Here are today's general risks from asteroids or comets both tiny and very large. Importantly, even relatively small rocks can still be threatening, as the surprise 56-foot (17-meter) rock that exploded over Russia and blew out people's windows in 2013 proved.

The odds keep growing that an asteroid big enough to wipe out a city will collide with Earth in seven years, according to NASA. But the chance of an actual impact is still quite slim. NASA first discovered “2024 YR4,

YR4 probably won’t come nearly as close to Earth anytime soon as the space rock in this artist’s illustration. But astronomers can’t yet rule out a potentially catastrophic encounter projected for December 2032.

YR4 has grabbed headlines lately, after NASA calculated a 1-in-32 chance of an impact in 2032 – the highest chance ever for an asteroid of hazardous size. Thankfully, new observations have now halved that probability.