All Questions
Tagged with astrophysics neutrinos
18 questions
39
votes
4
answers
6k
views
Are neutrino stars theoretically possible?
Since neutrinos
have a small mass and
are affected by gravity,
wouldn't it be theoretically possible to have such a large quantity of them so close to each other, that they would form a kind of a ...
- 775
56
votes
2
answers
6k
views
Neutrinos vs. Photons: Who wins the race across the galaxy?
Inspired by the wording of this answer, a thought occurred to me. If a photon and a neutrino were to race along a significant stretch of our actual galaxy, which would win the race?
Now, neutrinos ...
user10851
16
votes
1
answer
585
views
Where do high-energy neutrinos come from?
Last week the IceCube South Pole Neutrino Observatory published a press release reporting the possible discovery of two neutrinos with energies of over 1 PeV.
Would anyone here be willing to help me ...
- 3,905
9
votes
1
answer
502
views
Can I stand on a neutrino star?
Hypothetically, if neutrinos lost their energy in the expanding universe, slowed down, and collapsed in a vast and otherwise empty region under their own gravity, they might form a large object ...
- 12.9k
14
votes
3
answers
937
views
How would cold neutrinos get trapped by stars?
Continuing on from the cool physics Q&A'd on the threads Where are all the slow neutrinos?, Is it possible that all "spontaneous nuclear decay" is actually "slow neutrino" ...
- 135k
12
votes
3
answers
528
views
If neutrinos travel faster than light, how much lead time would we have over detecting supernovas?
In light of the recent story that neutrinos travel faster than photons, I realize the news about this is sensationalistic and many tests still remain, but let's ASSUME neutrinos are eventually proven ...
Matias Nino
6
votes
2
answers
943
views
Free neutrons in the sun's core?
In the standard description of proton-proton fusion, the first step of the interaction proceeds through the unbound diproton $\rm^2He$:
$$
\begin{aligned}
\rm p + p &\to \rm {}^2He^*
\\
\rm ^2He^* ...
rob♦
- 94.2k
3
votes
1
answer
296
views
Solar neutrino Spectrum - Why are there discrete energies for Be and pep?
What is the reason why some reactions give a continuum for the energy of the released neutrinos and others give only a discrete value ($\ ^7B$ and $pep$ )?
Thanks for your help. Please feel free to ...
- 653
3
votes
1
answer
92
views
No tremendous neutrino-flux for SNIa?
Why do neutrino account for 99% of the energy release for a SN II, while it is not expected to be the case for SN Ia?
Is it because the densities are not high enough to induce inverse beta-decay?
(...
- 3,902
3
votes
3
answers
354
views
Why don't the nuclear fusion processes inside the sun produce electron antineutrinos $(\bar\nu_e)$?
Why don't the nuclear fusion processes inside the sun produce $\bar\nu_e$ despite having the same mass as $\nu_e$? Is the reason as simple as "there is no production channel for $\bar\nu_e$s.&...
- 27.2k
40
votes
3
answers
11k
views
Why do the neutrinos (with mass) from a supernova arrive before the light (no mass)?
I've already read the below questions (and their answers) regarding neutrinos vs. electromagnetic waves propagating through space, but I'm still not clear on something.
Neutrinos arrived before the ...
- 1,867
20
votes
2
answers
7k
views
Sun light takes 1,000/30,000/100,000/170,000/1,000,000 years bouncing around inside to then reach the Earth
When light (photon particle) is generated inside the Sun, it takes a long time to bounce around inside to later escape and travel outwards.
Neutrinos escape immediately.
The numbers for the years ...
- 548
10
votes
1
answer
3k
views
How much of neutrinos pass through a neutron star?
Neutrino rarely interact with matter however neutron star is extremely dense and I suppose only an insignificant amount of neutrinos can pass through the densest object in the universe second to black ...
- 13.1k
8
votes
1
answer
516
views
Is a Betelgeuse supernova able to neutralise earth's nuclear arsenal?
According to an article on newscientist.com, a neutrino beam could neutralise nuclear bombs by inducing a slow meltdown of the nuclear fuel. The neutrino generator
would need to be more than a ...
- 1,297
3
votes
1
answer
419
views
neutrinos by formation of "neutron pairs"
Here :
http://www.newscientist.com/article/dn20084-neutron-star-seen-forming-exotic-new-state-of-matter.html
are news on superfluidity in a neutron star. The necessary bosons they say are pairs of ...
- 6,944
3
votes
4
answers
462
views
How can the Cosmic Neutrino Background (CνB) have a temperature? How can any neutrino have a 'temperature'?
The word temperature usually refers to the average velocity of massive particles, correct?
And the Cosmic Microwave Background (CMB) has a 'temperature' based on the temperature of a 'black body' that ...
- 4,709
2
votes
0
answers
116
views
Why is the scientific community, and especially the astrophysicists, so skeptical about sterile neutrinos?
As rob pointed out in a comment in my previous question :
"There were hints about sterile or missing neutrinos in LSND, in the low-statistics region of MiniBoone, and in a number of other ...
- 4,448
1
vote
3
answers
2k
views
Electron density in the Sun
I'm currently working on solar neutrino and in order to make a numerical simulation, I need the potential felt by electron-neutrino :
\begin{equation}
V_e(r) = \sqrt{2} G_F N_e(r)
\end{equation}
where ...
- 75