Three large asteroids dubbed the “potentially dangerous” Apollo class will pass close to Earth on Christmas Day.
A potentially hazardous object (PHO) is a near-Earth object (NEO) large enough to cause serious drama if it were to collide with Earth.
Here’s what you need to know.
Just in time for Christmas
The largest of the three (named 2022 TE14) is roughly the size of a 50-story building with estimated dimensions ranging from 95 to 210 meters in diameter.
A slightly smaller asteroid the size of a soccer field (designated 2013 YA14) will pass a few hours earlier on Christmas, measuring between 51 and 110 meters in diameter.
2022 YL1 completes the asteroid flyby trio with a diameter of almost 85 meters – about the size of the wingspan of a Boeing 777.
A fourth asteroid will also fly by our region of space on Christmas Day, but with a diameter of just 17m it is not considered a threat to Earth.
Don’t fret, however. Near Earth Objects (NEO) are constantly zooming past Earth, sometimes as many as 10 asteroids per day.
The National Aeronautics Space Administration (Nasa) monitors more than 29,000 NEOs flying within 48 million kilometers of Earth orbit. Of these, only 15,000 are classified as Apollo-class asteroids.
Near-Earth Objects, or NEOs, pose potentially catastrophic threats to our planet. A near-Earth object is an asteroid or comet that passes close to Earth’s orbit. + pic.twitter.com/SXBKJnY73W— Near Earth Objects (@ws_neo) January 23, 2022
An Apollo-class asteroid is orbiting our Sun and could potentially intercept Earth’s orbit at some point in its orbit.
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Threat to Earth?
That depends on the asteroid and the conditions of its orbit as it hurtles through space.
According to Jay Tate, director of the UK observatory Spaceguard Centre, asteroids “can be disturbed fairly easily, allowing them to develop orbits that intersect those of planets”.
This is 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 reverse the path of an asteroid if it came to that. Hopefully…
NASA’s DART project
NASA successfully changed the orbit of an asteroid back in October 2022.
Back then, the space agency was testing the Double Asteroid Redirection Test (Dart) spacecraft by deflecting the orbit of a 160-meter-wide rock called Dimorphos.
Before we get our hopes up, however, NASA Dart program scientist Dr. Tom Statler that NEOs come in “various guises” so the test results are not comprehensive.
“We shouldn’t be too eager to say that a test on one asteroid will tell us exactly how any other asteroid would behave in a similar situation,” he said at the time.
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Even a “small” space rock just 35 meters in size could easily destroy an entire city. However, size does not necessarily determine the extent of damage it could cause.
A more practical measure is the absolute magnitude (H) of the NEO, which is the measurement when an asteroid was 1 astronomical unit (au) away and 1 au away from the Sun and placed at zero phase angle.