To Catch Deep-Space Neutrinos, Astronomers Lay Traps In Greenland's Ice

sciencehabit shares a report from Science Magazine: High on Greenland's ice sheet, particle astrophysicists are this week drilling boreholes in a search for the cosmic accelerators responsible for the universe's most energetic particles. By placing hundreds of radio antennas on and below the surface, they hope to trap elusive particles known as neutrinos at higher energies than ever before. Detectors elsewhere on Earth occasionally register the arrival of ultra-high-energy (UHE) cosmic rays, atomic nuclei that slam into the atmosphere at colossal speed. Researchers want to pinpoint their sources, but because the nuclei are charged, magnetic fields in space bend their paths, obscuring their origins. But theorists believe that as UHE cosmic rays set out from their sources, they spawn so-called cosmogenic neutrinos in collisions with photons and, because neutrinos are not charged, they travel to Earth as straight as an arrow. The hard part is catching them.

Neutrinos

[Anonymous Coward]

Some astronomical number of them passes through your body every second - trillions * trilllions - but the chances of one interacting with your body in your lifetime are maybe 1 in 4.

High Energy Neutrinos Different

[Roger W Moore]

You are talking about extremely low energy neutrinos left around after the Big Bang. The problem with them is that they have insanely low energies (just like the cosmic microwave background) making them almost impossible to detect because they hardly ever interact and when they do they barely have enough energy to change the energy level of an electron in an atom.

The neutrinos we go after with IceCube are a little different. At extreme energies, there are very few neutrinos but they are much more likely to interact. In fact, while at lower energies (even those much higher than the Big Bang relic neutrinos) neutrinos will happily pass through the Earth. However, at extreme energies the weak force, through which neutrinos interact, becomes much stronger and the Earth starts to become opaque.

This is actually why we need to start adding detectors in other locations - like Greenland or off the coast of Vancouver Island [p-one.nu] - than just the south pole because, at these energies, detectors can only see neutrinos coming from close to the horizon where there is enough shielding to remove cosmic ray shower backgrounds but not enough material to block the neutrinos themselves.

Re:

[gtall]

Flunkie: Errrr. . .Mr. Feinman, why are you wasting your time with quantum science, it will never amount to anything.

Richard: Science is a web of interconnecting ideas, it advances by bits and bobs.

Flunkie: Science, schmience, look it, you cannot even see the damn particles you are writing rule about. Hell, given your math, it isn't even clear where or when they exist. Stop wasting money and do some productive work.

Richard: Here's some shiny beads, you can play over there in the corner with them and no one

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[jbengt]

No, I'd say the "hard part" is justifying any of this work, since "catching them" to pinpoint a source light years away is information we intend to do basically nothing with because of an utter and complete lack of capability.

And you call yourself a geek mux.

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[geekmux]

No, I'd say the "hard part" is justifying any of this work, since "catching them" to pinpoint a source light years away is information we intend to do basically nothing with because of an utter and complete lack of capability.

And you call yourself a geek mux.

Yes. Being knowledgeable about enough of our actual capability to do anything with the data we're capturing, takes an understanding of quite a few areas.

It also helps to understand and accept the fact that there are a lot of bullshit jobs in the world today, justified by little more than greed and/or corruption.

Science, is hardly immune to that.

Fire

[Roger W Moore]

No, I'd say the "hard part" is justifying any of this work, since "catching them" to pinpoint a source light years away is information we intend to do basically nothing with because of an utter and complete lack of capability.

Back in the stone age lightning came from a few kilometres up in the clouds and yet by studying how it interacted with the material around them our distant ancestors discovered fire. Once they knew it existed they then figured out how to make it themselves.

I'm glad you were not around then to tell them they were wasting their time studying something that came from a source that they had no capability to reach. If they had listened to that we would all now be sitting in our cold, dark caves slowly freezi

Re:

[geekmux]

No, I'd say the "hard part" is justifying any of this work, since "catching them" to pinpoint a source light years away is information we intend to do basically nothing with because of an utter and complete lack of capability.

Back in the stone age lightning came from a few kilometres up in the clouds and yet by studying how it interacted with the material around them our distant ancestors discovered fire. Once they knew it existed they then figured out how to make it themselves.

Those ancient ancestors were still using grunts to communicate. They couldn't even enunciate the word "material", much less formulate concepts around it. They discovered how nature creates fire initially.

And observing a lightning bolt doesn't actually teach anyone about how to "make" fire for yourself, since that's about as realistic as using that energy source to send a car back in time. The only thing they were likely doing before they figured out how to make fire via a completely different method was d

Teaching Yourself

[Roger W Moore]

observing a lightning bolt doesn't actually teach anyone about how to "make" fire for yourself

Yes, it does if you engage a modicum of thought. First, it tells you that fire exists and the first step to making something is knowing that it can exist. Next, careful observation of fire from lightning tells you that the thing you want to make is hot. Now at this point, it does get a bit tricky but I hope you might be able to manage to follow the logic. I suspect the thinking process of our early ancestors was something like: fire from lightning is hot and exists on wood, what happens if I make some wood

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[geekmux]

observing a lightning bolt doesn't actually teach anyone about how to "make" fire for yourself

Yes, it does if you engage a modicum of thought. First, it tells you that fire exists and the first step to making something is knowing that it can exist. Next, careful observation of fire from lightning tells you that the thing you want to make is hot. Now at this point, it does get a bit tricky but I hope you might be able to manage to follow the logic. I suspect the thinking process of our early ancestors was something like: fire from lightning is hot and exists on wood, what happens if I make some wood hot? At that point all it takes is a paleolithic genius, let's call him OneStone, to remember that when he rubbed his hands together they got warm and to then think, what happens if I rub two sticks together? Will that make the wood hot and create fire?

