Asteroid's sudden flyby shows blind spot in planetary threat detection - Reuters.com

WASHINGTON, Jan 29 (Reuters) - The find of an asteroid the size of a tiny shipping motortruck specified days earlier it passed Earth connected Thursday, albeit 1 that posed nary menace to humans, highlights a unsighted spot successful our quality to foretell those that could really origin damage, astronomers say.

NASA for years has prioritized detecting asteroids overmuch bigger and much existentially threatening than 2023 BU, the tiny abstraction stone that streaked by 2,200 miles from the Earth's surface, person than immoderate satellites. If bound for Earth, it would person been pulverized successful the atmosphere, with lone tiny fragments perchance reaching land.

But 2023 BU sits connected the smaller extremity of a size group, asteroids 5-to-50 meters successful diameter, that besides includes those arsenic large arsenic an Olympic swimming pool. Objects that size are hard to observe until they rotation overmuch person to Earth, complicating immoderate efforts to brace for 1 that could interaction a populated area.

The probability of an Earth interaction by a abstraction rock, called a meteor erstwhile it enters the atmosphere, of that size scope is reasonably low, scaling according to the asteroid's size: a 5-meter stone is estimated to people Earth erstwhile a year, and a 50-meter stone erstwhile each 1000 years, according to NASA.

But with existent capabilities, astronomers can't spot erstwhile specified a stone targets Earth until days prior.

"We don't cognize wherever astir of the asteroids are that tin origin section to determination devastation," said Terik Daly, a planetary idiosyncratic astatine the Johns Hopkins Applied Physics Laboratory.

The astir 20-meter meteor that exploded successful 2013 implicit Chelyabinsk, Russia is simply a once-every-100-years event, according to NASA's Jet Propulsion Laboratory. It created a shockwave that shattered tens of thousands of windows and caused $33 cardinal successful damage, and nary 1 saw it coming earlier it entered Earth's atmosphere.

Some astronomers see relying lone connected statistical probabilities and estimates of asteroid populations an unnecessary risk, erstwhile improvements could beryllium made to NASA's quality to observe them.

"How galore earthy hazards are determination that we could really bash thing astir and forestall for a cardinal dollars? There's not many," said Daly, whose enactment focuses connected defending Earth from hazardous asteroids.

AVOIDING A REALLY BAD DAY

One large upgrade to NASA's detection arsenal volition beryllium NEO Surveyor, a $1.2 cardinal scope nether improvement that volition motorboat astir a cardinal miles from Earth and surveil a wide tract of asteroids. It promises a important vantage implicit today's ground-based telescopes that are hindered by daytime airy and Earth's atmosphere.

That caller scope volition assistance NASA conscionable a extremity assigned by Congress successful 2005: observe 90% of the full expected magnitude of asteroids bigger than 140 meters, oregon those large capable to destruct thing from a portion to an full continent.

"With Surveyor, we're truly focusing connected uncovering the 1 asteroid that could origin a truly atrocious time for a batch of people," said Amy Mainzer, NEO Surveyor main investigator. "But we're besides tasked with getting bully statistic connected the smaller objects, down to astir the size of the Chelyabinsk object."

NASA has fallen years down connected its legislature goal, which was ordered for completion by 2020. The bureau projected past twelvemonth to chopped the telescope's 2023 fund by 3 quarters and a two-year motorboat hold to 2028 "to enactment higher-priority missions" elsewhere successful NASA's subject portfolio.

Asteroid detection gained greater value past twelvemonth aft NASA slammed a refrigerator-sized spacecraft into an asteroid to trial its quality to sound a perchance hazardous abstraction stone disconnected a collision people with Earth.

The palmy demonstration, called the Double Asteroid Redirection Test (DART), affirmed for the archetypal clip a method of planetary defense.

"NEO Surveyor is of the utmost importance, particularly present that we cognize from DART that we truly tin bash thing astir it," Daly said.

"So by golly, we gotta find these asteroids."

Reporting by Joey Roulette; Editing by Andrea Ricci

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