Hacker News

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.

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.

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...

Since neutrinos don’t interact with much of anything, its path doesn’t deviate from its origin. Different origins emit neutrinos of different levels of energy. When a neutrino hits a nucleus, the blue light emitting particle in ice follows the same direction. Measuring the direction and magnitude of the vector we can classify its origin.

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.

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

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.

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...

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

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!

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

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.

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.

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

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.

thanks!

thank you

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.

I won't even go down to that level of yours where you think people would say waste, fraud, and abuse for no reason. Read the news, see how much waste, fraud, and abuse Trump's administration has uncovered. The left and the entire academia were entirely moot about all of that horrible stuff going on in our country.

I don't see academia shouting at every street corner to think about all this brain implant craze because there are people who are being tortured for years remotely using brain implants and other invasive techniques. Zero word from academia 'bout that. Oh, wait, yeah, history shows the crazy psychos from the intel agencies doing terror on human subjects on unimaginable scale were recruiting from the academia. Yeah, okay, plenty critical thought by the academia when nothing has been done to prevent that from happening again.

I guess they're all compliant now, as there's no real pushback for using remotely controlled terrorists with brain and body implants to wreak havoc on the populace. Like I said, nobody asks any really hard questions anywhere.

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.