What a great story. That article was inspiring and easy to understand. It makes me proud to be a human, really!
The IceCube Neutrino Detector at the South Pole Hits Paydirt
61–70 of 109 posts
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#62Earlier quoted context omitted.
That's exactly why the author gets paid. By local I meant near the source, not near us.
Not saying you are wrong about the terminology, but if local photons are "produced at the source", the use of "local" seems to be redundant. When would a photon not be created at the source? What is a non-local photon, only CMB photons?
I am probably being confusing because there are distinct photons involved here... the ones that protons interact with to make neutrinos, and the gamma rays (which are of course, just high-energy photons) detected by FERMI or MAGIC. '
The neutrinos are produced in the process:
proton + photon -> (usually) Delta_1232 (basically an excited proton, which is very unstable so that's why you may not have heard of it)-> neutron + pion -> proton + neutrinos, provided there is enough energy available to make pions. The same process also makes gammas (from a neutral pion instead of a charged pion), but there are also lots of other processes that produce gammas (which again, are just high-energy photons).
The protons are accelerated at the source. The photons that the protons interact with to make neutrinos may either be local to the source (i.e. in the same galaxy, such that the neutrino is produced within the galaxy) or the proton could propagate some distance, bending in the intergalactic magnetic field and, if it's energetic enough, interact with a CMB photon (which are very low energy but everywhere in the universe, courtesy of the big bang). The former are likely the astrophysical neutrinos, while the latter are by definition the GZK neutrinos. The astrophysical neutrinos are at lower energy because inside galaxies, photons with higher energy than the CMB photons are available, allowing pion production at lower energies.
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#63Earlier quoted context omitted.
That's an interesting technique that I've never heard of. Do you have fast shortcuts/keybindings for removing the # when you are ready, or is it '(left arrow x N) + ^H' each time?
^A ^D
^A ^D it is. But since you bring up moving the cursor, it also is very helpful to 'xset r rate 160 80' to speed it up substantially in Xwindows.
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#64Earlier quoted context omitted.
That's an interesting technique that I've never heard of. Do you have fast shortcuts/keybindings for removing the # when you are ready, or is it '(left arrow x N) + ^H' each time?
^A ^D
I assume (by trying on zsh) that this is a configuration change you made vs. some keybinding I've yet to discover?
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#65Nice article. Some guys in my place are working on a new machine which generates and detects neutrinos. It's called DUNE. It uses a super conducting linear proton accelerator to generate them and 100s of massive liquid helium cooled wire detectors 800miles away! Super exciting project.
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#66Earlier quoted context omitted.
Use mosh and you will have a much better experience. It's made for high latency connections.
Some mission critical production systems don't really want you installing . That's probably a highly unpopular view on HN, but having downtime on IceCube, for example, means they may miss an extremely rare event (neutrino hitting something and generating muons/photon shockwaves) that they could detect.
Something released in 2012 isn't exactly what I'd call "trendy". Technically it really does have some improvements for poor latency and high-packetloss connections.
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#67Earlier quoted context omitted.
Use mosh and you will have a much better experience. It's made for high latency connections.
Some mission critical production systems don't really want you installing . That's probably a highly unpopular view on HN, but having downtime on IceCube, for example, means they may miss an extremely rare event (neutrino hitting something and generating muons/photon shockwaves) that they could detect.
Mosh has been around for a while, it's not like "current trendy software". I thought people use it for bad connections (and envied them because of my stuff in the jungle that isn't performant enough for ssh).
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#68My coworker went down to the South Pole to install Debian on the IceCube cluster (funny story: it's hard to cool servers there because the air is really dry) ~14 years ago. Basically, a 48 hour trip both ways just to insert a CD and press reset. We were all jealous.
>it's hard to cool servers there because the air is really dry Not sure how this could be the case. Dry air has higher thermal conductivity than moist air.
The heat capacity of dry air is lower though, which I suspect is more important than the conductivity. Lower pressure also lowers heat capacity; you'll see a lot of electronics equipment with a specified maximum operating altitude of 10,000 feet for that reason. Incidentally, South Pole is around the same elevation, with local weather conditions varying the pressure over that range at times...
The bigger problems with keeping ICL (the IceCube Lab - where the computers on top of the detector live, also the biggest datacenter on the continent) are somewhat more mundane though:
* If memory serves, there's one air handler that brings in outside air. Like anything else, it occasionally breaks or needs maintenance, sometimes in the middle of winter.
* Anything that has to operate in outside-ish conditions there, like the air intake for example, needs to be simple and robust. I think that early on in ICL's life, they had problems with frost clogging up the intake louvers, but that was before my time with the project.
* South Pole Station gets Cold, and so you need to be careful with mixing a little bit of outside air with much warmer inside air, to keep the heat evenly distributed and temperature from fluctuating too much.
* The station's HVAC is controlled by a DDC (https://en.wikipedia.org/wiki/Direct_digital_control) system, which is reputedly a pain to work on, and sometimes people get ideas about ways to improve it, which of course leads to new and interesting quirks in the system...
edit: formatting
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#69Recovering astroparticle physics PhD here. I read this news with great interest because I thought they might have finally detected the flux of neutrinos predicted by the GZK process[1]. But, this can't be the case because 1) 10^14 eV is probably on the low side for GZK neutrinos, and (more importantly!) 2) that flux would be fairly isotropic, and not from point source. But still! Exciting results! IceCube is an ambit…
Curious: alcoholics have Bill Wilson to help them recover ... who do astrophysicists have? (the kind of question that reveals search engine limitations)
Jack Daniels?
Re: The IceCube Neutrino Detector at the South Pole Hits Paydirt
#70Earlier quoted context omitted.
A pity some of our new billionaires don't make a hobby out of funding genuine science research. Rather than, say, adventures in space tourism.
what if scientists actually considered being economically competent? There is no law of nature that holds that scientists must be aloof savants.
I think setting up machinery and waiting for discoveries like this one can be compared to being patient at the slot machines; it is essentially economically equivalent to gambling. Eventually, as a person living in society you may run out of quarters before you hit the "jackpot." Yes, you can use your quarters today on other things in society that are more guaranteed to bring you more quarters, but, we don't know what kind of "jackpot" is waiting for humanity until we hit it. This makes a sad, difficult decision in the life of a scientist, which is why we should have more rich people funding (since a lot of them have gambling problems any way, ie: stock market, brothels, etc)
edit: to sum up, this would be an efficient economy at scale. Some one with money already puts someone with expertise to good use :)