Neutrino tomography of Earth • Hacker News Board

Re: Neutrino tomography of Earth

#31

Post by godelski » Wed, Nov 07, 2018, 6:50 AM UTC

not2b wrote: post #6

gpuhacker wrote: post #5

Earlier quoted context omitted.

An in space detector is (at least to my understanding) not that easy, as you need the surface of the Earth to interact with the neutrinos. These interactions result in muons, which allow to detect that there was a neutrino in the first place. Also, there is a pretty big source for neutrinos pretty close to Earth, but Earth is in its orbit, as opposed to the other way around.

The IceCube neutrino detector consists of about a cubic kilometer of ice. You're not going to put one of those in orbit.

There are other types of neutrino detectors. Not that it really makes the problem any easier to solve, but this isn't the only way.

Re: Neutrino tomography of Earth

#32

Post by godelski » Wed, Nov 07, 2018, 6:51 AM UTC

InclinedPlane wrote: post #10

phkahler wrote: post #3

Would it be feasible to put a source and detector in orbit so we could get high resolution CT images of the interior of the earth? IIRC the detector used here is very large, but there are smaller ones and a directed source would go a long way towards making the detection simpler.

Neutrino detection generally requires large volumes and large masses (for very large values of "large"), neither of which are as yet feasible for space based systems. The IceCube neutrino observatory, for example, makes use of a volume of ice that is on the order of a cubic kilometer (over 900 million tonnes). Suffice it to say, building cubic kilometer solid structures in space that weigh hundreds of millions of ton…

That's also understating the size. While the final detection is happening in the ice, the column of air above it is also important.

Re: Neutrino tomography of Earth

#33

Post by godelski » Wed, Nov 07, 2018, 7:01 AM UTC

richardbdrowley wrote: post #26

stocknosticator wrote: post #14

https://mobile.twitter.com/stocknosticator/status/7425391560... Looks like my prediction will come true.

> Neutrino detection will revolutionize oil and other natural resource discovery. No.

To be fair, it probably will. But the ability to do it in a cheap enough manner is certainly far enough away that the value of those resources will likely be much lower than they are today.

Accurate, cheap, and small neutrino detectors would revolutionize any industry dependent upon locating things within... well... anything. But that statement is as meaningful (if not less) as "faster computers will revolutionize the automotive industry."

Re: Neutrino tomography of Earth

#34

Post by [deleted] » Wed, Nov 07, 2018, 7:46 AM UTC

InclinedPlane wrote: post #10

phkahler wrote: post #3

Would it be feasible to put a source and detector in orbit so we could get high resolution CT images of the interior of the earth? IIRC the detector used here is very large, but there are smaller ones and a directed source would go a long way towards making the detection simpler.

Neutrino detection generally requires large volumes and large masses (for very large values of "large"), neither of which are as yet feasible for space based systems. The IceCube neutrino observatory, for example, makes use of a volume of ice that is on the order of a cubic kilometer (over 900 million tonnes). Suffice it to say, building cubic kilometer solid structures in space that weigh hundreds of millions of ton…

[deleted]

Re: Neutrino tomography of Earth

#35

Post by [deleted] » Wed, Nov 07, 2018, 7:46 AM UTC

InclinedPlane wrote: post #20

lootsauce wrote: post #16

Earlier quoted context omitted.

Could we not just land a detector on the far side of the moon. Thats pretty large no?

You need to have the reaction mass to make use of. Most neutrino detectors use special chemicals in custom tanks, IceCube uses antarctic ice. You would need not just mass but ice or water for a neutrino detector, ideally highly compressed optically clear ice. The only possible candidate in the Solar System that fits that bill at present is Europa. Though it's possible that similar conditions might also exist on Mars…

[deleted]

Re: Neutrino tomography of Earth

#36

Post by dotancohen » Wed, Nov 07, 2018, 9:14 AM UTC

logfromblammo wrote: post #12

gpuhacker wrote: post #8

Earlier quoted context omitted.

Exactly

You might be able to tow it in from elsewhere using a light sail, however. Beyond our current technology, but might be doable by 2100, or sooner with a fortuitous comet trajectory.

And once it is in orbit, how do you propose stationkeeping against exospheric drag? Preferably a solution that will remain reliable for 10^n (n>>3) years.

Re: Neutrino tomography of Earth

#37

Post by lolc » Wed, Nov 07, 2018, 9:22 AM UTC

Nice but I'm still left wondering what the J/bit of neutrino transmission would be. Wouldn't it be cool if we could replace the long fiber optics stretching around the globe with direct-through neutrino stations?

Re: Neutrino tomography of Earth

#38

Post by russdill » Wed, Nov 07, 2018, 10:00 AM UTC

lolc wrote: post #37

Nice but I'm still left wondering what the J/bit of neutrino transmission would be. Wouldn't it be cool if we could replace the long fiber optics stretching around the globe with direct-through neutrino stations?

Given the difficulty in neutrino detection, I seriously doubt it would replace fat links. You could gain quite a bit of advantage when it comes to trading though using a low bandwidth link.

Re: Neutrino tomography of Earth

#39

Post by mnw21cam » Wed, Nov 07, 2018, 10:24 AM UTC

russdill wrote: post #38

lolc wrote: post #37

Nice but I'm still left wondering what the J/bit of neutrino transmission would be. Wouldn't it be cool if we could replace the long fiber optics stretching around the globe with direct-through neutrino stations?

Given the difficulty in neutrino detection, I seriously doubt it would replace fat links. You could gain quite a bit of advantage when it comes to trading though using a low bandwidth link.

https://what-if.xkcd.com/73/ gives a fairly decent summary of the level of interaction of neutrinos.

Re: Neutrino tomography of Earth

#40

Post by phkahler » Wed, Nov 07, 2018, 2:08 PM UTC

godelski wrote: post #31

not2b wrote: post #6

Earlier quoted context omitted.

The IceCube neutrino detector consists of about a cubic kilometer of ice. You're not going to put one of those in orbit.

There are other types of neutrino detectors. Not that it really makes the problem any easier to solve, but this isn't the only way.

That's what I was thinking. They have sent neutrinos from one lab to another with a man-made source and a detector smaller than 1km^3. The idea is to put a strong source in orbit and aim it at an orbiting detector. Over time this configuration would be used to scan the entire planet. Still a huge challenge.