When the asteroid Apophis, “The God of Chaos,” flies past Earth at an extremely close distance in 2029, the gravitational pull of our planet could trigger earthquakes and landslides that completely alter the surface of this asteroid.
According to a new study, landslides and vibrations could change asteroid Apophis when it passes close to Earth in 2029.
Named after Apep, the ancient Egyptian god of chaos, Apophis is a 340-meter-long peanut-shaped asteroid. While this new close encounter will not destroy our planet, it could obliterate a city.
Illustration of a giant asteroid heading towards Earth. The asteroid “God of Chaos” Apophis will come very close to Earth in 2029. (Photo: JuanCi via Getty Images)
When Apophis was discovered in 2004, astronomers calculated that it could pass extremely close to Earth in 2029. More detailed observations in 2021 allowed scientists to determine Apophis’ trajectory with greater accuracy, indicating that the likelihood of it colliding with Earth is lower than originally estimated. Currently, Apophis is predicted to come within 32,000 kilometers of Earth on April 13, 2029, bringing it closer than some artificial satellites.
At this distance, Apophis is unlikely to significantly impact Earth in 2029. But what will happen to the asteroid itself after this close encounter? This question has intrigued Ronald-Louis Ballouz, an asteroid scientist at the Johns Hopkins University Applied Physics Laboratory in the United States.
Ballouz noted that small meteoroids continuously bombard the surface of asteroids in a process known as space weathering. However, astronomers have long observed that asteroids near planets like Earth typically do not exhibit weathered surfaces. Ballouz stated that the exact physical mechanisms that remove evidence of weathering remain unclear. One possibility is that a planet’s gravity pulls rocks on the surface of an asteroid, pushing them away and exposing the underlying layer.
A separate 2023 study indicated that Earth’s gravity would cause the asteroid to spin faster or slower depending on its approach direction in 2029. New simulations have confirmed this finding.
These simulations also revealed that changes in Apophis’ tumbling motion would destabilize the slopes of surface rocks, potentially causing landslides in extreme cases. Unlike seismic tremors, these changes will occur gradually over tens of thousands of years.
Moreover, this encounter could provide a mechanism for refreshing the asteroid’s surface. Ballouz and his colleagues hope that NASA’s OSIRIS-APEX mission will confirm their hypothesis.
Reusing a spacecraft that collected samples from the asteroid Bennu, OSIRIS-APEX is scheduled to study Apophis during the 2029 encounter. It will spend 18 months observing this asteroid to analyze its chemical composition and map its surface.
