Asteroid just passed dangerously close to Earth. We noticed it when it was too lateChristian Fernsby ▼ | July 26, 2019
A 100-metre-wide asteroid passed 70,000 kilometers from Earth. The point is, it was discovered by the Brazilian SONEAR survey just days ago.
World 2019 OK would have been visible with a pair of binoculars
The asteroid, reassuringly designated 2019 OK, is not a threat to Earth right now.
At closest approach and with dark skies, 2019 OK would have been visible with a pair of binoculars as point of light drifting slowly across the sky. But three days before that it was 1,000 times fainter, and thus harder to spot.
What's more, for the past month it has been relatively close to the Sun in the sky, so it has only been visible around twilight.
2019 OK was finally tracked down by the SONEAR survey on Wednesday, and soon after that it was independently detected by the ASAS-SN telescope network.
Before its discovery as a near-Earth asteroid, 2019 OK was imaged by other telescopes, but its significance wasn't recognised. But these earlier images did help astronomers nail down the asteroid's orbit.
2019 OK has a very elliptical orbit, taking it from the asteroid belt beyond Mars to within the orbits of both Earth and Venus. As each orbit takes 2.7 years, it isn't always going to pass as close to Earth as it did this time. It will make close approaches in the future, but hopefully not quite this close. ■