Tonight’s Rare Near-Earth Asteroid Flyby: Watch NASA’s Live Stream of the 1,600-Foot Space Rock

A colossal near-Earth asteroid, officially cataloged as 387746 (2003 MH4), will make its closest approach to our planet this Saturday, 24 May 2025, thrilling sky-watchers while giving NASA’s planetary-defense systems another real-world test. The space rock, measuring an estimated 335 metres across—roughly the height of the Eiffel Tower—will streak past Earth at a blistering 30,060 km/h (about 14 km/s) but remain a safe 6.68 million km away, or about 17 times the distance to the Moon. Although 2003 MH4 is large enough to qualify as a “potentially hazardous asteroid” (PHA) under NASA’s criteria, its orbital calculations—refined with decades of observations—show zero chance of impact during this flyby. The asteroid’s passage, however, underscores why PHAs remain under constant surveillance by NASA’s Center for Near-Earth Object Studies (CNEOS) and international partners. When and how to watch • Closest approach: Saturday, 24 May, 10:37 UTC (06:37 ET). • Apparent brightness: roughly magnitude 13, requiring an 8-inch or larger backyard telescope. • Livestreams: the Virtual Telescope Project will broadcast real-time views from observatories in Italy starting at 02:30 UTC, and several amateur astronomers plan similar webcasts on YouTube. Why scientists care Large flybys like 2003 MH4 provide a valuable opportunity to refine asteroid-tracking algorithms and characterize the object’s shape, rotation and composition via radar. NASA’s Goldstone Solar System Radar in California and the Green Bank Telescope in West Virginia will ping the asteroid’s surface, producing centimeter-scale images that help model its spin state and any potential moonlets. A busy month for space rocks 2003 MH4 caps a parade of sizeable asteroids in May: Boeing-sized 2025 HY2 safely zipped by on 7 May, a stadium-length 2002 JX8 passed on 9 May, and house-sized 2025 KL crossed Earth’s orbital neighborhood on 24 May just hours before the main event. None posed an impact threat, but together they highlight the dynamic nature of Earth’s cosmic neighborhood. Planetary defense progress The 2022 DART mission proved that a kinetic impactor can nudge an asteroid’s trajectory. Building on that success, the upcoming NASA-ESA Hera mission will revisit the DART-altered Dimorphos system to measure long-term effects, refining models that would be applied if an asteroid were ever found on a collision course. Bottom line Asteroid 2003 MH4’s flyby offers a dramatic yet harmless reminder of the constant ballet of near-Earth objects. For astronomers, it’s a scientific windfall; for the public, it’s a front-row seat to celestial mechanics in action—no planetary-defense alarms required this time.