A team of researchers has detected isotopes of plutonium and iron in samples of ocean crust, which are not usually found in terrestrial conditions.
Man has always been drawn to the stars. And he has wondered for centuries about the actual existence of alien life forms. A constantly evolving research, both bold and stubborn, that has allowed us to arrive at discoveries that were previously thought impossible, or at least difficult to replicate.
In a historical period in which UFOs are back in the limelight thanks to the recent declarations of the Pentagon, it is particularly noisy a recent discovery related to materials that are not found in terrestrial conditions, but that happened without bothering sophisticated space rockets.
A group of scientists has in fact found a rare radioactive isotope of plutonium dating back millions of years at the bottom of the ocean. According to the authors of the discovery, the presence of the dangerous element, technically known as plutonium-244, indicates that the Earth's surface is periodically reached by particles of matter ejected during supernova explosions or the collision of neutron stars. Now embedded 1,500 meters below the Pacific Ocean in the oceanic crust, the alien plutonium is thus the result of "violent cosmic events" that occurred in deep space millions of years ago.
According to the paper published in the journal Science, stellar matter has been deposited on our planet at least twice in the past ten million years. The study's lead author, Anton Wallner, of The Australian National University, explains this phenomenon:
The story is complicated: perhaps this plutonium-244 was produced in supernova explosions or it could have been generated by a much older, but even more spectacular event such as the detonation of a neutron star.
The process of rapid neutron capture has been successfully reproduced in the laboratory, with very precise conditions, but it remains uncertain how and in what events it might occur in space. To figure it out, Wallner and his team - all collaborators from Australia, Germany, Japan, Israel and Switzerland - set out to search for isotopes of extraterrestrial origin among Earth's rocks. Considering that these isotopes are typically radioactive, according to their decay period one can in fact determine the age of cosmic events.
Plutonium-244 has a half-life of about 80 million years. Any traces of plutonium present on Earth, according to the scientists, must have formed only recently, as it goes through a physiological radioactive decay too fast to survive from the moment the planet formed. In the same samples, the authors also found two anomalies of the radioactive isotope iron-60, with a half-life of 2.6 million years and known to be emitted during supernova explosions. In Earth time, they correspond roughly to 6-8 and 2-3 million years ago.
Both of these elements are heavy and should have decayed into stable forms eons ago. Since they were found in their present state, this could imply that the cosmic event occurred only a few million years ago. Whatever the truth, it is certain that further studies of these isotopes will allow us to carve out a new look at the astrophysical origin of heavy chemical elements. And to understand much more about the massive explosions in space that occurred in the Solar System millions of years ago.