Cosmic Rays from Supernovae May Explain Earth-Like Planets

Researchers from the Institute for Cosmic Ray Research, University of Tokyo, have made a significant breakthrough in understanding the formation of Earth-like planets. This study, published in Science Advances, suggests that cosmic rays generated by nearby supernovae could explain the presence of short-lived radioactive elements, such as aluminum-26, which played a crucial role in the development of rocky planets like Earth.

Instead of relying on a rare event where supernova ejecta directly impacts a protoplanetary disk, the researchers propose a more common mechanism called a 'cosmic-ray bath.' This process allows the young solar system to be enriched with necessary radioactive elements without being destroyed by the supernova explosion.

Their simulations indicated that these cosmic rays could produce the required amounts of radioactive elements at typical distances of about one parsec from a supernova, thereby making the conditions that shaped Earth potentially common in star-forming regions.

The findings imply that if cosmic-ray baths are prevalent in stellar nurseries, then the formation of water-depleted rocky planets may not be as rare as previously thought. This research not only enhances our understanding of planetary science but also opens new avenues in astrobiology and the search for habitable planets in the universe.

The work was led by Ryo Sawada and highlights the interconnectedness of astrophysical processes, suggesting that cosmic-ray acceleration might play a key role in the habitability of planets around sun-like stars.