The Perseid meteor shower, an annual celestial event beloved by millions of skywatchers around the world, is about to make its annual return to the night sky. And thanks to a new Moon, there’ll be no bright moonlight to hinder the view.
This year’s Perseid shower will reach its peak on Sunday night, 12 August 2018, and early morning on the 13 August. You can also see some Perseids, though fewer in number, for several nights before and after that date.
The radiant will be visible from around 22:00 BST and at this time there will be the highest chance of seeing `Earth grazing meteors’. These are meteors that skim the Earth’s atmosphere and so have long, blazing tails.
The shower will be visible all over the United Kingdom, as long as the skies are clear. Unlike a lot of celestial events, meteor showers are easy to watch and no special equipment is needed, although a reclining chair and a blanket make viewing much more comfortable.
These “shooting stars” can appear anywhere and everywhere in the sky. So the best direction to watch is wherever your sky is darkest, usually straight up. Faint Perseids appear as tiny, quick streaks. Occasional brighter ones might sail across the heavens for several seconds and leave a brief train of glowing smoke.
When you see a meteor, track its path backward. If you eventually come to the constellation Perseus, then a Perseid is what you’ve just witnessed.
The higher the radiant, the more meteors you’ll see. But when the shower’s radiant is still low above the horizon, the few Perseids that do appear can be spectacularly long “Earthgrazers” skimming far across the sky along the top of the atmosphere.
Occasionally you might spot an interloper. The weaker Delta Aquariid and Kappa Cygnid showers are also active during Perseid season, and there are always a few random, “sporadic” meteors. All of these track back to other parts of the sky.
Any light pollution will cut down the numbers visible. But the brightest few meteors shine right through light pollution. In fact, a NASA analysis of all-sky images taken from 2008 to 2013 shows that the Perseids deliver more bright meteors (those that outshine any star) than any other annual meteor shower.
Meteors are caused by tiny, sandgrain- to pea-sized bits of dusty debris streaking into the top of Earth’s atmosphere roughly 129 kilometres (80 miles) up. Each Perseid particle zips in at 60 km (37 miles) per second, creating a quick, white-hot streak of superheated air. The nuggets in Grape Nuts cereal are a close match to the estimated size, colour, and texture of typical meteor-shower particles.
These particular bits were shed long ago by Comet Swift-Tuttle and are distributed all along the comet’s 133-year-long orbit around the Sun. Earth passes through this tenuous “river of rubble” every year in mid-August. The comet is so named because it was independently discovered by Lewis Swift and Horace Parnell Tuttle in July 1862.
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