In August as Earth’s orbit crosses the dust ejected by the comet Swift-Tuttle, it provides a fabulous spectacle for viewers on Earth.
It is a regular occurrence every year and will reach its peak between the 10th of August (San Lorenzo) and the 12th. This year the observation may be a little disturbed by the presence of a quarter of a crescent Moon, which however will set before 1 a.m. on the 12 th of August on the opposite side of the sky to the radiant Perseus.
Despite talk of “shooting stars”, the Perseids are actually debris (dust and ice) left behind by the comet Swift-Tuttle as it goes around the Sun. The comet last reached perihelion, the closest point to the sun in December 1992 and will do so again in July 2126, where, according to experts, it should be visible to the naked eye like the comet Hale-Bopp in 1997.
The Swift-Tuttle comet is not a danger to the Earth (at least not for the next 1000 years), but it’s still very big: almost 10 km in diameter, much like the object that hit the Earth 65 million years ago, wiping out the dinosaurs.
This meteor shower is one of the most spectacular and significant of all those encountered by our planet in its orbit around the Sun. As the particles enter the atmosphere, they burn up, producing fireworks. This phenomenon is called the ‘Perseid’ meteor shower and it gets its name from the constellation Perseus, from where the shooting stars seem to come.
It is estimated that with the naked eye and in favourable conditions it will be possible to see up to 100 meteors per hour impacting with the Earth’s atmosphere at a rate of about 59 kilometres per second, causing 20 kilometre long light trails.
What does San Lorenzo (St. Lawrence) have to do with the Perseids? And why do we need to make a wish?
The celestial event, first observed in 36 ad, falls right near the date when we celebrate the martyrdom of S.t Lawrence, burned alive on a blazing gridiron on the 10th of August 258 a.d.
Due to this coincidence, the shooting stars that occur on the night of San Lorenzo are said to represent the tears shed by the Saint during his torture, they drift eternally in heaven only to descend on Earth the 10th of August. Hence the popular belief that for all those who remember the pain of the Saint, by watching his “tears” they will see their wish come true.