But the chance – fortunately – remains extremely small.

Asteroid Apophis caused quite a stir at the end of 2004. Scientists predicted that there was a relatively high chance that the asteroid would hit Earth in 2029. Fortunately, after thoroughly studying the asteroid’s orbit, the researchers were able to rule out that it would pose a danger to our planet in nine years’ time. But that may be different in 2068.

2029
The orbit of asteroid Aphophis has long been puzzling. And that is not very surprising. The asteroid seems to have foreseen it every time on our Earth. As mentioned, astronomers first concluded that Aphophis might be on a collision course with our Earth by 2029. Later this turned out to be a bit too premature. However, Aphophis will approach our earth very close on April 13, 2029. The 300-meter asteroid will sweep close to Earth, allowing you to see it with the naked eye as it hurtles through the belt of communications satellites. Fortunately, it stays that way. “We have known for some time that Aphophis will not hit Earth during its short flyby in 2029,” says researcher Dave Tholen. But that does not mean that the danger has definitely passed.

Small chance
While we probably won’t have much to fear for asteroid Aphophis in the coming decades, it may be different in 2068. Researchers have previously established that There was a slim chance that the asteroid would head back to Earth in that year. That conclusion, too, was subsequently dismissed. But astronomers now argue in a new study that we have to be careful with that. Because of the so-called Yarkovsky effect, the asteroid may still be in danger of colliding with our home planet.

Yarkovsky-effect
What is the Yarkovsky effect? All asteroids radiate the energy they absorb from sunlight as heat, in order to maintain thermal equilibrium. In other words, radiation – from the sun, for example – exerts force on a small celestial body. And this shifts the trajectory of this object slightly. This thermal force can have a significant effect over time, moving objects’ trajectories many kilometers. In the study, the researchers kept a close eye on the orbit of asteroid Aphophis using the Subaru telescope. And this shows that asteroid Aphophis is also subject to the Yarkovsky effect.

Collision course
The team found that Aphophis’ orbit shifts about 170 meters annually. And that is alarming. Because it means that the asteroid could be on a collision course with Earth again in 2068.

Avert
Fortunately, scientists are keeping a close eye on these types of potentially dangerous space rocks (see box). Because according to most, it is never early enough to devise smart strategies in case an asteroid is on a collision course with Earth. At the moment, some plans have already been devised. So scientists have one a whole step-by-step plan in case an asteroid has envisioned it on our planet. Other asteroids that may be heading towards our Earth in the future are also being thoroughly investigated (think of asteroid Bennu, for example). In addition, NASA is going to try to change the orbit of asteroid Didymos. NASA hopes to gain important knowledge through this should we ever end up in a situation where we have to deflect objects.

More about Potentially Dangerous Asteroids

Astronomers speak of a Potentially Hazardous Asteroid if it gets close to Earth (in the future) and is large enough to cause significant regional damage if it strikes Earth. Meanwhile, the Minor Planet Center has collected a huge laundry list of dangerous asteroids. Fairly known asteroids on this list are Ryugu (currently visiting spacecraft Hayabusa2) and Bennu (currently orbiting spacecraft OSIRIS-REx). Researchers have now discovered more than 18,000 Earth shearers. The largest specimens are of course the easiest to find; It is estimated that astronomers have already tracked about 90% of all Earth shearers larger than a kilometer. The big challenge now, however, is to also map as many smaller (up to a size of about 140 meters) asteroids as possible. New instruments are currently being built for this, such as the Large Synoptic Survey Telescope, which will be operational in 2022. And in the future – with new technologies and techniques – the hunt for space rocks smaller than 140 meters will also be started. It is estimated that millions of asteroids are still waiting to be discovered in the latter category.

–

The researchers will continue to track the orbit of asteroid Aphophis. Scientists do not yet know how big the Yarkovsky effect is. Through further observations, the team hopes to further refine this so that we will also learn how exactly it affects Apophis’ orbit. However, we don’t have to worry about anything right now. Because astronomers will know well before 2068 whether and how likely the asteroid is actually targeting our planet.