Catching High Energy Aliens With Cherenkov Light (with a picture of a sonic rainboom - what else?)

New Particle Gadgeteering post: Catching High Energy Aliens With Cherenkov Light

Cherenkov detectors are awesome.

Comments

[Booster Spice]

If the highest energy incident is a billion? times the LHC, which has been likened to coliding high speed trains, shouldnt it appear on seismic arrays as meteoritic impact as the energetic cascade impacts the ground in a shock boom?

[Misplaced Mage]

Now, the real trick would be to spot Cherenkov light emanating from the vacuum in deep space, and not when something impinges upon the Earth’s atmosphere. Since Cherenkov light is a result of particles moving faster than the speed of light in a medium interacting with particles in said medium, would observing Cherenkov light emanating from free space be evidence of particles traveling faster than c interacting with virtual particles during the instant of time that they actually exist?

[Georg]

I'm still fairly sure the first alien spacecraft to approach the earth will be greeted by some irate radio astronomer/physicist, telling them to please turn off that terrible subatomic radiation source because they've only got a few minutes on the equipment to make an observation of the Lesser Shelmotheh Globular Cluster, and their spaceship drive is spewing mueons all over the spectrum.

[Southpaw]

I should have guessed that the water detectors were detecting Cherenkov light. Fascinating, awesome science.

4800964 Heh, "Get out of the way and while you're at it, stop spamming primes on the hydrogen bands! We get it, you're here. Can't you see we're doing Science?

[Misplaced Mage]

4800964
There's an idea—first proof of extraterrestrial intelligence that doesn't come via SETI processing mountains of radio telescope data, but rather from grad students monitoring a giant vat of water at the bottom of a played-out gold mine in South Dakota.

---

"What's it say! What's it say!"
"Well, if those are the first 113 primes, and that's the first 71 members of the Fibonacci sequence… apply the right hand rule… carry the three… then it reads, 'S.E.N.D.H.E.L.P.I.M.B.E.I.N.G.H.E.L.D.P.R.I.S.O.N.E.R.I.N.A.N.A.L.I.E.N.N.E.U.T.R.I.N.O.D.E.T.E.C.T.O.R.'"
"…"
"…"
"Did you see any unusual output?"
"Nope!"
"Then I'll just recycle this drive for the next run's data."

[Georg]

4801149 I've done something fairly close for a writeoff.

[AppleTank]

I wonder if any sci-fi FTL has animated the photonic boom

[Pineta]

4800906

If the highest energy incident is a billion? times the LHC, which has been likened to coliding high speed trains, shouldnt it appear on seismic arrays as meteoritic impact as the energetic cascade impacts the ground in a shock boom?

A common comparison is that the LHC beam energy of 14TeV is about the same as the kinetic energy of a flying mosquito, while that of a high energy cosmic ray is about the same as that of a well-shot tennis ball. The significance is that all that energy is in a single proton. It can create a shower of particles, but it won't make the Earth shake much. I did hear of an idea to 'listen' for neutrino interactions in the sea using sensitive microphones. Apparently the Ministry of Defence have a facility in one of the Scottish islands for listening out for submarines, and a team of physicists were able to borrow it to see if they could hear any particles. I don't know if they succeeded - although I assume they didn't make any amazing discovery or we would of heard. (Unless the MOD covered it up.)

[Pineta]

4800937

Now, the real trick would be to spot Cherenkov light emanating from the vacuum in deep space, and not when something impinges upon the Earth’s atmosphere. Since Cherenkov light is a result of particles moving faster than the speed of light in a medium interacting with particles in said medium, would observing Cherenkov light emanating from free space be evidence of particles traveling faster than c interacting with virtual particles during the instant of time that they actually exist?

Indeed. The fact that we see cosmic rays at all means they must travel less than the speed of light. If they moved faster than light, they would emit Cherenkov light, and thus lose energy and slow down. And as we saw neutrinos from supernova 1987a at the same time as the light, we know they move at light speed (+/- 1 part per billion or so).

[Super Trampoline]

How large are these flashes of light, and are they primarily in the visible spectrum by chance or for some other reason?

[Pineta]

4801558

How large are these flashes of light, and are they primarily in the visible spectrum by chance or for some other reason?

Size depends on the energy of the incoming particle. The CTA array has telescopes spread over a large area (~100m if I remember correctly). The spectrum intensity increases for shorter wavelengths, but you also have to look at the transparency of the medium. The full calculation is complicated - the result is blue. But you also get radio Cherenkov detectors - which are flown on balloons over Antarctica, and look for radio waves produced by neutrino interactions in the ice below (they only see the very highest energy particles - but with a detector the size of a continent, there's a chance of sizing a few).

[MSPiper]

4800906
4801528
To clarify: high-energy cosmic rays have far more energy on a per-particle basis, but each LHC beam consists of trillions of particles, whereas cosmic rays consist of just one. The result is that while any given high-energy cosmic ray impact packs quite a bit more punch than an LHC impact, the LHC beams as a whole contain a lot more total energy.