Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: IcyScythe on August 16, 2007, 06:54:07 pm
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Thought this might interest some of you guys. Part of my love for Freespace is my fascination with deep space and I'm guessing it's the same for many of you:
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml
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Are you accusing me of being a space nut?
The NERVE!
*quietly hides small collection of nasa mission patches, stack of printed star charts, and "Satellite hunter" rigged binoculars*
:nervous:
an astronaut moving faster than it would theoretically arrive at a destination before leaving.
I've always wondered about that.
From my totally uneducated perspective I don't think time is nearly so simple in action.
I'd wager that if you could go faster than light you would arrive before we could witness you arriving at your destination from here, but still be on time here. If you returned then you would return before you observed you leaving, but still return at a standard time.
Kind of like a bullet or jet flying faster than sound. It could leave and return before its sound but its sound is not linked to its current position.
Not that we'd really have a way to test any of this.
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The idea behind space and time as most people see it now is exceptionally flawed. The real idea is that if you travel a light year at the speed of light, It is only by visual perception that time speeds up or slows down. If I traveled one light day at the speed of light from one point with a recording telescope to another, it would take one day. However, when I arrive, the secondary telescope records that I arrived just as I departed... But from the other, it looks as if it took two days to get there. The time has not changed in any way, shape or form. It is just the perception of it that is distorted, because light takes a day to travel between those two points.
The idea that you can change the dynamics of space and time by traveling faster than the speed of light breaks every fundamental rule of science we know to date.
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"The pair say they have conducted an experiment in which microwave photons - energetic packets of light - travelled "instantaneously" between a pair of prisms that had been moved up to 3ft apart."
How would they be able to tell? How far were the prisms from each other? Notice how it says "up to 3ft apart."
If they can't measure the space between two prisms, why should I believe that they can tell the difference between the speed of light, and a speed higher than light?
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"The pair say they have conducted an experiment in which microwave photons - energetic packets of light - travelled "instantaneously" between a pair of prisms that had been moved up to 3ft apart."
How would they be able to tell? How far were the prisms from each other? Notice how it says "up to 3ft apart."
If they can't measure the space between two prisms, why should I believe that they can tell the difference between the speed of light, and a speed higher than light?
Well I'm pretty sure it wasn't visually.
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Meh. As much as I suspect it's some kind of an overlooked fluke in the experiment arrangements themselves, I have to say...
If light's speed in vacuum is broken, it doesn't break causality. It would only mean that now this whatever phenomena marks the velocity of causality.
Also, it would not mean that the theories of relativity (special and general) would suddenly stop being accurate. They would remain accurate on their defined area of accuracy, similar to how Maxwell's equations are a special case of quantum electrodynamics... or how NEwton's mechanic works fine at subrelativistic velocities and low energy densities.
Assuming that the light's speed is the "ultimate velocity of causality", so to speak, is a good assumption based on experiments and observations thus far, but not much more (heh - as if any theory could be more :p). It seems to work - but then again, blind people shouting in dark could think that the speed of sound (or mechanical wave motion) is the ultimate velocity of causality.
...obviously I'm a sucker for anything that could bring reasonable long-distance lagless communications and FTL travel to reality, so I naturally hope that this is real and accurate.
Also, the pings for Moon colonies would always be greater than 1.3 seconds if FTL communication isn't made possible. How are those poor kids in Moon colonies gonna play BtRL with Earth-dwellers in the future, huh? So I really wish this to be true... but my sceptic side keeps telling me it probably isn't. :(
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lmao @ pingtimes :p
i wanna go ftl before i die ;)
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Ick, bad article. I've read about the same experient on a german science site : http://www.wissenschaft.de/wissenschaft/news/281702.html (http://www.wissenschaft.de/wissenschaft/news/281702.html)
I couldn't find an english version right now, but in short: The gap was crossed by virtual particles which takes no time. Things like this have been done before, the only new thing here is that it worked over a distance of several centimeters.
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"virtual particles"?
