Asteroid 99942 Apophis, often referred to as the “god of chaos,” is set to make close flybys of Earth in 2029 and 2036.
Although it was previously thought to pose no risk of hitting Earth during these flybys, a new study suggests the odds of an impact may be slightly higher than we once believed.
What is Apophis?
Discovered in 2004, Apophis raised concerns because early observations placed it at level 4 on the Torino impact hazard scale.
On this scale, 0 means there’s almost no chance of an impact, while a 10 means a certain collision that would cause catastrophic global damage.
Level 4 is the highest score ever assigned to any object monitored by NASA.
At this level, there’s at least a 1 percent chance of an impact capable of regional devastation, according to NASA.
Apophis was initially thought to have a potential collision with Earth in 2029, but further observations ruled out this scenario.
Since then, astronomers have also ruled out an impact in 2036 and 2068, although these will still be close encounters.
More recent observations have confirmed that Apophis is not currently on course to hit Earth.
1. Apophis will miss Earth
— ESA Operations (@esaoperations) June 19, 2024
Apophis will miss Earth when it flies past our planet on 13 April 2029. If you only remember one of these facts, make sure it’s this one. pic.twitter.com/coOtFY5r2i
What’s the New Concern?
In a recent study, Canadian astronomer Paul Wiegert explored the possibility of Apophis being redirected towards Earth by a collision with another space object.
While Apophis is a large asteroid at 340 meters (1,100 feet) wide, a small impact from an object as small as 0.6 meters (2 feet) could nudge it into a new trajectory.
For Apophis to hit Earth in 2029, it would need to collide with an object around 3.4 meters (11.2 feet) wide.
Such a collision could push Apophis into a “keyhole” path near Earth, which would set it on a trajectory for a future impact.
Wiegert’s study suggests that the odds of such a collision occurring are extremely low.
In fact, the chance of a 3.4-meter object impacting Apophis before 2029 is estimated at less than 1 in 2 billion.
However, there is a slightly higher chance that a smaller impactor could alter its path enough to result in a collision further down the line, though this is also highly unlikely.
Even then, Wiegert calculated the odds at less than 1 in a million for an impact later in Apophis’ future.
What About Monitoring?
Another important factor is that Apophis has been largely unobservable by telescopes since May 2021.
This is due to its position relative to Earth and the Sun, which has placed it in the daytime sky, making it difficult to track.
The asteroid will remain in this position until 2027, leaving us unable to monitor it for six years.
When Apophis becomes visible again, astronomers will be able to check if its path has changed.
If Apophis has been nudged by a smaller object during this time, the effects should be measurable by 2027.
Wiegert suggests that by the time Apophis becomes observable again, any significant change in its path would likely be detected through telescopic observations.
What Does This Mean?
Despite the study’s findings, the risk of Apophis impacting Earth remains incredibly low.
Even if an impact were to occur, it would be an exceedingly rare event, requiring a precise hit from a very small object at the right angle.
The chance of this happening before 2029 is still virtually nonexistent, and future risks are similarly slim.
In short, while there’s a slightly higher chance of an impact than before, it’s still nothing to worry about.
NASA and astronomers worldwide will continue to monitor Apophis as it approaches Earth in the coming years, ensuring we remain informed about any changes.
For now, Apophis remains a fascinating object of study rather than a threat to life on Earth.