The Lemon Fool

Milky Way: Icy observatory reveals 'ghost particles'

BBC Science-Environment

An astronomical detector buried in Antarctic ice has provided a view of our Galaxy that has never been seen before.

"The blurry, extraordinary image is of the Milky Way, but it is composed of the "ghostly" particles that are emitted by the reactions that power stars.

The particles are neutrinos, which are extremely difficult to detect on Earth.

To find them, scientists turned a vast block of Antarctic ice into a detector."

As an interesting aside on the above, I was wondering if there are any experts on detection of subatomic particles here who can answer a question:
How frequently, given all the human eyeballs on planet Earth, is there a human 'detection' of a strike by a subatomic particle, via the vitreous humour in the eyeball of a human?

I'll get my claim in first! Some time during the day in the late 1980s, while sitting/lying/squatting on top of my bed at home, I had a single, very short, bright flash in my right eyeball. Never seen that before or since. At the time I thought...

Astronaut Mike Mullane mentioned something similar:

I had just nodded off when a streak of light flashed in my brain and startled me awake. Veteran astronauts had warned me about this phenomenon. The flash was the result of a cosmic ray hitting my optic nerve. The electric pulse generated by that impact caused my brain to 'see' a streak of light even though my eyes were closed. I wondered what these cosmic rays were doing to the rest of my brain. Oops, there goes second grade.

Mike Mullane: Riding Rockets.

RC

The flashes of light in eyes are caused by Cherenkov radiation: In simple terms a kind of shockwave produced by particles travelling faster than the speed of light in the aqueous humour of the eye. These are common events for astronaut caused by cosmic rays (atoms of atomic nuclei) passing thorough the humour of the eye. The are no cosmic rays at ground level as they do not get through the earths atmosphere and the flux of the common muons are about 1 per square centimetre per minute. Cherenkov radiation creates cones of light about the direction of the particle that creates them, so to see Cherenkov light at ground level requires many things to be fortuitous and is therefore rare, but possible.

Regards,

What Prof Sakar notes is true, but he does not emphasise how neutrinos are so much more useful than cosmic rays for observing distant objects. Cosmic rays are atomic nuclei, stripped of electrons, hence charged and are bend by the magnetic fields in the galaxy and so they do not point at the source, but neutrino do and could in principle be used to find new sources of them. I know both Francis Halzen who runs Ice Cube and Subir `and I have attended very many lectures of icecube and know other scientists working on this project.

Regards,