NASA's Goldstone Planetary Radar Observes Fast-Spinning Asteroid

This series of 41 radar images obtained by the Deep Space Network's Goldstone Solar System Radar on July 28, 2025, shows the near-Earth asteroid 2025 OW as it made its close approach with our planet. The asteroid safely passed at about 400,000 miles (640,000 kilometers), or 1.6 times the distance from Earth to the Moon. The asteroid was discovered on July 4, 2025, by the NASA-funded Pan-STARRS2 survey telescope on Haleakala in Maui, Hawaii. These Goldstone observations suggest that 2025 OW is about 200 feet (60 meters) wide and has an irregular shape. The observations also indicate that it is rapidly spinning, completing one rotation every 1½ to 3 minutes, making it one of the fastest-spinning near-Earth asteroids that the powerful radar system has observed. The observations resolve surface features down to 12 feet (3.75 meters) wide. Asteroids can be "spun up" by sunlight being unevenly absorbed and re-emitted across their irregular surfaces. As photons (quantum particles of light) carry a tiny amount of momentum away from the asteroid, a tiny amount of torque is applied and, over time, the asteroid's spin can increase – a phenomenon known as the YORP effect. For 2025 OW to maintain such a fast rotation without breaking apart, it may be a solid object rather than a loosely bound rubble pile like many asteroids. The Goldstone measurements have allowed scientists to greatly reduce uncertainties in the asteroid's distance from Earth and in its future motion for many decades. This July 28 close approach is the closest asteroid 2025 OW will come to Earth for the foreseeable future. Animation available at https://photojournal.jpl.nasa.gov/catalog/PIA26587