The aftermaths of supernovae always produce X-rays, but if the supernova’s blast wave strikes dense surrounding gas, it can produce a particularly large dose of X-rays that arrives months to years after the explosion and may last for decades, according to X-ray observations of 31 supernovae and their aftermath obtained from NASA’s Chandra X-ray Observatory, NASA’s Swift and NuSTAR missions, and ESA’s XMM-Newton X-ray observatory. This threat can damage the atmospheres of planets up to 160 light-years away. Earth is not in danger of such a threat today because there are no potential supernova progenitors within this distance, but it may have experienced this kind of X-ray exposure in the past.
Before this new study, most research on the effects of supernova explosions had focused on the danger from two periods: the intense radiation produced by a supernova in the days and months after the explosion, and the energetic particles that arrive hundreds to thousands of years afterward.
However, even these alarming threats do not fully catalog the dangers in the wake of an exploded star.
University of Illinois at Urbana-Champaign astronomer Ian Brunton and his colleagues discovered that, in between these two previously identified dangers, lurks another.
“If a torrent of X-rays sweeps over a nearby planet, the radiation would severely alter the planet’s atmospheric chemistry,” Brunton said.
“For an Earth-like planet, this process could wipe out a significant portion of ozone, which ultimately protects life from the dangerous ultraviolet radiation of its host star.”
If a planet with Earth’s biology were hit with sustained high-energy radiation from a nearby supernova, especially one strongly interacting with its surroundings, it could lead to the demise of a wide range of organisms, especially marine ones at the foundation of the food chain.
These effects may be significant enough to initiate a mass extinction event.
“The Earth is not in any…
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