Astronomers have spotted gold and platinum being scattered into space as they observed a cataclysmic event unfolding 130 million light-years from Earth for the very first time.
The observations are all the more remarkable because the huge burst of energy and light produced when two neutron stars collided was spotted first by researchers in the emerging field of gravitational wave astronomy, and then watched by more conventional telescopes on Earth and in space.
All the gold, platinum and other heavy elements we have on Earth are produced by these kinds of extreme events, but astronomers have never actually seen it happen before.
The story of the observation involved international teamwork carried out in record time. First, the LIGO and Virgo observatories in the US and Italy spotted a gravitational wave signal deep in space. Then, just two seconds later, two space telescopes orbiting Earth, ESA’s Integral and NASA’s Fermi gamma-ray space telescope, picked up a gamma-ray burst from the same patch of sky.
The alarm was raised, and that same day, August 17, 2017, the global astronomy community swung into action to try to pinpoint the source from the large area of the southern sky where the gravitational signal was ‘heard’.
Telescopes from the European Southern Observatory in Chile together with telescopes in Hawaii joined the search, before the Swope telescope from Carnegie Science finally identified a new pinpoint of light, the area of the universe where two neutron stars were colliding, sending a shower of precious metals out into the cosmos.
Two neutron stars coalescing – a long-predicted event called a kilonovae- is not actually considered unusual, but what’s new is that the gravitational wave telescopes allowed scientists to spot it as it was happening, thereby giving them a chance to train their light-sensing instruments on the right part of the sky to watch the show for the very first time.
The observations may also provide evidence that kilonovae are the source of short-duration gamma-ray bursts, another exciting development in this field of astronomy.
So what will happen to all that gold and platinum? Well, it will have been scattered into the environment around the star, and then either eventually become part of a new star, or merge into a protoplanetary disk and then into a new planet, just as happened with early Earth.
For the astronomers, meanwhile, the next step is to try to repeat the experience. With the discovery published in several papers in the journal Nature, the team are primed for a new run of the gravitational wave detectors and have requested observing time on ESO telescopes, with the hope of being once again at the right place at the right time to witness the opening of a kilonovae-shaped scientific treasure chest once again.