When the asteroid Apophis, known as 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 might completely alter the surface of this asteroid.
According to a new study, landslides and tremors could change Apophis when it comes close to Earth in 2029.
Named after Apep, the ancient Egyptian god of chaos, Apophis is a peanut-shaped asteroid measuring 340 meters in length. Although this new encounter will not destroy our planet, it could potentially devastate a city.
Illustration of a giant asteroid heading towards Earth. The “God of Chaos” Apophis is set to come very close to Earth in 2029. (Image: 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’s trajectory with greater accuracy, indicating that the likelihood of it colliding with Earth is lower than originally estimated by researchers. 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 have much impact on Earth in 2029. But what will happen to the asteroid itself after this close encounter? This question has captured the interest of Ronald-Louis Ballouz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in the United States.
Ballouz noted that small meteoroids continuously bombard the surface of the asteroid in a process known as space weathering. However, astronomers have long observed that asteroids that fly close to planets like Earth often do not show weathered surfaces. He explained that the exact physical mechanisms that remove evidence of weathering remain poorly understood. One possibility is that the gravitational pull of a planet drags rocks on the surface of an asteroid, pushing them away and exposing the underlying layers.
A separate study in 2023 indicated that Earth’s gravity would cause the asteroid to spin faster or slower depending on its orientation during the 2029 approach. New simulations have confirmed this finding.
These simulations also revealed that changes in the rotation of Apophis could destabilize the slopes of surface rocks, potentially leading to landslides in extreme cases. Unlike seismic tremors, these changes are expected to occur gradually over tens of thousands of years.
Furthermore, this encounter could provide a mechanism for refreshing the surface of the asteroid. Ballouz and his colleagues hope that NASA’s OSIRIS-APEX mission will validate their hypothesis.
Reusing spacecraft that collected samples from the asteroid Bennu, OSIRIS-APEX is scheduled to study Apophis during the 2029 encounter. It will spend 18 months examining this asteroid’s chemical composition and mapping its surface.
