Shoutbox

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Originally posted by Mattike
Another possible way to travel through time is to establish two worm holes, where if you go through the first one, you get to the second one. And, because this means that you travel a long distance (let's say: the 1st is on Earth and the 2nd on Mars) in a short period of time, you generate a high speed which means you travel through time!

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no, it doesn't mean you travel through time at all. It means you covered a big distance.

I never understood why when I travel at v->c will everyone else on the earth age?
Special relativity thingo explanation?

sweet

my opinion on this - "we're all gonna die" and nobody will praise me for being a prophet because we'll all be gone

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Originally posted by John Anderton
I never understood why when I travel at v->c will everyone else on the earth age?
Special relativity thingo explanation?

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the thing is they don't...

that is, relativly speaking. Only when you travel back again, you'll notice that they will be older.

This is because time slows down the faster you travel. This has even been proofed IIRC, by sending an atomic clock to space and when it came back it was several thousands of a microsecond further.

Maybe explained wrongly... anyways, look up time dialation (another one of Einsteins subjects on Special Relativity)

EDIT: here is something (googled): http://www.phys.unsw.edu.au/einsteinlight/jw/module4_time_dilation.htm

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Originally posted by John Anderton
At 0.99999999*c you would take about 76 or so years to reach the nearest star so excuse me for thinking that travelling at the speed of light won't give us shit.
All we can use (for travelling at v->c) is to travel within the solar system quickly. If you want interstellar travel, you my friend need to travel faster than light. Warp travel
Gogo Star Trek(ie) ()

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Sigh, learn physics at the speed you quoted it would only take 5.2066272 HOURS - my estimation of a few seconds was under more of an assumption of 0.99999..9 (to many decimal places). But 76 years is absolute rubbish...
You're even wrong in Newtonian Physics, using Newtonian Physics it would only take just over 4.2 years (since the nearest star is 4.2ly and you're almost travelling at the speed of light)

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Originally posted by CookieRevised
This is because time slows down the faster you travel. This has even been proofed IIRC, by sending an atomic clock to space and when it came back it was several thousands of a microsecond further.

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Yes you are 100% correct about time dilation and time passing slower in the moving frame of reference (ie. for the person/object that is moving), although the proof wasnt quite as easy. At school they teach that experimental evidence was provided by synchronising 2 atomic clocks and sending one around the world in a plane, when they were returned the one which was moving (on the plane) was noted to be running behind the one which remained grounded, in reality however, gravity also affects time and space and as such the results were not as simply due to Special Relativity alone (it has however since been proven using more complex reasoning).
Another source of evidence was given by radioactive particles which are created when radiation from the sun hits the atmosphere (or something like that), whilst these particles (cant remember the name of the specific particles which are most often noticed) have a half-life of about 2 microseconds and as such many are not expected to reach anywhere near the surface of the earth before they decay, however, their extremely high velocities result in them reaching the surface in a greater quantity than would be predicted indicating that time for these particles has advanced slower, and hence it has taken longer for them to decay relative to us on the ground.

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Originally posted by John Anderton

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Originally posted by Volv
Like I said before, the effects depicted in Star Wars and Star Trek (in terms of travel, not the flashing lights) do not require travelling faster than the speed of light, by travelling at 0.999999999 times the speed of light you can reach any point in the universe within a couple of seconds at most (and that is real physics, and is actually possible). Although by the time you get there Earth would have aged many billions of years (although the people in the spaceship would have only aged the few seconds which it took) - Special Relativity

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At 0.99999999*c you would take about 76 or so years to reach the nearest star so excuse me for thinking that travelling at the speed of light won't give us shit.
All we can use (for travelling at v->c) is to travel within the solar system quickly. If you want interstellar travel, you my friend need to travel faster than light. Warp travel
Gogo Star Trek(ie) ()

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Exactly! If it takes 8 minutes for light to get from the Sun to Earth, then it would take more than just a few seconds to go "anywhere" in the universe. Then you also have to factor in that it would be near impossible to get between 2 points in the universe without running into an obstacle, be it a planet, star or black hole etc. As for going back in time, I think that idea comes from the theory that time dilates for the object (in this case you), making two different time streams, that will never catch up. (seeing as light, by definition, can never go faster than the speed of light) But you would still be in the "current time" wherever you stopped ther journey I think...

