Asteroids

Asteroids are the rocky and metallic leftovers from the building of the planets, and almost every meteorite is a piece of one. Here are 40 of the most interesting, the ones passing Earth this year, and how astronomers keep track of them all.

Where meteorites come from

Most asteroids orbit the Sun in the main belt, between Mars and Jupiter. More than a million larger than a kilometre are thought to exist there, yet together they would make a body far smaller than our Moon. When asteroids collide, fragments are knocked off. Over millions of years, the gentle push of sunlight and the pull of Jupiter steer some of those fragments onto orbits that cross Earth's, and a few eventually fall as meteorites. Comparing meteorites with the colours of asteroids, and with samples brought back by spacecraft, links the rocks in our collections to their sources: the howardites to Vesta, the LL chondrites to bodies like Itokawa, and the most primitive carbon-rich meteorites to asteroids like Ryugu and Bennu.

Notable asteroids

Passing Earth soon

The next known asteroids to pass within 19 Moon distances. All are predicted misses.

• 2 Nov 2026: 524522 Zoozve (2002 VE68) 6,000,000 km, 16 times the Moon's distance; roughly 210 m to 460 m across
• 3 Nov 2026: 2021 VC4 2,300,000 km, 6 times the Moon's distance; roughly 11 m to 25 m across
• 5 Nov 2026: 2017 WJ2 5,600,000 km, 15 times the Moon's distance; roughly 88 m to 200 m across
• 6 Nov 2026: 2001 KF54 7,200,000 km, 19 times the Moon's distance; roughly 290 m to 650 m across
• 9 Nov 2026: 2025 UF5 7,200,000 km, 19 times the Moon's distance; roughly 8 m to 17 m across

All close approaches

Keeping watch

Survey telescopes scan the sky every clear night, and their measurements are combined to work out each new asteroid's orbit, years and centuries ahead. More than 90 per cent of near-Earth asteroids larger than a kilometre have been found, and none of them is on course to hit Earth in the foreseeable future. The search now concentrates on smaller ones.

When an asteroid has just been discovered, its orbit is uncertain, so a computer works out a whole range of possible future paths. If Earth falls anywhere inside that range, the asteroid goes on a watch list with a calculated chance of impact. These chances are almost always tiny, and as more observations come in, the range narrows and the asteroid is usually removed from the list altogether. 2024 YR4 and Apophis both followed exactly that path.

The watch list currently holds 2,227 objects. About 95 per cent of them are smaller than 50 metres, the size that would break up high in the atmosphere. None is rated above zero on the Torino scale, which runs from 0 (no hazard) to 10.

The largest objects on the list, with the chance that they miss Earth on every listed date:

From open tracking data. Most entries have been seen only briefly, and further observations normally rule out every impact. Figures last updated 1 Nov 2026.

If a sizeable asteroid were ever found on a collision course, it would most likely be spotted years or decades ahead. In 2022 the DART mission showed that a spacecraft can change an asteroid's path, so a warning like that would give time to act.

Words to know

• Asteroid
• Asteroid belt
• Near-Earth asteroid
• Potentially hazardous asteroid
• Rubble pile
• Yarkovsky effect
• Asteroid family
• Kirkwood gaps
• Sample return