It’s a rather weighty question that has stumped scientists and alchemists for centuries. But now Midland astronomers think they have discovered the origins of gold itself – just don’t ask them to try to recreate it here on Earth.

Academics at the universities of Warwick and Leicester now believe that significant quantities of various heavy elements – including gold – are created by the collisions of dead stars.

Within these extreme events ‘short-duration’ gamma ray bursts are emitted and it is these that are so elemental to the creation of gold and some of the other heavy metals.

The evidence, discovered using NASA’s Hubble Space Telescope, is in the detection of a new kind of stellar blast called a kilonova, which results from the energy released when a pair of compact objects crash together.

Hubble observed the fading fireball from a kilonova last month, following a short gamma ray burst (GRB) in a galaxy almost four billion light-years from Earth.

A kilonova had been predicted to accompany a short-duration burst, but had not been seen before, and Dr Andrew Levan of the University of Warwick said it held clues to the origins of gold.

“These kilonova are powered by radioactivity, but because their conditions are so extreme they can build up the heaviest elements, including gold,” he said.

“Until now there has been a big question about where all the gold in the universe comes from, but it now seems that it is created in the debris of these extreme mergers of stars as massive as the sun, but only a few miles across.

“We are made of stardust, but gold is made from neutron stardust.”

A kilonova is about 1,000 times brighter than a nova, which is caused by the eruption of a white dwarf star, which is made of electron-degenerate matter.

Gamma ray bursts are mysterious flashes of intense high-energy radiation that appear from random directions in space.

Short-duration blasts last at most a few seconds, but they sometimes produce faint afterglows in visible and near-infrared light that continue for several hours or days.

The afterglows have helped astronomers determine that bursts lie in distant galaxies.

Astrophysicists have predicted short-duration bursts are created when a pair of super-dense neutron stars in a binary system spiral together.

This event happens as the system emits gravitational radiation, creating tiny waves in the fabric of space-time.

Nial Tanvir of the University of Leicester, who led the research, said: “This observation finally solves the mystery of the origin of short gamma ray bursts.

“Many astronomers, including our group, have already provided a great deal of evidence that long-duration gamma ray bursts (those lasting more than two seconds) are produced by the collapse of extremely massive stars.

“But we only had weak circumstantial evidence that short bursts were produced by the merger of compact objects. This result now appears to provide definitive proof supporting that scenario.”

In a recent science paper, Jennifer Barnes and Daniel Kasen of the University of California at Berkeley and the Lawrence Berkeley National Laboratory presented new calculations predicting how kilonovas should look.

They predicted the same hot plasma producing the radiation will also block the visible light, causing a gush of energy from the kilonova to flood out in near-infrared light over several days.

A golden opportunity to test this model came on June 3 when NASA’s Swift space telescope picked up the extremely bright gamma ray burst.

Although the initial blast of gamma rays lasted just one-tenth of a second, it was roughly 100 billion times brighter than the subsequent kilonova flash.

From June 12 to 13, Hubble searched the location of the initial burst, spotting a faint red object and an independent analysis of the data from another research team confirmed the detection.

Subsequent Hubble observations on July 3 revealed the source had faded away, therefore providing the key evidence the infrared glow was from an explosion accompanying the merger of two objects.