The Perseid shower occurs every August when Earth passes through the debris trail left by comet 109P/Swift‑Tuttle. The tiny grains, typically no larger than a grain of sand, were released from the comet’s nucleus thousands of years ago and have since been traveling on nearly unchanged orbits around the Sun.
During their multi‑year residence in interplanetary space the particles endure extreme temperature swings and constant bombardment by the solar wind and cosmic radiation. These processes slightly alter their surfaces but leave their mass and trajectory essentially unchanged.
When the grains finally encounter Earth’s atmosphere they strike air molecules at speeds exceeding 20 kilometres per second. The kinetic energy is converted into heat, causing the grain to vaporize and ionize the surrounding air, which produces the bright streak of light we perceive as a shooting star.
The Perseid peak usually falls around August 12, when observers under dark skies can count up to 100 meteors per hour. The event offers both amateur skywatchers and scientists a valuable opportunity to study the composition of cometary dust and the dynamics of meteoroid streams.