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DUNE scientists observe first neutrinos with prototype detector at Fermilab
- pjs_ 2y agoThirty thousand tons of liquid argon
- fnordfnordfnord 2y agoA bit more than that. >Combined, the four detector modules will hold nearly 70,000 tons of ultrapure liquid argon. https://lbnf-dune.fnal.gov/how-it-works/detectors-and-computing/ https://lbnf-dune.fnal.gov/how-it-works/detectors-and-comput...
- bloopernova 2y agoNon-physicist question: What purpose do neutrinos serve in the complex world of elementary particles? Are they "just" a side effect of radioactive decay, or do they facilitate some other reaction? (edited to change the original question from "what are neutrinos for?" to the current question which was suggested by a grandchild comment)
- pif 2y ago> what are neutrinos for? I'm not sure I understand your question, sorry! > Are they "just" a side effect of radioactive decay They are (as fas as we know) elementary particles as several other elementary particles. > do they facilitate some other reaction? Again, I'm not sure I get the sense of your question, but I'd say no, as they are the most elusive particles we know.
- pfdietz 2y ago[flagged]
- bathtub365 2y agoA more charitable reading of the question could be, “what purpose do neutrinos serve in the complex world of elementary particles?” Everyone benefits when physics and physicists are more approachable
- pfdietz 2y ago[flagged]
- simiones 2y agoThe rules of physics have a very clear purpose: to predict how and when some natural phenomenon occurs. So the question can be re-phrased as: why did we come up with the notion of a neutrino, what phenomenon did it explain? We certainly didn't just happen to see one colliding with with something, we knew they have to exist far before the first one was ever detected.
- pfdietz 2y agoWay to totally miss the point. I wasn't talking about the rules we create; I was talking about the actual rules in the physical world. These exist independent of us. They function, they don't predict. The notion that those actual rules have some sort of purpose reeks of a medieval mindset, where the world is the creation of God and has His Purpose, which it is the function of natural philosophers to figure out.
- warkdarrior 2y agoSo you reinterpreted the OP's question in the most meaningless way you wanted to, and then declared "How does this question make any sense?". Nice contribution to the discussion! /s
- pfdietz 2y agoYes, I interpreted "neutrinos" to mean "neutrinos", instead of something else. How utterly terrible of me.
- gus_massa 2y agoOversimplifiying, they are chargeless electrons. If you have an electron(negative) and a proton (positive), then the charge may jump and you get a neutrino(no charge) and a neutron(no charge). It's more common in the other direction. If ypu have a neutron(no charge) it splits into a proton(positive), an electron(negative) an an antineutrino(no charge).
- perihelions 2y ago- "do they facilitate some other reaction?" They are not carriers of a fundamental force, if that's what you are thinking about. https://en.wikipedia.org/wiki/Force_carrier https://en.wikipedia.org/wiki/Force_carrier
- at_a_remove 2y agoNeutrinos were originally a kind of mathematical placeholder to allow for conservation of lepton number (electrons, muons, etc). Turns out that they're real! More to the point, you have six basic leptons (and their antiparticles) if you count the types of neutrinos and six basic quarks (and their antiparticles). It's an interesting parallel. They react with very little, as it turns out. Chargeless, and so they care not for electromagnetic forces. Strong nuclear force is also a miss. Originally, it was thought that only the weak nuclear force was the way they could interact with matter, but with confirmation that they have a non-zero mass, they can also interact with gravity. This makes them both hard to detect, but also an excellent way to peer through things like clouds of interstellar dust, or through the Earth.
- jfengel 2y agoEven zero mass particles interact with gravity. Anything with energy does. Having non zero mass means that at least in theory we could slow them down to get a better look at them. But so far we have no idea how, which means that we don't even know what the mass actually is. We just know from the way from the types of neutrinos observed that they can change type, and they couldn't do that if their mass were zero.
