Last Sunday, the so-called “Super Bowl asteroid” safely flew by Earth, following weeks of reports that focused on how closely it would skim Earth, and what would have happened had it smashed into our planet. While Asteroid 2018 CB wasn’t as large as the previous week’s Asteroid 2002 AJ129, it stood out for the fact that it flew by much closer on Friday, and how it was only discovered five days prior, unlike other near-Earth asteroids that had been discovered well before their close encounters.
According to CNET, Asteroid 2018 CB made its flyby at around 10:30 a.m. Pacific time on Friday, safely skimming our planet but doing so at a distance of only 39,000 miles (64,000 kilometers) from Earth. As noted by NASA Center for Near-Earth Object Studies manager Paul Chodas, the asteroid was relatively small in size, but was possibly larger than the meteor that crashed into the atmosphere over Chelyabinsk, Russia, in 2013, and also one of the few objects that are generally expected to make such a close approach to Earth.
“Asteroids of this size do not often approach this close to our planet – maybe only once or twice a year,” said Chodas.
The aforementioned Chelyabinsk meteor was only about 50 to 60 feet (17 to 20 meters) wide, but when it exploded over the Russian city in February 2013, it created shockwaves strong enough to shatter windows in over 3,600 apartment blocks, and even knock people off their feet, The Guardian wrote. Thousands were hospitalized for injuries related to the asteroid impact, mostly due to falling debris, but also due to skin and retinal burns caused by the intense brightness of the space rock.
In contrast, Asteroid 2018 CB was believed to be substantially larger, with its width of about 50 to 130 feet (15 to 40 meters), making it possibly longer than a blue whale, as several publications noted. But Live Science added that the asteroid’s size was only a small part of what made it interesting to many observers, as astronomers were only able to spot 2018 CB on Sunday, February 4, only five days before its very close flyby.
According to Live Science, it’s not unusual either for asteroids to be spotted just a few days before they skim past Earth, as there are many near-Earth objects that literally fly under the radar and zoom past our planet without ever being detected. The publication added that asteroids are especially hard to track when compared to other space objects due to their small size. Putting things in context, Asteroid 2018 CB measures a mere fraction of Vesta’s diameter; Vesta, which is the universe’s largest known asteroid, is 329 miles (530 kilometers) wide.
At the moment, NASA is still hard at work as it gathers information on up to 90 percent of all asteroids with diameters of more than 460 feet and likely paths that would take them within about 4.65 million miles (7.48 million kilometers) of Earth. Live Science pointed out that these asteroids are all at least nine times larger than Asteroid 2018 CB, which would have made the latter object extremely difficult to spot from a distance, and only allowed astronomers to spot it as it was “basically knocking on our door.”