There is far too much gold in the universe, or at least in the neighborhood where we live. It might not be a problem, because we value gold very much. No one knows from where it came. And this intrigues scientists. Where does so much gold come from in the known universe?
Since the Earth melts at the time it form. Nearly all of the gold present on our planet at that time was likely to have sunk into the planet’s core. Consequently, it assumes that most of the gold in the Earth’s crust and mantle deliver to Earth later. By asteroid impacts during late heavy bombardment, about 4 billion years ago.
Example of Gold
For example, gold deposits in South Africa’s Witwatersrand, the richest known gold resource on Earth, were attributed to a meteorite that formed the Vredefort crater 2.02 billion years ago. However, this scenario is currently in question. Either way, it was probably another external impact. Even if we assumed that the gold that we find in the crusts comes from within. It also had to come from somewhere in the original cloud from which the Earth has formed.
1. Gold-bearing rocks from the Witwatersrand basin in South Africa
So where does all our gold and not ours originally come from? Several other theories exist involving supernova explosions so intense that they cause a star to capsize. Unfortunately, even such strange phenomena do not explain the problem.
Gold is an element, which means that it cannot be made by simple chemical reactions – although alchemists tried centuries ago. To make a shiny metal, seventy-nine protons and 90 to 126 neutrons must be bound together to form a uniform atomic nucleus. This is an intense fusion reaction.
Such a fusion does not occur frequently enough, or at least not in our immediate cosmic neighborhood, to explain the gigantic wealth of gold that we find on Earth and elsewhere in the solar system.
New research has shown that the most widespread theories about the origin of gold, i.e. neutron star collisions (2), also do not provide an exhaustive answer to the question of its abundance.
Gold from space
Gold would fall into the black hole
It is now known that the heaviest elements are formed when the nuclei of atoms in stars capture particles called neutrons. For most of the old stars, including those found in the dwarf galaxies in this study. The process is fasting and therefore called “r-process”, where “r” stands for “fast.”
There are two distinguishing places where the theoretically the r-process takes place. The first potential place is a supernova explosion that creates large magnetic fields – a magnetorotational supernova. The second is two neutron stars merging or colliding.
To look at the production of heavy elements in galaxies as a whole. Caltech scientists have studied several nearby dwarf galaxies in recent years with the Keck telescope on Mauna Kea, Hawaii. They want to see when and how the heaviest elements in the galaxies form.
The results of these studies provide new evidence for the thesis that the dominant sources of the r-process in dwarf galaxies occur over relatively long time scales. This means that the heavy elements create later in the history of the universe.
Since magnetorotatory supernovae are assumed to be a phenomenon of the earlier universe. The lags in heavy element production identify neutron star collisions as their primary source.
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Spectroscopic signatures of heavy elements, including gold, were observed in August 2017 by electromagnetic observatories in the neutron star fusion event GW170817. After gravitational wave detectors confirmed the event as a neutron star fusion. Current astrophysical models suggest that a single neutron star fusion event generates 3 to 13 masses of gold larger than all of the Earth’s gold.
Neutron star collisions create gold as they fuse protons and neutrons into atomic nuclei and then eject the resulting heavy nuclei into space. Similar processes, which in addition would provide the right amount of gold, could occur in supernova explosions.
‘But stars massive enough to produce gold in such an eruption turn black holes,’ Chiaki Kobayashi (3), an astrophysicist at the University of Hertfordshire in the UK and lead author of the latest research on the subject, explained to Live Science. So, in an ordinary supernova, gold, even if it forms, gets sucked into a black hole.
Chiaki Kobayashi from the University of Hertfordshire
What about those weird nematode supernovae? This type of stellar explosion, a so-called magnetorotatory supernova, is a very rare supernova. A dying star spins so fast in it and surrounds by such a strong magnetic field that it capsizes on its own when it explodes.
When it dies, the star fires white-hot jets of matter into space. Because the star has turned inside out. Its jets are full of gold nuclei. Already the stars that makeup gold are a rare event. The stars that create gold and launch it into space are even rarer.
According to the researchers, however, even colliding neutron stars and magnetorotational supernovae do not explain why this abundance of gold on our planet came from. Unfortunately even with this second potential source of gold added, this calculation is wrong.” It is difficult to accurately estimate how often small neutron stars. Which are very dense remnants of ancient supernovae, collide with each other.
But it’s probably not very common. Scientists have only observed this once. Estimates show that they do not collide frequently enough to produce gold found in the solar system. Interestingly, the authors quite accurately explain the amounts of lighter elements in the Universe. Such as carbon 12C, as well as heavier than gold, such as uranium 238U.
Their models explain the amounts of an element such as strontium – through the collisions of neutron stars and europium – through the activity of magnetorotatory supernovae. These were elements that had previously presented scientists with difficulty in explaining the proportion of their occurrence in space. But gold, or more precisely, its quantity, is still an enigma.