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There is too much gold in the universe. Nobody knows where it came from.



Something is raining gold across the universe. But nobody knows what it is.

Here’s the problem: gold is a file element, which means you can’t go beyond the ordinary chemical reactions – though alchemists tried for centuries. To make the metal sparkle, you need to bond 79 protons and 118 neutrons together to form one atomic nucleus. It is an intense nuclear merger reaction. But such intense melting doesn’t happen frequently enough, at least not nearby, to create the gigantic gold treasure upon which we find Land and elsewhere in the solar system. And a new study has found that the most commonly theorized origin of gold ̵

1; collisions between neutron stars – can’t even explain gold’s abundance. So where does the gold come from? There are other possibilities, including supernovae so intense that they turn a star inside out. Unfortunately, even such strange phenomena cannot explain how dull the local universe is, the new study finds.

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Collisions between neutron stars create gold by briefly shattering protons and neutrons together into atomic nuclei, then spewing those heavy, newly bound nuclei across space. Regular supernovae cannot explain the universe’s gold because stars massive enough to melt gold before dying – which is rare – become black holes when they explode, said Chiaki Kobayashi, an astrophysicist at the University of Hertfordshire in the UK. and lead author of the new study. And, in a normal supernova, that gold is sucked into the black hole.

And what about those strangest and stellar supernovae? This type of stellar explosion, a so-called magneto-rotational supernova, is “a very rare, very fast spinning supernova,” Kobayashi told LiveScience.

During a rotational-magneto supernova, a dying star spins so fast and is destroyed by magnetic fields so strong that it flips over as it explodes. As it dies, the star launches incandescent jets of matter into space. And since the star has been overturned, its jets are chock full of gold cores. Stars that melt gold are rare. Stars that melt gold and then spew it into space in this way are even rarer.

But even neutron stars and magneto-rotational supernovae together can’t explain Earth’s gold mine, Kobayashi and his colleagues found.

“There are two stages in this question,” he said. “Number one is: neutron star mergers are not enough. Number two: even with the second source, we still can’t explain the amount of gold observed.”

Previous studies were right that neutron star collisions release a shower of gold, he said. But those studies didn’t take into account the rarity of those collisions. It’s difficult to accurately estimate how often tiny neutron stars – themselves ultra-dense remnants of ancient supernovae – slam together. But it’s certainly not very common: scientists have only seen it happen once. Rough estimates also show that they don’t collide often enough to have produced all the gold found in the solar system, Kobayashi and his co-authors found.

“There are two stages in this question,” he said. “Number one is: neutron star mergers are not enough. Number two: even with the second source, we still can’t explain the amount of gold observed.”

Previous studies were right that neutron star collisions release a shower of gold, he said. But those studies didn’t take into account the rarity of those collisions. It’s difficult to accurately estimate how often tiny neutron stars – themselves ultra-dense remnants of ancient supernovae – slam together. But it’s certainly not very common: scientists have only seen it happen once. Rough estimates also show that they don’t collide often enough to have produced all the gold found in the solar system, Kobayashi and his co-authors found.

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“This article is not the first to suggest that neutron star collisions are not enough to explain the abundance of gold,” said Ian Roederer, an astrophysicist at the University of Michigan, who looks for traces of rare elements in distant stars. .

But the new article by Kobayashi and his colleagues, published on September 15 The Astrophysical Journal, it has a big advantage: it’s extremely comprehensive, Roederer said. The researchers poured a mountain of data and fed it into robust models of how the galaxy evolves and produces new chemicals.

“The paper contains references to 341 other publications, which is about three times more references than typical papers in The Astrophysical Journal these days,” Roederer told Live Science.

Bringing all that data together in a useful way, he said, amounts to a “Herculean effort”.

Using this approach, the authors were able to explain the formation of light atoms such as carbon-12 (six protons and six neutrons) and heavy like uranium-238 (92 protons and 146 neutrons). That’s an impressive range, Roederer said, covering elements that are usually ignored in these types of studies.

Mostly, the math worked.

Collisions between neutron stars, for example, produced strontium in their model. That matches observations of strontium in space after the collision of a neutron star that scientists observed directly.

Magneto-rotational supernovae explained the presence of europium in their model, another atom that proved difficult to explain in the past.

But gold remains an enigma.

Something out there that scientists don’t know has to do with gold, Kobayashi said. Or it is possible that neutron star collisions produce more gold than existing models suggest. Either way, astrophysicists still have a lot of work to do before they can explain where all that fantasy comes from.

Originally published in Live Science.


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