Slashdot Mirror
AMANDA Maps Cosmic Neutrinos
Uosdwis writes "Remember those 'little neutral ones', neutrinos? You know those little guys have no charge, are invisible and just about no mass. Well a University of Wisconsin-Madison professor has created an array, burried in the antarctic, to detect them with help from the National Science Foundation and produced a map of nuetrinos in the cosmos. A different method than the tau neutrinos found a few years ago, and show the 'natural' neutrinos are at a higher energy level."
Posted AC to avoid the appearance of Karma Whoring.
.jpg files to bring the server to its knees!
AMANDA Maps Cosmic Neutrinos
It's probably just as well the link wasn't included in the original story, 'cause I bet it won't take many downloads of those multi-meg
Right here.
'SBEMAIL!' is better than a goat!!
Yes and no. Yes, neutrinos are created in many kinds of nuclear reactions, and yes, they do travel at lightspeed with some awe-inspiring ability to travel clear through anything, and yes, they could be used for SETI; but no, nobody's going to be using them for SETI.
The reason for this is any civilization advanced enough to have fission--much less fusion, MAM, quark-gluon conversion or other exotic energies--is first going to progress through a much lower-tech level, during which point their civilization is going to glow like a supernova in certain bands of the electromagnetic spectrum. (Earth, for instance, far outshines the Sun in several wavelengths.)
Rather than peek at the cosmos with a neutrino telescope to see the (relatively small) signatures of an individual fusion reactor here or there, it makes more sense to look at the cosmos with radio-astronomy tools to look for planets that are brighter than stars. Find one like that, and dollars to donuts says it's got intelligent life.
To give you an idea of just how quiet the cosmos is... if you were to stand on Pluto and turn on a cell phone, you'd create a radio signal so loud it would drown out literally everything in the night sky (at least on its band). It's quiet out there.
Ice is used in this case because you want these detectors deep under the Earth's surface to shield from atmospheric muons and other background particles. This experiment exploits the fact that Antarctic ice is very clear and deep. Similar experiments have been done by dropping PMTs deep into the ocean (as well as the Sudbury and SuperK experiments that use water tanks in deep underground facilities).
You can differentiate between electrons and muons pretty easily in a Cherenkov detector because electrons produce much more light and in a much larger cone from both the initial electron as well as the electrons that get produced in the ensuing electromagnetic cascade. Muons won't produce the EM cascades. The cosine of the Cherenkov light cone angle goes as the inverse of the particle velocity, and the number of photons produced goes as 1 minus the inverse of the velocity.
Hi, I work for this project (or rather its successor, IceCube) and I have to clarify something. I believe the sky map shown is a map of neutrino BACKGROUND events, not a map of neutrino sources. Background events occur when energetic cosmic rays strike the earth and produce neutrinos which travel through the earth and trigger the detector. Any extraterrestrial neutrino sources would show up as "hot spots" in the sky map under discussion (with the exception of diffuse sources). At this point, AMANDA is NOT claiming the detection of any extraterrestrial source, AFAIK. Most predicted sources are thought to require a larger detector, which is currently under construction.
EOT