The first close encounter is expected to occur on July 23 when the asteroid 2017 BS5 — there are so many asteroids whizzing by our planet each year that NASA doesn't bother to get cozy with them or give them cuddly names — will come within 3.15 lunar distances, or about 752,900 miles, of Earth. The asteroid is roughly 300 feet in diameter, about the size of the Statue of Liberty.
But while 2017 BS5 may sound alarming, there's actually a more worrisome flying rock heading our way later this year. On October 12 the asteroid 2012 TC4 is going to be passing by Earth. Now, 2012 TC4 isn't nearly as large — it's only 88 feet in diameter, not even half the length of a football field — but it poses more of a threat just because of how close it will be. The asteroid will pass by at 0.15 lunar distances from the Earth, just 35,838 miles away.
That may not sound like much of a threat, but keep in mind that the moon is about 230,000 miles away from Earth. In other words, in the context of space, the school-bus-size 2012 TC4 is going to be coming pretty close to the planet.
A list of known asteroid close approaches to Earth - less than 5 Lunar Distance - within the coming year. pic.twitter.com/7Ac8IkYxP6— Ron Baalke (@RonBaalke) May 22, 2017
This won't be the first time we've had a close brush with this particular asteroid either. It zipped by us in January 2012, according to CNN, coming within 36,750 miles of Earth that time around. However, the asteroid was dismissed as being any real threat at the time since it's believed that even if it had veered toward us, the asteroid would have broken up in the atmosphere before any large portion could actually smash into the planet.
NASA is taking the same approach this time around, and Sentry, the monitoring system set up at the Center for Near Earth Object Studies, has not placed odds on any of these asteroids actually striking the planet or posing a significant threat.
Of course, it's worth keeping in mind that in the past, NASA officials have warned that we aren't currently prepared to deal with an impending asteroid strike in the first place. "The biggest problem, basically, is there's not a hell of a lot we can do about it at the moment," Joseph Nuth, a researcher at Goddard Space Flight Center in Maryland, said in December, according to the Daily Mail. While asteroids and comets rarely hit Earth, there's always the chance that they will.
After all, it has happened before. Back in 2013 an asteroid hit without any warning in Chelyabinsk, Russia, injuring hundreds of people. And that wasn't even a dinosaur-killer-level asteroid. But those have been known to happen as well, as Nuth pointed out. "They are the extinction-level events, things like dinosaur killers; they're 50 to 60 million years apart, essentially," he said. "You could say, of course, we're due, but it's a random course at that point."
Either way, for right now, these asteroids are all expected to come in pretty close as they swing by, but not pose a threat.
The other asteroids passing by will be much less flashy. The last three flybys will take place starting on December 3 of this year, then again on February 24 and April 2 of 2018. While all three of those rocks will be relatively close, they are expected to zip past us at a more comfortable distance, between 3.69 and 4 lunar distances.