Particles faster than light measured - Technology & Science - CBC News

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- 09-23-2011CommonTaterWell, he did say it was only a theory....
- 09-23-2011phantomotap
xkcd: Neutrinos

Soma - 09-23-2011Salem
Perhaps neutrino's are not restricted to travelling solely in Spacetime.

You can make a lot of progress going from A to Z, if you don't have to visit the whole alphabet along the way.

Fire off a few billion neutrino's, and detect a handful at the other end.

Then blindly assume there was "no cheating" going on in the race. - 09-23-2011AndrewHunter
That article is misquoting Einstein's theories, specifically Einstein said nothing can accelerate from < c to past c. Particles can in fact be created at faster than the speed of light. As for those experiments, we would have to see what the parameters were exactly, the detectors in use, blah, blah, blah.

- 09-23-2011VirtualAce
I just heard about this earlier today. Very interesting stuff and most of it far above my head....but interesting nonetheless. So if the speed of light is no longer the speed limit of the universe does this mean we may actually be able to attain it in the future. I've also heard that it would theoretically require an infinite amount of energy to travel that fast but do not know enough about it to agree or disagree.

- 09-23-2011CommonTater
Even Einstein said it was only a theory...

Personally I don't see how it's realistic to think there is a hard limit to how fast we can go... Think about this one...

You are in a rocket ship heading along at half the speed of light. Inside your ship, control signals are flowing around as needed. Since electrical signals generally move at some significant fraction of the speed of light ( Wave propagation speed - Wikipedia, the free encyclopedia ). Does it not strike you as entirely possible that a signal travelling from the back of the ship to the front exceeds the speed of light by quite a significant margin?

We see this effect all the time in 2 way radio communications. It's called the "Doppler Effect" where a signal from a source travelling toward you is shifted slightly higher in frequency and one travelling away is shifted lower... If you have a high velocity source (like a satellite) travelling toward you, broadcasting a signal, is the signal travelling at C*VF + Vsource? Yes it is, that's how the doppler effect works... That radio wave might well be exceeding the speed of light... - 09-23-2011Mario F.
I'd only have to assume so. But this discovery can put us back in pre-Einstein times and would destroy basically most of what we know about the laws of the Universe. The limit on the speed of light was "artificially created" (I support that to be the correct term) so the formulas we use today don't break.

That conclusion is inferred from the complete formula devised by Einstein which reads:

E = mc²/√(1-v²/c²)

Where:

E = Energy

m = mass

v = velocity

c = speed of light

The formula we usually see (E = mc²) is a simplification that assigns 0 to v. That is, the formula we all know only demonstrates the attributes of E, m and c for resting objects.

Now, with the complete formula, you'll notice that as you increase the velocity, the object mass keeps increasing. With that comes the need to increase energy for the object to keep travelling at the same speed. As your velocity increases you have greater and greater demands for energy, ad infinitum, without ever breaking the speed threshold.

So you need infinite energy because you gain infinite mass. - 09-23-2011cyberfishQuote:

Personally I don't see how it's realistic to think there is a hard limit to how fast we can go... Think about this one...

You are in a rocket ship heading along at half the speed of light. Inside your ship, control signals are flowing around as needed. Since electrical signals generally move at some significant fraction of the speed of light ( Wave propagation speed - Wikipedia, the free encyclopedia ). Does it not strike you as entirely possible that a signal travelling from the back of the ship to the front exceeds the speed of light by quite a significant margin?

(Please correct me if I am wrong. I have only taken an introductory course in theoretical physics, many years ago)

When you are traveling at half the speed of light relative to some inertial frame of reference (let's say ground), time passes slower on your rocket than on the ground. So say if you are moving at 0.75c, and you fire a bullet in the same direction at 0.75c, in your frame of reference (on the rocket), the bullet is moving at 0.75c.

However, to the ground frame of reference, the bullet is not moving at 1.5c, because time is faster. Speed is distance / time. Observer on the ground will see that the bullet moved the same distance, in longer time. They will see the speed of bullet as something between 0.75c and c, say 0.85c. The effect gets more pronounced the closer you are to speed of light. If you are at 0.99999c, your 1 second could be years on the ground. If you are moving at c, your clock is stopped compared to clock on the ground. This is why it's a popular concept in science fiction that if you can travel faster than speed of light, you can go back in time.

This effect is called time dilation, and has been experimentally verified, even at just human speeds. If you take 2 atomic clocks, make sure they are synchronized, and take one of them around the earth in a jet, when you compare them later, the stationary one would be ahead. The amount of time dilation measured also agree with predictions made decades ago before such measurement is possible. - 09-23-2011CommonTater
Time dilation only makes sense if you believe there is a limit to the speed you can travel... the speed limit only makes sense if you believe the time dilation theory... it's circular logic... not science at all.

- 09-23-2011cyberfish
But time dilation has been experimentally verified, with very real clocks and very real jets.

- 09-23-2011Mario F.
And time dilation is in fact what the second part of Einstein formula describes:

D = √(1-v²/c²)

The idea here, to demonstrate the challenges of travelling at the speed of light is to assign the speed of light to v. The result will be 0. Which means, if you are travelling at the speed of light time will stop, and with that, any chances of ever slowing down again.

Incidentally, because space and time are a continuum, the dilation of space is also a consequence demonstrated by the same formula. To any outside observer, the faster an object moves the more it seems to shrink. At the speed of light, D becomes 0, which means the object disappears forever. - 09-23-2011gardhr
Nah. Probably due to an error in measurement. Wouldn't this be fairly simple to confirm or refute by, say, comparing relative fluctuations in neutrino activity originating from the direction of the sun's core and the visible appearance of solar flares, perhaps? A distance of ~90-million+ miles would more than sufficient to produce a noticable gap, methinks.

A radio signal sent from the rear to front of the vehicle would still be clocked at C, no matter what the speed or acceleration of the ship is (including 99.999999999999999999% C).

Doppler shift is a change in frequency, not propagation. - 09-23-2011whiteflagsQuote:

Personally I don't see how it's realistic to think there is a hard limit to how fast we can go...

Infinity welcomes careful drivers. - 09-23-2011Mario F.
To add to that:

if I'm inside a ship moving at 100 km/h and I move from the back of the ship to the front of the ship in a car doing 20 km/h, I'm moving at 20 km/h relative to the ship and 100 km/h relative to space.

My body (and this would also be true if I was being dragged by a rope attached to the ship and tried to pull myself inside) is a part of the mass required to move the ship at 100 Km/h. Ship and occupant constitute a single body of mass.

Similarly, If I'm driving my car at 150 Km/h and my daughter reaches out from the back seat, she didn't just yanked my right arm off my shoulder at 150 km/h plus whatever speed she applied to her gentle tapping. - 09-23-2011gardhr
Or rather, 80 km/h with respect to that particular reference frame (notice I didn't say "space", which implies an absolute coordinate system).

This has less to do with physical contact than an equivalence in velocities, though. If you and I were traveling perfectly alongside eachother, in a vacuum, windows open, travelling at say 99% C, then we could play a game of toss just as if we were stationary (and in a relativistic sense, we would be).