# Is this really true or it's just science fiction?

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• 03-29-2002
Betazep
Yeah... like I said....

Quote:

Then I posted a bunch of Newtonian thinking, not that I believe that relativity and time dilation isn't real... just for a contrasting point of view.
• 03-29-2002
stevey
would the time dilation effect still happen if a space ship were to enter a wormhole in our galaxy and appear in another galaxy (far far away) ??????
sci-fi i know, but wormholes do theoretically exist, and as i understand it you won't have actually travelled anywhere in the conventional sense.
so i was hoping time-dilation wouldnt occur, because lets face it, we live in a galaxy 100,000 light years across so even at light speed we can't travel very far, and when we come back there won't be anything we'd recognise.
so only a true WARP drive or wormhole is gonna get us anywhere at all !!!
• 03-29-2002
Betazep
Quote:

Here's how you would go about this problem if you want to make the absolute minimum number of assumptions. Suppose the traveler is moving at a very fast speed, constantly emitting light pulses. Because he coveres distance between each pulse, the interval between received pulses (on the planet) is longer than the inverval of emitted pulses (on the spacecraft). Say this ratio is 3:2. The traveler emits a pulse every 10 minutes.

Pulse 1 emitted at 10 min, recieved at 15 min.
Pulse 2 emitted at 20 min, recieved at 30 min.
Pulse 3 emitted at 30 min, recieved at 45 min.

At this pulse the spacecraft turns around and heads back. Now, since he's heading back, the relationship inverts to become 2:3.*

Pulse 3 emitted at 30 min, recieved at 45 min.
Pulse 4 emitted at 40 min, recieved at 52 min.
Pulse 5 emitted at 50 min, recieved at 58 min.
Pulse 6 emitted at 60 min, recieved at 65 min.

And indeed there's a discrepancy. This is, of course, due to relativistic time dilation.

* This is not arbitrary. This inversion relationship has to be true if, for example, two rocket ships traveling next to each other should be able to exhange information in the same way as two stationary observers.

Well such a drastic comparison couldn't be tested since at about(whatever) 300km per second, a space ship would have to be pretty damn far away for a light pulse to take 15 minutes to reach earth, and the pulse itself would be slowed and diffused as it passed through different media. SO accuracy wouldn't be so clean anyway, but you could probably rule out error factors...

So that is theory based upon the theory (which I am not saying is wrong) that has other variables including the effects on the pulses themselves.... (sound has a doppler effect... do we know that light does not when we travel at high velocity?)

but I understand what you are saying. And you are right. Hey... Einstein is backing you.... :D
• 03-29-2002
shtarker
>>Exactly my point. If your mass is infinite then you will require an infinite more amount of energy.

But you have an infinite amount of energy. Even if there is infinitely more mass than there is energy, at infinity they are both the same amount.
• 03-29-2002
shtarker
>>sci-fi i know, but wormholes do theoretically exist, and as i understand it you won't have actually travelled anywhere in the conventional sense.

Last I head, some math genius went through the whole theory of worm holes and found some pretty big flaws, so I wouldn't really count of intergalactic warp drives any time soon.
• 03-29-2002
stevey
Quote:

Originally posted by shtarker
>>sci-fi i know, but wormholes do theoretically exist, and as i understand it you won't have actually travelled anywhere in the conventional sense.

Last I head, some math genius went through the whole theory of worm holes and found some pretty big flaws, so I wouldn't really count of intergalactic warp drives any time soon.

well its debatable, but Stephen Hawking seemed to think they are theoretically possible, i read his book .also discusses warp drives. oddly enough he's a star trek buff. mebe weve both seen too much !!!!! :) beam me up Scotty !

its far fetched, but it's a pity to discount the possibility, because i was thinking when reading this thread, getting a space ship to light speed isnt really possible, and that if we are to actually explore our galaxy (never mind another one), then even light speed is snails pace given the immense distances involved.
• 03-29-2002
Procyon
Quote:

Originally posted by Betazep
Well such a drastic comparison couldn't be tested since at about(whatever) 300km per second, a space ship would have to be pretty damn far away for a light pulse to take 15 minutes to reach earth, and the pulse itself would be slowed and diffused as it passed through different media. SO accuracy wouldn't be so clean anyway, but you could probably rule out error factors...
Actually, 15 light-minutes is only about the distance from Earth to the Sun and back. (And in any event outer space is too empty to affect the speed of light significantly.) And while the experiment I mentioned can obviously not be directly tested with current technology, many other relativistic effects can; I was just offering a hypothetical experiment to counter yours, which had a few flaws.

