Curious: alcoholics have Bill Wilson to help them recover ... who do astrophysicists have?

(the kind of question that reveals search engine limitations)

Jack Daniels?

Large paychecks from industry/finance

Nah, the IceCube neutrinos are probably photonuclear with local photons rather than CMB photons.

Is this how other people hear software developers when we talk about code?

Except that we physicists can usually understand you :)

(since many of us spend most of our time writing code too...)

Yes. And the same goes with finance people, and people in lots of other fields. Jargon rich conversations that outsiders think is mumbo-jumbo.

I'm the author of the Spectrum article: this is the exact reason why I get paid for my job :)

You did a great job of inspiring me to understand something I have, literally, not even the foggiest iota of a clue about. I finished your article in awe at the human species.

Then I consider that a job very well done :) We can do some pretty neat stuff as a species when we want to...

You did great. Precise, informative, and evocative. Really fun to read.

Thanks!

>"After 3.9 billion years of hurtling unhindered through the vast reaches of the universe, a ghostly neutrino particle died on 22 September 2017. It was annihilated when it collided with an atom in the frozen darkness two kilometers beneath the surface of the south polar ice cap."

Your article says the neutrino came from far away, which disagrees with that post that says it was probably "photonuclear with local photons".

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.

Basically when talking about multiple particles, and using the term source, it would be clearer to say "source of x". Yet three times now you've just said "the source".

It seems needlessly confusing so I think there is some reason I'm not grasping that you keep saying "the source".

>"The protons are accelerated at the source."

So by "source" you mean "source of the protons"? And "local photons" means "produced near the source of the protons"?

If you're in a field in a windy day you cannot tell where the wind is originating from. If you're in a room with a fan turned on, you can tell where the wind is being sourced. The source of the wind has been localized in this latter scenario, whereas in the first you can detect the wind but you can't tell what the source of the wind is. That's the gist of the local versus non-local neutrinos being detected.

So if I know the source but you don't, its local to me but non-local to you?

Great article, thanks!

OT: I keep meaning to join IEEE - do you get any commission or perks for referrals?

I don't get any commission or perks, but I would honestly still encourage you to join the IEEE: It takes its mission of "foster[ing] technological innovation and excellence for the benefit of humanity" quite seriously, plus you get a copy of IEEE Spectrum every month, filled with cool articles from me and my colleagues -- if there's a deliberately moving electron associated with a topic somewhere, we're likely to cover it. :)

To translate (correctly, i hope): the neutrinos come from far away and interact with local nuclei, generating photons within the vicinity of the neutrino/nuclear interaction, rather than the photons coming from far away space.

The opposite, the IceCube neutrinos are likely produced in proton-photon interactions near the source with photons from the source rather than being produced in proton-CMB photon (GZK) interactions elsewhere.

> Recovering astroparticle physics PhD here

If I may ask: why 'recovering'?

There's a massive oversupply of people who want to do science vs science that people will pay to have done. Supply and demand are balanced by making the environment so toxic that most leave. Hence 'recovering.'

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.

Agreed. If Musk had wanted to make a science contribution, he might have launched one of these [1] instead of a Tesla.

[1] https://en.wikipedia.org/wiki/LARES_(satellite)

Would they have allowed their satellite to be launched on an untested platform?

That's the idea of putting a 'worthless' payload up first.

A tungsten or brass (LAGEOS) sphere covered in optical and radar retroreflectors is cheap and inert. The major cost for that type of mission is the launch.

Given 3-6 months, $<1M all-in, and a team of engineers and scientists, it would be quite possible to get something ready to rock. Such an instrument would allow an ever-improving test of solar-system dynamics for many millenia.

If Elon is reading and plans to do something similar again, get in touch ([email protected]). We'll make science happen.

Or, just launch a dense one of these: http://www.landfallnavigation.com/davis-emergency-radar-refl...

Agreed. I'm not a Musk fanboy, but most rockets are initially tested with inert dummy payloads. The choice wasn't between a Tesla and a science satellite, but between a Tesla and sand.

The problem is that each professor trains more than a dozen PhDs over their career but they open up only one spot once they retire. Exponential growth in scientists isn't sustainable, no matter how many billionaires like science.

It’s worth noting that this isn’t an iron-clad law of nature. We could train fewer students and hire more staff scientists, for example, but the people who decide such things are largely the folks who “made it” so....

I think "tourism" is probably a bit unfair, but it sure wouldn't hurt to see more people go the way of D. E. Shaw.

It's really sad that the only ways to fund science seem to be charity and war.

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 :)

This drives me nuts. If a quaint, ivory tower environment ever existed at all, it’s long, long gone. Science these days is incredibly fast-paced and competitive (for better or worse) and running a successful lab takes a similar level of managerial chops, hustle, and luck to running small business.

If you have actual suggestions, please do share them, but taking the mickey out of people trying to figure out the universe on $45k/yr is just mean.

Value capture in science is a known hard problem. Snide comments suggesting that it is tractable do not make it so.

The US may never have come to be what it is today if all Columbuses were bound to their homes.

I'm not in astro, but have a physics degree. It's pretty well known that only a few of us get to stay in basic research after we finish our degrees. Most of us have to make the transition to some "real world" activity. Some have an easier time of it than others.

While it's also well known that you don't go into certain fields to make the big bucks (astrophysics, viola da gamba performance, etc.), a corollary is that you do go into those fields because they're highly addictive. So, referring to it as "recovering" might be appropriate.

Disclosure: The people I know who are astrophysicists, and violists da gamba, both now have successful careers as software developers.

Yes: I've a physics degree as well, but I'm a sci/tech journalist now. I'm sometimes asked to talk to physics students as an example of someone using their degree as the basis of a career outside academic research.

Presumably he's out in industry making the big bucks now.