Asteroid's sudden Earth flyby calls for robust planetary threat detection
On January 26, a truck-sized asteroid zoomed past our home planet from pretty close by, fortunately causing no harm. This asteroid, named 2023 BU, was not predicted to cross Earth until a few days before the encounter. Our failure to detect the risky space object points to a blind spot in our ability to distinguish asteroids that could prove to be disastrous.
Why does this story matter?
Asteroid 2023 BU was recently discovered on January 21 and crossed approximately 3,500 kilometers above the southern tip of South America. Had the space rock made its way to Earth, it would have been burned up the atmosphere, with only small fragments possibly reaching land. The sudden flyby of the asteroid makes one wonder where we stand in our defense against asteroid strikes.
Asteroids like 2023 BU are particularly hard to detect
For years now, NASA has focused on detecting asteroids much larger and potentially more menacing than 2023 BU. 2023 BU falls under the lower end of the asteroid group, ranging 5-to-50 meters wide, which includes space rocks as big as an Olympic swimming pool. What's concerning is that objects the size of 2023 BU are hard to detect until they drift closer to Earth.
How frequently would a 5-meter space rock target Earth?
The chances of being impacted by a space rock, termed 'meteor' once it enters Earth's atmosphere, in the 5-to-50 meter size range is quite low. A 5-meter rock is predicted to target Earth once a year, and a 50-meter rock once every thousand years, says NASA. But using existing technologies, astronomers cannot flag such small but potentionally risky rocks until few days prior.
The location of potentially hazardous asteroids is unknown
"We don't know where most of the asteroids are that can cause local to regional devastation," said Terik Daly, a planetary scientist. "How many natural hazards are there that we could actually do something about and prevent for a billion dollars? There's not many."
NASA is currently working on the NEO Surveyor mission
A crucial advancement to NASA's detection strategies will be NEO Surveyor, a $1.2 billion telescope that is currently under development. The mission will survey 90% of asteroids, 460 feet in size or larger that come within 48 million kilometers of the Earth's orbit. The telescope has significant advantages when compared to the current ground-based telescopes which are hindered by daytime light and Earth's atmosphere.
The DART mission was the first-ever attempt at planetary defense
Last year, NASA was successful in its DART mission, which was the first-ever attempt at planetary defense. The DART spacecraft crashed into its target—a 520-foot-long asteroid called Dimorphos—and altered the orbit of the asteroid forever. NEO Surveyor can be crucial in detecting asteroids in time, especially now that we know from DART that we can alter the path of a risky asteroid if needed.
