23 votes

How can astronomers pinpoint the location of the source of a neutrino?

You correctly state that neutrinos do not interact too often. The physical parameter describing that is the effective cross-section. So what you observe in a detector is not the neutrino itself, but ...
B--rian's user avatar
  • 5,616
19 votes
Accepted

Can exoplanets be found using neutrino detectors?

The answer is presumably no. Let's assume that the nearest possible exoplanet is in the Proxima Centauri system, and it presents an electron antineutrino luminosity identical to that of Earth. The ...
HDE 226868's user avatar
  • 36.3k
19 votes
Accepted

Is there a limit to the Schwarzschild radius?

Due to the uncertainty principle, it's expected to be impossible to form a black hole smaller than about a Planck mass. Such a black hole would have a Schwarzschild radius approximately equal to the ...
Sten's user avatar
  • 4,501
15 votes
Accepted

How much mass does the Sun lose as light, neutrinos, and solar wind?

The solar neutrino luminosity is about 2.3% of its electromagnetic luminosity (i.e. light). So the extra mass lost in the form of neutrino energy is 2.3% of your original calculation. The average ...
ProfRob's user avatar
  • 149k
15 votes

Is the earth bombarded equally in all directions by neutrinos?

There are only two types of neutrino source that are "bright" enough to be reliably detected. The sun and nearby supernovae. The source of solar neutrinos is nuclear fusion, which is also the source ...
James K's user avatar
  • 118k
13 votes

Neutrinos passing through black holes

In general, don't think of black holes as material objects like stars or planets. We can ascribe properties like mass, charge and angular momentum to them, but if you're near a black hole and reach ...
HDE 226868's user avatar
  • 36.3k
12 votes
Accepted

How much mass per year may the black hole at the center of the Milky Way gain by capturing neutrinos?

Not enough to worry about. Most neutrinos we detect on Earth come from the sun. The black hole at the centre of the galaxy is not so close to a star as the Earth is so you would expect the neutrino ...
James K's user avatar
  • 118k
12 votes

When did our neutrino detectors become sensitive enough to detect supernovas in the core of the Milky Way?

IMB was running from 1982, and we know that this could detect supernova neutrino because it detected 8 in 1987. Previous scintillation methods depended on the detection of neutrinos from a ...
James K's user avatar
  • 118k
11 votes
Accepted

Could not slow neutrinos orbit galaxies and clusters, thus comprising a large component of even COLD dark matter?

These neutrinos would have to be really cold. The cosmic neutrino background is at 1.9K, and they are considered hot dark matter, because they would have been highly relativistic at the epoch of ...
ProfRob's user avatar
  • 149k
10 votes

How are neutrinos produced in blazar jets?

Neutrinos are typically produced in AGN jets through what we refer to as hadronic processes. Protons are accelerated to relativistic speeds and interact with nearby photons. Depending on the ...
HDE 226868's user avatar
  • 36.3k
10 votes

Is there a limit to the Schwarzschild radius?

In classical General relativity, there is no limit. However it is unclear exactly how a black hole with a mass less than one Planck mass would behave. (One Planck mass is about 0.02 mg, or roughly ...
James K's user avatar
  • 118k
9 votes

How can astronomers pinpoint the location of the source of a neutrino?

High energy muon neutrinos occasionally interact and produce a muon. Energy and momentum must be conserved in the process and the muon heads off in the same direction as the neutrino. The relativistic ...
ProfRob's user avatar
  • 149k
8 votes

Is the earth bombarded equally in all directions by neutrinos?

In addition to neutrinos from the Sun and other discrete sources in the Universe (see James's answer), there is also expected to be a cosmic neutrino background. Although this is yet to be detected (...
ProfRob's user avatar
  • 149k
7 votes
Accepted

What object in the universe is most opaque to neutrinos?

... So what object will absorb the highest fraction of neutrinos passing through it, or at least be a good candidate? Feel free to assume a certain energy range of neutrinos. Exclude black holes ...
Rob's user avatar
  • 2,636
7 votes

Delay between neutrino pulse and visible flash of supernova

The neutrino pulse associated with the core-collapse supernova SN1987A in the Large Magellanic Cloud, were estimated to have arrived at the Earth about 3 hours before the rise of the supernova light ...
ProfRob's user avatar
  • 149k
6 votes
Accepted

Is there an equivalent of the red shift effect for cosmic rays?

