h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Have you ever travelled at light speed? Have you? I very much doubt it. And neither did Einstein.
I believe that when we reach (or nearly reach) lightspeed that we suddenly grow extremely weary and become a bit nausious.

There: that's far less exciting than all that 'dilation' nonsense made up by some 'Einstein' guy I've never heard of - and therefore must be true.

If you've never heard of Einstein then you obviously don't know what you're talking about on this subject!!

The phenomenon has been scientifically proven - if you want to disagree then by all means show me the proof!

Grrrr, I would *really* like to know why nothing can go faster than light. There's nothing special about light, it's just another form of energy. So why is its speed terminal???

I think it's all to do with the universe expanding. Expanding at the speed of light that is! So if you could travel faster than the speed of light then you would fall out of the universe but nature doesn't want this to happen, so when you start getting close to the speed of light it says "uh oh (like the teletubies) someone is trying to out run us" and then it makes you put on some extra weight so you can't run so fast!

Yeah, well you'd never catch ME going at light speed.

You wanna know why you can't travel faster than light? Here's why:

When you travel at "reletivistic speeds" (speeds great enough for these effects to be felt), you gain weight. This is because energy is mass, according to E=mc^2. When you go really fast, you have alot of energy, therefore, you have alot of mass. This is an expodential process. As you approch light speed, you gain more mass. So, you need more energy to go faster. Then, you get heaver. Then you need more energy to go faster. Etc. You would need infinite energy to travel at light speed. Sorry.

Ah, well, I'm no expert on this one, but the light speed limit is believed to be THE limit due to the equations that have been proven, including the one surrounding time dilation. At exactly light speed, in a vacuum this tends to happen:

1) Length becomes zero
2) Mass becomes infinite
3) Time stops for the object that is travelling at that speed.

Now, how many objects have YOU seen that looked like that? And remember, we're talking about an absolute vacuum as well... you dont get many absolute vacuums, just a lot of very near ones.

Firstly, I would like to say that I know very little of Physics. Secondly, I read the other day (and I think it was on the BBC website) that a scientist in Russia has proved Einstein wrong by making a particle travel 10km @ the speed of light. Apparently it was measured as being at both ends of the track at the same time.

Will PS of Tea
:-p

So I've got this space ship - stacks of fuel, all the decks arranged perpendicular to the direction of travel. I turn on the engines and start accelerating at a comfortable 1g. After a while I start to reach *relativistic* speeds (relative to what? the Earth I left behind? forget it, I am interested at what happens to me - or maybe relative to the cosmic background radiation or relative to the 'average' speed of the rest of the universe or perhaps the quantum vacuum fluctuations - I don't know) So I am heavier and need to turn up the engines inorder to maintain my acceleration of 1g - or do I? Since the fuel I am chuckking out the rear of my spaceship is also 'heavier' I should only need to keep the engines running at the same rate.
So, I have been accelerating merrily at the rate of 1g for ages now - my calculations indicate that I ought to be moving at several times the speed of light by now. I am not, of course, but that doesn't stop me getting to alpha centauri in what for me is classical time (i.e. the distance divided by the speed I ought to be doing if I really had been accelerating at 1g for so long.) By the way - at the half-way point I swing the ship around and decelerate at -1g thus prolonging the artificial gravity effect.
Please, everybody, point out the flaws in this argument. (The best one I have heard so far is the increasing friction/drag caused by colliding with quantum background fluctuations - Particle anti-particle pairs and such like).

This isn't ENTIRELY (okay, at all) to do with what you said, but apparently, (according to my friends, who are, let's face it, not the most reliable of sources) 'scientists' have managed to make light travel er... FASTER than the speed of light. I.e. it travels faster than it did in the first place. However, it's still only travelling at the speed of light, by default. No-wonder Trekkies invented 'warp' speed - it's far less confusing.