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"virtual particles"?
http://en.wikipedia.org/wiki/Virtual_particle (http://en.wikipedia.org/wiki/Virtual_particle)
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The idea behind space and time as most people see it now is exceptionally flawed. The real idea is that if you travel a light year at the speed of light, It is only by visual perception that time speeds up or slows down. If I traveled one light day at the speed of light from one point with a recording telescope to another, it would take one day. However, when I arrive, the secondary telescope records that I arrived just as I departed... But from the other, it looks as if it took two days to get there. The time has not changed in any way, shape or form. It is just the perception of it that is distorted, because light takes a day to travel between those two points.
The idea that you can change the dynamics of space and time by traveling faster than the speed of light breaks every fundamental rule of science we know to date.
you are either being sarcastic or are ignorant. you have that very much backwards, 'every fundamental rule of science we know to date' requires that time slow down for you the faster you go, c "the speed of light" is basicly the speed of propigation in the universe, it is infinity. sence light has energy, but no mass, it must move at the maximum velosity, c, light moves at the same rate any event in the universe moves, including time.
the whole "you will get there before you leave" is a misinterpretation, it is imposable to move faster than c, this is one of the reasons, by "you will get there before you leave" it means that time for you not everyone else would have flown in reverse. if you move at the speed of light you will experience no passage of time, the faster you go the shorter your trips will be, but when you get back a whole bunch of time would have passed.
get it?
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Special relativity doesn't necessarily forbid all faster than light movement, just as long as information can't do it.
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What if we're already traveling at the speed of light?
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you are either being sarcastic or are ignorant. you have that very much backwards, 'every fundamental rule of science we know to date' requires that time slow down for you the faster you go, c "the speed of light" is basicly the speed of propigation in the universe, it is infinity. sence light has energy, but no mass, it must move at the maximum velosity, c, light moves at the same rate any event in the universe moves, including time.
the whole "you will get there before you leave" is a misinterpretation, it is imposable to move faster than c, this is one of the reasons, by "you will get there before you leave" it means that time for you not everyone else would have flown in reverse. if you move at the speed of light you will experience no passage of time, the faster you go the shorter your trips will be, but when you get back a whole bunch of time would have passed.
get it?
It's WAY more complicated than that, much more so than can be put into words... But I should let you know that most of your statement conflicts with itself in one way or another. Finite and infinite cannot be used to describe the same object or principle, even such a complex thing as space time. On top of that, light is not without mass. A resting photon is without mass, but it is also without energy, matter, or irradiation. There is a reason why black holes can survive, most of their mass after the event horizon comes from absorbed light... which they could not absorb if light had no mass. Just because we cannot currently measure the mass of light does not mean it is zero. It may very well be indefinitely low, but it cannot be zero. 0.000000_1 != 0
Anyway, it may be true that c is infinite, but that would mean that time is not a non-static, but rather space. It would mean 299,792,456 m/s is twice as fast as 299,792,454 m/s. Either that, or an object is moving at 149,896,229 m/s is moving at half the speed of time...
Ow! Thinking makes my head hurt like math!
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Somehow I knew that article would end up linked here.
By the way, the time dilatation is not only a visual effect, but it is a real effect. The time is indeed going slower in a system that is moving faster. This has been confirmed with satellite experiments.
* Takes out popcorn and watches the debate with a grin *
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By the way, the time dilatation is not only a visual effect, but it is a real effect. The time is indeed going slower in a system that is moving faster. This has been confirmed with satellite experiments.
* Takes out popcorn and watches the debate with a grin *
Tell me, were these satellite experiments using a system that was moving closer or further from their line-of-sight?
* Adds a new variable to the equation with a grin *
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Actually, satellites' time goes faster than on Earth surface, due to weaker gravity field* at high altitude. This effect is way more prominent than the pitiful orbital velocities (compared to relativistic velocities), which can be handled very well with classical physics and don't really cause any significant** time dilatation.
Also, you need to remember that special relativity is indeed very special and in it's simplest form it is limited to constant motion (constant relative velocity); anything else and things get real complicated real soon. Satellites don't travel at constant velocity... round and round they go and go, where (and when) they stop, who knows... :p
*Yes, I know that gravity isn't actually a field force in general relativity, but it gets complicated if I say that at high altitude the space and time are less stretched by the mass/energy of Earth, thus making time go faster...
** Yes, there is an effect of time dilatation due to orbital velocity, but it's very very small. Gravitation potential difference makes a much more prominent change in the measurements of time on surface and orbit.
