Billions of neutrinos pass through your body every second, and for the first time scientists now know where most of them are coming from.
While it's been known for a while many of them are produced by the Sun, a large number have come from much further away -- another galaxy, it turns out.
Scientists from the University of Tasmania and AUT University in Auckland have discovered a major source of the energetic subatomic particles -- a quasar surrounding a supermassive black hole at the centre of another galaxy.
Known as PKS B1424–418, the quasar first appeared on telescopes belonging to AUT's Institute for Radio Astronomy and Space Research in 2011. By 2013, it had grown four-fold and changed its shape.
Prior to this discovery, the source of most of the cosmic neutrinos bombarding Earth was unknown.
Institute director Prof Sergei Gulyaev says the findings rival the much-celebrated discovery of gravitational waves in February.
"Our role now will be to look at future events and see if we can confirm that quasars are responsible for generation of the most energetic particles in the universe," says Prof Gulyaev.
"This discovery reminds me of the one made here in New Zealand in 1948 when, for the first time, radio emission coming from the sky was identified with well -known astronomical objects such as supernova remnants and galaxies. What we have today is the beginning of a new era in neutrino astrophysics and physics of cosmic rays."
Quasars are formed when a supermassive black hole -- possibly millions times the mass of the Sun -- starts accruing mass very quickly, starts spinning at close to the speed of light and begins emitting energised particles.
Their findings are outlined in journal Nature Physics.