Asteroid passes closer to Earth than some satellites

There’s definitely no reason to panic, but a huge asteroid is about to pass close to Earth in the next few hours.

The size of a bus, the space rock, known as 2023 BU, will pass quickly through the southern tip of South America shortly after 9 pm, Brasília time, this Thursday (1/26).

The expectation is that the asteroid will be 3,600 km from our planet, which can be considered a close pass.

This shows how there are asteroids of significant size lurking close to Earth that have yet to be detected.

This one was only captured last weekend by amateur astronomer Gennadiy Borisov, who operates in Nauchnyi, Crimea, the peninsula that Russia seized from Ukraine in 2014.

Subsequent observations have refined what we know about the size and, above all, the orbit of 2023 BU.

That’s why astronomers can be so confident it won’t hit the planet, despite entering the arc occupied by the world’s telecommunications satellites, which lie 22,000 miles above us.

The asteroid is estimated to reach its lowest altitude at 9:27 pm on Thursday.

Even if 2023 BU was on a direct collision course with Earth, it would be difficult to do much damage.

With an estimated size of 3.5m to 8.5m in diameter, the rock would likely disintegrate high in the atmosphere. But it would produce a spectacular fireball.

For comparison, the famous Chelyabinsk meteor, which entered the Earth’s atmosphere over southern Russia in 2013, was an object approximately 20 meters in diameter. It produced a shock wave that shattered windows in the Earth’s surface.

Scientists at NASA, the American space agency, say that the orbit of 2023 BU around the Sun will be modified by its passage by Earth.

Our planet’s gravity will pull it in and adjust its trajectory through space.

“Before encountering Earth, the asteroid’s orbit around the Sun was practically circular, which roughly corresponds to Earth’s orbit, taking 359 days to complete its orbit around the Sun,” the agency said in a statement.

“After the encounter, the asteroid’s orbit will be further elongated, moving to more or less midway between the orbits of Earth and Mars at its furthest point from the Sun. The asteroid will then complete one orbit every 425 days.”

There is a huge effort underway to find asteroids of larger proportions that could really do damage if they hit Earth.

The real giants out there, like the 12km-wide boulder that wiped out the dinosaurs, have probably already been spotted and are nothing to worry about. But when it comes to something smaller, say 150m in diameter, our inventory has gaps.

Statistics indicate that perhaps only around 40% of these asteroids have been sighted and evaluated to determine the level of threat they may pose. These objects would cause city-scale devastation if they hit the ground.

This text was published in https://www.bbc.com/portuguese/internacional-64412105