Hm.  A mini universe?  How can you have a mini universe?  Is that like a mini bar?  Can I pick things out of it?  But I do realise it would have been so much cheaper in the usual universe.

Hell... if they make their universe, I'd like to have permission to form some planets like cheerios.

However, the scientists should focus more on travelling that fast, instead of making small objects do it.  Hm, maybe if they can go that fast, we can all ride on them like in Dr. Strangelove, and in the future we may all have our own universe, with uhm universal stuff.

The future is bright, the future is hopefully not Windows based.

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Originally posted by SpunkyLoveMuff

Exactly! If it takes 8 minutes for light to get from the Sun to Earth, then it would take more than just a few seconds to go "anywhere" in the universe. Then you also have to factor in that it would be near impossible to get between 2 points in the universe without running into an obstacle, be it a planet, star or black hole etc..

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Sigh, learn physics and learn Special Relativity, at 0.99999999 times the speed of light it would only take 5.2066272 HOURS to reach the nearest star, if you were travelling at the 0.999999999999999999999999999999999999 times the speed of light (to a very large number of decimal places) it would take only a few seconds to reach any point in the universe (THIS IS WHAT SPECIAL RELATIVITY IS ABOUT).
In case you havent realised, objects dont behave the same as light. I posted about this on the page before, read the thread before posting incorrect info.

EDIT: As for hitting objects, travelling 'faster than light' in Newtonian Physics (that is, ignoring Special Relativity) it would have exactly the same dilemma, unfortunately you would not enter some type of weird protective worm hole in a different dimension or anything crazy like that just by travelling at any speed (faster or slower than light) and hence you are just as likely to collide with any objects.

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Originally posted by John Anderton
I never understood why when I travel at v->c will everyone else on the earth age?
Special relativity thingo explanation?

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This is related to why it only takes a couple of seconds to reach any point in the universe at a speed just below 'c'.
The fact is that for the people on earth, they see you travelling at 0.99...9c, and observing you, they see that you reach your destination in (distance / 0.99....9c) seconds (just like Newtonian Physics would predict). However, due to the effects of time dilation (that is, a moving object passes through time more slowly), time for you (on the spaceship) is passing 'slower', meaning that for every one of your seconds, you're actually covering more distance than for every one second on earth. So therefore according to you (on the spaceship) it has taken significantly less time to travel to your destination than it has as observed from Earth (because your time elapsed slower than time on Earth), therefore you have only aged by however long it took you to reach your destination (as observed from the spaceship) whereas Earth (and the people on it) has aged by however long it took you to reach your destination as they observed it - clearly [i hope] you can see that you have aged less than those on earth as more time has elapsed on Earth than on your spaceship.

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Originally posted by SpunkyLoveMuff

Then you also have to factor in that it would be near impossible to get between 2 points in the universe without running into an obstacle, be it a planet, star or black hole etc.

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Actually, the universe is mostly made up of empty space. Thus unless the size of the craft you were using was around the size of a galaxy or something absurd like that you would never really hit anything.
Universe is mostly empty space

Its only dodgy science books which make us think that the universe is full of stuff, when in fact even our solar system is empty space.

As an analogy think of the atom; if an atom was the size of a football field the Nucleus would be about the size of a pin in the middle of this field. Although yes, quantum mechanics and the heisenberg principle does make this analogy a bit invalid.
If atoms are 99.999999999999% empty space...

Although the universe is mainly empty space, there is the occasional hydrogen atom scattered out there. Now sure, that's not bad, cause on Earth you crash into Oxygen and Nitrogen particles every time you move.

But then you're not moving at 0.9999c or whatever. Raindrops are enough to damage missiles travelling at Mach 11 (around 3740m/s). So, travelling over 80,000 times faster than that, a hydrogen particle may just be enough to cause serious damage to an object.

But, by the time we've invented an engine that goes that fast, we'll probably have invented force fields and the like.