NASA usually keeps a close eye on asteroids approaching our planet, but one has managed to slip through the net.
An asteroid called 2023 NT1 came within about 62,000 miles of Earth, about a quarter of the distance between Earth and the Moon, on July 13.
But it wasn’t until two days after its approach that NASA scientists detected it, because it was coming from the direction of the sun and was obscured by light.
Now speeding away from Earth at about 25,000 miles per hour, 2023 NT1 is up to 200 feet in diameter, larger than the Leaning Tower of Pisa.
This also makes it larger than the 60-foot Chelyabinsk meteorite, which injured more than 1,600 people when it entered Earth’s atmosphere in 2013.
2023 NT1 is up to 200 feet in diameter more than the length of the Leaning Tower of Pisa, but smaller than other close-approach asteroids.
newly discovered #asteroid 2023 NT1 passed about 1/4 of the distance from the Moon on July 13, but was not discovered until July 15, when it came close to Earth in the daytime sky. It can be up to 200 feet across, possibly larger than the asteroid that caused the meteor crater in Arizona. pic.twitter.com/VLXB4ChTMJ
—Tony Dunn (@tony873004) July 16, 2023
According to data from NASA and the international astronomical union2023 NT1 made its closest approach to Earth at 10:12 UTC (11:12 BST) on July 13.
The first reported observation two days later was made by ATLAS South Africa, a system of four telescopes dedicated to detecting dangerous asteroids.
At up to 200 feet (60 meters) across, 2023 NT1 could be larger than the asteroid that caused the meteor crater in Arizona, he said. amateur astronomer Tony Dunn on Twitter.
The historic impact crater near Flagstaff, about 3,900 feet in diameter, is believed to have been caused by a rock that struck Earth about 50,000 years ago.
Despite its closeness, 2023 NT1 is not large enough to be considered “potentially dangerous.”
An asteroid is defined as ‘potentially hazardous’ if it is within 0.05 astronomical units (4.65 million miles) of Earth and is larger than 459 feet (140 meters) in diameter.
At a maximum of 200 feet, 2023 NT1 only fits one of those criteria.
Fortunately, 2023 NT1 passed without a hitch, but the episode highlights that we have a problem detecting some asteroids due to glare from the sun.
An asteroid is defined as ‘potentially hazardous’ if it is within 0.05 astronomical units (4.65 million miles) of Earth and is more than 459 feet (140 meters) in diameter (file image)
Like 2023 NT1, the Chelyabinsk meteor from a decade ago was not noticed because its ‘radiant’, the point in the sky from which it originated, was close to the sun.
The Chelyabinsk meteor exploded in a fireball over Russia a decade ago with an estimated energy equivalent to 500,000 tons of TNT sending a shock wave twice around the world.
To combat the threat of sunlight-blocked space rocks, the European Space Agency (ESA) will launch its orbiting observatory NEOMIR around 2030.
The observatory will act as an early warning system to detect and monitor any asteroid approaching Earth from the direction of the sun.
NEOMIR will be stationed at the ‘L1’ Lagrange point, a position in space between Earth and the Sun where objects sent there tend to stay put.
Undisturbed by Earth’s atmosphere, its infrared telescope will be able to spot asteroids 65 feet (20 meters) and larger that currently lurk in the sunlight.
Planetary defense has been a big topic over the past 12 months, in part due to NASA’s successful Double Asteroid Redirection Test (DART) mission.
In September last year, the DART spacecraft intentionally crashed into Dimorphos, the small asteroid moon in the Didymos double asteroid system.
To combat the threat of sunlight-blocked space rocks, the European Space Agency (ESA) will launch its orbiting observatory NEOMIR around 2030 (artist’s impression)
Although this asteroid did not pose a threat to Earth, the hope is that the success of humanity’s first planetary defense test may provide a blueprint for defending our planet against future threats from space.
It was the world’s first test of a kinetic impact mitigation technique, using a spacecraft to deflect an asteroid by changing its orbit.
Unfortunately, there are some types of space rocks that could prove difficult or impossible to deflect with any man-made object, a new study suggests.
‘Rubble Pile’ asteroids, like Itokawa, about 1.2 million miles away, are made up of loose boulders and rocks that have clumped together under the influence of gravity, so much of it is empty space.
Such an asteroid would act as a “space cushion” in that it would absorb any impact energy and continue on its trajectory, the study authors said.