Yes, there is a "retardation of the co-moving velocity" of particles. It is important to take it into account to understand the time history of peculiar velocities of galaxies and for ...
eshaya's user avatar
  • 3,641
6 votes

Multi-messenger astronomy: what is the potential of simultaneous detection of gravitational waves and neutrinos from a supernova?

This article basically seems to answer the question. They quote from an earlier study: "Although no CCSNe have currently been detected by gravitational-wave detectors, previous studies indicate ...
Steve Linton's user avatar
  • 10.3k
6 votes
Accepted

Why do neutrinos take time to scatter?

You are barking up the wrong tree. The passage you quote is talking about how neutron stars cool after they have formed. Neutrinos are emitted in a burst lasting a few seconds after core collapse but ...
ProfRob's user avatar
  • 149k
5 votes

Is there any cosmological evidence that neutrinos travel at a speed other than c?

I can find plenty of evidence for electrons travelling at speeds less than c. The neutrino is said to be a fermion like an electron. But I can't find any evidence of neutrinos travelling at speeds ...
StephenG - Help Ukraine's user avatar
5 votes

Is there any cosmological evidence that neutrinos travel at a speed other than c?

A paper by Wie et al. (2016) uses the coincidence between gamma rays from Gamma ray bursts and individual 3-30 TeV neutrinos to estimate the difference in propagation speed between neutrinos and ...
ProfRob's user avatar
  • 149k
5 votes

How can astrophysicists discriminate between pp-chain solar neutrinos and CNO-cycle ones?

Nuclear reactions can have particular energy spectra, which arise based on how energy and momentum are distributed among the product particles. This holds true for neutrinos produced in the many ...
HDE 226868's user avatar
  • 36.3k
4 votes

Can exoplanets be found using neutrino detectors?

Other answers are good at explaining that we are bad at detecting neutrinos - or that neutrinos are bad at being detected. However, it should be also be pointed the differences between neutrinos and ...
Pere's user avatar
  • 1,750
4 votes

Could not slow neutrinos orbit galaxies and clusters, thus comprising a large component of even COLD dark matter?

It's an interesting but frustrating question. ;) As you mentioned, we can't detect slow neutrinos. Direct detection of them may never be technically feasible. One answer of the linked question does ...
PM 2Ring's user avatar
  • 13.6k
4 votes

How Are Radioactive Decay Rates Influenced by Neutrinos - On Earth and Other Dense Planets

Resurrection alert. I was Googling the subject and found this paper refuting an earlier paper claiming to have observed a neutrino-based effect on beta decay in radon. Edit: another study here ...
Neil Moss's user avatar
  • 141
4 votes

Star - Black Hole binary. Star core Collapses. Does the black hole immediately grow from neutrinos?

Yes. Neutrinos which hit the BH will add to its mass. But you may be thinking that the neutrinos pass through the nascent supernova without interaction. In a dense enough environment, neutrinos do ...
Mark Olson's user avatar
  • 7,620
4 votes
Accepted

Could we detect neutrinos from a supernova in Andromeda?

Not yet. The first supernova from which neutrinos have been detected was SN 1987A in the large magellanic cloud at roughly 51kpc distance - like you write. Current detectors are not sensitive enough ...
planetmaker's user avatar
  • 18.9k
3 votes

How Does IceCube Trace a Neutrino to its Source?

You ask a number of questions. I'll try an answer them. Yes, galaxy clusters (except the one we are part of) are many millions of light years away and so the neutrinos from them (which travel at a ...
Steve Linton's user avatar
  • 10.3k
3 votes

Is there an equivalent of the red shift effect for cosmic rays?

The de Broglie relation suggests the "wavelength of a particle" is proportional to the reciprocal of its momentum. Like all wavelengths, the de Broglie wavelength is effectively stretched by ...
ProfRob's user avatar
  • 149k
2 votes
Accepted

Could neutrinos be at least a part of Dark Matter?

Ethan Siegel has a good discussion of this question here. Read that for more detail, but briefly, the main issue is that neutrinos move too fast - they are a form of what cosmologists call "hot ...
Eric Jensen's user avatar
  • 4,864

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