Asteroid 2026 TU3 passed Earth on October 7 at just 0.83 lunar distances. Here is what the flyby means.

A lunar distance is the average Earth-Moon gap, about 384,000 km. The asteroid passed at roughly 318,000 km.

It was moving at 14.28 km per second. That is over 51,000 km per hour at closest approach.

2026 TU3 is an Apollo-type near-Earth object. These asteroids cross Earth's orbit around the Sun.

It was spotted only on October 6, a day before the pass. Small, fast rocks are often found this late.

Its orbit is still uncertain. Astronomers gave it a condition code of 8, meaning preliminary.

It is not classed as potentially hazardous. No diameter has been measured yet.

Such flybys are common and harmless. Each one helps scientists improve tracking of near-Earth objects.

Bigger asteroids are tracked years in advance. The small ones remain the hardest to spot early. Amateur astronomers also help track new objects. Their observations feed into global databases.