Quote:

So that is theory based upon the theory (which I am not saying is wrong) that has other variables including the effects on the pulses themselves.... (sound has a doppler effect... do we know that light does not when we travel at high velocity?)
Well, certainly, light has a Doppler effect. When in my experiment the ratio of emission to reception of the pulses was 3:2 that's nothing but a Doppler effect. But the Doppler effect doesn't change the speed of light. If these effects observed were medium-dependent (like sound) their nature would depend on our velocity through that medium, but many different lines of experiment say that's not the case; the speed and nature of propagation of light is the same no matter what your velocity is.

Quote:

but I understand what you are saying. And you are right. Hey... Einstein is backing you.... :D
OK; That's good to know... but there are plenty of people around who will argue against anything, so one can never be too careful.
• 03-30-2002
jinx
Consider this: (from popSci)

A person watches a time machine to see wheather a copy of himself emerges on, say, Tuesday. If it does not, on wednesday, he journeys back in time one day - emerging from the time machine on the same Tuesday when he had not emerged before. This can be reversed: If he does emerge on Tuesday, he simply waits until wednesday to choose not to go back in the time machine. In either case, a paradox is created: The time traveler is ther on Tuesday and not there at the same- a phenomenon that, intruigingly, echoes the same fundamental mysteries of particle behavior at the quantum level.

All of you should read this article not matter how much you believe you know at: http://www.popsci.com and while you're in the quantom leap: http://popsci.com's anti-matter article
• 03-31-2002
CoderBob
So Betazep, you're going to believe an uneducated skeptic who is too arrogant to admit he cannot understand the math and science behind Relativity?

Special Relativity (the one that does not deal with accelerations and decelerations) is a fairly simple concept that, when properly explained, can be understood with a fair bit of ease. Mind you, it is relativity only in the sense that the absolute speed is that of light, and that light is always the same speed: it has nothing to do with spatial position. In fact, Special Relativity is mainly an extension of Galileo's Dictum - that we cannot sense velocity without an outside reference - to include the idea that we cannot sense velocity with some kind of light detector [compared with, for example, dropping a ball]. That light's speed remains constant to an observer while maintaining Galileo's dictum, time dilation is a necessary result. If, for example, a ship is moving and a beam of light is projected downward, to an outside observer it travels along the hypotenuse of a triange, so for a longer distance, than for the inside observer, who sees it travel straight down a leg of the triangle. Because the speed of light is constant to both observers, the observer inside the ship must have time pass less rapidly than for the outside observer viewing light moving farther, yet at the same speed, resulting in a greater time. If the beam of light were a ball instead, the speeds would be different, and nothing would be wrong with the differing perceptions of speed; hence, time only dilates because of light. That's the simple explanation that I have heard.

Of course, in science, truth is what works - if Relativity describes reality then it is of value: and it is certainly capable of describing time dilation with regards to GPS and other high-speed situations. Even if Relativity is not correct, it is handy.
• 03-31-2002
Shiro
There's not much math required to understand special relativity. Even performing calculations with relation to special relativity can be quite easy, at least in easy situations.
• 03-31-2002
vasanth
According to physics time does change depending on velocity.. i.e. when you leave earth.. But biologically your body will wear out at the same time as it was on earth... So as far as this discussion goes.. When you come back to earth you will find that your body is equally worn out as of others of your age.. But in terms of physics your age is different..
• 03-31-2002
Shiro
So you think that time doesn't have influence on the biological system? I think your body is a physical object which is ruled by laws of physics and therefore I think that if you reach high speeds (theoretically), your biological time is slowing down. The reason why we probably won't notice great changes it is that speeds which human bodies can reach are very low in relation to speed of light.
• 03-31-2002
CoderBob
I think he meant that if you have spent the equivalent of seventy years in a space ship, your body will be that of a seventy something year old (depending on when you leave Earth); I don't think he means that people on Earth the thousands of years ago that you left it - in their timeframe - will have the same bodies.
• 03-31-2002
Procyon
Quote:

Originally posted by vasanth
According to physics time does change depending on velocity.. i.e. when you leave earth.. But biologically your body will wear out at the same time as it was on earth... So as far as this discussion goes.. When you come back to earth you will find that your body is equally worn out as of others of your age.. But in terms of physics your age is different..
No, this is completely incorrect. If this were true it would violate the whole premise of relativity in the first place. If the rate your body aged relative to the clocks nearby depended on your velocity, there would have to be an absolute standard of rest - the speed which caused biological systems to age most slowly relative to your clock. This would violate the postulates of relativity.
• 03-31-2002
Nutshell
I just odn't see why travelling at high speeds will be relative to the time. They are seperate things, also, time is abstract. You use time and speed to calculate the distance.
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