Two years ago, astronomers detected an extremely high speed particle, known as a "cosmic ray", crashing into the Earth's surface. After years of research, they still aren't sure what its source was. Read more here:

Two years ago, astronomers detected an extremely high speed particle, known as a "cosmic ray", crashing into the Earth's surface. After years of research, they still aren't sure what its source was. Read more here:


http://dlvr.it/SzNdR3