- AnimalMuppet 2y ago> Having non zero mass means that at least in theory we could slow them down to get a better look at them. But so far we have no idea how... How about cosmic expansion? Of the neutrinos emitted early in the universe, shouldn't most still be around, given how weakly neutrinos interact? And, given how much everything in the early universe is receding from us, shouldn't they be slowed down in our frame of reference? If they were emitted when the universe became transparent to neutrinos, what Z would that correspond to? What velocity would we observe in the local frame of reference? (Does it depend on how close to c their velocity is? Do we know?) What would we expect the density of such neutrinos to be? Enough that we could observe it? (One "gotcha" is that slower-moving neutrinos might have a smaller interaction profile than fast-moving ones, and so be harder to detect.) Wikipedia says decoupling was at 1 second after the Big Bang, and that neutrinos from that era have energy of 1e-4 to 1e-6 eV (compared to current neutrinos that may be as much as 0.8 eV).
- Koshkin 2y agoNeutrinos can interact with atoms, producing high-energy charged particles.
- nilkn 2y agoNeutrinos must exist to satisfy conservation of lepton number. Specifically, the weak interaction can change flavor. In beta decay (for example), a down quark changes into an up quark, which converts a neutron into a proton and emits an electron. Conservation of lepton number implies that another particle must also be emitted with the properties of a neutrino.
- matja 2y agoThey preserve the spin quantity in particle interactions. E.g. in beta decay a spin-neutral atom has a neutron that decays into a proton and an electron. Neutrons, protons and electrons have spin 1/2, so an extra 1/2 spin came about. An anti-neutrino has spin -1/2 which is emitted to balance the spin quantity.
- mensetmanusman 2y agoThey serve the same purpose as every particle field, a store of energy as it moves between forms in this waterfall of existence towards maximum entropy.
- MaxikCZ 2y agoDo they have purpose to us / our technology?
- mensetmanusman 2y agoPossibly the military can use them to communicate with submarines.
- Iwan-Zotow 2y ago> What purpose do neutrinos serve in the complex world of elementary particles? To utterly confuse physicists, no other purpose detected
- perihelions 2y agoFascinating that there's a neutrino beam cutting straight through the earth, in a chord hundreds of miles long, and they expect to be able to measure dozens of events per second (edit: at the closer of the two detectors—not the 800 mile one). If they were to modulate this beam, they could tweet-by-neutrino in near real-time. - "DUNE is split between two locations hundreds of miles apart: A beam of neutrinos originating at Fermilab, close to Chicago, will pass through a particle detector located on the Fermilab site, then travel 800 miles through the ground to several huge detectors at the Sanford Underground Research Facility (SURF) in South Dakota." - "The DUNE detector at Fermilab will analyze the neutrino beam close to its origin, where the beam is extremely intense. Collaborators expect this near detector to record about 50 interactions per pulse, which will come every second..."
- deleted 2y ago[deleted]
- pif 2y ago> Fascinating that there's a neutrino beam cutting straight through the earth, in a chord hundreds of miles long This is not the first time! Search about neutrinos from CERN to Gran Sasso.
- perihelions 2y agoOPERA collaboration! https://en.wikipedia.org/wiki/OPERA_experiment https://en.wikipedia.org/wiki/OPERA_experiment
- scheme271 2y agoThe K2K experiment also sent a beam from KEK to SuperK in Japan. I think there might have been one or two other exeriments like this. If you spend the time and money to create a neutrino detector, doing an experiment like this is a reasonable add on.
- JumpCrisscross 2y ago> they could tweet-by-neutrino in near real-time We demonstrated in 2012 a neutrino-based link which “achieved a decoded data rate of 0.1 bits/sec with a bit error rate of 1% over a distance of 1.035 km, including 240 m of earth” [1]. To put that into perspective, a through-the-core beam would reach its antipode about 24 milliseconds before its circumnavigating partner [2]. [1] https://arxiv.org/abs/1203.2847 https://arxiv.org/abs/1203.2847 [2] assuming a spherical earth with diameter 12 756 km [a] and circumference 40,075 km [b], and thus distance difference of 7 282 km, and a speed of light of 300mm m/s [a] https://imagine.gsfc.nasa.gov/features/cosmic/earth_info.html https://imagine.gsfc.nasa.gov/features/cosmic/earth_info.htm... [b] https://en.wikipedia.org/wiki/Earth%27s_circumference https://en.wikipedia.org/wiki/Earth%27s_circumference
- hn72774 2y agoIs there any current or potential overlap with gravity wave science like LIGO? The article touches on black holes and supernovae. I am curious to learn more. > It will enable scientists to explore new areas of neutrino research and possibly address some of the biggest physics mysteries in the universe, including searching for the origin of matter and learning more about supernovae and black hole formation.
