Some of you may of heard it Yesterday, but there is unconfirmed reports that scientists have found particles that travel faster than the speed of light. The particle in question is a neutrino, which by definition is a electrically neutral subatomic particle. While it might not seem like a big deal to many, it challenges many of the fundamental things that are taught in Psychics. To me its very surprising anything like this is possible. Light has strange properties as it behaves both like a wave and a particle. Which caused a debates for many years among scientists until Einstein came along. Basically, he proposed that light was a photon which are small individial waves that are about the size of a particle. Not that I have any great knowledge of it, but this will surely have a signigicant impact on the world of Cosmology (think Steven Hawking). Surely there must be places in spaces where time itself it being warped. An article about it can be found here
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I read this yesterday. Personally, I shall wait until corroborating evidence (i.e. when it is replicated in other independent experiments) is presented before I get too excited.
Mukki has it right -- it is better to wait for corroborating evidence. This is a single experiment -- which contradicts other experiments, and goes against a theory with over a century of high precision experiments riding on it, including the extremely sensitive GPS devices they used to compute position and distance of the labs involved. The most likely outcome of this is that an error will be found when the scientific community has more information and is analyzing the data.
If it is not an error, scientists will still be happy, of course -- there will be new things to learn.
I'm kind of expecting that the reason may either be completely mundane, or even if it's something that requires a change in our understanding of physics, it's something else than FTL travel of particles being possible. After all, the measured speed is only 0.0000002% above c. This might indicate that it's a mundane error.
Some possibilities come to mind. It could be that:
- regardless of the seemingly high care taken to measure the time very accurately, there was some kind of really tiny calibration error somewhere.
- the distance between the two measurement points was measured just a tiny bit wrong (after all, getting the distance wrong by 0.0000002% doesn't sound like an unlikely cause).
- there's a physical factor, still completely within current knowledge of physics, that was not taken fully into account, such as the curvature of spacetime near a gravity well (such as the Earth is). I wonder if this might be somehow related to the so-called flyby anomaly.
- there's an unknown factor affecting the curvature of spacetime, and hence the distances between points, such as some kind of dark matter.
- the equations for spacetime curvature calculations need adjusting for an unknown reason. (OTOH this and the two previous are unlikely because it would affect all measurements of c, including traditional measurements of light itself.)
- an unknown or dismissed quantum effect is in play, making it appear as if the particle traveled faster than c, when in fact it didn't.
My opinion on this isn't worth a lot, but the first idea that came to my mind was this:
Warp wrote:
- an unknown or dismissed quantum effect is in play, making it appear as if the particle traveled faster than c, when in fact it didn't.
My intuition tells me that quantum effects show us that the way we think of subatomic particles must be fundamentally wrong. I really hope I'll still be alive until a better thought model gets developed. News like these always make me most excited. ^^
I really hope it wasn't just an error. But even from an error we could at least learn how to better carry out similar experiments in the future, so I guess this is good news in any case.
Did they take into account that the earth is spinning in their calibrations? Is that something that would need to be taken into account? Like, the earth is spinning in the opposite direction of neutrino travel so you get speed of light in direction of neutrino movement + whatever speed the earth is spinning at that radius in some other direction.
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jimsfriend wrote:
Did they take into account that the earth is spinning in their calibrations? Is that something that would need to be taken into account? Like, the earth is spinning in the opposite direction of neutrino travel so you get speed of light in direction of neutrino movement + whatever speed the earth is spinning at that radius in some other direction.
From what I gather, some of the earliest experiments in determining the speed of light showed that things don't work like that. Time and space dilate in such a way that the speed of light is constant no matter the setup.
A hundred years from now, they will gaze upon my work and marvel at my skills but never know my name. And that will be good enough for me.
Did they take into account that the earth is spinning in their calibrations? Is that something that would need to be taken into account? Like, the earth is spinning in the opposite direction of neutrino travel so you get speed of light in direction of neutrino movement + whatever speed the earth is spinning at that radius in some other direction.
