An asteroid once thought to pose a threat to Earth may be visible to the naked eye for up to two billion people when it safely whizzes past our planet in 2029.
“Apophis is a large, 340-meter asteroid that will pass safely past the Earth closer than geosynchronous satellites on April 13, 2029, which happens to be a Friday, because nature has a sense of humor,” said Richard Binzel, a professor of planetary sciences at the Massachusetts Institute of Technology (MIT), in a keynote lecture at the EPSC-DPS Joint Meeting 2025 in Helsinki on Sept. 8.
Despite being classified as a potentially hazardous asteroid, there is no danger posed to Earth by Apophis, only opportunities, as it will pass us at a distance of 5.9 Earth radii during the April 2029 flyby. Binzel said that the precision of Apophis’ calculated orbital path is due to extensive astrometry and radar ranging over 20 years.
A close approach to Earth by an asteroid the size of Apophis — which takes its name from the ancient Egyptian deity of chaos and darkness — is extremely rare, occurring just once every 7,500 years on average, according to Binzel. And this exceptional close encounter offers a unique opportunity for both planetary science and planetary defense.
The coming flyby allows the chance for spacecraft to get up close and observe how interactions with Earth’s gravitational field and magnetosphere influences and changes Apophis, boosting our understanding of asteroid physics. Measuring the properties of asteroids is also crucial for planetary defense capabilities, which agencies across the world are developing.
“I think it’s an equation: Planetary defense equals applied planetary science,” said Binzel.
“This will be on the final exam,” he quipped. “The final exam is in 2029. We have to study and prepare now for the final exam in 2029.”
Planned missions to study the asteroid with before-and-after observations and flybys include Europe’s RAMSES mission — based on the Hera spacecraft to follow up on NASA’s 2022 DART mission impact — Japan’s DESTINY+, both of which are expected to launch in 2028, and NASA’s OSIRIS-APEX, which is already en route for a flyby after its sampling mission of asteroid Bennu. (OSIRIS-APEX’s future is in doubt, however; it’s one of the 41 projects slated to be canceled if President Donald Trump’s 2026 NASA budget request is enacted.)
While preparations are being made for space-based observations, the asteroid is also expected to attract large numbers of viewers on the ground. Apophis’ closest approach is expected to be visible to two billion people living all over Africa and in Western Europe as it passes within just 10% of the Earth-moon distance.
“This is four times more people than saw Neil Armstrong walk on the moon. Think about what a world event this is going to be,” Binzel said.
“This is an unprecedented natural experiment that has been set up for us that maybe happens once in human history,” said Thomas Statler of NASA Headquarters.
While scientists prepare for making the most of the Apophis event, Binzel stressed that the event will not endanger the planet. “I want you to take away three things,” he said. “Those three things are: Apophis will safely pass the Earth. Apophis will safely pass the Earth. Apophis will safely pass the Earth.”
