We now know the shape of notorious asteroid 2024 YR4 that dominated headlines recently — it’s probably ‘suburban,’ too

The asteroid 2024 YR4 — the one that caused a stir earlier this year due to its potential collision course with Earth — has a surprising tale to tell. A new study reports that this space rock likely hails from the central region of the main asteroid belt between Mars and Jupiter — a cosmic “suburb” scientists don’t typically associate with asteroids that cross paths with our planet.

Shortly after its discovery late last year, astronomers calculated that 2024 YR4 had a 1.3% chance (1-in-83) of impacting Earth in December of 2032. This alarming probability briefly landed the asteroid atop impact risk lists maintained by NASA and the European Space Agency, triggering planetary defense discussions and prompting intensive follow-up observations to refine the object’s trajectory. Many experts emphasized, however, that the risk would likely go down by quite a bit once better observations could be made.

Sure enough, by late February, the threat to Earth had dropped to near zero. By early April, pictures of the asteroid captured by the James Webb Space Telescope confirmed the building-sized rock would safely fly past Earth in 2032. Of note, the asteroid, approximately 60 meters in diameter — roughly the width of a football field — still has a 2% chance of striking the moon.

Nevertheless, new observations of 2024 YR4 from both the Gemini South telescope in Chile and the Keck Observatory in Hawaii provide compelling evidence that the space rock indeed journeyed from this unlikely region. The asteroid’s retrograde spin — in that it rotates on its axis in the opposite direction to its orbit around the sun — offers a key clue to its origin. According to the new study, the Yarkovsky effect, a subtle force arising from the asteroid’s uneven sunlight absorption and re-emission, can cause the space rock to drift inward over long periods, eventually leading to a near-Earth orbit.