Newly named 2017 AG13, the asteroid was measured to be between 25-35m tall, and was first spotted on Sunday night by the Catalina Sky Survey.
It was travelling at a leisurely speed of 16km (10 miles) per second.
“This is moving very quickly, very nearby to us,” an expert with astronomy news website Slooh, Eric Feldman, said during a hastily arranged live broadcast of the fly-by yesterday.
It is believed that the rock was approximately the same size as the asteroid that exploded in the sky over Chelyabinsk, Russia back in 2013.
While you were hitting snooze, we nearly hit an asteroid! At 7:47 AM EST an asteroid we only first spotted Saturday gave us a wake up call. pic.twitter.com/BbAQc7e2EJ
— Slooh (@Slooh) January 9, 2017
The scary part of this story is the very late detection of the asteroid, despite our efforts. It is believed that the rock would have exploded high up in our atmosphere, with a force of over 700 kilotons. To give you an idea of comparison, the Nagasaki bomb was 20 kilotons. Wow.
The Planetary Society believes that it has identified over 60% of near Earth objects which are bigger than 1.5km. This is not including the massive number of smaller asteroids that would be undetected.
Experts have stated though that the probability of a critical asteroid impact on Earth in the next 100 years is less than 0.01%.