Sky Matters with Niall Smith

IN ANCIENT lore it was said that a shooting star was a “sign of a soul going to heaven”. Borne out of a lack of understanding of what causes these random streaks of light in the night sky, it was perhaps not surprising and indeed, to this day, one continues to hear people use the phrase. The actual origin of shooting stars is now reasonably well understood, but there is more than one source for this phenomenon and new research has suggested some interesting results, of which more in a moment.

The first source of meteors is small dust particles spewed out in the tails of comets. As Earth passes through them at speeds ranging from 40,000km/h to an incredible 260,000km/h, the friction between the dust particles and the Earth’s atmosphere results in instant vaporisation, unless the dust particle is larger than a grain of sand, in which case it can take a couple of seconds before vaporisation is complete. In November, we will have the opportunity to see shooting stars caused by the Earth passing through the tail of comet 2P Encke on the night of November 11/12th (the so-called Taurid meteor shower) and through the tail of 55P Temple-Tuttle on the night of November 17/18th (the so-called Leonid meteor shower).