Large Hadron Collider Particle Speed At Collision

Well, all it matters, is the collision energy, that has the potential if high enough, to "brake" known particles to something more elementary. Absolute and relative between particles speeds, are, well, both relative. Inconsistencies to Newtonian predictions is what lead to relativistic extensions in the first place. If you were hypothetically riding the back of the accelerated particle, approaching relativistic speeds (according to an external observer) your inertial time (and perception of it) having slowed (according to relativity), then, if you had a police speed radar handy that wouldn't have to obey relativity limits, yes, it would show opposite particle approaching you at 2C, and you both should be fined for exceeding light speed limit. It's just that you won't find such a radar. S.M.

No, the particles do not collide at a relative velocity to each other of 2c. The space/time distortions keeps things below c.

No. The sums don't work that way. The total relative velocity is always less than c for particles that have rest-mass and exactly c for particles that don't.

I think that was an interesting question myself. Although considering that neither particle is actually traveling faster than the speed of light, then I would say nothing is breaking that speed limit. But then you have to wonder about the particles being ejected.

Anyway it's pretty interesting stuff. It amazes me what science can pull off

And btw, I was reading this article about the gigaelectronvolt (GeV) while looking in to this stuff. It appears they're actually describing the mass of these particles increasing during the process rather than concentrating on speed.

Here's an article that directly asks the same question the OP asked as well.

Yes, it is quite common to see particle mass expressed in terms of energy. The rest-mass of an electron, for instance, is slightly less than 511 keV - around half the energy you'd get if you brought an electron and a positron (an anti-electron) together (slowly), annihilating them to produce a flash of gamma rays and neutrinos.

What lets physicists 'get away with it' is that Nature herself makes no distinction between mass and energy. To her they are simply different forms of the same thing, 'mass-energy.' That's what the equals-sign in E = mc² means: when it comes to making distinctions between mass and energy, Nature herself couldn't care less. To her there is no difference; none at all.

"Those are Man's distinctions, not Mine. Glad you finally saw the light, btw, but please don't abuse it."

Oops. Too late.

Einsteins theory stipulates that nothing can travel faster than the speed of light regardless of the relative velocity of the observer. This means that an observer standing on the ground between the two particles sees each particle travelling towards him at almost the speed of light while a (hypothetical) observer travelling with one of the particles sees the other particle as travelling towards him at a faster speed than the ground observer but still slower than the speed of light.

The formula for the velocity of particle 2 as seen by a person travelling with particle 1 is ((velocity of particle 1)+(velocity of particle 2))/(1 + ((velocity of particle 1 X velocity of particle 2)/(speed of light squared))).

Assume both particles are travelling at a speed of 0.9c (0.9 X speed of light) towards each other (as measured by a stationary observer on the ground). Using the above formula gives (0.9+0.9)/(1 + (0.9X0.9)/1) = 1.8/1.81 = 0.994c as the speed that an observer travelling at the same velocity as one of the particles would measure the speed of the other particle.

Wow. As simple as it was, that formula just blew my mind. GA lol

In the application of the formula

[ (0.9+0.9)/(1 + (0.9X0.9)/1) = 1.8/1.81 = 0.994c ]

in the second half of the left expression, where it reads in part X0.9)/1) how did that come out to 1.81(c)?

I'm assuming you left out the closing right paren in your second expression on the left side, i.e., (1 + (0.9X0.9)/1) )(added by me), without which it doesn't evaluate at all. But if it should be as I've shown it, then this expression evaluates to (1+(1.8)/1) equals 1+1.8 equals 2.8.

What did I miss?

With

as reference, and where, in his example

v and u both equal 0.9c, we've got

s = (0.9c + 0.9c) / [1 + (0.9c * 0.9c / c²) ]

s = 1.8c / [1 + (0.81c² / c²) ]

s = 1.8c / 1.81

s = 0.99(44..)c .

Thank you. Stupid struck. Clarification (and knowledge struck harder) (and, probably, just in time).

I'll try to duck quicker next time stupid comes tooling along.

Lol! Gawd I hate it when that happens - and it happens a lot more these days. That or I'm simply more aware of it. Either way it can be pretty discouraging!

My wife says I'm getting older. She's right. We all are. Rats!!

And I tried Sooo hard!!!

At the rate of sixty seconds per minute - and sometimes faster (depends on how much fun you're having versus the inlaws coming over for an extended stay. Mine did that for a year one week. It's all relative. )

You needn't even invoke something so exotic as the LHC to get such conditions of relative speed, and you can do it on your own kitchen table - just aim two flashlights at each other!

The particles from each one - photons - are travelling at at even higher speeds (c) than the ones in the LHC (because photons don't have rest-mass) relative to their flashlight, so what is the sum of the photons' speeds relative to each other? It is also c.

It's not intuitive at all, but it's true nonetheless - and took an Einstein to first figure out why. The sums of relative speeds of physical objects - any physical objects; photons, protons, cars, spaceships, you name it - never exceed c. Ever.

Moreover, it is not the 'speed of light' *itself* that is the limit, btw, in spite of the term's popular usage. Light just happens to travel at that same speed, c. More fundamentally it is the limit on how fast *information* can travel. Quantum mechanics, for example, describes certain systems whose (entangled) components superficially appear to violate this speed limit, but even in these systems no information is actually being exchanged faster than c. It is truly a fundamental speed limit.

Einstein had afterthoughts of calling his theory of relativity, "Invariantentheorie". Invariant mass is a measure of total energy. It tells you how much mass can be created from the energy imparted in the system. If a system has no momentum, E=mc2 applies. So knowing the energy at rest is equivalent to knowing its invariant mass. If you have two beams with the same energy collide, they will have equal and opposite momentum. At the point of impact, the added momentum of the two particles will be zero. So all the energy in the two particles will now be converted to mass. I guess that is the aim of colliders so they can identify particles.

Now suppose you had a single beam and a sitting duck target with zero momentum. Not all the energy is available to make new particles. It turns out that if we increased the energy in the moving particle we would only get back the square root of the energy. By placing two moving beams on a path to collide we do not simply get twice the energy . That would be Newtonian thinking. The two beams will collide with much higher energy because of the relativistic theory.

The speed is the problem of thinking in Newtonian terms. Remember it is the energy imparted to the mass that will limit the speed. The amount mass all be converted to energy at the speed of light is approached and therefore have the mass gets smaller. It really never reaches the C. It is a limit on the speed so to speak. Consider yourself on the particle approaching another particle travelling at your same speed near the speed of light. Your speed relative to the approaching speeding particle will always be less than the speed of light. Read Lisa Randall, Knocking on Heavens Door .

We are trying to break a Higgs boson ??

My vocabulary is broken.