THE BURNED OVER DISTRICT

Because you never know when a sizable chunk of space rock may decide to fly into the same patch of space as our planet does, scientists are scanning the skies to keep an eye potentially dangerous wanderers. Sometimes even they are surprised.

“I thought everyone was getting worried about something we knew was coming,” Duffy, who is lead scientist at the Royal Institution of Australia, told The Washington Post. Forecasts had already predicted that a couple of asteroids would be passing relatively close to Earth this week.

Then, he looked up the details of the hunk of space rock named Asteroid 2019 OK.

“I was stunned,” he said. “This was a true shock.”

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 Washington Post. 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 and what Duffy considers “uncomfortably close.”

The asteroid’s presence was discovered only 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 shot 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 more than half a mile wide or larger, have already been identified by NASA and its partners.

“Nothing this size is easy to detect,” Duffy said of Asteroid 2019 OK. ″You’re really relying on reflected sunlight, and even at closest approach it was barely visible with a pair of binoculars.”

Brown said the asteroid’s “eccentric orbit” and speed were also likely factors in what made spotting it ahead of time challenging. 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.”

Turns out it was not a 'dinosaur killer' but it could have taken out a city. So maybe if it had struck DC then maybe you could call it a dinosaur killer, but the rest of us would have felt sorry for whatever city that got wiped out and cut the science budget again.