Where will you be on April 13th, 2029?
If the skies are clear that evening, step outside just after sunset. Somewhere in the fading light, a small point will be moving – not a satellite, not a plane, but an asteroid.
It’s called Apophis. And for the first time in recorded human history, an asteroid of this size will pass close enough to Earth to be visible to the naked eye.
It sounds like the premise of a disaster film. But this is not that story.
RM Block
Apophis will not hit Earth. Its orbit is now known with remarkable precision. Scientists are describing the encounter as something far rarer: a once-in-a-millennium opportunity to observe how an asteroid behaves under the pull of Earth’s gravity.
Long before that moment arrives, however, another challenge is already under way – not tracking the asteroid, but explaining it. That’s because when people hear the terms “asteroid” and “close approach” in the same sentence, they tend to imagine the worst.
At the European Planetary Science Congress last September, one talk cut cleanly through that instinctive fear. The speaker was Richard Binzel, a professor of planetary science at Massachusetts Institute of Technology (aka MIT), whose career has unfolded alongside some of the most important moments in modern astronomy.
Binzel has spent decades studying asteroids, but he is perhaps best known for helping the rest of us to understand when not to panic.
In the 1990s, as astronomers began detecting more near-Earth objects, they faced a dilemma. Early observations often came with uncertainty. An asteroid might appear to have a small chance of impacting upon Earth decades into the future because its precise orbit was not yet fully known.
What should be done with that information? For Binzel, the answer was clear. “We have to report what we know when we know it,” he says. But that created a second challenge – how to communicate risk without amplifying fear.
Binzel’s solution was the Torino Scale, a simple system that ranks asteroid risks from zero upwards. Most objects fall at zero; there’s no threat, no cause for concern. The system’s goal, Binzel explains, was to be “informative but not alarming”.
It is a deceptively powerful idea. Because in 2029, when Apophis appears in our skies, billions of people will be watching, and what they feel in that moment will depend not just on the science, but on how that science has been communicated.
When I spoke to Binzel, he had just settled into a sabbatical in Paris. What was meant to be a short interview quickly became something else; a wide-ranging conversation that moved from asteroids to Pluto, from early mentors to the future of planetary defence.
Binzel’s ability to tell these stories is rooted in his own. He grew up under dark skies in rural Ohio, where his grandfather, a chemical engineer, would take him outside at night and point out the stars. The books he was given were far beyond his level, but he read them anyway, again and again, until they began to make sense.
As a teenager, Binzel spotted a small advertisement in the US magazine Sky & Telescope for an astronomy summer camp. He applied, was accepted and it changed everything.
The camp was run by a young astronomer named Joseph Patterson, whose enthusiasm for teaching drew in a generation of future scientists, among them a young Neil deGrasse Tyson. Binzel would go on to publish his first scientific paper at just 15.
Looking back, Binzel describes luck differently. “The definition of luck,” he says, “is when preparation meets opportunity.” From there, he found himself repeatedly at the edges of discovery.
As a student, Binzel worked with Eugene Shoemaker, a pioneer of planetary science who had once hoped to travel to the Moon as an astronaut, but instead trained the Apollo crews who would go in his place.
Another turning point came in 1978, when Binzel happened to be present on the day Pluto’s moon was discovered.
Pluto, a distant and much-loved icy world at the edge of the solar system, was long thought to be alone. The discovery of its largest moon, Charon, transformed it into a system, allowing scientists to measure its mass and begin to understand its nature.
[ Apophis asteroid will miss us in 2036 but remains threatOpens in new window ]
Years later, Binzel would observe one of the key events that confirmed that relationship, watching as Charon passed in front of Pluto and subtly altered the light reaching Earth. “I’m the only one in the world who knows this is real,” he remembers thinking, as the data came in before dawn.
Moments like that are rare. Most of science, Binzel says, is slow, methodical work, building layer upon layer until, occasionally, something reveals itself.
Apophis is different. Discovered in 2004, the asteroid initially appeared, albeit briefly, to pose a small risk of impacting upon Earth. For a few days, it rose to level 4 on the Torino Scale, the highest ever recorded. But as more data came in, that risk quickly disappeared.
Today, scientists are unequivocal. It will pass safely. It is, Binzel emphasises, a “safe passage by the Earth”; not a threat, but an opportunity.
Apophis is a near-Earth asteroid, a fragment from the main asteroid belt between Mars and Jupiter, gradually nudged over time into an orbit that crosses Earth’s path. On April 13th, 2029, it will pass within 32,000km of our planet; closer than many satellites.
Encounters like this are thought to happen only once every thousand years. “Nature is handing us a once-in-a-millennium opportunity,” Binzel explains. And space agencies are preparing to meet that opportunity.
The European Space Agency’s Rapid Apophis Mission for Space Safety (Ramses) will arrive at Apophis before its close approach, observing how its shape, surface and motion respond to Earth’s gravitational pull, and helping scientists to better understand how asteroids behave.
Meanwhile, Nasa’s OSIRIS-REX spacecraft, short for Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer, collected samples from the asteroid Bennu in 2020 and returned them to Earth in 2023.
The spacecraft has since been repurposed as OSIRIS-APEX, the Origins, Spectral Interpretation, Resource Identification and Security–Apophis Explorer mission.
It will rendezvous with Apophis, studying how the asteroid’s surface, shape and motion may have been altered by Earth’s gravitational pull – a rare chance to observe, in real time, how a close planetary encounter affects an asteroid.
The asteroid Bennu itself is a relic of the early solar system. We now know, from those OSIRIS-REX samples, that Bennu is a rubble-pile asteroid rich in carbon and water-bearing minerals, offering clues to the chemistry that may have helped seed life on Earth.
Apophis offers something different – a live experiment. When OSIRIS-REX released its sample capsule into the Utah desert in September 2023, its mission might have seemed complete. But the spacecraft did not stop. Its trajectory had already been recalculated, its purpose extended. Renamed OSIRIS-APEX, it is now on course to meet Apophis, not by chance, but by design. Because in astronomy, alignment is everything.
[ Asteroid flashes by Earth in cosmic close call, says NasaOpens in new window ]
Orbits align. Paths cross. Objects that have travelled silently through space for millions of years suddenly appear, briefly, within reach of human understanding.
Apophis is one such alignment. And perhaps, in his own way, so is Binzel.
From the dark skies of his childhood, to a summer camp that set his course, to moments of discovery about Pluto and beyond, his career traces the arc of modern planetary science; not through a single breakthrough, but through a series of moments where he was ready when opportunity appeared.
We are aligned to this moment too. A species that has existed for only a brief instant in cosmic time now finds itself able to predict the path of an asteroid decades in advance, to send spacecraft to meet it, to ask not “will it destroy us?” but “what can it teach us?”
On April 13th, 2029, billions of people will look up. Some will see a moving point of light.
Others will see something more; a reminder that we are part of a much larger story, one we are only just beginning to understand.
Dr Niamh Shaw is an engineer, scientist and writer
