The massive IceCube neutrino detector, buried in the Antarctic, has detected a total of 28 neutrinos that could have extraterrestrial origin. Scientists are excited about the discovery, as it could be a first step towards a completely new way of doing astronomy.
Neutrinos are weakly-interacting particles. They are very light, even as far as particles are concerned, and they don’t carry an electrical charge.
This means that they interact with other particles only via the very short range weak interaction. In practice, this allows neutrinos to travel great distances and pass through objects without being altered.
On very rare occasions, when they come very close to an atom’s nucleus for example, they do interact with regular matter.
But this happens so infrequently, that detectors have to be massive, and the IceCube certainly is. It’s made up of 5,000 sensors distributed over a volume of over one cubic kilometer.
Neutrinos are generated by a variety of processes and many are created on Earth, in the atmosphere for example.
But scientists are interested in neutrinos coming from outer space, which could be used to pinpoint the location of active neutrino sources.
The scientists operating IceCube have now announced that they have detected 28 neutrinos, out of the thousands it picks up each year, that may have an extraterrestrial origin. All are highly energetic, and two had energies over 1 petaelectronvolt (PeV).
That’s 70 times more energetic than any particle the LHC will be capable of accelerating once it comes back online in a couple of years.
There’s still testing to be done to verify that the neutrinos are indeed extraterrestrial. Even then, the data is still too little to be of much scientific value.
One of IceCube’s goals is to detect point sources of high-energy neutrinos. This could help explain the origin of highly energetic cosmic rays, for examples, and there are many other applications, if there is enough data.