Astronomers Glimpse Cosmic Origins of Gold, Platinum, in Neutron Star Collision

October 16, 2017

An artist's depiction of two neutron stars colliding. (Carnegie Institution for Science)

Astronomers have for the first time witnessed a pair of dead neutron stars colliding, and have confirmed that the heaviest metals in the universe, from gold to platinum, are formed in explosions like this one spotted 130 million light-years away. The discovery was announced Monday and involved thousands of astronomers globally, including a team at Columbia University. 

When a massive star dies in a supernova, its dense remnant becomes a neutron star. If two of these stars fall into orbit together, they eventually merge in a powerful explosion that sends out gravitational waves, or ripples in space-time. In August, gravitational waves from a pair of colliding neutron stars was picked up by the Virgo and Nobel Prize-winning LIGO observatories in Italy and the United States. Two seconds later, NASA’s Fermi space telescope measured high-energy gamma waves from the same explosion. Those measurements, coupled with theoretical work done earlier at Columbia, told astronomers where to aim their telescopes, and how to interpret the bright flashes of blue and red light observed from the ground.  

Columbia astronomer Brian Metzger coined the term kilonova to describe the hypothetical collision of neutron stars, and built the models that allowed researchers to calculate how much gold, uranium, platinum and other heavy metals would be produced in such a blast.  Columbia astronomer Zsuzsa Marka developed the LIGO alert system that allowed other astronomers to quickly aim their telescopes in the right place to capture the predicted flash of light once the gravitational waves had been detected. Her colleague and husband, Szabi Marka, started LIGO’s gamma ray bursts-related gravitational wave searches about 15 years ago, and is a pioneer in multi-messenger astronomy, an emerging field that simultaneously gathers and studies the light, gravitational waves, and subatomic particles, sent out from astronomical events.

Highlights from media coverage of the discovery are included below.

Astronomers just proved the incredible origin of nearly all gold, platinum, and silver in the universe
Business Insider

LIGO Detects Fierce Collision of Neutron Stars for the First Time
New York Times

Gravitational waves just showed us something even cooler than black holes
Popular Science

Astronomers Tally All the Gold in Our Galaxy
Discover magazine

Gravitational Wave Astronomers Hit Mother Lode
Scientific American

Gravitational wave astronomy starts in earnest
The Economist

Colliding stars spark rush to solve cosmic mysteries

—By Kim Martineau