Neutrinos: Faster Than Light? (Page 3)
CoIin: I already have a pet universe. I kidnapped 100 Christians and turned them into mice using a radical new rapture simulation technique I developed which went slightly wrong.
Unfortunately they were able to escape and now form a mouse colony in my house - a bit like the early Christians in the catacombs of Rome.
Well, determined to eradicate them, I've bought ten cats, put down mousetraps and rat poison all over the place, and if I'm really lucky, I get to batter one to death directly with the broom.
Much to my astonishment though, they have concluded that the owner of the house loves them and have even taken to worshipping me .
Some of the more cerebral rodents among them believe that all this carnage and horror is a result of their own free will, while others dismiss evil as simply illusory.
Others claim that being eaten alive by a cat once in a while is necessary to serve as a contrast. Otherwise how would they be able to appreciate the euphoria of not being eaten alive?
Still other sanguine sages aver that suffering is necessary in order to facilitate "learning" and have adopted the maxim, "That which doesn't batter me to death with a broom makes me stronger".
Their education shall continue...
DawnGurl: MIT Technology Review:
Various theoreticians have pointed out that there is a formal mathematical analogy between the way certain metamaterials bend light and the way spacetime does the same thing in general relativity. In fact, it ought to be possible to make metamaterials that mimic the behaviour of not only our own spacetime but also many others that cosmologist merely dream about.
Key word: mimic
A new universe has not been created; just an imitation. Thats why the physicists call it a "toy" universe.
Nonetheless a useful tool for exploring quantum mechanics.
(Edited by DawnGurl)
CoIin: There's a discussion on page 1 of this thread about two photons exiting a light source in opposite directions. What is their relative velocity? Is it possible that the c of one and the c of the other combine to make 2c thus defying the cosmic speed limit?
Here's me in the middle holding a lightbulb with photons X and Y moving away from me at the speed of light.
X <<<<<<<< >>>>>> Y
Part of the confusion in this conundrum may arise from the way the arrows are drawn. Let's redraw it so that I'm moving away from X, and Y is in turn moving away from me. Hence:-
X >>>>>> >>>>>> Y
Here's the general solution to the problem:-
P >>>>>>> [V1] >>>>>> Q >>>>>> [V2] >>>>>>> R
P, Q, R are bodies moving in a straight line
V1 is the velocity of Q relative to P (or vice versa)
V2 is the velocity of R relative to Q
Let V3 be the velocity of R relative to P
In classical mechanics V3 is simply the sum of V1 and V2. Relativistic mechanics doesn't work that way, of course. I came across the equation we need today:-
...............V1 + V2
V3 = -------------------
................V1 x V2
........1 + -----------
In our lightbulb example V1 and V2 are both the speed of light, c. If you plug these values into the equation, no surprise, V3 comes out as c, and not 2c.
If V1 and V2 are both 0.9c (see my 2nd to bottom post on page 1), we can't just add them together to get 1.8c. We plug them into the equation, and according to my calculations V3 comes out to be 0.9945c
No need to panic . All is well in the cosmos
(Edited by CoIin)
Corwin: Wow.... so, It took you ten months to get up to speed on a thought that I was on?
Well, better late than never, I guess.....
Maybe ten months from now you'll talk to me again.... and hopefully it won't take longer than that for you to pull your head out of your ass.
Ms_Mafdet_The Great: Here you all go:
Sorry, didn't mean to crash the party
Blackshoes: I thought this was a interesting Article ..I hope you enjoy it as much as I did ..
Just about two days ago I warned that there will be a lot of nonsense about relativity coming out these days, and promptly there are already three articles here on Science2.0 alone that are exactly what I feared: Physicists with only basic knowledge about relativity claiming that particles cannot possibly go faster than light and portraying anybody who holds otherwise as a moron (not literally, but that seems to be the gist). Wake up guys – it is 2011 – modern physics has come a looooong way since Albert.
In modern physics, it is well understood how particles can travel with superluminal velocity without violating special relativity or causality. I will discuss such a mechanism here and the novel experiments it suggest in case the recent neutrino physics observations do hold up to scrutiny.
One possibility is very intuitive: Our three dimensional universe may well be due to a three (or more) dimensional membrane inside a higher dimensional, so called bulk space. This is called “universe on a membrane” or short “membrane universe” (MU). This is a well known scenario in string theory but not restricted to string theory. In the MU scenario, our light velocity c is the maximum velocity of excitations inside the MU membrane, the latter being by the way the very reason for why the MU universe observes Einstein relativity inside of it. That velocity c may be very small compared to the maximum velocity of particles that are not bound to our MU membrane, those that speed freely through the bulk space with perhaps, as indicated by the OPERA data, velocities thousands of times the speed of light.
Ms_Mafdet_The Great: " Wow.... so, It took you ten months to get up to speed on a thought that I was on?
Well, better late than never, I guess.....
Maybe ten months from now you'll talk to me again.... and hopefully it won't take longer than that for you to pull your head out of your ass."
Damn those time travelling neutrinos!!
Corwin: Nah... that was for Colin.
And I still feel that his explanation falls short. Any way you cut it, from the relative position of the observer holding the light-bulb, the photons are traveling in opposite directions from each other at the speed of light... therefor traveling at C*2 relative to each other (at least from our point of view - or rather our point of "non" view, as we cannot observe these photons traveling away from us).
When we look to the edge of the known Universe, we observe the red-shift in the most distant galaxies that shows that the Universe is expanding, Red-shift keeps the cosmic speed-limit in check from our relative point of view. But these are only the photons traveling towards us that we observe, while ignoring all the other photons traveling in the opposite direction away from us -- photons that are impossible for us to observe.
And as I've mentioned before, I'm no Physicist... but there's something going on here. I'm not saying that photons break the rules, I'm saying that we don't fully understand the rules yet.
"therefor traveling at C*2 relative to each other (at least from our point of view - or rather our point of "non" view, as we cannot observe these photons traveling away from us)."
Son, one of the most basic notions in special relativity is that relative velocity is bounded by 'c'. The Lorentz transformations are responsible for this, so you should probably pretend to read about those for a bit before you pretend to understand something. What you're doing is just adding velocities - applying the Galilean transformation - this is exactly one of the flaws of newtonian mechanics; Namely, the assumption relative velocities always follow this transformation.
Anyway, nothing you say really has meaning, so i'll just leave you to try and form sentences.. It probably took Collin ten months to bash himself in the skull hard enough to decipher your feeble stupor.
Corwin: The Lorentz Transformation have more to do with Time Dilation and relative "Simultaneity", regarding bodies in motion at differing velocities in respect to each other. Perhaps YOU should pretend to read about some of those things a bit before YOU pretend that you know more than someone else about it..... son.
Or perhaps you should stick to what you know best, and publish your thesis on your "Bourbaki Transformations -- How to transform yourself into a complete dick-wad in online discussion forums."
RoyalDarkness: Theretically just tachions can do that... neutrinos have real mass, while tachions have imaginary mass. But there is a maximum saying in physics, something is true till experiments say it is not.
Girlzoid: Einstein did not say that nothing can travel faster than the speed of light. He said that mass cannot. Neutrinos are exempt from this becaus they have no mass. This also means their speed is of little use to us since it is hard to interact with something that has no mass.