They come back every year, but the wonder remains the same. The Earth has been going through a field of comet dust until the end of August 17 and until the end of August 17 which turns into our sky into the rains of shooting stars. The peak is planned between August 11 and 12where the quantity of visible stars will be at its maximum. We explain to you why this phenomenon, called the Perseids, returns every year.
A comet that passes near the earth every 120 years
The phenomenon is linked to the comet 109P/Swift-Tuttlewhich passes near our planet every 120 years and then releases a cloud of dust. Each summer, the rotation of the earth brings us back to the region where the comet has left this swarm. “”The rains of shooting stars, it is these dust that enter high speed in the earth’s atmosphere“, explains Karl Antier, geophysicist by training and amateur astronomer for almost 30 years. With an average speed of 60 km/h, you will have to be careful to observe these flashes!
The last time the comet at the origin of the Perseids came close to the earth was in 1992. It was therefore the dust released in space over 30 years ago that you observe every summer! The consequence: The number of shooting stars observable in the sky decreases each yearand will find its maximum … around 2126, during the next passage of the comet. “”If we remember in 40 years, there will only be 40 perseids visible per hour at the height of summer, against 80 today“explains Karl Antier. In 1992, up to 300 shooting stars were observable each hour !
Geminids in December, quadrantides in January … Perseids are not the only stars rains to repeat themselves each year. But they are the ones who have the spotlight, because the summer climate is more conducive to lengthening in a field to observe the sky. Karl Antier gives you his advice to do so in the best possible conditions.
A full moon that disturbs
You have to start by getting away from any light pollution. Yesif you live in Marseille, it is better to leave the Marseille city for one night And find a field where an isolated beach far from lampposts and bright brands.
But this year, it’s no luck! The moon will be full on August 9, while the peak of the rain of stars is expected between August 11 and 12. However, the light of the moon makes dust observation more difficult. Thus, instead of the 80 shooting stars visible per hour when the optimal observation conditions are met, you can only observe 20 to 40 in August.
Another point of vigilance, choose a night when the atmosphere is as clean as possible: no clouds, humidity or dust in the air. “”In Provence, the climate is rather dry, it’s a chance!“, Rejoices Karl Antier. To maximize your chances, you will also have to cut sleep on sleep.”The stars are more visible at the end of the night, from two in the morning“, Explains the astronomer. The reason? If they are called the Perseids, it is because the stars are more visible in the region of the sky around the constellation of Perseus. Or,”, “This constellation is very low on the horizon at the start of the night, and very high in the sky at the end of the night“. At the start of the night, you can hope to see 5 to 10 shooting stars per houragainst 20 to 40 at the end of the night, specifies the specialist.
Finally, avoid them “barbecues between friends on the beach“, Advives Karl Antier. Not that the beach is a place of observation to be avoided, but because observing the stars will require all your concentration.”You have to focus on the sky, otherwise you will only see the brightest stars in the corner of your eye !, specifies the geophysicist.
For those who wish to share this beautiful moment, events are organized all summer to observe the Perseids.
