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Physicists detect signs of neutrinos at Large Hadron Collider

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Re: Physicists detect signs of neutrinos at Large Hadron Collider

#51

Post by misnome »

chasil wrote: post #40
dmitrybrant wrote: post #28

Earlier quoted context omitted.

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.

From 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."

Tau 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!

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#52

Post by Ma8ee »

mnw21cam wrote: post #22
Ma8ee wrote: post #5

Earlier quoted context omitted.

The thing with gravity is that it is kind of easy to detect, even for a layperson, while dark energy and dark matter haven't been detected at all, by anyone, but only used as mathematical devices to make indirect measurements of large scale structures align with our models. So, it isn't only the "average man on the street" that thinks there are good reasons to put them in very different categories of understanding.

Relevant xkcd: https://xkcd.com/1489/ The mouseover-text is the important bit: "Of these four forces, there's one we don't really understand." "Is it the weak force or the strong--" "It's gravity." That's even though it's the one with the simplest equations.

Is that an attempt to appeal to authority?

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#53

Post by zodiac »

hungryforcodes wrote: post #46
WitCanStain wrote: post #29

Earlier quoted context omitted.

If there were a way to reliably detect neutrinos in sufficient quantities they'd be ideal since you could send messages through the earth and at near light speed, I suppose.

As opposed to how we communicate now globally?

Communication via EM waves travel around the earth, not through it. (eg radio waves, fibre optic cables, satellite...)

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#54

Post by tsimionescu »

mnw21cam wrote: post #22
Ma8ee wrote: post #5

Earlier quoted context omitted.

The thing with gravity is that it is kind of easy to detect, even for a layperson, while dark energy and dark matter haven't been detected at all, by anyone, but only used as mathematical devices to make indirect measurements of large scale structures align with our models. So, it isn't only the "average man on the street" that thinks there are good reasons to put them in very different categories of understanding.

Relevant xkcd: https://xkcd.com/1489/ The mouseover-text is the important bit: "Of these four forces, there's one we don't really understand." "Is it the weak force or the strong--" "It's gravity." That's even though it's the one with the simplest equations.

> That's even though [gravity]'s the one with the simplest equations.

Aren't the equations for gravity non-linear, while the other 3 are linear?

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#55

Post by Koshkin »

LegitShady wrote: post #48
themodelplumber wrote: post #44

Earlier quoted context omitted.

I've wondered the same about gravitons. Notwithstanding the need for likely-huge sensing equipment for the first N years of development...

It's not yet clear if gravitons exist at all.

I have a hard time imagining a particle associated with the curvature of spacetime.

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#56

Post by ericbarrett »

YakBizzarro wrote: post #36
mrfusion wrote: post #35

Earlier quoted context omitted.

I guess if we found a way to provide say a trillion times more neutrinos than normal we could detect that more easily.

your "opponent" is the sun that is bombarding us with tons of neutrinos. your SNR would be probably bad

Yea, this. 100,000,000,000 solar neutrinos pass through your thumbnail every second. This number is not substantially different at night, either.

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#57

Post by LegitShady »

Koshkin wrote: post #55
LegitShady wrote: post #48

Earlier quoted context omitted.

It's not yet clear if gravitons exist at all.

I have a hard time imagining a particle associated with the curvature of spacetime.

the inability of current science to square relativity and its predictions of space-time with quantum mechanics is exactly the reason why we aren't sure, and one of the biggest open questions in physics.

I mean it could all be strings, or quantum gravity, or Wolfram's crazy graph theory automatons, or maybe something else entirely.

We don't know.

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#58

Post by hinkley »

adrian_b wrote: post #15
xwdv wrote: post #7

What happens if a neutrino interacts with something?

Usually the neutrino will interact with a nucleus and what happens is the reverse of a beta decay, i.e. either a proton will be changed into a neutron or a neutron into a proton, with the emission of an electron or a positron. So one atom will be converted into an atom of another element, which is a neighbor to it in the periodic table. Because one neutral lepton goes in and one charged lepton goes out, you might say…

Maybe we could start with processing nuclear waste though.

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#59

Post by wyldfire »

tehsauce wrote: post #47
retrac wrote: post #43

Earlier quoted context omitted.

The 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.

I think this would be impossible without truly alien materials.

Really? Seems like if we were motivated to do it, we could have a network of Earth satellite detectors in ~a century or so.

Re: Physicists detect signs of neutrinos at Large Hadron Collider

#60

Post by Faaak »

traeregan wrote: post #42
dmitrybrant wrote: post #28

Earlier quoted context omitted.

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.

> Unless we discover a new type of matter that interacts more strongly with neutrinos How about astrophage? :)

Fore 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
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