The Perseids, Explained
The year's most reliable meteor shower peaks in mid-August. What you're actually watching, and how to see the most of it without any equipment.
Every August, Earth ploughs through a trail of debris left behind by a comet called Swift-Tuttle. The result is the Perseid meteor shower — the most dependable display of the northern year, and the easiest piece of astronomy to take part in, because it requires nothing but a dark sky and patience.
What you're looking at
The particles are small. Most are the size of a grain of sand, and almost none survive to reach the ground. What you see isn't the debris burning — it's the air in front of it, compressed and heated to incandescence as the particle enters the atmosphere at roughly sixty kilometres per second. The streak is a column of glowing air, and it's gone in under a second.
They appear to radiate from a point in the constellation Perseus, which is where the shower gets its name. That's a perspective effect, the same way parallel railway tracks appear to converge. The particles are travelling on parallel paths; you're seeing them head-on.
How to actually watch
Get away from streetlights if you can, but don't let a lack of dark sky stop you — the brightest Perseids punch through suburban glow.
Look up, not at Perseus. Meteors appear all across the sky, and the longest, most dramatic trails show up well away from the radiant.
Give your eyes twenty minutes to adapt and then leave your phone alone. A single glance at a screen resets the adaptation, and the difference is dramatic.
Lie down. Craning your neck for an hour is the main reason people give up early.
What to expect
Published rates assume a perfectly dark sky and a radiant directly overhead, so treat them as an upper bound. From a reasonable suburban garden you might see a meteor every few minutes during the peak. The hours after midnight are better than the hours before, because you're then on the leading edge of Earth's orbit, sweeping the debris up rather than waiting for it to catch you.
Moonlight matters more than almost anything else. A bright moon during the peak can cut the visible count by more than half.
Good Luck!