What if a space rock had slammed into our planet — and nobody even saw it coming? That nearly happened on June 15, 2002, when an asteroid came within a mere 75,000 miles of Earth. Hurtling through space at 6.2 miles per second, the object — later designated 2002MN — went completely undetected in real time because its approach path aligned with the direction of the sun, effectively blinding astronomers to its presence.
It wasn't until days after 2002MN had already sailed past our planet that anyone even realized how close the encounter had been. The first sighting of the space rock came from LINEAR, an MIT Lincoln Laboratory based in New Mexico, and 14 additional observations of 2002MN followed after that initial detection. The Near-Earth Objects Information Center, headquartered in Leicester, England, played a role in tracking information about the close call.
Had 2002MN actually collided with Earth, the consequences could have been devastating — comparable to the destruction witnessed in Siberia in 1908, when a space rock struck the surface. This harrowing near-miss underscored the urgency of planetary defense, and NASA has since poured tremendous resources into identifying and tracking these rocky threats, with the goal of developing countermeasures in case one ever heads our way. To date, the agency has detected 602 near-Earth asteroids exceeding 1km in size. Objects of that scale, given their enormous mass and velocity, carry the potential to trigger global devastation.
Fortunately, researchers who have mapped out the future trajectory of 2002MN offer some reassurance. The asteroid isn't expected to have another close brush with Earth for several years, and no potential impacts are anticipated until at least 2050.