One day, as Charlene was teaching her regular Physics-101 course, she got a question from a senior student in her class. The student was wondering what kind of event in the universe caused the creation of heavy elements, in particular precious metals (such as gold and silver)? She was surprised, actually not by the question, but by the timing of the question. Just a month before that, researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) had detected a set of gravitational waves, and were able to quickly identify the source. The underlying event was the merger of two neutron stars, 130 million light-years from us. So imagine, 130 million years ago two special celestial bodies crashed into each other and we observed it from earth in 2017.
During the month between the first capture of the event, and the question of the student, around 70 different observatories, research institutions, and laboratories studied the rays generated by this collision in every possible frequency: visible light, radio frequency, X-Ray, Gamma-Ray, etc. These observations, and a number of other mathematical principles and empirical observations, show that 98% of the matter in the universe (Hydrogen and Helium) was created during the early phase of the Big Bang. Furthermore, while the elements until Iron (element number 26 on the periodic table) have been made through common star explosions at the end of their lives, elements beyond Iron, and certainly precious metals are mostly made through the collision of 2 neutron stars, which would have lived ‘together’ for 100s of millions years, before they start their swan dance around each other. For the record, a Neutron star is what remains of the core of a massive star (whose mass is 1-3 times the mass of our Sun) that collapses after it runs out of its fuel (Hydrogen) and explodes as a supernova. The neutron star contains about a Sun's worth of mass packed in a celestial sphere with a radius of 10 to 20 kms.
As for the merger of 2 Neutron stars, we do not know how common such collisions/ mergers are, but our best current estimates are that only 0.5% of the stars are neutron stars and only 5% of these neutron stars are in a binary form which would create such events. Consequently, our best estimates are that only 0.025% of the stars in the Milky Way galaxy could provide the precious metals at their ‘death’. This gives us a new perspective on what it means to be a ‘precious metal’ or simply ‘precious’.
Studying these phenomena is part of science, real science. We, however, deal with Fictional Science, as well, for we do not appreciate an absence of solution, and thus resort to imaginary solutions, if those solutions are consistent with a layer of romanticism and poetic virtue. And this is where Chemistry swings into action.
The word ‘Chemistry’ emanates from the word ‘Kimia’ which means rare. In ancient times in the Middle and Near East, there were scientists working in a field called (Kimia-gari), which translates into ‘working the rare’. They tried to convert basic metals, such as iron, bronze and nickel, into gold and silver. They did not succeed, but thanks to them, humanity developed the science of Chemistry, an integral part of Life sciences. Thus we have witnessed that imaginary solutions (wanting to create gold out of normal metal) can generate real science and technology.
April 7, 2023, Cambridge,
Berta Seintan, PhD & Charlene Wardin, PhD