Two colliding neutron stars remaining after supernova explosion can produce heavy elements such as gold.
gold scientific discoveries

Does the Earth’s gold come from stars?

98% of matter in the universe was created during the Big Bang, but not precious metals. So how was gold created then? Until now, scientists have thought that gold arises as a result of a supernova explosion, but recent observations by NASA scientists seem to contradict this theory.

The gold elements existing on the Earth today, have not been created by geological processes, but only concentrated by them. Heavy chemical elements such as gold, silver, platinum, lead or uranium were created in space. Two possible scenarios for the origin of heavy elements are considered:

  • the supernova explosion (the explosion ending the star's life) or,
  • the collision of two neutron stars, ultra dense objects that themselves are the product of a supernova explosion.

Scientists are now more focusing on the second option. The observation of a rapid short burst of rays (GRB - short gamma-ray burst) made on June 3, 2013, by NASA telescopes let them draw a theory on the collision of two neutron stars - remnants of stars that ended their lives exploding as supernovae. The unique glow remaining for several days at the GRB flash point suggests that enormous amounts of heavy elements, including gold, were created at the time of the explosion.

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses – quite a lot of bling!” - says Edo Berger of the Harvard-Smithsonian Center for Astrophysics (CfA).

Why is a rare event as the supernova explosion necessary to create gold?

Let's start from the very beginning. Scientists assume that some 13.7 billion years ago at the point of infinite density called the initial singularity, the Big Bang occurred. During the Big Bang, 98% of the matter that forms the universe today (100 - 200 billion galaxies) was created. Particles that later formed chemical elements showed up, mainly light gases: helium, hydrogen and lithium. Interestingly, non of the heavy chemical elements or key elements to the creation of life (coal, oxygen or nitrogen) were formed during the Big Bang. Some of them were formed later inside the stars, but some of them, like gold needed something much more spectacular to be born. They needed an unimaginable great energy which is released as the result of a collision of two ultra dense objects – neutron stars.

Stars (especially the first stars in the universe) are mainly composed of the simplest and lightest element - hydrogen. Due to the great weight and pressure caused by the huge amount of hydrogen in their interiors, a nuclear reaction occurs, which in time leads to the formation such elements as helium, carbon or oxygen, and later iron and nickel. However, the enormous energy of stars is not inexhaustible and over time the pressure inside the star fades and the star collapses. Most of the stars go out slowly, like a bonfire after the wood is burned out, but there are exceptional cases of giant stars whose collapse causes a huge explosion called a supernova explosion.

Pulsar highly magnetized, rotating neutron star
Pulsar highly magnetized, rotating neutron star

Such spectacular death of a star many times greater than the Sun throws dust and gases into space, and in the place of the explosion leaves small, but unimaginably dense clusters of matter called neutron stars.

If a double star (a team of two stars orbiting one mass center and interacting with each other by gravity) ends its life and, as a result of a supernova explosion, two neutron stars are created - there is a good chance that gradually they will collide, leading to the liberation of enormous energy.

Thanks to the energy released during such thus, the iron group elements present in the star instantly absorb neutrons increasing their atomic mass rapidly. The elements of high atomic masses are born here (Au - 196,97, Pt - 195.08, Pb - 207,2, U - 238,03). As a result of the explosion, the newly created elements are thrown into space together with dust and gases. The gold particles glide in space until they encounter an object.

How did gold come to the Earth

During the formation of the planet, when the Earth was still a growing sphere of matter, it must have been reached by the particles thrown into space by spectacular supernova explosions and by extremely rare collisions of neutron stars. The cloud of dust and gases, encountering newly forming planets on their path, was absorbed by them. Heavy chemical elements, due to their density and gravitational force, collapsed towards the center of the planets, and light accumulated on the surface. After the formation of the Earth there is practically no trace of heavy elements in its crust, only the most popular rock-forming compound - silica (SiO2).

The creation of so desirable by man ore deposits requires rapid geological events that bring heavy elements back to the Earth's surface. Man will have to count for such a rare and complex geological processes, until he learns how to acquire raw metals from deeper parts of the planet, or how to capture very valuable objects from space. Psyche asteroid, which is a fragment of the old core of a broken planet, which consists almost entirely of iron, nickel, gold, platinum is such a cosmic phenomenon. In 2023, the first space probe will reach her - the race for its resources has already begun.

sources: Dana Berry, SkyWorks Digital, Inc., Harvard-Smithsonian Center for Astrophysics, dr Rupert Hochleitner Der neue Kosmos-Mineralienfuhrer; Monica Price, Kevin Walsh Pocket Nature Rocks and Minerals; wikipedia; American Museum of Natural History; scitechdaily: E. Berger, W. Fong, R. Chornock (Harvard) An r-Process Kilonova Associated with the Short-Hard GRB 130603B, Janet Anderson, Megan Watzke NASA'S Chandra Finds Superfluid in Neutron Star's Core.

2 Replies to “Does the Earth’s gold come from stars?

Comments are closed.