7 ms·
While neutrinos are not very difficult to generate, they are extremely, astoundingly difficult to detect. Unless we discover a new type of matter that interact
by dmitrybrant 5y ago
While neutrinos are not very difficult to generate, they are extremely, astoundingly difficult to detect. Unless we discover a new type of matter that interacts more strongly with neutrinos, we're stuck with cavern-sized detectors that can detect single-digit numbers of neutrinos (out of many trillions), unreliably.
- mrfusion 5y agoI guess if we found a way to provide say a trillion times more neutrinos than normal we could detect that more easily.
- YakBizzarro 5y agoyour "opponent" is the sun that is bombarding us with tons of neutrinos. your SNR would be probably bad
- retrac 5y agoThe same problem is faced by optical communication during the day with the sensors exposed to sunlight. SNR can be increased a fair bit with even slight directionality. If sensitivity of detection is one day high enough, I think it would be theoretically possible to obtain directional information about neutrinos, by building a whole network of sensors and synthesizing an aperture.
- tehsauce 5y agoI think this would be impossible without truly alien materials.
- wyldfire 5y agoReally? Seems like if we were motivated to do it, we could have a network of Earth satellite detectors in ~a century or so.
- retrac 5y ago"If the sensitivity gets high enough" is the big if to my conjecture. We may never be able to detect enough neutrinos to be reliably detect multiple coming from the same source passing through multiple detectors.
- nine_k 5y agoWe need to put a few kilotons of extremely pure water (or maybe other transparent substance) into each satellite. Not impossible, but likely this amount of orbital lift capacity is better used for other projects.
- CamperBob2 5y agoFor conventional electronic and optical purposes this isn't a huge deal. You "just" modulate the signal to be transmitted onto a fixed-frequency carrier, and have the receiver ignore everything that's not a sideband of that particular carrier frequency. It's one of those cases where "just" really does apply. IR remote controls work this way, using a slow bitstream to key a 40 kHz carrier that drives the IR LED. Scientific applications that need even greater sensitivity can take advantage of the fact that the expected phase of the carrier is known as well as its frequency. Devices called lock-in amplifiers are used to run a wide variety of experiments and processes using that principle. Doing this stuff with neutrinos rather than photons, however, is one of those * * * * * exercises that the textbook authors put in as a joke.
- postalrat 5y agoNot so bad if your detector can detect the direction the neutrino came from.
- rowanG077 5y agoAs long as you have multiple detectors and a neutrino stream crosses them you can obtain the direction. I assume this is what the poster meant.
- ericbarrett 5y agoYea, this. 100,000,000,000 solar neutrinos pass through your thumbnail every second. This number is not substantially different at night, either.
- devoutsalsa 5y agoUnless I orient the thin edge of my thumbnail so I’m presenting the smallest possible cross section towards the sun!
- thelittleone 5y agoI'm not embarrassed to admit I just tried this. I will walk around with thumbnail oriented thusly and make my observations. Perhaps the origin of the thumbs up? If anyone asks I will casually explain that I'm reducing my thumbail cross section to minimise the unknown effects of solar neutrinos.
- devoutsalsa 5y agoIf you can detect neutrinos below your thumb, I’m officially impressed!
- scythe 5y agohttps://www.nature.com/articles/s41567-018-0319-1 https://www.nature.com/articles/s41567-018-0319-1
- alok-g 5y agoWhat would be the number of photons falling per second on the same? :-)
- ericbarrett 5y agoGood question! I can't find a truly authoritative source, but a few calculations on the web put photon flux at the earth's surface at 10^21/m^2/s, give or take. Assuming your thumbnail is one square centimeter, that would be 10^17 photons per second, or 100,000,000,000,000,000, but only during the day :)
- deleted 5y ago[deleted]
- chasil 5y agoFrom the article: "Casper said that there have only been about 10 observations of tau neutrinos in all of human history but that he expects his team will be able to double or triple that number over the next three years."
- misnome 5y agoTau neutrinos, yes, but electron and muon neutrinos are significantly easier to identify - the problem with tau neutrinos is that when they interact, they produce a tauon, which very, very quickly decays so it's hard to know if it was a tauon decaying to, say, a muon or electron - which look identical to their respective neutrino flavours, or one of those neutrinos to begin with. This is not to say that it's _easy_ to detect the other kinds, you still need a large number of neutrinos and a large volume for detection. The example that always comes up is submarine communication - which has two problems - detecting a sparse and intermittent signal to get a useful bitrate out, and generating a beam of sufficient intensity to begin with, let alone a beam that is steerable!
- make3 5y agoso 30
- chasil 5y agoAt the maximum.
- traeregan 5y ago> Unless we discover a new type of matter that interacts more strongly with neutrinos How about astrophage? :)
- Faaak 5y agoFore those that haven't read it, "Hail Mary" from Andy Weir is a quite good book IMHO. It reads quite rapidly and it's very enjoying
- deleted 5y ago[deleted]
- booleandilemma 5y agoAmaze.
- moffkalast 5y agojazz hands