An astronomy story has made big news headlines this week. Usually most people are not unduly interested in the happenings in the heavens (either because such events are difficult to comprehend, or because they are regarded as remote to human interests), however this story does directly involve matters which humans take great interest in. Scientists and theorists working for the Harvard-Smithsonian Center for Astrophysicists have announced a spectacular new theory concerning the origin of gold (and other heavy elements like platinum and uranium): the cosmologists believe that the heaviest natural elements are created when two neutron stars collide or when a neutron star collides with a black hole (here is an easy summary of neutron stars, extremely tiny supernova remnants with a mass greater than the sun). Elements as complicated as iron are manufactured by normal stars in the course of their lifetime, however the creation of heavier elements is more mysterious. Until now, chemists and physicists had imagined that gold, platinum, uranium, and what have you, come from supernovae—however computer models of various types of supernova events did not supporting that conjecture. The scientists at the Harvard-Smithsonian Center for Astrophysicists based their hypothesis partly on the massive gamma radiation burst detected on June 3rd, 2013 from 3.9 billion light years away in a galaxy located in the constellation Leo. Gamma ray bursts tend to be associated with hypernovae/supernovae caused by the collapse of super-giant stars, but the June 3rd burst was different. In certain rare circumstances, two neutron stars are in a binary system together. Over time, the orbits decay and the stars come together in a cataclysmic event which releases energy tantamount to that of a supernova. Based on the unusual exotic energy signatures of the June 3rd gamma ray burst, it seems that scientists caught a rare peek at such an event.
I will confess that I am having trouble imagining two objects the size of small cities (yet each with a mass greater than the sun) slamming into each other at astronomical speeds. Apparently such events only happen every 100,000 years or so in a galaxy the size of the Milky Way. When the neutron stars come together, a black hole is ripped in the fabric of spacetime. Huge parts of the neutron stars fall into the black hole and vanish from this universe, but other portions of the neutron stars (which, as the name hints, are made up largely of neutrons) are jettisoned into space. Edo Berger, one of the astrophysicists who authored the new theory described the process with an earthy metaphor, saying, “several exciting things happen very quickly…. Most of the material collapses to form a black hole. Some of it is spewed into space. That material is rich in neutrons, which drives the formation of heavier and heavier elements, the way mud piles up on an off-road vehicle.” The gold, platinum, and heavy elements are created in astonishing mass (like many earths made entirely of gold). The elements are diffused through the cosmos and become part of newly forming star systems. Gold is strange stuff anyway. The gold present on Earth during its nebular formation is believed to have sunk deep into the center of planet’s molten core where it is inaccessible. All the gold that rappers and kings wear (and that Ron Paul and draugers hoard) first began falling to Earth 200 million years after the planet’s final formation on asteroids. The great gold strikes are well named: gold on the surface of Earth is there because of meteor strikes (although billions of years of geology have buried and twisted and hidden these cosmic remnants).