From what I gather, some of the earliest experiments in determining the speed of light showed that things don't work like that. Time and space dilate in such a way that the speed of light is constant no matter the setup.
Basically, yes. The speed of light is always constant. Take, for example, the brain bender that asks: "What would happen if you are driving at the speed of light and turn on your headlights?" Factoring out the fact that it's physically impossible (you would, theoretically, have infinite mass at such speeds (Newton's laws of motion back this up pretty well), nothing would happen. The beams would not present themselves ahead of you; they would stay right where they originated.
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I have a serious question: what stops a spaceship from just accelerating indefinitely? How long would it take to reach the speed of light with normal thrusts (ignore fuel consumption)? Would something drag it down? Would it implode like a black hole (due to near infinite mass) and destroy the thrusters?
A measurement was made that would, if correct, indicate that neutrinos travel very slightly faster than c. So one (or both) of the following is true:
a) Neutrinos travel faster than c
b) the measurement was flawed.
Even the authors of the recent paper consider b) more likely. They make this very clear in their paper, if anyone bothers to read it. They published their results to gain help with finding the error, or to get someone else to independently verify the experiment. They did not announce any scientific breakthrough.
But since that's quite boring, a lot of media are slapping on a tacky headline and spreading claims that none of the authors ever made. Then some forum posters repeat the same nonsense.
Luckily there has been an independent measurement of neutrino speeds quite a while ago:
http://io9.com/5843112/faster-than-light-neutrinos-not-so-fast
Now consider a supernova explosion. In particular, consider Supernova 1987A:
This was an explosion about 160,000 light years from earth. The thing is, the neutrinos and the photons from the explosion reached us at almost exactly the same time. In the cause of intellectual honestly, I need to point out that the neutrinos were detected first, by about 3 hours, but this is because the envelope of the explosion was optically thick and the photons had to bounce around a while, while the neutrinos just streamed right out.
But how much of a delay between neutrinos and photons would we expect if the OPERA result applied?
(delta) t = 2 x 10^-5 * 160.000yr = 3.2 years
In other words, if the effect really were this large, we would have seen the neutrinos from SN 1987A way back in 1984. Yeah, we would have noticed that.
Which is just another hint that the recent results are due to measurement error.
Either way, more research needs to be done to either find the errors or confirm the findings. Until that's done, the prudent assumption is that neutrinos continue to travel at c, and that the hype around the new paper is completely unsubstantiated.
I was not implying that the neutrinos got a little push, I was wondering if the target was moving toward the neutrinos.
However, I don't really know anything about physics at all, so meh.
I have a serious question: what stops a spaceship from just accelerating indefinitely? How long would it take to reach the speed of light with normal thrusts (ignore fuel consumption)? Would something drag it down? Would it implode like a black hole (due to near infinite mass) and destroy the thrusters?
Nothing really "stops" it from travelling that fast. With what exists today, nothing of significant mass can accelerate that fast, primarily due to the fact that the thrusters are pushing something that approaches the aforementioned infinite mass. It'd be like trying to push a building with your own two hands; eventually, the mass is just too great for any further acceleration to be possible, hence why light travels at the speed that it does.
As far as implosion goes: the answer is no, it would not. It would be dense beyond any conceivable form of recognition, but it would not implode.
Current projects: Yoshi's Island Disassembly
Yoshi's Island any% TAS with Carl Sagan
I don't think the scientists claim they have accelerated particles over the speed of light. They have detected them.
If that is the case—and I expect that it is—ToR hasn't been violated in any way. It just never had any confirmations that particles like this actually (can) exist prior to this.
Warp wrote:
Edit: I think I understand now: It's my avatar, isn't it? It makes me look angry.
I have a serious question: what stops a spaceship from just accelerating indefinitely? How long would it take to reach the speed of light with normal thrusts (ignore fuel consumption)? Would something drag it down? Would it implode like a black hole (due to near infinite mass) and destroy the thrusters?