- lnauta 2y agoThis is the dream of multi-messenger astronomy: Simulations show that next generation gravitational wave detectors will be able to detect the initial part of the wave before the actual merger of objects (or collision?). If you can identify this signal in time, you could make the 'regular' telescopes look into that particular direction and look for a signal in light, and you could use a neutrino detector at the same time (think IceCube, KM3NeT, Baikal and others that look at large parts of the sky) to look in the neutrino channel. This way you would have gravitational wave-, light- and neutrino-channels from a single object. This is still many years (decades?) away, but would be incredible for studying exotic objects. If you mean, measuring the neutrino baseline difference when a GW passes through the Earth, perhaps. I never thought about it, but its definitely intriguing.
- hn72774 2y ago> If you mean, measuring the neutrino baseline difference when a GW passes through the Earth, perhaps. I never thought about it, but its definitely intriguing. That's where my mind went. Lasers need a lot of precise controls for vibration and such, and neutrinos move through matter almost like it doesn't exist. If the emitter and detector were on opposite sides of the earth, and gravity effects the neutrinos since they have mass, would that increase the resolution of a gravity wave detection? The multi-messenger concept is fascinating too. Seems like the volume of discover is going to keep increasing exponentially.
- itishappy 2y agoThe main issue I foresee with this plan is getting a useful reading. We measure distances with photons by interfering them with a known reference. This raises a number of problems for neutrinos: 1. Neutrino reflection. LIGO and LISA use ultra precise mirrors. Can we build a neutrino mirror? Could we get away with something else instead, say sending beams around opposite sides of the Sun to combine them using gravitational lensing? 2. Neutrino interference. Is this a thing? Pretty sure it's not a thing. 3. Neutrino speed. Photons move at the speed of light. Neutrinos don't. Since we measure time and convert, we need a precise value for neutrino speed, which we currently lack.
- _hark 2y agoI worked on this experiment as an undergrad ~10 years ago during my freshman year! We built a Cherenkov radiation detector, focusing magnets, and did tons of simulations. This is all from memory, but I remember the beamline setup was to get protons from the accelerator there, smash them into a target, which produced various charged particles which could be focused with the magnets, sent down a long pipe where they would decay into neutrinos et al. Then, there's a near detector and a far detector (far detector deep underground in South Dakota). The aim is to measure the neutrino flavors at both detectors to better understand the flavor oscillations (and look for asymmetries between neutrino/anti-neutrino oscillations, hopefully to help explain the matter/antimatter asymmetry in the universe). The particular bit I worked most on was studying the effects of adding an additional solid absorber at the end of the beamline, which was needed to absorb all the particles that didn't decay in the pipe. It would produce more neutrinos that were unfocused, so would affect the near-far flavor statistics (since these would be detected at the near detector but not the far since they were unfocused, ruining the statistics). It was a great intro to doing physics research :-)
- teaearlgraycold 2y agoHow far away is the far detector?
- fnordfnordfnord 2y ago800 miles. https://lbnf-dune.fnal.gov/how-it-works/detectors-and-computing/ https://lbnf-dune.fnal.gov/how-it-works/detectors-and-comput...
- insane_dreamer 2y agoFascinating. But I (non-physics person) don’t understand how the neutrinos won’t interact with atoms in the earth’s crust and their trajectory be deviated in the long journey between the 2 sites.
- collinvandyck76 2y agoIt's a big part of what makes them hard to detect. They interact with almost nothing. (source: i'm not a physics person either, but i watch a lot of physics videos)
- tocs3 2y agoI have been watching Amazon and Alibaba for neutrino detectors. None so far. How big is the experiment (outside distance)? It would be great to do a giant CAT scan of the Earth.
- scheme271 2y agoNeutrinos don't really interact much with other matter so you need either a really intense source of neutrinos or a really big detector (think multiple tons of stuff ) or both. So you're talking about a 10m x 10m volume plus you need the detector to be in a place that doesn't get much other radiation so you need to bury it a few hundred meters underground.
- johnea 2y agoThis is super nerd interesting and everything, but does this have any real effect on everyday life? I am very supportive of advancing science, but I just wonder if this is the top prioriy for spending in the current world...
- kridsdale3 2y agoMaybe one day, like faster communication through the planet. People were saying the same question you asked about radio waves only 100 years ago.