Speaking of light not traveling at the speed of light:

I heard that a few months (years?) ago, the managed to make a beam of light trave around thirty miles per hour. Really. If I remember right, they somehow took a normally opaque crystal and made it transparent, but not much. Then, when the light traveled through it, it slowed to 30 mph.

Another weird thing. I got the following email from a friend:



From the London Sunday Times - 4 June, 2000

SCIENTISTS claim they have broken the ultimate speed barrier: the speed of light.

In research carried out in the United States, particle physicists have shown that light pulses can be accelerated to up to 300 times their normal velocity of 186,000 miles per second.

The implications, like the speed, are mind-boggling. On one interpretation it means that light will arrive at its destination almost before it has started its journey. In effect, it is leaping forward in time.

Exact details of the findings remain confidential because they have been submitted to Nature, the international scientific journal, for review prior to possible publication.

The work was carried out by Dr Lijun Wang, of the NEC research institute in Princeton, who transmitted a pulse of light towards a chamber filled with specially treated caesium gas.

Before the pulse had fully entered the chamber it had gone right through it and travelled a further 60ft across the laboratory. In effect it existed in two places at once, a phenomenon that Wang explains by saying it travelled 300 times faster than light.

The research is already causing controversy among physicists. What bothers them is that if light could travel forward in time it could carry information. This would breach one of the basic principles in physics - causality, which says that a cause must come before an effect. It would also shatter Einstein's theory of relativity since it depends in part on the speed of light being unbreachable.

This weekend Wang said he could not give details but confirmed: "Our light pulses did indeed travel faster than the accepted speed of light. I hope it will give us a much better understanding of the nature of light and how it behaves."

Dr Raymond Chiao, professor of physics at the University of California at Berkeley, who is familiar with Wang's work, said he was impressedby the findings. "This is a fascinating experiment," he said.

In Italy, another group of physicists has also succeeded in breaking the light speed barrier. In a newly published paper, physicists at the Italian National Research Council described how they propagated microwaves at 25% above normal light speed. The group speculates that it could be possible to transmit information faster than light.

Dr Guenter Nimtz, of Cologne University, an expert in the field, agrees. He believes that information can be sent faster than light and last week gave a paper describing how it could be done to a conference in Edinburgh. He believes, however, that this will not breach the principle of causality because the time taken to interpret the signal would fritter away all the savings.

"The most likely application for this is not in time travel but in speeding up the way signals move through computer circuits," he said.

Wang's experiment is the latest and possibly the most important evidence that the physical world may not operate according to any of the accepted conventions.

In the new world that modern science is beginning to perceive, sub-atomic particles can apparently exist in two places at the same time - making no distinction between space and time.

Separate experiments carried out by Chiao illustrate this. He showed that in certain circumstances photons - the particles of which light is made - could apparently jump between two points separated by a barrier in what appears to be zero time. The process, known as tunnelling, has been used to make some of the most sensitive electron microscopes.

The implications of Wang's experiments will arouse fierce debate. Many will question whether his work can be interpreted as proving that light can exceed its normal speed - suggesting that another mechanism may be at work.

Neil Turok, professor of mathematical physics at Cambridge University, said he awaited the details with interest, but added: "I doubt this will change our view of the fundamental laws of physics."
Wang emphasises that his experiments are relevant only to light and may not apply to other physical entities. But scientists are beginning to accept that man may eventually exploit some of these characteristics for inter-stellar space travel.



I've never checked to see if this is a real article in the London Times, but if this is real, it's suprising that no news organizations in the States have picked up on it yet.

I just checked the-times website, it seems to be completely legit. That is amazing.



Lucas

Assuming, of course, that E actually does = mc^2. Which it might not. I mean, it seems to, but then again it also seemed for a while that maggots grew spontaneously out of beef, and that Michael Jackson was maintaining the sort of career that wasn't likely to be destroyed by a few eccentricities. But of course, many theories are destroyed by a few eccentricities, as Kepler will attest. Saying the the speed of light is "absolutely true," especially considering the numerous paradoxes associated with it, is very unscientific and sort of pigheaded. And if there's one thing science teaches us, it's that the pigheaded are generally proven to be wrong, vis a vis the Catholic church circa Galileo's days.

