A comet flying in the sky
Asteroid 2021 UA1 is the third-closest asteroid that has ever approached our planet, passing over Antarctica on Sunday at a higher altitude than the International Space Station, but lower than the communication satellites that orbit the Earth.
The celestial object had a diameter of only two meters, meaning that if it had come closer to our planet it would have likely been burned up in our atmosphere.
“The reason the planet’s fly-by was so surprising was because it was behind the sun, coming from the daytime sky, so it was undiscoverable prior to closest approach”, Tony Dunn, an astronomer who runs the website Orbitsimulator, tweeted.
Newly-discovered #asteroid 2021 UA1 missed Antarctica by only 3000 km Sunday evening.
It came from the daytime sky, so it was undiscoverable prior to closest approach.https://t.co/Y0zY7mAYue pic.twitter.com/R9VpMo2X9G
— Tony Dunn (@tony873004) October 27, 2021
There are only two asteroids that have come closer in Earth’s history: one was asteroid 2020 QG, which came just 1,830 miles over the southern Indian Ocean – but was also small enough not to pose a threat to Earth – and asteroid 2020 VT4, which flew by a few hundred miles away on Friday the 13th.
Although these asteroids are too small to affect the Earth, the possibility of a larger one causing considerable harm to the planet is one that many scientists are preparing for.
In May, Nasa conducted a simulation over the course of a week in order to prepare for such an eventuality but concluded that there is no technology on Earth that could stop it happening.
The only response would be to evacuate the area before the asteroid hit, however the impact zone was across large parts of North Africa and Europe.
Chinese researchers have considered send more than 20 rockets that could stop a giant asteroid.
China’s National Space Science Centre found in simulations that 23 Long March 5 rockets, which weigh 900 tonnes when they leave the planet, hitting simultaneously could divert an asteroid from its original path by nearly 9,000 kilometres – 1.4 times the Earth’s radius.
