Collisions between Apophis, the “God of Destruction”, and other bodies could increase the chances of it hitting Earth. A study has found that the “God of Chaos” asteroid could be transformed by tremors and landslides during its flyby of Earth in 2029. ESA has awarded OHB Italia SpA a €63 million contract to begin preparatory work on the agency’s proposed Ramses mission to the infamous asteroid Apophis.
A chance encounter with another asteroid could bring Apophis too close to Earth during a future flyby. On Friday the 13th, 2029, Earth will be visited by a fascinating and terrifying visitor in the form of the asteroid “God of Destruction” Apophis. The asteroid, named after the Egyptian serpent god of chaos and destruction, is so large that it will pass within 19,000 miles (30,600 kilometers) of Earth, so close to our planet that it will be visible to the naked eye, Wiegart reports in a study of Apophis in The Planetary Science Journal.
New research has found that if other much smaller space rocks collide with Apophis, the asteroid could change direction and Earth might not be in close proximity to it during subsequent passes or in extreme circumstances, even during the 2029 flyby.
Study author Paul Wiegert, an astronomer at the University of Western Ontario, said the odds of an asteroid hitting Apophis in a dangerous way are very low. “Basically, the odds of an asteroid striking Apophis enough to put it in danger of impact after 2029 are about 1 in a million, and only 1 in a billion that it could hit Apophis with Earth in 2029.”
“I calculated the probability that the asteroid Apophis, whose current trajectory is expected to pass close but safely by our planet in 2029, would be deflected onto a more dangerous path by an unexpected strike from a small asteroid,” Wiegert explained. “This is the same type of small asteroid that sometimes appears in our atmosphere as ‘shooting stars’ or ‘fireballs’ and could similarly unexpectedly strike Apophis.”
Wiegert explained that his research asked whether an asteroid collision between 2021 and 2027, when our telescopes won’t be able to observe Apophis, would deflect it enough to make it dangerous.
An illustration shows the asteroid Apophis, the god of destruction, approaching Earth. Robert Lee/NASA/The Planetary Society
“Asteroid Apophis is virtually undetectable between now and 2027 because it is in the daytime sky, so it could collide with us without us knowing about it right away,” he continued.
Discovered in 2004, Apophis (full designation Apophis 99942) immediately topped the charts measuring the risk of so-called potentially hazardous asteroids (PHAs) — asteroids 460 feet (140 meters) wide or larger that come within 20 lunar distances of Earth.
Due to its size and trajectory, Apophis has remained at the top of the European Space Agency’s (ESA) “collision risk list” of potentially hazardous space objects and NASA’s Sentry Risk Table for nearly two decades.
That was until a close flyby of the asteroid in March 2021 allowed NASA scientists to determine that Apophis would not, in fact, collide with Earth for at least 100 years.
A new study suggests that chance encounters with other space rocks could change the direction of the 1,000-foot-diameter (305-meter) Apophis and set it on a collision course with Earth in 2029 or later, meaning it could once again be at the top of the risk charts.
Wiegart calculated the effect that objects of different sizes would have if they collided with Apophis, and then used the number of objects of those sizes that collide with Earth each year to determine the probability of such a collision.
“An asteroid about 60 centimeters (24 inches) in diameter could, if it hit Apophis from the right direction, put Apophis on a collision course after 2029. But to hit Apophis, again from the right direction, to create a collision risk in 2029, you would need an asteroid 3 meters (10 feet) in diameter,” Wiegart said. “Such impacts are extremely rare.”
An illustration of NASA’s Double Asteroid Redirection Test (DART) as it approaches its target. NASA/Johns Hopkins APL
Looking at the angle needed to deflect Apophis so that it could collide with Earth during a future pass, Wiegart found that the odds of the asteroid being deflected and hitting our planet after 2029 are 1 in 1 million. The odds of an asteroid roughly 3 meters in diameter hitting Apophis and sending it on a collision course with Earth in 2029 are 1 in 2 billion.
These low odds are fortunate, given the massive damage Apophis would cause if it were to collide with Earth. The Planetary Society estimates that if Apophis were to collide with Earth, it could release energy equal to more than 1,000 megatons of TNT, equivalent to the detonation of dozens or even hundreds of nuclear warheads.
This could spread devastation over a radius of hundreds of miles. While it would not come close to the devastation caused by the asteroid 65,000,000 years ago that wiped out the dinosaurs and two-thirds of all species on Earth, millions of people would die if Apophis hit a densely populated metropolis.
If we find that Apophis is on a collision course with Earth during its next passes in 2029, 2036, and 2068, we will have some options to try to deflect it. For example, just as a small collision could move the God of Destruction space rock toward Earth, another small collision could change its trajectory again if space agencies get enough warning.
In 2022, NASA tested this idea by hitting the Dimorphos and Didymos asteroid system with the Double Asteroid Redirection Test (DART) impactor and measuring the change in its motion.
Other sabotage techniques range from the powerful, such as hitting an asteroid with a nuclear weapon, to the highly unusual, such as painting one side of an asteroid black, causing it to absorb more solar radiation, shifting its center of mass and changing its trajectory. These methods are well-founded scientifically, but have not yet been tested.
While Apophis is unlikely to live up to its fearsome name when it collides with Earth in 2029, its scientific impact will be immeasurable. Plans are already underway to use spacecraft and satellites to rendezvous with the asteroid as it approaches our planet.
“The upcoming close pass of Apophis in 2029 is a natural milestone for our planet as we enter an era where we, as a global community, have the opportunity to avoid catastrophic asteroid impacts like the ones that could have wiped out the dinosaurs,” Wiegart concluded. “The astronomical community as a whole continues to think about hazardous asteroids like Apophis and possible next steps.”
