Huge asteroid to pass by Earth in close call

A huge asteroid is about to sweep through Earth’s atmosphere in our fourth closest call on record.

An asteroid will sweep by Earth this week in our fourth closest encounter ever. Picture: Artist’s impression, NASA

A huge asteroid will sweep by Earth this week in our fourth-closest call with one of the space objects on record.

The space rock, dubbed 2023 BU, was discovered by NASA just last weekend and is now set to soar through Earth’s atmosphere, coming within 3400km of our planet’s surface on Thursday morning.

The asteroid will make its closest encounter at about 00:30 GMT on Friday, which is about 11:30am, Sydney time.

The huge object measures about 8.5m by 3.7m — the same size as the largest African elephants, and about half the size of the infamous Chelyabinsk meteor that hit Earth in 2013.

While 2023 BA cannot be seen by the naked eye, a live stream hosted by the Virtual Telescope Project in Italy will give space enthusiasts to witness the historic event.

The asteroid will sweep by Earth in our closest encounter for 300 years. Picture: ESA

The live-stream will be made available from Thursday, 19:15 GMT (or 6:15am on Friday, Sydney time) for people to catch a glimpse.

Australians will have another chance to spot a space object in early February, when a green comet will sweep by visible to the unaided eye.

Most asteroids pass beyond the distance of the moon, more than 380,000km away, but this one is much closer.

In fact, it will be Earth’s closest encounter with an asteroid for 300 years.

The asteroid is due to make the fourth closest pass of more than 35,000 past and future Earth approaches, according to NASA’s Centre for Near Earth Object Studies, which holds data since 1900.

It isn’t quite at risk of hitting Earth, astronomers say. Picture: NASA.

The space rock will fly by our planet at a whopping 53,000kph, at a distance of 10,500km from the centre of Earth and 3400km from its surface.

Experts have calculated its orbit, and insist there is no chance of the asteroid hitting Earth on this particular approach.

However, even if it did, it likely wouldn’t make it to the surface.

Space rocks that are smaller than 25m across are more likely to burn up if they enter Earth’s atmosphere, NASA says, meaning they cause minimal damage on the ground.

Though it won’t impact us, the asteroid will technically pass through our planet’s uppermost atmosphere.

Space enthusiasts will be able to watch the close call via live stream. Picture: NASA

This region, known as the Exosphere, extends for between about 10,000km and 200,000km above Earth. Most scientists, though, don’t consider it a true part of Earth’s atmosphere as the air is so thin.

Nevertheless, asteroid 2023 BU will pass well within the orbit of geostationary satellites above South America, but still far away from the International Space Station at 400 km from the Earth.

The space rock was discovered on Saturday at the Crimean Astrophysical Observatory in Nauchnyi, Crimea, by superstar astronomer Gennadiy Borisov — who also spotted the first comet ever seen that travelled into the solar system from interstellar space.

A fragment of the Chelyabinsk meteorite which came down in 2013. Picture: AFP.

2023 BU orbits the sun every 425 days, while its path occasionally intersects Earth’s orbital trajectory around our star.

It will next pass relatively close to us on December 6, 2036, but on that occasion will be well beyond the orbit of the moon.

The asteroid is about half the size of the Chelyabinsk meteor, which collided with Earth in Chelyabinsk, Russia in February 2013 in the largest recorded meteor strike in more than a century.

More than 1600 people were injured by the shockwave from the explosion, which was estimated to be as strong as 20 Hiroshima atomic bombs.