I suppose after OneGrunt was permantly blinded by the lightning bolt that went off close enough for SmoothBrain to deduce that heat created fire, yes one could follow this logic. And comparing hand friction to sticks making fire is quite a stretch. That is not a natural deduction, and it takes a hell of a lot more friction to actually make fire, so OneGrunt was probably quite frustrated trying for a while (especially when 90% of humans today would seriously struggle to "make fire" from scratch even armed

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[Roger W Moore]

Perhaps if we put our human brainpower towards space exploration instead of warmongering, we might stand a chance.

Ah but that's the rub - we do much better in the longer term by not just focussing on one thing exclusively. Think about domestic lighting. Back when there were candles if we had concentrated all our research on making a better candle then today we would probably have incredibly efficient oil lamps and gas lights but no electric light bulb or highly efficient LEDs. The former took an understanding of electromagnetism to develop and the latter requires an understanding of quantum mechanics.

I've heard it

Re:

[geekmux]

Perhaps if we put our human brainpower towards space exploration instead of warmongering, we might stand a chance.

Ah but that's the rub - we do much better in the longer term by not just focussing on one thing exclusively.

Some of the most technologically advanced things mankind has ever created, sit in the definition of "weapon of mass destruction". We focused like a laser to create the atomic bomb. And sadly, we succeeded, and created the world-on-a-trigger-finger we have today.

THAT, is how "smart" we are as a species.

And I agree with you. Perhaps if humans didn't focus on the one thing they're hopelessly addicted to, we might actually find a cure for the Disease of Greed that has plagued mankind for thousands of years,

As straight as ... light

[sgunhouse]

Naturally, gravity will bend neutrinos, just as it bends light. But close enough. Not sure how interactions between cosmic rays and photons are supposed to produce neutrinos though.

Re:

[Anonymous Coward]

Naturally, gravity will bend neutrinos, just as it bends light. But close enough. Not sure how interactions between cosmic rays and photons are supposed to produce neutrinos though.

The effect of the earth's gravity (and sun's) on light is much smaller than the effect of the earth's magnetic field on charged particles. Much much smaller.

They had better crack on, then

[ytene]

since, sadly, at the rate things are warming up, Greenland won’t have ice for that much longer.

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[RockDoctor]

The detector assemblies used in detectors like Ice^3 last for years to maybe a decade before they need changed out for repair, or replacement with new detectors of improved or different capabilities. So as long as there is likely to be ice at a location for a couple of decades, then it may be worthwhile putting a telescope at a particular location with a particular horizon (compared to other operating telescopes.

Looking beyond a couple of decades the way science is funded these days isn't worth doing. Few

Oblig xkcd quote...

[LordHighExecutioner]

there is plenty of space [xkcd.com] in Greenland for detectors!

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[Thud457]

But first they need to clear out the airplanes [airspacemag.com] and and secret nuclear bases [atlasobscura.com] the US left lying around up there.

Not the first ice-based neutrino detector

[JoshuaZ]

Note that this is not the first ice-based neutrino detector. IceCube is a similar system set up in Antarctica https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory [wikipedia.org] . But as TFA discusses, IceCube is set up to detect photons in the roughly visible wavelengths. This new detector will focus on detecting radio waves. TFA does not mention but there's another advantage also. IceCube largely detects neutrinos from the Northern Hemisphere. That's because it is in the Southern Hemisphere and the easiest neutrinos to detect against all the background are those which have come through Earth, which is acting as a massive shield against non-neutrino particles. Even buried deep underground, IceCube still gets a lot of noise from particles coming directly from the Earth's atmosphere which makes neutrino's coming from the South hard to distinguish. If this works, we'll possibly end up having good neutrino data from the Southern Hemisphere.

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[habig]

There are several radio-based neutrino efforts at the south pole, too. RICE was the first, deployed back with the AMANDA protptype more than 20 years ago. ARA and ARIANNA are current efforts (all have Wikipedia entries if you're curious). ANITA is a balloon-borne one that observes the ice sheet from above for even higher energy events. TFA is about current efforts to do the same in Greenland, which will indeed give us complementary sky coverage to the south pole efforts.

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[JoshuaZ]

Thanks! I forgot about those.

Cloaked Ship?

[douglasfir77]

I was under the impression that neutrino emissions where likely from a cloaked ship! THE ALIENS HAVE ARRIVED, THE ALIENS HAVE ARRIVED!!! :-p