A meteor shower happens when Earth passes through a stream of debris left by a comet, or occasionally an asteroid. The particles, mostly smaller than grains of sand, hit the atmosphere at tens of kilometers per second and burn up as streaks of light. Because Earth crosses the same streams every year, showers return on roughly the same dates.
Why meteors seem to come from one point
Meteors in a shower travel on parallel paths, so perspective makes them appear to spread out from one spot in the sky, the radiant. Each shower is named after the constellation containing its radiant: the Perseids from Perseus, the Leonids from Leo, and so on. See constellations.
The major annual showers
Peak dates shift slightly from year to year. Check a current calendar, for example the American Meteor Society’s meteor shower calendar.
- Quadrantids (early January): a strong but very short peak.
- Lyrids (late April): from Comet Thatcher, occasionally with bursts.
- Eta Aquariids (early May): debris from Halley’s Comet, best from the Southern Hemisphere.
- Perseids (peak around August 12 to 13): from Comet Swift-Tuttle, the most popular shower in the Northern Hemisphere thanks to warm nights and bright meteors.
- Orionids (October): also from Halley’s Comet.
- Leonids (mid-November): from Comet Tempel-Tuttle, famous for occasional meteor storms.
- Geminids (peak around December 13 to 14): from the asteroid 3200 Phaethon, often the richest shower of the year.
Other types of meteor events
- Sporadic meteors: random meteors not tied to a shower, visible on any night.
- Meteor storms: rare outbursts of more than 1,000 meteors per hour, such as the Leonid storms of 1833, 1966 and 2001.
- Fireballs: meteors brighter than the planet Venus. Very bright ones are called bolides and sometimes drop meteorites, see comets, asteroids and meteorites.
Tips for watching
- Get away from city lights and check the forecast for clear skies.
- Check the Moon: a bright moon hides faint meteors, see moon phases.
- Watch after midnight: your side of Earth is then facing forward in its orbit, so more meteors hit the atmosphere.
- No telescope needed: lie back on a reclining chair and look at a wide area of sky.
- Let your eyes adapt for 20 to 30 minutes, and use a red light instead of your phone screen.
- Be patient: published rates assume perfect conditions; real counts are usually lower.
