A cataclysmic collision between the remnants of a pair of dead stars may have seeded our solar system with precious heavy metals including gold and uranium, according to a newly published study. If such a heavyweight clash were to be observed in the present day, it would be the brightest point in the night sky.
Neutron stars are the remains of once massive stellar bodies that have exploded in dramatic supernovae. This violent event casts vast quantities of stellar material out into the surrounding space environment, but the ultra-dense core of the once majestic star lives on.
This core, or neutron star, would have a mass between one to three times that of our Sun crammed into a space just a few tens of kilometers in diameter. In short, they are phenomenally dense.
When a pair of neutron stars merge, they create powerful gravitational waves, that scientists are now able to detect on Earth with the help of incredibly accurate interferometers. Furthermore, the violence of the interaction unleashes enough energy to forge rare heavy elements, such as uranium and platinum.
According to the results of a new study, a collision between neutron stars may have occurred in our cosmic backyard billions of years ago, seeding the vast clouds of matter from which the planets of our solar system would form with precious heavy elements.
The study was carried out by Professor of Physics Szabolcs Marka from Columbia University and Assistant Professor Imre Bartos from the University of Florida. The pair analyzed the isotopic decay of elements discovered in ancient meteorites that had fallen to Earth. By tracking the decay, they were able to work out when the materials were created.
This data was then compared to numerical simulations of our galaxy. The scientists discovered a potential neutron star collision event that could account for the creation of the heavy elements.
The evidence suggests that the collision of the neutron stars took place about 4.6 billion years ago, a thousand light-years from our (future) solar system.
This may sound incredibly distant. However, when addressing the violent deaths of super-dense stars, it's only fair to place the events in the proper context. The Milky Way is thought to stretch across roughly 100,000 light-years of space, and against this cosmic yardstick, the heavyweight collision took place very close indeed.
So close in fact that it influenced the makeup of the planets and parent star of our home system, endowing Earth with 0.3 percent of its heaviest elements.
"This means that in each of us we would find an eyelash worth of these elements, mostly in the form of iodine, which is essential to life," comments Bartos. "A wedding ring, which expresses a deep human connection, is also a connection to our cosmic past predating humanity and the formation of Earth itself, with about 10 milligrams of it likely having formed 4.6 billion years ago."
The research has been published in the journal Nature.
Sources: University of Florida, Columbia University