- johnea 2y agoSounds like research should start on it in another 100 years then...
- cthalupa 2y agoRadio waves became "useful" because people continued studying them. Neutrinos becoming "useful" would require us continue to study them, not waiting an arbitrary amount of time to study them. The study of neutrinos is important to our fundamental understanding of how the universe functions. By themselves they might not have some earth shattering ramifications for our day to day life (or they might!), but there's a lot of unanswered questions about how things work at a really fundamental level and neutrinos are among the things we have questions about. Answering these questions would have significant impact on basically every other more "macro" field of study.
- dotnet00 2y agoThat just means the tech moves to 200 years away.
- dang 2y ago[stub for offtopicness. you're all correct, but it's fixed now]
- ceejayoz 2y agoI really hope someone on the team has Atreides as a last name.
- snapcaster 2y agoSo jealous they get to call themselves Dune scientists
- hyperific 2y agoNot Dune as in Arrakis, DUNE as in Deep Underground Neutrino Experiment
- KSteffensen 2y agoAre you absolutely sure there is no Arrakis involved in the choosing of that acronym?
- jajko 2y agoMaybe some Arrak?
- Dansvidania 2y agoI firmly believe somebody is still giggling about the choice of acronym they managed to get approval for.
- vlovich123 2y agoIt always struck me as weird that proponents of the Fermi paradox use lack of radio signals as indication we're alone. Ignoring that radio signals were audible from Earth for maybe 100 years before we significantly reduced the power associated (& switched to digital) and started encrypting everything (makes everything look like noise). Once you start to consider neutrinos as a communication medium which we're just barely scratching the surface of, or whatever future technology might be possible with advances in science and engineering, then it becomes clear we don't know what to look for on the technological front for an advanced civilization (other than knowing it's unlikely to be 1950s analog radio waves).
- cthalupa 2y agoLack of radio signals is a pretty tiny portion of the Fermi paradox. Fermi himself wasn't even thinking of them at the time according to the other Los Alamos scientists that were part of the conversation, but instead about having evidence of actual visitation. While the galaxy is mindbogglingly vast, even with the slower methods of interstellar travel that we could feasible achieve based on our current knowledge, we're talking about timeframes to traverse it that are not large on geological timescales, much less cosmological ones. There's lots of interesting reasons to pay attention to radio signals beyond 'Aliens broadcasting TV, music, and talk radio' - lots of neat stuff has radio waves as a consequence - and since we're already listening in and interpreting that data, it's pretty cost effective for us to also look for it in a technosignature context. But there's a reasonably wide variety of other technosignatures we actively look for today, and others that scientists attempt to infer out of data gathered for other reasons. Also, the whole way you've phrased your comment is kind of strange. The Fermi paradox doesn't advocate the idea that we're alone - it's about the discrepancy between how ubiquitous intelligence life should be in the universe at large based on our understandings of how life came into existence and how little evidence we have that that is the case. "We weren't looking at/for the right things" would 100% be a reasonable answer to the paradox that the overwhelming majority of scientists in the related fields would take no issue with if we suddenly discovered alien life through some different technosignature than we currently look for. Something like a dyson sphere or swarm would never have come into the conversation when Fermi first proposed the question (and he wasn't the first person to ask where everybody was, either) but are now seen as plausible enough that respected scientists in the field pour over things like the Kepler data looking for evidence of them. The Fermi paradox doesn't really need "proponents" - as long as we have no evidence of intelligent life or our understandings of how common intelligent life should be in the universe change, the paradox will stand. But I don't think there's any real faction of people that want it to stand, though. Every scientist or enthusiast on the subject I've ever spoken to or read thoughts on the subject would love to have an answer to the paradox.
- kouru225 2y agoAnd they did it all without House Atreides too
- elihu 2y agoI'm far from an expert in this area, but as I understand it, neutrino and anti-neutrino detectors have some application in nuclear non-proliferation, as you can use them to identify the whereabouts of nuclear reactors, and maybe even fissile materials if your detector is close enough. I wonder if this new neutrino detector has similar potential applications?
- epgui 2y agoI'm not an expert, but that sounds unrealistic today considering how much difficulty we have making basic measurements of neutrinos.
- emilybaul 2y ago[flagged]