If this type of question has been asked and answered, I aplogise; I did a keyword search but came up empty. If it has appeared already, could someone send the URL of the original thread?
In one of the threads going on now in this board re designing a magnetic repulsion system for car safety, a respondent suggest that only a field generated with supercooled materials and associated tubing could such a system even be conceived (even bearing in mind all the other objections raised to the very lovely idea from the OP).
Well, the supercooled Hadron supercollider has such spooky magnetic force it whips around a particle at 99.9 % the speed of light, pushing the particle along despite its enormous relativistic mass. (Instead of these poetic adjectives, I don’t know any of the real figures. Help, anyone?)
Now for the old favorite. Since the collider can line up that particle with such precision, what would happen if you put a car, say, in the startup whip-around antechamber, and then shoot it into the main go-round tunnel? Granted its initial mass is fantastically bigger than a particle, but I would settle for 1% of the speed of light.
The magnetic fields aren’t actually what gets the particle up to speed; that’s all done by electric fields. What the magnetic fields do is keep the particles moving in a circle, so they stay inside the machine, rather than just shooting out in a straight line.
It probably wouldn’t, actually. The LHC dipoles deliver up to 8T continuous, the can pincher delivers 5T momentarily, and dumps 3000J, and only just crushes a can I can squash with my fingers. It’s a nice thought, though.
You can shrink coins using a pinch, too. Google it, it really does look like fun (sparks, flashes of light, exploding coils, and the chance of blowing your local power grid).
Among the multitude of technical issues that would make this problematic, the biggest is probably that the beampipe at the LHC is only about 3 cm’s in diameter, so unless we’re talking hot wheels or something, we’re in trouble.
However, if you ignore all the technical problems, and you want to do a straight energy comparison, how about this:
At nominal running conditions, the stored energy in a single LHC beam is roughly 400 megajoules. If we take a car with mass 1000kg and give it the same energy as a single LHC beam, its definitely not relativistic, and will have a velocity of about 900 m/s, or about 2000 mph. Fast, but not that fast.
Remember, the LHC beams are just really not that massive. Nominal conditions is something like 10^13 protons per beam, which is roughly 10^-14 kg.
would it? Maybe I’ve just grown tired of it or they’ve run out of good myths, but I’ve seen enough magic-bullet “myths” to cause me to lose interest in the show.
I know nuttin from nuttin about electrical engineering, as you’ve no doubt surmised. Your calculations deal with simply applying that force straight on, and then we’d get a giant rail gun, right?
A previous poster told me that the magnetic rings in the collider are to keep the particle going circular, rather than going straight. I understand joules, thank god, but don’t even know how to put the question as to how much magnetic “force” () would be needed to whip that car around the pipe a few times? There are a million components to measuring magnetic stuff, and I’m left helpless.
Questions:
Doesn’t the car pick up speed at each go-round?
2.The motion, at high enough velocities that I see standing outside the merry-go-round, would show me a more massive car, my Chevy becoming a Hummer, free of charge, and I’d feel very good about myself, right?
How many megajoules, as well as pertinent discrete figures of about magnetic fields to allow circular motion, would it take to achieve for a real car 1% the speed of light? Say the diameter of the pipe is slightly larger than that of the car.
If the car is a charged subatomic particle, then it picks up speed at each of the RF cavities distributed around the ring. If the car is a car, then I don’t know when it picks up speed, since I don’t know what technology we want to use here. The accelerating technology in the LHC will not accelerate a car (even a HotWheels[sup]TM[/sup]) nor would the magnetic steering in the LHC keep a car traveling in a circle.
If you choose to define mass in a certain way, then yes. But, nobody really defines it that way these days. In modern parlance, the mass of the car stays the same. (The keywords “relativistic mass” should get you loads of old threads on the subject.) Also, at 1% the speed of light (as suggested in your next question), the relativistic effects are only at the 1-part-per-20000 level, so you wouldn’t get a Hummer for free anyway but rather your original Chevy with, say, a topped-off coolant level.
For the magnetic fields: as above, no field strength will steer the car in a circle. The LHC magnets steer the beam in a circle because the protons are electrically charged.
For the energy: you’d need to give the car 7 million billion joules of kinetic energy. If you were willing to wait a month for the thing to get up to speed, you would need about 3 gigawatts of power continuously over that month.
My calculation was even simpler than that - it was just saying assume we managed to get all the energy in a single beam into a car, how fast would the car be going? It completely ignored how you got that energy there.
One thing to remember (which I think might be tripping you up) is that the LHC doesn’t work by just applying a huge electric field over the length of the thing. As Pasta alluded to, the LHC uses a far more complex system of oscillating electric fields. You can imagine it like a series of buckets - if you’re in the bucket you gain some energy; if you’re not, you might lose some energy or even get knocked out of the system. When you dump protons into the thing, its not like one giant line of protons - instead its more like pulses of protons that each fall into the sweet spot of the electric field.
This is why the whole car thing is really problematic. Even ignoring not fitting into beampipe and the lack of charge, the machine was not really meant to work on anything with any kind of macroscopic spatial extent. Part of the field would be slowing it down, another part speeding it up, and a third part doing nothing. You wouldn’t be accelerating the thing at all.
Alas, humanity has much to learn before we can build a Super Chevy Collider.
I’m afraid you’ll have to settle for less than that . . . the particles the LHC accelerates are protons(*), which have a mass that is roughly a billionth of a billionth of a billionth of a kilogram. All other problems of accelerating a car aside, they’re just way too massive.
You can’t assume indefinite acceleration for the car. The magnets have to be strong enough to keep it on the curving circular path of the accelerator. Once the mass/energy/momentum of the projectile gets too high for the magnets to keep up with, it will hit the sides and stop accelerating.
Since this is GQ, I’ll point out to others that the linked video is from The Onion, lest a few actually think it’s a real story. I’m compelled since many people really are under the impression that the LHC is all finished. (Sorry if I’m being a party-pooper Leo Bloom!)
) would be needed to whip that car around the pipe a few times? There are a million components to measuring magnetic stuff, and I’m left helpless.