As to what time dilatation is - it is real, obviously. There is no other way that myons borne of cosmic radiation bombardment in the upper atmosphere could ever get to Earth's surface - their half-life is way too short and they should by all experimental data be decimated before reaching the surface... but, as their velocity is so great, their observed half-life lengthens, as the rate of time passage slows down for those fast particles.
Photons are interesting buggers, by the way... they do have momentum, and energy, but according to my knowledge they do not (or rather, should not) have gravitational effect on their surroundings. After all, photon's energy always consists of relative energy - the observed energy of the photon depends solely of the relative motion between the observer and the photon, and obviously the energy of the photon in the emitter's inertial frame. And relative (aka kinetic) energy does not cause gravitational effects, since it would mean that all the fast-moving particles such as neutrinos should be collapsing to small event horizons... which doesn't happen, quite obviously.
By the way, ever thought what is the photon's energy in it's own reference frame? :drevil:
EDIT: The direction of relative velocity doesn't make a fundamental difference in the time dilation itself, but it obviously does affect observations. A good example of what the directions affect (or rather, don't affect) is the "twin paradox", which obviously isn't a paradox at all after you go through it a few times carefully...
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The shivans are coming!
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Tell me, were these satellite experiments using a system that was moving closer or further from their line-of-sight?
* Adds a new variable to the equation with a grin *
I cannot imagine any way this could affect a clock.
Yeah, the photons own reference frame is a funny thing. And also the interpretation of its existance with regards to the outside world.
Mika
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beaking the speed of light with a photon doesnt intrest me, let us know when they break it with an atom. paticle teleportation is something theyve always been able to do in a lab.
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I'm telling you, my idea of a Quantum Microwave machine is coming to pass! It will cook your food before you place it in the oven! :D :hopping: Muahahaha!!!
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I just want to back up Herra Tohtori. Scuddie, you're dead wrong - but I don't blame you; this is one of those things that doesn't really make much sense unless you do the math.
It's actually fairly basic; you only need some Newtonian physics, a bit about the Michelson-Morley experiment, and a good grasp of algebra. You can derive the infamous E=MC^2 and the basics of special relativity by yourself, if you've got a good textbook to guide you.
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By the way, the time dilatation is not only a visual effect, but it is a real effect. The time is indeed going slower in a system that is moving faster. This has been confirmed with satellite experiments.
* Takes out popcorn and watches the debate with a grin *
Tell me, were these satellite experiments using a system that was moving closer or further from their line-of-sight?
* Adds a new variable to the equation with a grin *
:doubt:
they put a clock synchronized to one on earth on a satellite then brought it down and the times were different. way different.
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By the way, the time dilatation is not only a visual effect, but it is a real effect. The time is indeed going slower in a system that is moving faster. This has been confirmed with satellite experiments.
* Takes out popcorn and watches the debate with a grin *
Tell me, were these satellite experiments using a system that was moving closer or further from their line-of-sight?
* Adds a new variable to the equation with a grin *
:doubt:
they put a clock synchronized to one on earth on a satellite then brought it down and the times were different. way different.
Yeah, and they used atomic clocks. So they were all, like, atomic... and stuff. Yeah.
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There are more things in heaven and earth then are dreamt of in all philosophy
How true Petrach :p
Methinks the more we discover the more fangled and confusing it will get, till we reach a point where nothing will make sense to us...too complex for our meager brain to phantom :blah:
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Posted by: TrashMan
Insert Quote
There are more things in heaven and earth then are dreamt of in all philosophy
How true Petrach
Methinks the more we discover the more fangled and confusing it will get, till we reach a point where nothing will make sense to us...too complex for our meager brain to phantom
That is already old news. See "Quantum mechanics", "Particle Physics" and "Quantum Electro Dynamics" for a reference.
Mika
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By the way, the time dilatation is not only a visual effect, but it is a real effect. The time is indeed going slower in a system that is moving faster. This has been confirmed with satellite experiments.
* Takes out popcorn and watches the debate with a grin *
Tell me, were these satellite experiments using a system that was moving closer or further from their line-of-sight?
* Adds a new variable to the equation with a grin *
:doubt:
they put a clock synchronized to one on earth on a satellite then brought it down and the times were different. way different.
So the power went out again... Big deal, I get that all the time :p.
