Scientists May Have Detected Neutrinos From Another Galaxy

The Bad Astronomer writes "A experiment called IceCube — consisting of sensitive light detectors buried deep in the Antarctic ice — has detected two ultra-high-energy neutrinos, each with over a peta-electronVolt of energy (a quadrillion times the energy of a visible light photon), the highest energy neutrinos ever seen. The two events, nicknamed Bert and Ernie, have a 99% chance of originating outside our galaxy, likely created either by a supermassive black hole or an exploding gamma-ray burst."

Re:ID Tags on the particles?

[tnk1]

Neutrinos, as matter, have plenty of characteristics that could be used to identify them. And saying that it comes from a specific place is not really that difficult since things coming in from space don't take U-turns or pit stops. They come at us in a straight line only perturbed by gravity or other objects that we can observe and compensate for. So if a particle has a certain energy level and direction that does not match anything inside the galaxy, you can do a pretty reasonable job of figuring out where it came from.

As for black holes, yes, nothing is coming out of a black hole's singularity, but the black hole does affect matter outside its event horizon and it is expected that certain black holes will cause matter to be accelerated in such a way that it attains highly energetic characteristics. This is what they mean, or they mean that the neutrino was created in the initial supernova/hypernova that generated the black hole to begin with. Probably the former, as most large black holes are probably generated by accretion over time, and not sudden stellar compression.

Please explain : aren't neutrinos, ah...'neutral'?

[Altesse]

Please explain for the layman that I am, how can these neutrinos be so energetic ? I thought neutrinos were very elusive particles that don't interact much with matter, and that's why they're so difficult to detect. With that much energy, these neutrinos should interact with matter and do heavy 'damage', à la cosmic particles, no ?

Could dark matter be super low-energy neutrinos?

[Thagg]

Back when it was thought that neutrinos were massless, it was impossible to believe that there were huge masses of neutrinos surrounding galaxies, as they would have to travel at the speed of light. But now that we know that neutrinos have mass, maybe they could travel a lot more slowly, slow enough to be captured by a galaxy.

Think about it; there are a huge amount of neutrinos created every microsecond in every star in every galaxy, and they hardly interact with anything. They've been accumulating since the big bang.

What happened to the early photons? Those created as the universe first became transparent initially were very high energy indeed, but as the universe has expanded they've lost energy, to the point that they correspond to a temperature of just 3 degrees kelvin. What happens to neutrinos of a similar vintage?

Re:Neutrinos???

[marcosdumay]

Well, ok. Welcome to the XXI century, I have some news for you:

1 - We didn't spray nuclear bombs through the Earth at the 60's. You didn't have to hide in that shelter.
2 - You must have noticed that technology evolved a bit. Unfortunately, space exploration and nuclear fusion didn't move as fast as expected.
3 - We know that neutrinos exist, that they have mass, and that they come in 3 different flavours (and oscilate between them).
4 - But, no, they are not responsible for the dark mass. We still don't know WTF is that.