A flash of light detected about a mile below the South Pole likely solves a century-old cosmic mystery—and potentially opens up a new kind of astronomy involving ghostly subatomic particles called neutrinos.
In the early 1900s, physicist Victor Hess discovered that Earth is being constantly bombarded by energetic particles coming from outer space, which we now call cosmic rays. Since then, scientists have been hunting for the astrophysical accelerators responsible for hurling the most tremendously energetic of these particles across the cosmos.
Most cosmic rays, though, have an electrical charge, and their paths get bent by the magnetic fields scattered throughout space, making it difficult to follow their footsteps home. That’s why now, the hunt has focused on neutrinos, chargeless and nearly massless particles that can be reliably traced back to their source.
Leading that charge is the IceCube Neutrino Observatory in Antarctica, which—along with a few of its friends—has at last traced a handful of energetic cosmic neutrinos to a galaxy far, far away. The find adds to an emerging era in astronomy when particles other than just photons can be used to study and reveal the cosmos.
“It’s exciting, no doubt, to have finally nailed the cosmic accelerator,” says the University of Wisconsin-Madison’s Francis Halzen, lead scientist with IceCube. The results are reported today in three papers appearing in Science and the Monthly Notices of the Royal Astronomical Society.
Read the original article here