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 got so angry.
But the Sun does have its moments — most famously, in the predawn hours of Sep. 2, 1859. At that time, a brilliant aurora lit up the planet, appearing as far south as Havana. Folks in Missouri could read by its light, while miners sleeping outdoors in the Rocky Mountains woke up and, thinking it was dawn, started making breakfast. “The whole of the northern hemisphere was as light as though the Sun had set an hour before,” the Times of Londo...