Alien particles may cause a radio to squeak. Scientists are using a new model to determine the type and cosmic source of incoming cosmic particles.
In this case, the researchers are using LOFAR, the big international radio telescope. Normally, this telescope receives weak radio waves from the early universe. But now and then, an ultra short, bright radio pulse is observed. Your car radio would translate this into a little noise - the last signal of an elemental particle entering the atmosphere. Now, astronomers have unraveled the radio code of these intruders to determine their type and their cosmic source.
Supernovas, dying stars and black holes have all been named as sources of cosmic particles. Until now, though, no one studied the sources in depth.
Cosmic particles are elementary particles that travel through the universe with an energy that's a million times bigger than the largest particle accelerator on earth. With almost the speed of light, they collide like bullets with the atmosphere before falling apart into a cascade of other, even smaller particles. Their interaction with Earth's magnetic field leads to a short radio signal.
While finding the signal is somewhat easy, knowing what caused it is another matter entirely. In this latest study, though, researchers succeeded in calculating and modeling what kind of particle came in for the first time ever.
"Because of the enormous energy, most astrophysicists assume that cosmic particles originate deep in the universe, like black holes in other galaxies," said Stijn Buitink of the Vrije Universiteit Brussel and first author of the new paper. "But we think they come from a nearby source and get their energy from a cosmic accelerator in the Milky Way-perhaps a very big star..."
The new model that the researchers created enables astronomers to identify incoming particles and opens up a new window to the high-energy universe and high-precision measurement of cosmic particles.
Currently, the astronomers are busy bringing the technique to new places; they're placing hundreds of radio antennas on the pampas and implementing the LOFAR technique. This, in turn, could make it possible to study cosmic particles with an even higher energy and unprecedented accuracy.
