Subrata Chakraborty, a project scientist in chemistry at the University of California at San Diego, and colleagues have solved the mystery of the oxygen isotope concentration in meteorites that are the oldest known rocks in the universe according to their report in the Oct. 24, 2013, issue of the journal Science.
The researchers replicated conditions in the primordial universe of 4.6 billion years ago by adding silicon monoxide solid, oxygen, and hydrogen together and vaporizing a plume of silicon monoxide gas into the mixture with a laser. This combination of minerals and gases has been observed in the oldest known remnants of star forming nebulae in the known universe. The oldest asteroid material found on Earth also has the same chemical composition.
The resulting solid rock that precipitated from the irradiated gas mixture had the same combination of oxygen isotopes in the same proportions as the oldest known asteroids that have fallen to Earth.
The variation in the isotopic oxygen content of the rocks the researchers created was dependent on the amount of hydrogen present and governed by a well-established chemical principle called symmetry.
These experiments explain why the most ancient stone remnants of the universe’s early life have a predominance of heavy isotopes of oxygen in the silicon based rock instead of the oxygen-16 isotope that is most common in Earth rocks.