This is also the source of the classic blue glow in water cooled nuclear reactors. Electrons move through the water faster than light and leave behind a kind of 'sonic boom' of photons in its wake.

Thank you, I lost my mind, briefly, reading that part.

Light slows down in dielectric materials because as an em wave it interacts with the polarization of molecules. Neutrino has very little interaction with matter, OTOH.

https://news.ycombinator.com/item?id=49977885

Correct, they do have a probability of interacting, but it's extremely low, depends of the energy of the neutrino (its momentum) but basically it can go through 1 light year of lead and still have only a 50/50 chance of interacting.

to put things to scale 1 ly is 9,460,730,472,580,800 meters, or 63,241.077 astronomical units, the distance from the Earth to the Sun.

Needless to say, it's pretty weakly interacting as far as interaction goes...

A cubic kilometer is a volume, it does not dictate the shape.

The upper layers of detectors are buried over a kilometer below the surface in order to shield the array from most cosmic rays.

If they drilled down any further they'd reach the interior of the hollow earth, obviously not permitted

Since neutrinos don’t interact with much of anything, its path doesn’t deviate from its origin. Different origins emit neutrinos with different levels of energy. When a neutrino hits a nucleus, the blue light emitting particle in ice follows closely the same direction. Measuring the direction and the magnitude (lighting energy) of the vector we can classify its origin. Collecting a bunch of the same signature we know there's an object at that direction emitting at that energy level. From the vector and energy we kind of know whether it’s from the solar system or not.

Identifying the origin let us see objects behind dust clouds or other obstacles.

We know this because

- In the beginning, for the first couple of events, only because they have way higher energies than anything in the solar system could produce - By now, with enough data collected, their origin correlates very well with the milky way - we are close to identifying several far away galaxies as well

This is the significance. Contrary to some statements published today, IceCube was not primarily built to study Neutrinos, it was built to study the universe using Neutrinos.

That's why we care where they are coming from, we want to learn about the astrophysical objects that produce them.

If it did they should get the Novel prize.

Neutrinos are very weakly interacting and hence you need a massive amount of some matter through which they can pass so as to have a decent probability of getting an interaction.

Ice at kilometer level depths is exceptionally clear and transparent since the pressure (from layers above) removes any air bubbles and hence any Cherenkov radiation due to neutrino interaction does not get scattered. This means observations can be done clearly and precisely.

Finally, the rigidity of Ice can hold the sensors precisely and the depth guarantees that no unnecessary external noise from the surface can affect the measurements.

All the above are ideally met by the Ice at the south pole and hence the IceCube Neutrino Observatory was established there.

H2O is the key, not ice. Ice is nice because it's rigid, so you don't need a boat [1]. They're also working on making detector under the sea [2].

[1] https://www.amusingplanet.com/2015/07/the-surreal-world-of-n...

[2] https://news.cnrs.fr/videos/detecting-neutrinos-at-the-botto...

Among other things this ice is super transparent.

I am adopting “Furthest possible end of any logistics chain” as a more refined version of “middle of fucking nowhere”. Thank you.

This was fascinating, thank you for posting! Here is a video I found of the different types of sleds they use on the traverse - https://www.youtube.com/watch?v=mjrQrKjotpA

The book about it can also be used to detect neutrinos too?

This is quite nuanced and not as most people assume.

It is the "phase velocity of light in that medium" that is exceeded.

phase velocity of light in a medium = speed of light / refractive index of the medium.

Thus the EM wave is slowed down in a medium and so a charged particle can exceed it producing Cherenkov radiation. This is similar to a sonic boom in atmosphere when speed of sound is exceeded. In both cases the object is traveling faster than the wavefront.

It is only in vacuum that "phase velocity of light" = "group velocity of light" = c (i.e. 300,000 km/sec)

What really is the speed of light in a medium/vacuum, group or phase velocity? - https://physics.stackexchange.com/questions/450377/what-real...

And remember, the "speed of light in the medium" depends on the wavelength of the light. This is why prisms separate light by color.

Optical sonic boom.

How can we make neutrinos useful to us? - https://www.youtube.com/watch?v=F0HQp2nBFhI

What are neutrinos good for? - https://www.youtube.com/watch?v=-6iyyM5XRx4

If it moves, we can communicate with it. Your mobile phone's neutrino signal will not lose a single bar, wherever you are on Earth, or in the solar system, or in the galaxy.

Neutrinos need a large detector volume for efficiency because they interact so rarely. You can’t detect them directly so you need a transparent medium to detect their collision byproducts. Good detector mediums are water and ice, and are underground to minimise background light. There are relatively few places you can do this. Mine caverns and under the sea are the most common, but marine detectors are notoriously hard to build. Francis Halzen proposed using ice. At the Pole, the glacial plateau is 2 miles high and the breakthrough was confirming that the ice is in fact highly transparent if you go deep enough.

Why the pole specifically? You could probably build a second IceCube 100 miles away, but how are you going to get that materials there? Pole has a skiway for large aircraft and infrastructure to house a large number of people. The traverse (SPoT) only became operational near the end of construction - the initial holes were drilled in 2005 and almost everything had to be flown in.

