An undetected Asteroid comes rushing towards Earth one summer day. This may sound like an opening line to a top-selling comic book series, but this was the reality for scientists this past July.

Whether it be through the news or a multitude of memes and tweets that resulted from the event, most of us have probably heard of the massive asteroid that just nearly missed Earth this past summer. For many, this is the extent of their knowledge of this abrupt, terrifying event. Even some scientists were scratching their heads about how Earth was narrowly missed by an object 130m (426ft) in diameter which was only detected a day in advance. 

The first valid detection of Asteroid OK 2019 was on July 24, 2019, when it was only 930,000 miles away from Earth. This was partly because of the full moon in mid-July, which slowed down the discovery rate.

Also, due to its position and location in the sky, it was relatively undetectable by instruments in the Northern Hemisphere. Additionally, Pan-STARRS1 telescope recorded an image of 2019 OK on June 28, 2019, but it did not cause any alarm because it was too faint to be seen as a threat at that time.

It was again seen by the same telescope on July 7th, but ironically, it was moving directly towards the telescope and Earth, so its apparent motion was too slow (0.01 degrees/day) to be recognized as a moving object. It was only recognized properly a few hours before it was predicted to pass the Earth.

As soon as it was detected, scientists were hard at work trying to calculate the potential damage and closest proximity to Earth. Three hours before its nearest encounter to Earth, the asteroid’s existence was announced to the world via Minor Planet Center’s Near-Earth Object Confirmation Page (NEOCP). Understandably, the world was terrified. Although, a large majority only found out about it after the fact. 

In hindsight, this event may seem comical, but the seriousness of the threat should not go unnoticed. On the day of its closest proximity to Earth, OK 2019 was only 65,000 kilometers from Earth. For reference, that’s only one-fifth of the distance to the moon.

If it had only been a few kilometers closer, there would be catastrophic effects. If it had come in contact with Earth, it would have released as much power as the fifty megatons generated by Tsar Bomba, a Soviet hydrogen bomb which goes remembered as the most powerful nuclear weapon ever detonated. It would have released explosive energy of about ten megatons of TNT. This would have similar effects to the Tunguska event in 1908, the largest asteroid impact ever recorded on Earth which flattened 770 square miles of forest land in Siberia.

While amusing to some and frightening to others, the event shed light on the faults in the tracking of celestial objects. Many scientists are now working hard to ensure that no future asteroids are overlooked. Satellites are being updated to account for any similar future events.