
Neutrino tomography of Earth - lainon
https://www.nature.com/articles/s41567-018-0319-1
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jboggan
This is really brilliant, literally jaw-dropping. I was really blown away by
the idea and construction of the detector itself and this application is
astounding.

[https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory](https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory)

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bacon_waffle
My favourite story about the construction of IceCube relates to the drilling
of the holes to deploy the detector. They used two types of drill, which melt
the firn (compacted snow) on top and ice lower down. One is a sort of conical
heat exchanger, the other circulates water through a Big water heater on the
surface.

In the early days of South Pole Station (late 1950s), supplies were airdropped
in - the cargo planes of that era couldn't land on the snow and going overland
was very difficult. Many of the parachutes wouldn't open properly, and so lots
of supplies (including a bulldozer) and parachutes wound up buried in the
snow. South Pole slowly accumulates snow, so that debris has gotten deeper and
deeper below the surface over time.

Of course, the holes required to build IceCube had to go deeper than those
supplies, but the drill can't go through things that don't melt, so in some
cases the holes had to be moved off the nominal grid. According to the story I
heard, one of the holes ran in to a bunch of meat, which floated to the top of
the bore...

~~~
sohkamyung
No mentions about finding meat here, but you might be interested in this story
at IEEE Spectrum about the construction of IceCube from 2011 [1].

[1] [https://spectrum.ieee.org/aerospace/astrophysics/icecube-
the...](https://spectrum.ieee.org/aerospace/astrophysics/icecube-the-polar-
particle-hunter)

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Balgair
Supplementary Figure 6 is pretty cool! There seems to be a lot of strange
things happening at the mantle-crust boundary that will take some further
study to understand.

All said, this is a MAJOR advance in our understanding of the Earth and the
science thereof. This technique should allow for some pretty amazing things in
the future.

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phkahler
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.

~~~
InclinedPlane
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 tonnes is outside of our engineering
capabilities at present. However, within the next several decades this might
be feasible.

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

~~~
InclinedPlane
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 (we know there are sub-surface
glaciers, but we don't know how deep they go or how pure the ice is. And
potentially some of the large sub-surface oceans (on Ganymede, Enceladus,
etc.) might work too but we know even less about their properties.

~~~
pvg
Not all detectors were optical so if you found a moon made of, say, dry
cleaning fluid, you'd still be good.

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lolc
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?

~~~
russdill
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.

~~~
mnw21cam
[https://what-if.xkcd.com/73/](https://what-if.xkcd.com/73/) gives a fairly
decent summary of the level of interaction of neutrinos.

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peter303
Frankly this idea has been repeated every few years since the invention of
tomography 40 years ago. Hopefully someone will actually do it one of these
years.

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caf
In theory, would IceCube be able to detect neutrinos generated by the same
mechanism in the atmosphere of Venus?

~~~
sohkamyung
In theory, yes. In practice, probably very difficult. They did detect a
deficit in neutrinos from the direction of the moon though [1].

[1]
[https://icecube.wisc.edu/news/view/131](https://icecube.wisc.edu/news/view/131)

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k_sze
Could this technique be useful on other planets?

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stocknosticator
[https://mobile.twitter.com/stocknosticator/status/7425391560...](https://mobile.twitter.com/stocknosticator/status/742539156090281984)

Looks like my prediction will come true.

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richardbdrowley
> Neutrino detection will revolutionize oil and other natural resource
> discovery.

No.

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godelski
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."

