Excitement about exoplanets skyrocketed when rocky Earth-like planets were discovered orbiting in the habitable zone of some of our closest stars – until hopes for life were dashed by the high levels of radiation bombarding those worlds.
Proxima-b, only 4.24 light years away, receives 250 times more X-ray radiation than Earth and could experience deadly levels of ultraviolet radiation (UV) on its surface. How could life survive such a bombardment? Cornell astronomers say that life already has survived this kind of fierce radiation, and they have proof: you.
Lisa Kaltenegger and Jack O’Malley-James make their case in a new paper, “Lessons From Early Earth: UV Surface Radiation Should Not Limit the Habitability of Active M Star Systems,” published 9 April 2019 in Monthly Notices of the Royal Astronomical Society. Kaltenegger is associate professor of astronomy in the College of Arts and Sciences and director of Cornell’s Carl Sagan Institute, at which O’Malley-James is a research associate.
All life on Earth today evolved from creatures that thrived during an even greater UV radiation assault than Proxima-b and other nearby exoplanets currently endure. The Earth of four billion years ago was a chaotic, irradiated, hot mess. Yet in spite of this, life ...