When the asteroid Apophis, the “god of chaos,” passes very close to Earth in 2029, our planet’s gravity could trigger tremors and landslides that could completely reshape the asteroid’s surface. Landslides and tremors could change the face of the asteroid Apophis when it hits Earth in 2029, according to a new study.
Named after Apep, the ancient Egyptian god of chaos, Apophis is a peanut-shaped asteroid 1,100 feet (340 meters) long. While a collision with a space rock this size wouldn’t destroy our planet, it could easily destroy a city.
Illustration of a huge asteroid heading towards Earth. The asteroid “God of Chaos” Apophis will come exceptionally close to Earth in 2029. ESA — P.Carril
Given that distance, Apophis probably won’t have much of an impact on Earth in 2029. But how will the asteroid itself fare after this close encounter?
That question intrigued Ronald-Louis Ballouz, a scientist who studies asteroids at the Johns Hopkins University Applied Physics Laboratory. Tiny meteoroids constantly bombard asteroid surfaces in a process called space weathering. But Ballouz added that astronomers have long noticed that asteroids that pass close to planets like Earth often lack weathered surfaces. The exact physical mechanism that removes evidence of weathering is not well understood, Ballouz said. One possibility is that the planet’s gravity pulls on rocks on the asteroid’s surface, throwing them off and exposing the underlying rock.
To test this hypothesis, Ballouz and a team of international researchers created computational models of Apophis. Little is known about the asteroid’s physical characteristics, so the researchers based their models on a similar bilobed asteroid called Itokawa, which has been studied in more detail. The researchers then simulated each model’s motion toward Earth, tracking both large-scale and small-scale physical changes.
The researchers found that two physical processes caused by Earth’s gravitational tugs are likely to shape Apophis’s surface during its 2029 encounter. One is tremors that will likely begin an hour before Apophis reaches its closest point to Earth and continue for some time afterward.
A visualisation of the lobed asteroid Itokawa, which was used as a surrogate for the asteroid Apophis in the new study. ESA
The magnitude of the tremors is difficult to estimate, Ballouz said. However, “Apophis’ gravity is about 250,000 times weaker than Earth’s,” he added. “So we think it would be plausible for events of much smaller magnitude to shake everything on its surface.”
This means that earthquakes could be intense enough to lift boulders off the surface of Apophis. While some rocks might escape, most would fall back onto Apophis, creating distinct surface patterns that could be recognized by a passing spacecraft.
Another process that could “renew” Apophis’s surface is a change in its tumble. The tumble occurs because the asteroid does not rotate around a fixed axis or time period; instead, it tumbles through space like a poorly thrown football.
An unrelated 2023 study found that Earth’s gravity would cause the asteroid to spin either faster or slower depending on its orientation during its 2029 approach. New simulations confirmed this finding. They also showed that changes in Apophis’s tumble would destabilize sloping rock surfaces, potentially triggering landslides in extreme cases. Unlike seismic tremors, these changes would occur gradually, over tens of thousands of years.
ESA has signed a €63 million contract with OHB Italia SpA to begin preparatory work on the agency’s proposed Ramses mission to the infamous asteroid Apophis.
On April 13, 2029, the 375-meter-diameter asteroid Apophis will pass within 32,000 km of the Earth’s surface – less than one-tenth the distance from the Earth to the Moon. This extremely rare natural phenomenon will attract the world’s attention and provide a unique opportunity for scientific and planetary defense research.
Visualization of the European Space Agency’s proposed Ramses mission to the asteroid Apophis. OHB Italia
During the flyby, strong tidal forces will stress the asteroid and likely uncover new material from beneath its surface. A spacecraft at Apophis could observe these changes and teach scientists a great deal about the asteroid’s composition and structure, as well as how the asteroid responds to external forces. We must understand these properties if we ever hope to be able to deflect a dangerous asteroid from a collision course with Earth.
ESA will propose such a mission for approval and funding at its next Ministerial Council meeting in 2025 as the next Planetary Defence mission in its Space Security Programme. The spacecraft will be based on an adaptation of Hera, ESA’s first asteroid exploration mission, which launched successfully on 7 October 2024.
However, the Rapid Apophis Space Safety (Ramses) mission must be launched in early 2028 to arrive at Apophis in time to study it as it flies past Earth. Therefore, in July 2024, ESA Member States approved the use of existing Agency funds to begin preparatory work for the consolidation or early implementation phase of the mission.
This work will ensure that if the Ramses mission is fully supported in 2025, it can be implemented within this very tight schedule.
The funds were made available through ESA’s General Technology Support Programme and Space Safety Programme, and ESA, industry and all stakeholders worked tirelessly together to minimise the time needed to convert the funds into a contract. On 17 October 2024, ESA Director General Josef Aschbacher and OHB Italia Managing Director Roberto Aceti signed the €63 million contract at the International Astronautical Congress (IAC) in Milan, which will enable the work to begin.
Visualization of the European Space Agency’s proposed Ramses mission to the asteroid Apophis. OHB Italia
The funds will be used to begin the procurement process for certain urgent or long-term equipment, as well as to complete the overall design of the spacecraft, taking into account international cooperation opportunities currently under discussion.
“By developing and launching the Hera mission on time and within budget, we have demonstrated that ESA and its industrial and scientific partners are capable of meeting the challenging timelines required for asteroid missions,” said ESA’s Paolo Martino, who is leading the mission.
“With Ramses, we are raising the bar even higher, so we need to act now to ensure that if our member states decide to support the mission in 2025, we can get to work immediately and reach Apophis on time.”
