Vast explosions that throwing out gold, platinum and many of the world's most precious elements could regularly be happening throughout the universe, a NASA study has revealed.

Known as kilonova, they are a luminous flash of radioactive light that produces large quantities of important elements like silver, gold, platinum and uranium.

The immense explosions are caused by neutron stars colliding into each other, sending an intense jet of of high-energy particles through space.

The immense explosions are caused by neutron stars colliding into each other, sending an intense jet of of high-energy particles through space. Pictured, an artist's impression of the explosion

The phenomenon was first seen on October 16, 2017, when an international group of astronomers and physicists excitedly reported the first simultaneous detection of light and gravitational waves from the same source - a merger of two neutron stars.

At the time, that discovery was hailed as a 'new chapter in astrophysics'. 

The huge explosion rocked the fabric of the universe, distorting spacetime 

Now, astronomers have identified a direct relative of that historic event -  and say they could be far more common than thought.

'It's a big step to go from one detected object to two,' said study lead author Eleonora Troja, an associate research scientist in the UMD Department of Astronomy with a joint appointment at NASA's Goddard Space Flight Center.

The newly described object, named GRB150101B, was reported as a gamma-ray burst localized by NASA's Neil Gehrels Swift Observatory in 2015. 

Follow-up observations by NASA's Chandra X-ray Observatory, the Hubble Space Telescope (HST) and the Discovery Channel Telescope (DCT) suggest that GRB150101B shares remarkable similarities with the neutron star merger, named GW170817, discovered by the Laser Interferometer Gravitational-wave Observatory (LIGO) and observed by multiple light-gathering telescopes in 2017.

A new study suggests that these two separate objects may, in fact, be directly related.

The phenomenon was first seen on October 16, 2017, when an international group of astronomers and physicists excitedly reported the first simultaneous detection of light and gravitational waves from the same source - a merger of two neutron stars.

'Our discovery tells us that events like GW170817 and GRB150101B could represent a whole new class of erupting objects that turn on and off--and might actually be relatively common,' said Troja.

The results were published on October 16, 2018 in the journal Nature Communications.

'We have a case of cosmic look-alikes,' said study co-author Geoffrey Ryan, a postdoctoral researcher in the UMD Department of Astronomy and a fellow of the Joint Space-Science Institute. 

Two super-dense neutron stars collided in a stellar fireball dubbed a 'kilonova' 130 million light years from Earth in a discovery that could 'open a new chapter in astrophysics'. This graphic shows the sequence of events that led to the detection of the gravitational waves

'They look the same, act the same and come from similar neighborhoods, so the simplest explanation is that they are from the same family of objects.'

In the cases of both GRB150101B and GW170817, the explosion was likely viewed 'off-axis,' that is, with the jet not pointing directly towards Earth. 

So far, these events are the only two off-axis short GRBs that astronomers have identified.

The optical emission from GRB150101B is largely in the blue portion of the spectrum, providing an important clue that this event is another kilonova, as seen in GW170817. 

'Every new observation helps us learn better how to identify kilonovae with spectral fingerprints: silver creates a blue color, whereas gold and platinum add a shade of red, for example,' Troja added. 

This image provides three different perspectives on GRB150101B, the first known cosmic analogue of GW170817, the gravitational wave event discovered in 2017. At center, an image from the Hubble Space Telescope shows the galaxy where GRB150101B took place. At top right, two X-ray images from NASA's Chandra X-ray observatory show the event as it appeared on January 9, 2015 (left), with a jet visible below and to the left; and a month later, on February 10, 2015 (right), as the jet faded away. The bright X-ray spot is the galaxy's nucleus.

'We've been able identify this kilonova without gravitational wave data, so maybe in the future, we'll even be able to do this without directly observing a gamma-ray burst.'  

While there are many commonalities between GRB150101B and GW170817, there are two very important differences. 

One is their location: GW170817 is relatively close, at about 130 million light years from Earth, while GRB150101B lies about 1.7 billion light years away.

The second important difference is that, unlike GW170817, gravitational wave data does not exist for GRB150101B. 

Without this information, the team cannot calculate the masses of the two objects that merged. 

It is possible that the event resulted from the merger of a black hole and a neutron star, rather than two neutron stars.

As neutron stars collide, some of the debris blasts away in particle jets moving at nearly the speed of light, producing a brief burst of gamma rays.

'Surely it's only a matter of time before another event like GW170817 will provide both gravitational wave data and electromagnetic imagery,' said study co-author Alexander Kutyrev, an associate research scientist in the UMD Department of Astronomy with a joint appointment at NASA's Goddard Space Flight Center.

If the next such observation reveals a merger between a neutron star and a black hole, that would be truly groundbreaking,' 'Our latest observations give us renewed hope that we'll see such an event before too long.' 

WHAT ARE NEUTRON STARS?

Neutron stars are the collapsed, burnt-out cores of dead stars.

When large stars reach the end of their lives, their core will collapse, blowing off the outer layers of the star.

This leaves an extremely dense object known as a neutron star, which squashes more mass than is contained in the sun into the size of a city.

A neutron star typically would have a mass that's perhaps half-a-million times the mass of the Earth, but they're only about 20 kilometres (12 miles) across.

A handful of material from this star would weigh as much as Mount Everest.

They are very hot, perhaps a million degrees, highly radioactive, and have incredibly intense magnetic fields.

This makes them arguably the most hostile environments in the Universe today, according to Professor Patrick Sutton, head of Cardiff University's gravitational physics department.

The dense objects, in particular their cores, are key to our understanding of the universe's heavy elements.