains it and includes an example that may make more sense.

Consider a space ship traveling from Earth to the nearest star system outside of our solar system: a distance d = 4.45 light years away, at a speed v = 0.866c (i.e., 86.6 percent of the speed of light). The Earth-based mission control reasons about the journey this way (for convenience in this thought experiment the ship is assumed to attain its full speed immediately upon departure): the round trip will take t = 2d / v = 10.28 years in Earth time (i.e. everybody on earth will be 10.28 years older when the ship returns). The amount of time as measured on the ship's clocks and the ageing of the travelers during their trip will be reduced by the factor , the reciprocal of the Lorentz factor. In this case and the travelers will have aged only 0.500×10.28 = 5.14 years when they return.

The ship's crew members also calculate the particulars of their trip from their perspective. They know that the distant star system and the Earth are moving relative to the ship at speed v during the trip. In their rest frame the distance between the Earth and the star system is εd = 0.5d = 2.23 light years (length contraction), for both the outward and return journeys. Each half of the journey takes 2.23 / v = 2.57 years, and the round trip takes 2×2.57 = 5.14 years. Their calculations show that they will arrive home having aged 5.14 years. The travelers' final calculation is in complete agreement with the calculations of those on Earth, though they experience the trip quite differently.

If a pair of twins are born on the day the ship leaves, and one goes on the journey while the other stays on Earth, they will meet again when the traveler is 5.14 years old and the stay-at-home twin is 10.28 years old. The calculation illustrates the usage of the phenomenon of length contraction and the experimentally verified phenomenon of time dilation to describe and calculate consequences and predictions of Einstein's special theory of relativity.

http://en.m.wikipedia.org/wiki/Twin_paradox

 

[d_brennen]

Airline pilots lose around 2 seconds during their lifetime due to time dilation effects.

Amazing! Do you have a source for this Castiel?

 

[Amp34]

As Brian Cox stated, they are talking about 99.99r the speed of light, not 99 percent the speed of light as the OP said.


You can work it out using the Lorenz Factor equation

γ = (1 − v2/c2)−1/2.

Ok now we're getting pedantic (although I admit I was going to but recurring at the end, then thought people wouldn't care, I made the assumption people had watched the show)

Either way that quote is the exact wording of the show I watched.

 

[~>Dg<~]

Amazing! Do you have a source for this Castiel?

proof would be sweet but i fear its mathmatics at play or some nerd phyics nab who made a guess

physics is the route of all evil and can prove anything whether true or false

 

[bigjimmyauk]

wait so if you travel for 2 years earth time (2 minutes at 99.9%SOL) would you actually age 2 years or 2 minutes i mean would 2 years worth of facial hair grow in 2 minutes cause that would be pretty sic

 

[Amp34]

You would age two days if you were in the ship (I was wrong in the OP, I should have said day rather than minute)>

 

[Fenris]

wait so if you travel for 2 years earth time (2 minutes at 99.9%SOL) would you actually age 2 years or 2 minutes i mean would 2 years worth of facial hair grow in 2 minutes cause that would be pretty sic

I know practically nothing about it but I assume you would age relative to the travel time you experienced, not the time that would pass outside.

 

[bigjimmyauk]

You would age two days if you were in the ship (I was wrong in the OP, I should have said day rather than minute)>

So you would physically age 2 days as in the deterioration of cells etc etc but 2 years would have really passed for everyone else

 

[Castiel]

Amazing! Do you have a source for this Castiel?

Sorry, it is something I read in a physic journal somewhere that stuck in my head. I think they may have been referring to supersonic pilots.

 

[Castiel]

Ok now we're getting pedantic (although I admit I was going to but recurring at the end, then thought people wouldn't care, I made the assumption people had watched the show)

Either way that quote is the exact wording of the show I watched.

Sorry, I wasn't trying to be pedantic, just attempting to reconcile the math.

The problem with exponential equations is that even 0.01 degree can have massive consequences to the result.

 

[Castiel]

So you would physically age 2 days as in the deterioration of cells etc etc but 2 years would have really passed for everyone else

It's really a thought experiment. Subjectively you would age and time would pass normally. However, on your return those on Earth would have aged faster. Equally from the Earth persons perpective they would have aged and time passed normally and on your return it was you that aged far slower.

 

[SlugForAButt]

Stephen Hawkins went on a date the other night.
He arrived home later with cracked glasses, a fractured arm, a bruised temple and 3 broken fingers.
Apparently she stood him up...

 

[ChroniC]

Hawkins had a problem with paradoxes in this episode. I don't think he's right about the feedback thing he suggested though, I think its simpler.
Paradoxes cannot exist imo. Let say for instance you go and try and kill your grandfather in the age old tale, and lets assume that every possible thing that can happen will happen.

If you go back and try and seperate your sucess into 2 catergories, 1-everytime you kill ur grandad, and 2-every time you don't. (everytime you don't could happen, from say the bullet being deflected by a bird or a falling branch, remember everything that does happen will)
So you now have two categories, but one leads to you death, and ones leads to you failure. So in theory, no matter how hard you try you can never kill your grandad, because the eventualities that result in a sucess live in a category that leads to your death and thus cannot happen, so they dont. The universe then only has half the eventualities it started with, and they will always lead to your failure, no matter how hard you try.

 

[Philtor]

The fact is: In order to achieve the speed of light (to time travel) would require an infinite amount of energy. Even to get close to it would require a hell of a lot of energy. Marty McFly and the Doc are the only people who managed it

 

[d_brennen]

Stephen Hawkins went on a date the other night.
He arrived home later with cracked glasses, a fractured arm, a bruised temple and 3 broken fingers.
Apparently she stood him up...

Are you... Jim Davidson?

All amazing theory. Unimportant to humanity for time being. We won't last long enough!

 

[Philtor]

Whats black and sit's at the top of the stairs?

..............................................................

Stephen Hawkings in a house fire.

 

[Angilion]

so if i had a ship that could do this and i traveled for 1 minute away from earth then 1 minute back to earth i would be 2 years older?

doesn't make sense to me, surely i would be 2 minutes older?

You are right - you would be 2 minutes older. 2 years would have passed for people on Earth, but 2 minutes would have passed for you.

Say you did it right now. When you got back it would be late in 2012, but only 2 minutes would have passed for you (and your ship and everything in it).

It is that weird, but it is real. Time is not fixed. It has been repeatedly confirmed by experiment. The reason why we can ignore it is that the effects are negligable at any relative velocity that we encounter.

 

[DavidMarq]

As Brian Cox stated, they are talking about 99.99r the speed of light, not 99 percent the speed of light as the OP said.


You can work it out using the Lorenz Factor equation

γ = (1 − v2/c2)−1/2.

Are you sure?

0.99r = 1

Thus

99.99r = 100

So

99.99r % of c = c

 

[Angilion]

It's all Relative, baby!

Go read A Brief History of Time and then you may be a little wiser...

I'd add "Why Does E=mc2?" to that reading list. Brilliant book.

http://www.newscientist.com/article/mg20227141.700-review-why-does-e--mc2.html

Of course, it can be bought online from places I'm not allowed to mention here.