Scientists reveal the potential for massive, and potentially destructive, eruptions from the sun. On May 1, 2019, the star next door erupted. In a matter of seconds, Proxima Centauri, the nearest star to our sun, got thousands of times brighter than usual — up to 14,000 times brighter in the ultraviolet range of the spectrum. The radiation burst was strong enough to split any water molecules that might exist on the temperate, Earth-sized planet orbiting that star; repeated blasts of that magnitude might have stripped the planet of any atmosphere. It would be bad news if the Earth’s sun ever...