Download The fantastic journey of that ring on your finger: From

The fantastic journey of
that ring on your finger:
From the Big Bang to
your hand
Monthly Strategy Report May 2016
Alejandro Vidal Crespo
Unit Director of Market Strategies at Banca March
Monthly Strategy Report. May 2016
The fantastic journey of that ring on your finger: From the
Big Bang to your hand
According to the prevailing Big Bang theory, the matter that made up the early universe largely consisted
of hydrogen (the most basic element on the periodic table) and helium (the second gas on the scale). So,
where do the other elements—118 in total—come from? And although hydrogen and helium remain the
most abundant elements in the universe, accounting for 98.5% of observable matter, why on planets like
ours do we live surrounded by residual cosmic elements? Well, let’s start from the beginning of time…
Some 13.8 billion years ago, just after the Big Bang, the universe’s primordial elements began to form; in
terms of observable matter, the majority of atoms were hydrogen (75%) and helium (25%), with trace
amounts of other elements. Because they have mass, gravity began to act on these elements, pulling
them together into clouds of gas. These clouds grew increasingly more dense as the force of gravity
pushed the atoms closer and closer, eventually forming spherical structures. Once these structures
obtained enough mass, gravity fused the hydrogen atoms through high-speed collisions, and eventually,
four hydrogen atoms combined to create a single helium atom in a reaction that releases extremely high
amounts of energy in the form of light and heat: the nuclear fusion of hydrogen. And a star is born, in
the literal sense.
During the first billion-odd years of its life, the star is a stable structure because the pressure from the
expanding gases that comprise it (the heat source) is offset by the gravity that constricts it. So, in this
phase (the current phase of our Sun), the star exists in a tranquil and placid state. However, the reaction
that keeps the star alive continues, consuming fuel until nearly all of the hydrogen is depleted and, as
a result of this fusion, there is an abundance of helium. As combustion declines, so does heat, and once
the core cools slightly, the force of gravity causes the star to contract again, this time allowing helium
to fuse into carbon, and giving a “second life” to our now mature star. Helium fusion causes the star
to expand exponentially, becoming huge in size and red in colour. (When our Sun reaches this stage, in
about 6 billion years, it will expand to roughly the size of the Earth’s orbit; today, the Earth is 150 million
kilometres from the Sun.)
Here’s where things get tricky... If the star is relatively low in mass (up to 9-10x the size of our Sun), it
will form an inert carbon core unable to spark nuclear fusion and will slowly dim, expelling matter and
ultimately leaving a tiny hot residue known as a white dwarf. But, in more massive stars, gravity will
exert enough pressure to ignite carbon fusion, forming heavier and heavier elements like neon, oxygen,
silicon, and eventually iron; and that’s when the pandemonium begins.
Iron has the most stable atomic nucleus in existence and, unlike the aforementioned elements, it tends
to absorb the energy of nuclear reactions. So, when a heavy iron core forms in a star and that star is
compressed, rather than release the heat needed to offset the gravitational force, it is compressed
to the maximum. The outer layers crash into the core and rebound, sending shockwaves outward in
an effect similar to hitting a basketball with a mallet (don’t try this at home!). This triggers a colossal
explosion known as a supernova. The shockwave blows the outer layers of the star out into space at
extremely high speeds, dispersing all of the elements that comprise them. This detritus coalesces with
more hydrogen and helium to create new gas clouds that will condense and create another generation
of stars and rocky planets like our own. But what about elements heavier than iron? If we concede that
once we arrive at iron the star breaks apart, where then does the gold in my ring come from? Though
a small fraction of it may have been formed in the supernova, the majority of it originates elsewhere.
As we mentioned, the most abundant elements on Earth come from the outer layers of the exploded
star, but what happens to its core? It forms one of the most curious bodies in the universe, a neutron
Monthly Strategy Report. May 2016
star: imagine an object twice the mass of our Sun compressed into a sphere only 20 kilometres in
diameter rotating in mere fractions of a second (up to 700x/second). Because of its enormous density, a
cubic centimetre of this matter (the size of a sugar cube) would weigh 100 million tonnes, nearly 1,000x
the weight of the largest nuclear aircraft carriers in the US fleet. And if two of these bodies collide?
Does it happen? The answer is yes.
And when it does happen, the magnitude of the resulting phenomenon (known as a short gamma-ray
burst) is such that not only are a multitude of elements heavier than iron produced, but the remaining
mass collapses into an object so dense and with such strong gravitational effects that not even light can
escape it: a black hole, capable of altering the structure of spacetime. But more to the topic, this type of
explosion can generate chunks of gold up to 10x the size of the Moon. Talk about a goldmine…
The residue also forms clouds that are scattered across the universe for billions of years, until the star
formation process begins again. Let’s use our solar system (formed roughly 4.6 billion years ago) as an
example. Clouds of gas and dust condensed to form a star, our Sun, and from the debris, planets formed
in a state of liquid rock, with the heaviest elements (like gold) concentrated at their cores. More’s the
pity. But if nearly all of the planet’s original gold is in the core, again, where does the gold in my ring
come from?
The majority of it comes from magma fissures originating deep inside the Earth, while some is the
result of a massive meteorite shower 3.8 billion years ago, after an orbital dance between the gas giants
released millions of residual objects into the solar system, lodging heavy elements into the Earth’s crust
that we are able to extract today. And we have gold on the surface of the Earth... Eureka!
The gold in your ring may have been extracted at any point in human history. With some romanticism,
it is not difficult to imagine (you’ll allow a bit of poetic license) that part of your ring arrived in Cádiz
aboard a Spanish galleon riddled with cannon fire after battling at yardarms with a pirate ship in the
Bahamas, another part may have arrived by camel caravan from the Niger River basin, and still another
small portion may have been excavated by the Romans on the Iberian Peninsula.
So to recap, after forming part of the core of a megastar that suffered a cataclysmic explosion, the
particles that form your ring resided in a neutron star for hundreds of millions or billions of years until
it likely collided with a similar star, at which point, after narrowly escaping being swallowed by a black
hole, the particles were flung into space, where they drifted for billions of years before forming part of
an asteroid in the solar system. Later the gravitational force of a large planet caused the asteroid to fall
to Earth, where it waited patiently in a vein of gold to be extracted. Then, after going down aboard a
galleon, it may have been used to make ingots, coins, or teeth... go figure. And finally it arrives to adorn
your hand. What will the future hold?
Another Strategy Report somewhere else in spacetime will answer that. For now, we read on...