There's no lack of outsized, growing problems for humanity.
So we certainly don't need any news sites twisting the truth about the looming menace of colossal asteroids supposedly coming to threaten Earth. Yet, it's happening again. "A 'potentially hazardous' asteroid more than twice the size of the Empire State Building will make close pass by Earth," wrote CBS Tuesday morning. We'll spare you the other misleading headlines.
What the headlines don't say is that a well-documented asteroid will pass some 1.2 million miles from Earth on Tuesday. It won't skim or buzz by Earth. It's not nearly an imminent threat. It's not something NASA will warn society about. And if the space agency was concerned enough to issue a warning, such an announcement would be unprecedented.
"We have never actually issued a warning," NASA’s Planetary Defense Officer, Lindley Johnson, told Mashable last year.
Astronomers have followed the latest asteroid in question, asteroid 1994 PC1, for decades. Of the thousands of known asteroids the space agency follows, zero pose a threat for a long, long time.
"FACT: There is no known threat from any asteroid for at least the next 100 years," NASA tweeted last week, in hopes of defeating sensationalism about asteroid 1994 PC1.
Tweet may have been deleted
The significant asteroid threats are from the ones astronomers haven't yet found. For example, a sizable space rock (some 187 to 427 feet wide) surprised scientists in 2019. It came unsettlingly close, within about 45,000 miles of Earth.
Fortunately, your taxpayer dollars are hard at work sleuthing out these unknowns in our solar system. Astronomers have already detected over 27,000 near-Earth objects(space rocks in Earth's solar system neighborhood closer than some 28 million miles away), and have discovered some 1,500each year since 2015.
Rocks larger than 460-feet wide — enough to cause at leastmajor regional destruction — are particularly concerning. As of Jan. 13, 2022, nearly 10,000 of an estimated population of some 25,000 of these 460-foot-plus near-Earth objects have been found.
In the coming decades, finding the rest of these objects is critical. Then we can prepare for a potential impact.
"We need to be able to find these things early," Cathy Plesko, a scientist at Los Alamos National Laboratory who researches asteroid impacts, told Mashable last year. "We're getting there, but we're not there yet."
A satellite image of the Meteor Crater, also known as Barringer Crater, in Arizona. An asteroid some 150 feet across created this 4,000 foot-wide crater 50,000 years ago.Credit: USGS National Map Data Download and Visualization ServicesYou can read all about that possible scenario in this Mashable story.
But here's the short version: If NASA detects a potential impact — something larger than around 30 feet across (10 meters) with a greater than one percent chance of hitting Earth — the U.S. government will issue warnings.
And you wouldn't just hear from NASA. National leaders, such as those in the White House, would communicate with the public.
"At that point, the White House takes the lead on new information being released," NASA's Johnson explained. "It becomes a national emergency event." Crucially, this information will include what, exactly, is likely to happen. Will it probably explode in the sky, or will it collide with a region on Earth? Should you stay home? Will it likely land in the ocean?
The good news is it's quite unlikely a behemoth — a catastrophic object half-a-mile wide or larger — will come out of nowhere and destroy huge swathes of our humble blue planet. Astronomers have already located over 90 percent(and counting) of this giant class of space rock.
But if scientists locate a rock (say 200 feet wide or larger) that's on an imminent course to harm Earth's inhabitants in the future (say at least a few decades), we may have the ability to deflect such an object.
SEE ALSO:Many of the Webb telescope’s greatest discoveries won't come from any amazing picturesIn November 2021, NASA launched its DART mission. It's an unprecedented experiment to see how civilization could alter the path of a menacing asteroid, should one be on a collision course with our planet.
The DART spacecraft will hit the 525-foot-wide asteroid Dimorphoson around Oct. 1, 2022. Scientists will observe if we move the rock enough to change its trajectory.
Stay tuned. And avoid killer asteroid hype. One unknown day in the future, a real warning will come.
(责任编辑：時尚)
