They form a giant sphere known as the Oort cloud that envelops the solar system and stretches out to perhaps a couple of light-years from the sun. Yet last week astronomers announced the discovery of one with truly behemoth proportions: a giant comet that may measure hundreds of kilometers from edge to edge. The Bernardinelli-Bernstein comet is “certainly the largest comet we’ve seen in the modern astronomical era,” says Alan Fitzsimmons of Queen’s University Belfast. That’s going to be really fun to find out.”The comet is also a taste of what is to come in the near future of solar system astronomy. We’re going to see things like [the Bernardinelli-Bernstein comet] maybe on a monthly basis.”For the time being, C/2014 UN271 (Bernardinelli-Bernstein) remains the largest comet ever seen approaching the inner solar system, offering a glimpse into the secrets of our sun’s outermost reaches.