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Though none of us knew it until after it happened, an enormous asteroid labeled a “city killer” came close to making impact with the Earth last Thursday, and even more startling is the fact that scientists didn’t even know the object was headed our way until the last minute.
According to the Washington Post:
“This asteroid wasn’t one that scientists had been tracking, and it had seemingly appeared from ‘out of nowhere,’ Michael Brown, a Melbourne-based observational astronomer. According to data from NASA, the craggy rock was large, an estimated 57 to 130 meters wide (187 to 427 feet), and moving fast along a path that brought it within about 73,000 kilometers (45,000 miles) of Earth. That’s less than one-fifth of the distance to the moon.”
Brown added that the entire event definitely caught the world of astronomy off guard:
“It snuck up on us pretty quickly. People are only sort of realizing what happened pretty much after it’s already flung past us.”
— ASAS-SN (@SuperASASSN) July 25, 2019
But how exactly does an object big enough to destroy an entire city go unnoticed? How does something so gigantic sneak up on the very people who devote their lives to tracking such things? Astronomer Alan Duffy told the Post:
“First, there’s the issue of size, Duffy said. Asteroid 2019 OK is a sizable chunk of rock, but it’s nowhere near as big as the ones capable of causing an event like the dinosaurs’ extinction. More than 90 percent of those asteroids, which are more than half a mile wide or larger, have already been identified by NASA and its partners.”
Duffy’s explanation was echoed by Brown, who noted that last week’s asteroid had what he called an “eccentric orbit”:
“Its ‘very elliptical orbit’ takes it ‘from beyond Mars to within the orbit of Venus,’ which means the amount of time it spends near Earth where it is detectable isn’t long, he said. As it approached Earth, the asteroid was traveling at about 24 kilometers per second, he said, or nearly 54,000 mph. By contrast, other recent asteroids that flew by Earth clocked in between 4 and 19 kilometers per second (8,900 to 42,500 mph).
“’It’s faint for a long time,’ Brown said of Asteroid 2019 OK. ‘With a week or two to go, it’s getting bright enough to detect, but someone needs to look in the right spot. Once it’s finally recognized, then things happen quickly, but this thing’s approaching quickly so we only sort of knew about it very soon before the flyby.'”
It’s somewhat comforting to learn that the scientific community is actively working on measures that would deflect potentially destructive objects like asteroids, Professor Duffy revealed:
“One strategy involves gently pushing the asteroid slowly over time off its course and away from Earth, he said. The other, which he called a ‘very elegant solution,’ is the gravity tractor. If an asteroid is detected early enough, it could be possible to divert it using the gravity of a spacecraft, according to NASA.
For now, we can all rest easy and try not to obsess over the fact that we might well have been obliterated by a space rock. And this close call is a reminder that no matter how safe we may think we are, the universe always knows how to throw the ultimate curveball.
Here’s more on how NASA plans to prevent asteroids from hitting the Earth:
Featured Image Via MaxPixel