I'm not saying relativity is a load of fettered dingo's kidneys. It's incredibly useful for measuring star distances, powering fission generators, blowing up japanese towns and that sort of thing. I'm only saying that it should be considered with the same type of disjointed agreement we generally save for explaining the concept of hygeine to people living in the subway.

Oh, and by the by, this is not time travel. Using this method, one appears to have travelled through time to an observer at the firing end, because the effect is seen as the cause is being initiated. However, in none of the equations i've considered so far could the effect be made to appear before the cause had begun. I'm hardly more than a casual contemplator of this sort of physics, but feel that this helps buffer the shock of FTL travel for the general relativist because it means that cause and effect can still be linked in real time (outside of the system of energy that is how we see everything), but their perception cannot be. Of course, this is assuming that real time exists, which it unfortunately doesn't in relativity (but then again, neither does real space, space that is perfectly available to be filled and unbendable). If we operate for a moment outside the common world of time governed by the speed of light (since speed is a factor of distance over time, anyway, and both of these are relative, i see no reason why you can't just forget about the two relatives and create a new unit of speed not bound to mass distance and light time, basically an "empty" unit), it makes sense that the result would seem impossible in a spacetime based on light. After all, you'd have to go beyond the measurable capacity of both light and mass.

[I end now before I begin to babble. I go to either continue this conversation over coffee at Denny's or to drink an entire bottle of Fu-ki sake. If I were to shoot an image of myself doing this faster than the speed of light, it wouldn't necesarily show somebody the future, more likely it would show the present occurance to someone very far away. please don't ask me what would happen if the transmission were intercepted by a mirror, because i'm pretty sure i don't want to think about it]

I dont take anything in the world to be the solid gold truth. Read Orwell's 1984, that will give you a mind job on what could be happening right now in our lives.


Lucas

I'm really fat and tired. I must have travelled at near light speed then. Hey that was fun. I just travelled back in time to when I was thin, but since I was thin and had less mass I couldn't be back in time cause I couldn't have been fat in the first place.

Hehe, that one comment in the London Times article is hilarious! I think it goes something like "Before the pulse had fully entered the chamber it had gone right through it and travelled a further 60ft across the laboratory. In effect it existed in two places at once, a phenomenon that Wang explains by saying it travelled 300 times faster than light." and then it goes on to say that it was moving forwad in time. How laughable is that? Just because the pulse had moved at an enormous speed doesn't mean that it went backward's in time. It just means that it took an imeasureably small time to get to those two points. The pulse still "lived/existed" in all of those places between the gun, chamber, and wall. To live in those places and to travel a distance it would take time, however miniscule that may be. So in effect it doesn't affect the casuality principle and shouldn't be causing this "controversy" between physicists. Heck, you could of realized that without even having a basic knowledge of physics (I'm only in Grade 12 Physics). All it takes is some common sense. All in all though, it is still pretty cool that they got the pulse to go 300x that of the speed of light. Oh yah, how does light have momentum when it has no mass? Because I know that it exerts a pressure and that it has momentum. But I don't understand how it can have a momentum when it has no mass. Can some one please explain that!

Ciao! ~Tyler

I agree, that doesnt make much sense at all

momentum = mass * velocity

momentum and velocity are both vectors, whether it is relevent or not. But how does it have a momentum, does it create some sort of virutual momentum.


Lucas

Everybody

Aren't we forgetting something here:

No-one on Earth has demonstrated the
ability, mechanical or psychokinetic,
to achieve light speed. Aren't we
taunting ourselves a tad in discussing
this topic?

By the way, remember that Marmite is
currently a relatively cheap and simple
way to have fun. It is also an excellent
hangover restorative.

The Wall

It iss obvious that other life formes that travel in space must comunicate and the only way to do this over long distances is faster than light.