Astrophysical neutrinos are produced in the interactions of cosmic rays with an ambient medium of gas (protons) and photons of different energies. Once produced, these cosmic neutrinos can propagate cosmological distances and reach the Earth practically without interactions. They therefore carry unique information about the sources of cosmic rays, their acceleration and the composition of the most energetic phenomena in the universe. Looking at the neutrino sky

Those are the colorful names given to two events observed over the last couple of years by Ice Cube. What makes them remarkable is their very high energies; over 30 trillion electron volts (TeV).