ESA shares grainy video of July's unexpected asteroid 2019 OK flyby

Late in July, astronomers were caught off guard by the sudden presence of a large asteroid only hours away from zooming past Earth. Called 2019 OK, this asteroid measured around 426ft in diameter and came closer to Earth than the Moon. Experts previously shared a video showing the asteroid's trajectory in relation to our planet, but a new view from the European Space Agency shows the asteroid itself.

To help put things in perspective, the ESA points out that asteroid 2019 OK was around the size of a football field and its approach near Earth came within one-fifth the distance between our planet and the Moon. Despite that trajectory and ample size, scientists weren't aware of the asteroid's presence until July 25, a mere day before its flyby.

Using two different telescopes on the International Scientific Optical Network (ISON), the ESA managed to capture an observation of 2019 OK before it whizzed past Earth. The result is a video showing what appears to be a large black dot on a very grainy background — that dot, of course, is the asteroid.

The ESA was one of multiple agencies and institutions around the world that observed the asteroid as it neared and passed our planet. By retroactively looking for the space rock, astronomers were also able to spot it in space images previously captured and saved in sky survey archives.

New asteroids are discovered daily and teams around the world are dedicated to monitoring ones designated near-Earth objects (NEOs), which have the potential of one day becoming an issue for humanity. NASA and other space agencies have spent years developing possible methods for diverting these problematic space rocks, including controlled explosions.