While you were sleeping last night, an asteroid passed close to Earth—very close. The object is known only as 2017 BH30, and it passed within 40,563 miles of the planet. That’s closer than the orbit of the moon, which is 238,000 miles away. The troubling part here is that astronomers didn’t detect 2017 BH30 until just hours before its closest approach. Luckily, it wasn’t large enough to pose a serious risk.

Scientists estimate that 2017 BH30 is around 19-23 feet (6 or 7 meters) in diameter. That’s certainly far from planet-ending, but it could still pack a punch if it entered the atmosphere. For comparison, the 2013 Chelyabinsk meteor was just shy of 20 meters across, and it caused a spectacular explosion in the sky that broke windows and scattered fragments over a wide area. The debris from the explosion caused more than 1,000 injuries.

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