From the June 2019 issue

What will happen on Earth when Betelgeuse goes supernova?

Donald Craig Indianapolis
By | Published: June 24, 2019
Betelgeuse, shown here in a Hubble Space Telescope image, is a red supergiant about 500 light-years away in the constellation Orion the Hunter. Although astronomers predict this massive star will end its life as a supernova soon — at least in cosmic terms — the effects of such an explosion won’t pose a problem for life on Earth.
Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA
Betelgeuse is about 500 light-years away, not near enough to cause serious damage. We might see a little bit of damage to the ozone layer, or some small increase of radiation on the ground on Earth, but these would be too small to matter.

Based on the latest work with my collaborators, a massive star would need to be within about 150 light-years to cause measurable damage. We think that may have happened about 2.6 million years ago, and possibly contributed to an extinction event at the end of the Pliocene era that took out marine megafauna. (See the November 27, 2018, issue of the journal Astrobiology, and “Could a supernova explain an ancient mass extinction?” on page 11 of Astronomy’s April 2019 issue.) A supernova within about 25 light-years would probably cause a major mass extinction, which has likely happened one or more times in the past 500 million years.

The biggest current threat is probably a solar proton event, which occurs when the Sun releases high numbers of energetic protons that can disrupt communications and affect power grids. These events could be devastating for our technological civilization.

Adrian L. Melott
Emeritus Professor, Department of Physics and Astronomy, 
University of Kansas, Lawrence, Kansas