From the view of the really cool space ship you're no doubt using, you're always accelerating yourself with a constant force (assuming an ideal thruster that does not use up its supply of fuel to provide thrust; Somehow the matter in your ship isn't being lost).
If you place a marker at time t such that it matches your velocity at that time, and continue accelerating until t+1, you are moving away from that marker at exactly the same speed you would be if you've been accelerating from t to t+1000001 and dropped the marker at t+1000000. At all points, with the ideal thruster as above, you would never see any change in mass yourself.
But to the observer standing nearby and watching you zip by at near the speed of light (said observer has ideal eyes that can detect any object for any length of time, no matter how short), they will see you in a particularly thin space ship (lengthwise, in the direction you're traveling) with the marker trailing very closely (length contraction), and appears to be moving relative to you by a smaller difference than what you see yourself about that marker.
The observer does see you in a particularly heavy ship. On the other side, you see the observer as particularly heavy as well, traveling at such relativistic velocities. Why doesn't this observer collapse into a black hole and why should you? Nether one will ever become a black hole, no matter how fast you go relative to one another, but I ask this question to make you think things through.
Relativity is strange like that. There is no absolute frame of reference. It's very easy to think that there's this invisible grid and we happen to be traveling along it at some speed. I will ask: Why haven't we measured this invisible grid yet?
Did they take into account that the earth is spinning in their calibrations? Is that something that would need to be taken into account? Like, the earth is spinning in the opposite direction of neutrino travel so you get speed of light in direction of neutrino movement + whatever speed the earth is spinning at that radius in some other direction.
Speed c is independent on the speed of the observer. Even if the observer is moving at half-c in the opposite direction than the particle being measured (which is traveling at c), the observer will not measure the particle traveling at over c. These things do not follow everyday Newtonian physics, no matter how unintuitive it is.
FODA wrote:
I have a serious question: what stops a spaceship from just accelerating indefinitely?
Nothing. You can travel to Alpha Centauri and back in one second (assuming that you can withstand the acceleration). However, when you arrive back at Earth you'll see that over 4 years have passed there (even though you are only 1 second older than when you left). Yet if you measure your own speed during your travel, by measuring the speed of your surroundings (such as stars), you will notice that you never traveled at a speed over c. It's wonky like that.
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I have another question.... What if I'm traveling at 66% of c and someone else is traveling at 66% of c in the oposite direction? I will see him traveling faster than c?
Technically you can see things move at speeds faster than c. For instance, if you have a powerful laser with a dot visible at 100 km, and you spin the diode at, say, 3000 revolutions per second, at 100 km radius the dot will move around the circumference at over-c speeds. However, since light particles are moving from the center, and not along the circumference, this speed is meaningless; it can't carry information or otherwise allow for over-c interaction.
Warp wrote:
Edit: I think I understand now: It's my avatar, isn't it? It makes me look angry.
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I see what you did, but that's a little bit different than what I asked, because in your situation you aren't really moving something faster than c.
In the situation I mentioned, there is a body of matter moving in one direction and another body of matter moving in the opposite direction, so relative to each other one of them is faster than c. No? If c is a constant, then light moves at c, but the other object is moving faster.
As I understand it, in FODA's case, he will still see the object moving at c, because the reflected light that allows the object to be seen will travel at c; thus the visual information about the object's position will not exceed c.
It's also why measurements on relativistic speeds are conducted based on time of arrival vs. time of departure; it's impossible to measure otherwise.
Warp wrote:
Edit: I think I understand now: It's my avatar, isn't it? It makes me look angry.
I have another question.... What if I'm traveling at 66% of c and someone else is traveling at 66% of c in the oposite direction? I will see him traveling faster than c?
No, if you round both speeds to 2c/3, you'll see him traveling at 12c/13 (in special relativity). More generally, the composition of any two subluminal velocities will always result in a subluminal one.