But seriously, sending a satellite with a clock that was sync'd with Earth in and out of outer space wouldn't cause that big a difference, unless it was the nature of the clock in question. How long was it up there, and when was it done? Depending on the timeframe, it is to be expected. Every clock has a certain degree of inaccuracy. You have any linkage to show the info?
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Scuddie: Please see this article (http://science.nasa.gov/headlines/y2002/08apr_atomicclock.htm).
The good meaty stuff is about half-way down, starting with the following paragraph:
'Atomic clocks on board GPS satellites are stable "within 1 part in 10^12," says Lute Maleki who supervises JPL's Quantum Sciences and Technology Group. That means an observer would have to watch a GPS clock for 10^12 seconds (32,000 years) to see it gain or lose a single second. "To guide spacecraft from planet to planet we use clocks that are even better -- good to 1 part in 1014," he added.'
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timing is very important in space flight. being even a fraction of a second off on your burn time would mean possibly being thousands of miles off course. so it makes sense that theese clocks are really accurate. if the the velocity of theese clocks are causing then to tick slower. then nasa needs to start (or are probibly already) using time dialation as a variable in their formulae.
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Scuddie, you might be interested to learn that various everyday phenomenon only work because of Einstein's theory of relativity.
One good example is GPS devices, which must compensate for relativistic time dilation when relaying signals between themselves and satellites. GPS doesn't work without compensating for relativistic temporal effects.
This is a hands-on, practical demonstration of relativity.
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html (http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html)
Check that out, it's a great explanation. And no, it cannot be explained by technical glitches or inaccuracies in the clocks.
If you still don't buy it, I'll be happy to provide you with further explanation. It's actually very cool once you understand it.
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But seriously, sending a satellite with a clock that was sync'd with Earth in and out of outer space wouldn't cause that big a difference, unless it was the nature of the clock in question. How long was it up there, and when was it done? Depending on the timeframe, it is to be expected. Every clock has a certain degree of inaccuracy. You have any linkage to show the info?
no, seriously the time was slower, it DID cause that big of a difference, moving faster, and being in a gravity feild slow time down. they are atomic clocks, they are about the most accurate things in exsistance, and if it was just inaccuracy we wouldn't have been able to predict exactly how much they were going to be off from one and other before the experiment was preformed. time slows for you when you move faster.
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OK, so which clock was ahead? The one on earth or the satellite? Based on what you said, it means that the faster you go in your own relative speed, the slower you are to everyone else? That essentially means that the faster you are, the slower you are, and it's influenced by gravity. Doesn't make sense to me. Either you left something out, I'm not reading you correctly, or my idea that speed could modify space (not time) is correct.
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You're telling us you haven't heard of the Twin Paradox? (http://en.wikipedia.org/wiki/Twin_paradox)?
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If you launch a clock into orbit, bring it back down to Earth, and compare it to a clock that's been on Earth the whole time (and thus moving slower), the clock that was in orbit will be behind.
You are correct. As you go faster and faster, you will perceive time in the universe around you to speed up - if you are going fast enough, thousands of years of outside time could pass in what seems to be only a single year for you.
A clock that goes very fast and is then brought back to Earth will be significantly behind Earth clocks.
Think of it this way:
Everything moves at the exact same speed through space and time. To move faster through space, you've got to sacrifice some of your motion through time.
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actually gravity has the same effect as motion, so the clock in orbit might be ahead, it depends on the orbit, if it's a low altitude orbit then it would be moving fast and have highish gravity so time would flow slower, if it's a high altitude orbit, then it's far enough away from the planit the gravity it experiences is so low the time would be flowing faster there than on the surface of the planet.
this article (http://en.wikipedia.org/wiki/Time_dilation) lists a number of experiments related to time dilation, mostly from velocity but also from gravity.
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Hmmm... Based on that information, it means black holes are simply masses which distort time so much that it cannot change velocity, but also cannot grow in volume because while mass is acquired, time hasn't been able to reflect the change in growth, so the mass in inversely proportional to the difference of tim... AHHHHHH!!!
/me feels his brain explode
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Even physicists still have trouble with black holes, but not too much trouble.
They have some very odd properties, it's true.
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our current laws of physics stop working inside the event horizon of a black hole, but up until that point they work pretty good.