On 30 Oct 2025, an asteroid called 2025 UC11 passed 6,599 km from the centre of the Earth. Taking Earth's average radius of about 6,371 km, that is roughly 230 km above the surface. It was the closest asteroid flyby of 2025 in NASA's records, and it was one of 189 asteroids that came closer to Earth than the Moon during the year.
The data comes from NASA's Center for Near-Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory, and it also shows how small these objects were.
Close, but very small
JPL does not measure the size of most of these objects directly. It estimates a size range from each asteroid's brightness, its absolute magnitude (H), using reflectivity (albedo) limits of 0.25 and 0.05. Applying the standard formula with those limits, 2025 UC11's brightness (H 34.06) corresponds to an object roughly 0.4 to 0.9 metres across.
NASA only classes an asteroid as potentially hazardous if its orbit can bring it within 0.05 astronomical units of Earth, about 7.5 million km, and it is larger than about 140 metres, which corresponds to an H of 22 or brighter. None of the 189 asteroids that passed closer than the Moon in 2025 was bright enough to meet that size threshold: the brightest had an H of 24.7.
| Closest flybys of 2025 | Date | Distance from Earth's centre |
|---|---|---|
| 2025 UC11 | 30 Oct 2025 | 6,599 km |
| 2025 TF | 1 Oct 2025 | 6,780 km |
| 2025 BP6 | 26 Jan 2025 | 9,712 km |
| 2025 OS | 19 Jul 2025 | 10,458 km |
| 2025 TQ2 | 2 Oct 2025 | 11,239 km |
A record year for discoveries
Close-approach lists only include asteroids that have been discovered, and discoveries keep rising. According to CNEOS's discovery statistics, surveys found 3,239 near-Earth asteroids in 2025, the highest yearly total in CNEOS's data and 8.9 times the 363 found in 2000. Pan-STARRS was credited with 1,289 of the 2025 discoveries and Catalina with 880.
Flybys were not spread evenly across the year. October had 33, the most of any month, and September to November together had 82. CNEOS's data cannot say whether that reflects more asteroids passing or more being spotted, so the monthly pattern is not a measure of risk.
The fastest of the close flybys was 2025 WM20, which passed at 28.4 km per second relative to Earth on 24 Nov 2025, about 2.7 times the median speed of all 189.
Objects that did reach the atmosphere: fireballs
Smaller objects do reach the atmosphere. NASA's fireball database lists 33 events for 2025, detected by U.S. Government sensors. CNEOS defines a fireball as an unusually bright meteor, visual magnitude -3 or brighter, and says those that explode in the atmosphere are technically bolides.
The most powerful fireball of 2025 was recorded on 27 Mar 2025 at 14.3°N 111.5°W, with an estimated impact energy of 2.4 kilotons of TNT, at a peak-brightness altitude of 38.1 km. Only 4 events in 2025 reached 1 kiloton. CNEOS notes that objects causing fireballs are usually not large enough to survive the passage through the atmosphere intact, although fragments are sometimes recovered as meteorites.
What these numbers do not show
Only discovered objects. Close-approach lists include only asteroids whose orbits are known. The list used here was retrieved in September 2026.
Estimated sizes. Sizes come from brightness and assumed reflectivity, so each is a range, not a measurement. For comparison, the largest known asteroids are hundreds of kilometres across (see the largest asteroids in the Solar System).
Not every fireball. NASA states that its fireball table is not a complete list of fireball events; only the brightest are noted, and energies are approximate.
Primary sources
- NASA JPL CNEOS, Close Approaches and the SBDB Close-Approach Data API
- NASA JPL CNEOS, Fireballs and introduction
- NASA JPL CNEOS, Discovery Statistics by Survey and NEO Groups