Halley’s Comet Is Far Away. Its Dust Is Here.

Orion Over Mount Fuji

This is Lake Kawaguchi, looking south to Mount Fuji, at 3:30 a.m. on October 22, 2026. The Moon set at 1:30, the sky is fully dark, and Orion stands right above the summit.

Every few minutes a streak of light crosses the sky, usually gone in under half a second. These are the Orionids. Far from lights, with no Moon, one person can expect to see a dozen or more an hour.

Lake Kawaguchi · 22 Oct 2026, 03:30 · stars in their true places · time sped up

Out of One Point

Trace each streak backwards and they all meet in one place: near Orion’s raised arm, north of Betelgeuse, the orange star at his shoulder. That point is called the radiant, and the shower takes its name from the constellation it lies in.

The dust actually arrives along parallel paths. Like railway tracks meeting in the distance, or snowflakes rushing at a car’s headlights from somewhere far ahead, the meteors only seem to burst from one point. It is perspective.

A long exposure: an hour of meteors on one picture

A Speck of Dust, a Streak of Light

What glows is not a star but a speck of dust, most of them no bigger than a grain of rice. It plunges into the air at about 67 kilometres a second, starts to shine about 110 kilometres up, and is gone by the time it has fallen to about 100.

Air molecules hit it so hard that in an instant it heats to well over a thousand degrees and boils away, layer by layer. The light comes from those glowing hot atoms and from the air they knock into glowing, a little like the gas in a neon sign. The whole speck turns to vapour; no piece of it reaches the ground.

Slow motion · heights to scale

The Road Halley Travels

The dust comes from Halley’s Comet. It goes round the Sun about once every 76 years, from inside the orbit of Venus out past the orbit of Neptune. Each time it swings close, sunlight turns some of its ice to gas, and the gas blows out dust that was frozen inside, scattering it along the comet’s road.

Over thousands of years that dust has spread into a broad, thin band along the orbit, and the Earth crosses it twice a year: in May, when we see the Eta Aquariids, and in October, the Orionids. The comet itself is now out past Neptune’s orbit, 35 times as far from the Sun as we are, and has begun the long fall back.

In 2006 the Orionids suddenly ran two to three times stronger than usual. Two Japanese astronomers, Mikiya Sato and Jun-ichi Watanabe, traced the extra dust to Halley’s passes about 3,000 years ago; Jupiter’s pull had kept it bunched together ever since.

Orbit: JPL Small-Body Database · dust band schematic

Head-On

Halley’s Comet goes round the Sun the opposite way to the Earth. Near our orbit its dust falls sunward at about 42 kilometres a second while the Earth comes on at about 30. They don’t meet exactly head-on, so the speeds don’t simply add up to 72: the dust strikes the air at about 67 kilometres a second, fast enough to cross from New York to Washington in five seconds.

The side of the Earth facing forward along its orbit is the side where dawn is about to break, like the windscreen of a car driving through rain. That is why the radiant only rises between about 9 and 10 p.m., stands highest before dawn, and why the most meteors fall in those last dark hours.

Last Year’s Meteors, Measured

Every streak here is a real meteor. In the 48 hours from October 21, 2025 (UTC), cameras of the Global Meteor Network around the world filmed the same meteors from more than one place at once, which fixes where each one really was. They logged 2,143 Orionids.

Most lit up about 112 kilometres high and went out around 99, a third of a second later, having entered the air at about 67 kilometres a second. The typical one these cameras caught, brighter than most you’d see, weighed about 30 milligrams, about as much as a grain of rice. Traced back, their paths converge on Orion.

Data: Global Meteor Network (CC BY 4.0) · 21–23 Oct 2025 (UTC)

How to Watch in 2026

The best night of 2026 is October 21 to 22, and the nights either side are good too, because the shower’s peak is broad; the Moon sets about an hour later each night, so the night before is darker and the night after less so. On the peak night the Moon is more than three-quarters lit, so wait for it to set: before about 2 a.m. in Beijing, Shanghai, Tokyo or Taipei, around 2:30 in Hong Kong. Between moonset and the first light of dawn there are roughly three hours of real darkness.

Find somewhere away from lights, lie back and look up. You don’t have to stare at Orion: meteors appear all over the sky, and those farther from the radiant leave longer trails. Give your eyes twenty minutes to adjust, and keep your phone away. Leave the telescope at home; it sees only a small patch of sky at a time.

Lake Kawaguchi · 22:00 on 21 October to 05:00 on the 22nd · time sped up