Supernovae pose a threat to life on Earth, says NASA study

The study, authored by Ian Brunton, Connor O’Mahoney, and Brian Fields from the University of Illinois at Urbana-Champaign; Adrian Melott from the University of Kansas; and Brian Thomas from the Washburn University in Kansas, was published in the April 20, 2023 issue of the Astrophysical Journal.

The team studied X-ray observations of 31 supernovae and their aftereffects as captured by NASA’s Chandra X-ray Observatory, the Swift and NuSTAR missions, and the European Space Agency’s XMM-Newton. They showed that radiations can travel as far as 160 light-years, and can penetrate planets with lethal doses on the way.

Their research took a novel approach from most previous studies, and focused on the immediate aftermath of a supernova explosion and the energetic particles that arrive hundreds to thousands of years later.

Are we all gonna die?

When a planet is infiltrated by radiation of this intensity, its atmospheric chemistry could be severely affected. In Earth’s case, this could even wipe out a portion of ozone, without which organisms - particularly those at the foundation of the food chain - will not survive.

And before you breathe a sigh of relief, you might want to know that this could trigger a chain of reactions up the food chain, leading to an extinction event.

Years of exposure to these X-rays and the impact of ultraviolet radiation from the planet’s host star would produce nitrogen dioxide causing a brown haze in the atmosphere. The team concluded that a “de-greening” of land masses could also occur.

Although a lack of potential supernova progenitors within 160-light years rules out an immediate threat on Earth, X-ray exposure- to a similar degree- might have occurred in the past.

Additionally, many other planets in the Milky Way, including ones we are hopeful of being habitable, are not yet out of danger.

“Further research on X-rays from supernovae is valuable not just for understanding the cycle of stars, but also has implications for fields like astrobiology, paleontology, and the earth and planetary sciences,” said Brian Fields, advocating for follow-up observations of interacting supernovae.