Gold is a chemical element. It has many wonderful properties – it is very soft and ideal for fabulous jewelries; it is a great heat reflector; a conductor for electricity; and very inert so it can stay shiny and bright after thousands of years under standard conditions. It is also a ‘precious metal’ with very limited above-ground sources (the third most rare metal on Earth).
No wonder why we need gold. But where does it come from?
The Big Bang
Everything in this Universe started from the Big Bang, around 13.8 billion years ago, including the gold.
Following that gigantic explosion, the Universe expanded and cooled down, and lightest atoms appeared – 90% hydrogen atoms and 10% helium atoms.
After a few hundred million years, earliest stars underwent constant nuclear fusions. These reactions forced light elements together to make heavier elements, following the periodic table. These early stars made elements from carbon, nitrogen, oxygen, all the way towards iron, the heaviest element that a star can make. Up to this stage, no gold anywhere in the Universe.
For elements heavier than Iron, their productions required much higher pressure, temperature, and energy —bigger, cataclysmic explosions.
It takes a supernova, or two neutron stars
Iron has a very stable nucleus, which means the end of a series of nuclear fusions in a star. Without their fuel, a star soon collapsed and exploded as a phenomenon called a supernova. From the first ever supernova that occurred in our Universe, atoms of gold were manufactured and spread along with debris of star explorations.
On 17th of the October, a team of astronomers announced that they had detected gravitational waves again, and hence the first collision of two neutron stars we have ever seen. Apart from all other important reasons that make this discovery huge, the collision itself confirms another theory of the origin of gold in the Universe. Scientists monitored the afterglow from the collision to work out its chemical composition. After observed for four consecutive nights, they claimed the glow is the result of gold formation.
A Neutron star is what is left from a supernova explosion, combined with gravitational collapse. It is the smallest and densest form a star can be. The intense energy created from a collision between them was also enough to create gold.
Whether the gold was made by supernovas or neutron stars, after several million years, gold finally reached our planet. The vast majority of it, along with other rare metals such as platinum, sank with molten iron to make the core.
Can we find more gold ores? The answer is yes.
Gold can be concentrated from the seas. Since the same processes of gold depositing occur in both the ocean and on land, and 71% of the surface is covered by ocean, that is a significant area that is yet to be explored. Underwater gold mining robots are under developing and will be used in future.
More gold deposits can also be found in the plant’s core. Current scientific theories indicate that there is enough gold in the core by measuring the density of the core. The amount of gold underground is, in fact, enough to cover the surface of the earth with a 4-meter thick layer.
The problem is that the core is much deeper than we can mine. The deepest gold mine in the World is TauTona Mine in South Africa, which reaches 3.9 km below ground.
Gold in the trees
Australian researchers have found gold particles that are present in tree leaves, as an article published in Australian National Geographic magazine. Such as Eucalyptus tree, or so-called gumtree.
Researchers had confirmed that these nanoparticles that found in eucalyptus leave represented ore traces. Plants like trees with long roots that can delve very deep underground to search for water, and hence, they have the chance to encounter gold mines.
Nowadays, the price of gold is around $1,300 per ounce, but the discoveries have declined almost a half (45%) over the past ten years, and typically, it takes a decade to go from discovery to full-scale gold mine. Despite the huge demand for gold, the decline in above-ground gold ore indicates a need for new exploration technologies for gold deposits. ‘But such technologies have been seldom reported’, the article says.
Overall, eucalyptus trees might offer an alternative way to find gold deposits, for those ones that might be overlooked by other detectors.
We are just too greedy to give up all chances for gold.