[Mike 5]

Originally Posted by AntonioLao

If neutrinos have mass, that mean they can't travel at the speed of light. Yet the neutrinos from supernova http://zebu.uoregon.edu/~soper/StarDeath/sn1987a.html
was detected first before its light was detected by optical telescopes or by the naked eye.

The Sanduleak explosion is one of my favourite topics Antonio. I was perplexed by the same reasoning. Only last week I was checking on this and apparently the gravity collapse of a supernova releases the neutrinos immediately but captures all light rays for a short period of time. Neutrino detectors will generally see a supernova a couple of hours before the light reaches us simply because the light was trapped by gravitational collapse. As I heard photons have no mass, I am confused by this. Photons are affected by gravity, neutrinos apparently not. Here I am devising a totally curving space time, if neutrinos do not curve by gravitational pull, do they curve by themselves or is there linear travel after all? Very important for me to get details on this.

The Cherenkov radiation that is used to spot neutrinos in transparent liquids and solids is a cone of blue light the color of a gas flame, the tip points back to the origin of the neutrino either out in space or normally 70% of neutrinos here are from our own sun. The blue light is particles exceeding the local speed of light in that transparent medium - water, ice, dry cleaning fluid etc. and something like a smoke ring, and also like a sonic boom from concorde. From the evidence I found, each flash is in nanoseconds and spreads to fill a large house of water (Kamiokande) at a constant angle of 41 degrees - beautiful photos of this finally scrolled into my PC towards dawn after a night long internet trawl.

What is also confusing is the length of time being just 3 hours or so between the neutrinos - released at the explosion - and the light - held back by collapsing gravity. I had heard that neutrinos have a slight mass and therefore travel slightly below the speed of light, and figures of 99.99% were glibly quoted by someone or other but the truth is so near to 100% to any practical level of precision. Sanduleak is how many light years away. 150 what billion or thousand light years? 1987A actually exploded either before the origin of life on earth or the origin of human life - I forget which. I heard the photon retention is only a few hours in a collapsing supernova. Then all those light years later, the neutrinos and light are stilly a few hours apart? That appears so close to the speed of light as to be the same. Then again the mass of a neutrino is what fraction of an electron? is it one twentieth or one two thousandth.

I get angry at a world where education fails us. I care for these details, surf through such academic bullshit for real real real facts - then I cannot remember them for I am overloaded with the search. Above all children born who experienced those neutrino blasts either in the womb or at birth or in the first few months of cognition are now turning 19. I want to find children born during the neutrino blast - 7:36 GMT 23 February 1987. For about 10 specific seconds. My son Adam was 2 months old at the time, I am sure it affected him permanently and want to find others. Does anyone else sense the different quality of teenagers today? Difficult to assess of course. Time will tell.

Anyway I have wonderful lists of all the details somewhere on my hard drive from a hefty all night web crusade last week, about Kamiokande, Cherenkov radiation, and 1987A Sanduleak, awaiting ROBERT ARE YOU THERE to open a thread on all this in the science forum.

[dleviwing]

Sorry Mike, I was not paying attention to the forum header. Usually when I see science terms such as neutrino or mass in a title bar of the active topics pull-down, they are in the more scientific forums of TOEquest. I'll refrain from this forum.
Thanks;
Dave

PS: When the term mass is used in science, it is assumed that one is referring to "Rest Mass" A photon does not have rest mass but this quantum unit of energy does have "Relative Mass".

[michellemfry]

There are so many neutrinos in the universe. Were they sure they were detecting the supernova neutrinos and not some interfering ones? It's a little like trying to get a single photon source with the sun directly a foot behind you.

[AntonioLao]

Originally Posted by michellemfry

Were they sure they were detecting the supernova neutrinos

The neutrinos were coming from the general direction of the supernova even before it was optically detected.

[Mike 5]

Originally Posted by michellemfry

There are so many neutrinos in the universe. Were they sure they were detecting the supernova neutrinos and not some interfering ones? It's a little like trying to get a single photon source with the sun directly a foot behind you.

The neutrinos are detected by a cone of blue light spreading out at an angle of about 41 degrees if I remember correctly. That cone points back precisely to their origin either in our sun (70% of neutrinos detected) or random stars, or during the explosion of Supernova 1987A there were a dozen or so flashes of cones all pointing back towards the Large Magellan Cloud, where the star Sanduliak had exploded.

yes, there are many trillions of neutrinos passing through your left thumb every second and so on. Neutrinos are detected by Cherenkov radiation, the blue glow given off by plutonium reactors under water. Do an internet search on Kamiokande - I do not have the website handy but you can get full details and wonderful photos. Neutrinos cause subatomic particles to exceed the speed of light in water, or ice - Cherenkov radiation is similar to a sonic boom, occurs I believe within nanoseconds and the largest detectors are cut into the antartic ice over a kilometer or more.