Three asteroids zip past Earth just in time for Christmas

Three large asteroids, labelled as “potentially hazardous’ Apollo-class, will be passing close by Earth on Christmas day.

A potentially hazardous object (PHO) is a near-Earth object (NEO) which is large enough to cause serious drama if it were to collide with Earth.

Here’s what you need to know.

Asteroid fly-by

Just in time for Christmas

The largest of the three (named 2022 TE14) is approximately the size of a 50-story building, with estimated measurements ranging between 95 and 210 metres in diameter.

A slightly smaller asteroid the size of a football field (designated 2013 YA14) will drop by a few hours earlier on Christmas, measuring between 51 and 110 metres in diameter.

Completing the asteroid fly-by trio is 2022 YL1, measuring almost 85 metres in diameter – roughly the size of a Boeing 777’s wingspan.

A fourth asteroid will also be zipping by our region of space on Christmas day, but at only 17m in diameter, isn’t not seen as a threat to Earth.

Near-Earth-Objects

Fret not, however. Near-Earth-Objects (NEO) zip past Earth all the time, sometimes even up to 10 asteroids per day.

National Aeronautics Space Administration (Nasa) monitors more than 29 000 NEOs which pass within 48 million kilometres of Earth’s orbit. Out of those, only 15 000 are classed as Apollo-classed asteroids.

An Apollo-class asteroid orbits our Sun and could potentially, at some point in its trajectory, intercept Earth’s orbit.

READ: Phaethon: Gigantic, blue Near-Earth Object accelerates, acts strangely

Threat to Earth?

That depends on the asteroid and the conditions of its path as it zips through space.

According to Jay Tate, the director of the UK’s Spaceguard Center observatory, asteroids “can be disturbed quite easily, so they can develop orbits that cross those of planets”.

That’s both good news and bad news. Bad news in the sense that another stray rock could bump into it and put it on a collision course with Earth.

The other side of the coin is that we could potentially divert an asteroid’s path if it came to it. Hopefully…

NASA’s DART project

NASA successfully changed an asteroid’s path back in October 2022.

At the time, the space agency tested the Double Asteroid Redirection Test (Dart) spacecraft by deflecting the orbit of a 160-metre-wide rock known as Dimorphos.

However, before we get our hopes up, NASA’s Dart programme scientist, Dr Tom Statler, said NEOs come in “different guises”, so the test results aren’t inclusive.

“We should not be too eager to say one test on one asteroid tells us exactly how every other asteroid would behave in a similar situation,” he said at the time.

ALSO READ: Massive ‘planet killer’ asteroid discovered near Earth, hiding in sun’s glare

Even a ‘small’ space rock measuring only 35 metres could easily destroy an entire city. That said, size doesn’t necessarily determine the extent of the damage it could cause.

A more practical measure is the NEOs absolute magnitude (H), which is the measurement if an asteroid was placed 1 Astronomical Unit (au) away, and 1 au from the Sun and at a zero phase angle.