Telescope In The Ice does a great job of explaining the history and science behind the experiment.

The best science comes from areas that have no obvious use. The original insights into nuclear physics, quantum physics and relativity were all pure thought experiments. They led to the world we live in.

I'm personally very happy that we're still funding science that isn't obviously monetised.

The reason for Antarctica is that it's the only place you find cubic kilometres of stable ice that doesn't drift around.

My best guess would be just the remoteness.

1: Ice-mass that isn't contaminated by atomic testing fallout (if the ice has been there since the 40s it's without radioactive waste (faschinating to read about how WW2 wrecks is a prime resource of steel since it's a huge amount of steel without trace amounts of radionucletiods from testing fallout).

2: No current interference (nuclear power, radiowaves,etc) creating possible test uncertainties.

3: I'm sure there are other reasons

The negative naturally is cost, but since the expriment succeeded it will probably be useful for any attempts to send robots or even humanity into space beyond the solar system.

Where else would you go look for a cubic km of ice?

If we're serious about AI taking over jobs, we'll probably need to get more comfortable with any kind of undirected work-for-its-own-sake, not less.

Perhaps this was downvoted in ignorance?

This question could have avoided the offense:

What is the relation between Cherenkov relation and effective mass in longitudinal plasma waves?

Looking at the behance site it's a pretty good choice, glad some illustrators are still making a living in the AI age.

This image* from Wikipedia surprised me. The topside building is...you could say...the tip of the iceberg. The detectors span a huge area going over 2km deep. The predecessor AMANDA array was also down there.

*https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory#/...

There are many things that my brain just can't handle, the size of the universe, more than 3 dimensions and this fact especially.

If you ever feel lonely, think about all those little friends who come visit you!

Depending on how much space you occupy, closer to 500 trillion per second

A friend did that too, a lot of his job was going out in the snow and changing tapes, I guess better internet connectivity changed a lot

You travelled on-site?

Honestly, for a person like him, time spent flying and staying there is a waste.

Every year a few of the Nobel Prize winners attend the IgNobel Prize ceremony and dance on stage.

Oppenheimer was not associated with the meetings:

https://www.lindau-nobel.org/meetings/

I would imagine the problem is that there are too many of them.

For better or worse the prize can only go to 3 people. Over the years there are generally many dozens of people who make absolutely critical contributions to these kinds of experiments. In this case, though, the same guy was listed as the PI of the UW Madison group, and Madison is very clearly "the" operator of the project.

Halzen is by any measure an awesome physicist, but he's also a good "fit" for the Nobel because of this unique situation.

other relevant people are probably dead

Field work even in beautiful places can get stifling. When you don't have access to friends, family, routine, various freedoms... It can be a bit much.

I romanticized that kind of work, but I think my limit is roughly what you said at around 2 weeks. The novelty wears off. Especially because I miss my kids a lot after a few days.

Actually, another big one: I love cooking. When you eat what you're given and don't have a choice, even if the food is pretty good it's kind of... I don't know... I really just want to go home and make something that is distinctly 'my food', something I would only have at home.

Even so, I absolutely love field work. The stuff I do is nowhere near as crazy as the Antarctic. I'm typically on the semi-remote islands of the British Columbia coast. My wife goes to the Arctic; her experience is probably more like yours. Lots of time isolated on icebreakers. Occasionally visiting remote navy or military bases, though. Some indigenous communities. Not as middle-of-nowhere as the Antarctic! The longest she has done is 7 weeks, with ~4 days off of the ship.

Username checks out, Sir. Any interesting anecdotes? I too wish to feel bored sitting at the South POLE!

was there any clear sky ever? how did it look like? I'm assuming you went during daylight?

Sounds like the intro to a horror.

It depends on where you are, Away from the coast, there's no penguins or any large creatures.

thanks!

thanks!

thank you

IceCube observatory is for studying the high energy cosmic neutrinos from a distant galaxy or black holes. But the one proposed INO is to study the low and medium energy atmospheric neutrinos. INO was designed to study the mass ordering of neutrinos. Both observatories are for studying different aspects and properties of neutrinos and are not the same.

See https://en.wikipedia.org/wiki/Ice_Cube

Similar to the Millennium prize by the Clay institute, the amount of luck and effort you need to receive the prize don't make it worthwhile. Plus, it's generally expected to use that money for further research. It would be advisable to focus on other endeavors, if money is your motivator.

So, two years salary in the Bay Area where it's a lot warmer?

That doesn't make any sense. Photons would work much better.

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Did you read what I wrote? Waste, fraud, and abuse! They do virtually ZERO theoretical physics and then expend gazillions of resources on contraptions to study elusive stuff they could've derived theoretically first and in very elegant fashion. It's just making themselves indispensable at any cost. And they are clever, which is why they are successful in that enterprise so far, but it's not the enterprise that has anyone's interests in mind, except them being in control.