The new theory brings together puzzling clues from several different fields of research, including paleontology, geology and astronomy.
Narciso Benitez, an associate research scientist in astronomy in the Krieger School of Arts and Sciences at The Johns Hopkins University, says the missing smoking gun that brought the clues together was the revelation that a stellar cluster with many large, short-lived stars prone to producing supernovae had passed near Earths solar system several million years ago.
That discovery, made by co-author and Space Telescope Science Institute astronomer Jess Maz-Apellniz, led Bentez to check the scientific record for potential effects of nearby supernovae on the Earth.
Nobody had realized that this cluster of stars that Jess had tracked, which is known as the Scorpius-Centaurus OB association, could have been so close to Earth during the past several million years, Bentez says. And when I did a search, one of the first things that popped out was a 1999 finding where a team of German astronomers led by Klaus Knie detected the presence of a highly unusual isotope of iron in samples of the Earths crust drilled from the deep ocean bottom.
Knie had proposed that the iron isotope was debris from a recent supernova explosion that took place close to Earth. But astronomers had no plausible candidates for such a nearby explosion until Maz-Apellnizs work with the Scorpius-Centaurus association, which is also being presented at this weeks meeting of the American Astronomical Society.
Bentez compared data produced by Maz-Apellniz and Knies results, and found very good agreement, both in the amount of iron deposited and in its time distribution.