The rare element plutonium-244 has recently been discovered in the crust beneath the ocean. The discovery of this radioactive element shows scientists how heavy metals have played a role in star formation. Researchers say the isotope probably came to Earth with the iron-60 isotope.
Iron-60 is a lighter metal that forms supernova explosions, ending the life of giant stars. Scientists They believe Finding these two metals side by side indicates that both were probably made by supernovae. However, it is possible that other events, such as the merger of neutron stars, gave rise to plutonium-244.
Understanding how heavy metals are formed is important to scientists and is one of the three key questions in physics. Half of the heavier elements than iron are made by the melting process in the core of stars. The next half of these elements require higher densities of free neutrons, meaning they must have formed in environments such as supernovae, neutron star mergers, or the collision of black holes and neutron stars that are more energetic than stellar nuclei.
Researchers began searching for these elements on Earth to learn about the processes that make heavy metals. Some samples of radioactive heavy metals do not occur naturally on Earth. Scientists in particular have been looking to discover plutonium-244, which has a half-life of 80.6 million years.
Due to the long half-life of this isotope, all of the 244 plutoniums that existed at the time of Earth’s formation have long since disappeared. Therefore, every atom that researchers find from this isotope has an extraterrestrial origin. Plutonium-244 has been discovered at a depth of about 1,500 meters below the Pacific Ocean. This part of the earth has formed at a very slow rate, and every 400,000 years only one millimeter has formed. The specimen discovered by the researchers shows a time span of 10 million years.