A truck-sized asteroid will pass very close to Earth tonight

Our planet is set for a close encounter with an asteroid that was discovered on January 21 of this year. Designated 2023 BU, the asteroid will zoom over the southern tip of South America at about 4:27 pm (PST) or 7:27 EST, NASA's Jet Propulsion Laboratory said in a press release.

It was only on Saturday last week that amateur astronomer Gennadiy Borisov first spotted the celestial rock, which is estimated to be no larger than 28 feet (8.5 m across). Borisov, who is also the discoverer of interstellar comet 21/ Borisov, then passed on the information to the Minor Planet Center (MPC), the international clearing house for measurement of small celestial bodies.

The data was then posted to the Near-Earth Object Confirmation Page, which allowed other astronomers to look out for the space rock and collect multiple observations. The discovery was confirmed.

Asteroid 2023 BU's orbit

2023 BU has been designated as a small near-Earth asteroid, and further observations of the object have enabled astronomers to chart out a better map of its trajectory. Much like the Earth, the asteroid also follows a roughly circular orbit around the Sun, which takes 359 days to complete.

Understandably. the asteroid has made multiple flybys past us before this. According to the Small-body Database Lookup, the asteroid has practically zoomed past Earth every single year in the recent past but never has it come as close as it is coming today.

The box truck-sized space rock is expected to come as close as 2,200 miles (3,600 km) to the planet's surface, roughly a tenth of the distance that geostationary satellites orbit.

Impact of the Flyby

With the asteroid coming so mighty close to the planet, astronomers were concerned if the Earth's gravity could pull it toward itself. This presents a risk to the planet, and NASA uses an impact hazard assessment system called Scout to determine how dangerous such an event would be.

As per calculations of the system, the asteroid will not hurl toward the Earth as it comes close to the planet and continue in its orbit, which, however, is expected to be impacted. The near circular orbit of 2023 BU is expected to become a bit more elongated, with the asteroid now likely to take 425 days to complete its journey around the Sun.

In the unlikely event that the asteroid does proceed toward the planet, its small size would mean that it will largely disintegrate in the atmosphere, with some meteorites falling on the ground at the most.

This is the second asteroid to make such a close flyby past our planet in the past two months. As 2022 came to a close, asteroid 2022 YO1 was spotted for the first time as it flew barely 13,000 miles (21,000 km) away from the planet. 2023 BU's journey is much closer, though, and beats the record of all previous close flybys by more than thousands of miles.

Even with the success of its Double Asteroid Redirection Test (DART) Mission, NASA will need more than a few days to prepare for a mission that could divert an asteroid headed toward us. We need to look through bigger and better telescopes to avoid such a calamity.