Watching asteroids: a close one is coming; it came this week (Introduction)

by David Turell , Friday, July 26, 2019, 23:16 (1729 days ago) @ David Turell

A 'city-killer'-sized rock:

https://www.progressnews.network/2019/07/26/asteroid-2019-ok-just-missed-earth-and-scie...

"An undated image of an asteroid in space. NASA confirmed that on Thursday Asteroid 2019 OK passed about 73,000 kilometers from Earth, roughly one-fifth the distance to the moon.

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"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, told The Post. According to data from NASA, the craggy rock was large, roughly 100 meters wide, and moving quickly along a path that brought it within about 73,000 kilometers of Earth. That’s one-fifth of the distance to the moon and what Duffy considers “uncomfortably close.”

“'It snuck up on us pretty quickly,” said Brown, an associate professor with Australia’s Monash University’s School of Physics and Astronomy. He later noted, “People are only sort of realizing what happened pretty much after it’s already flung past us.”

"The asteroid’s presence was only discovered earlier this week by separate astronomy teams in Brazil and the United States. Information about its size and path was announced just hours before it rocketed past Earth, Brown said.

“'It shook me out my morning complacency,” he said. “It’s probably the largest asteroid to pass this close to Earth in quite a number of years.”

"So how did the event almost go unnoticed?

"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 1 kilometer or larger, have already been identified by NASA and its partners (my bold)

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"The last-minute detection is yet another sign of how much remains unknown about space and a sobering reminder of the very real threat asteroids can pose, Duffy said.
“It should worry us all quite frankly,” he said. “It’s not a Hollywood movie. It is a clear and present danger.”

"Duffy said astronomers have a nickname for the kind of space rock that just came so close to Earth: “City-killer asteroids.” If the asteroid had struck Earth, most of it would have probably reached the ground, resulting in devastating damage, Brown said.

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"Scientists are working on developing at least two approaches to deflecting potentially harmful asteroids, Duffy said. 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.

"People shouldn’t try to “blast it with a nuke,” Duffy said.

“'It makes for a great Hollywood film,” he said. “The challenge with a nuke is that it may or not work, but it would definitely make the asteroid radioactive.”

"In light of Asteroid 2019 OK, Duffy stressed the importance of investing in a “global dedicated approach” to detecting asteroids because “sooner or later there will be one with our name on it. It’s just a matter of when, not if.”

“'We don’t have to go the way of the dinosaurs,” he said. “We actually have the technology to find and deflect certainly these smaller asteroids if we commit to it now.'”

Comment: WOW! At least we know about the big, big ones that wiped out the dinosaurs.