The most famous meteor shower of the year was related by the Catholic Church since the Middle Ages with the tears that Saint Lawrence shed during his martyrdom at the stake, on August 10, 258. This celestial phenomenon is not unique. The truth is that they are neither shooting stars nor is it a mystical event: they are meteor showers.
Each meteor shower receives a name that associates this phenomenon with an area of the sky called radiant, where the direction of the meteors that penetrate our atmosphere seem to converge. In the case of the Perseids, the radiant is in the constellation Perseus, hence its name, and the meteors in question come from Comet 109P / Swift-Tuttle. These objects normally disintegrate in the atmosphere between 100 and 80 km in height with a speed of around 200,000 km / h.
Every year, from July 17 to August 24, this meteor shower is active, although the probability of seeing meteors increases daily until it reaches its peak. Depending on which year, it varies between August 11 and 13. According to the IMO, in 2021 its maximum intensity corresponds to the dawn of August 11 to 12. From here on, its intensity decreases.
Origin of the Meteor Showers
Throughout the year, different meteor showers can be observed from anywhere on our planet. This phenomenon has its origin mainly in the particles that a comet gives off when it approaches the Sun. These remains remain in space after the comet’s trajectory, so that when our planet, in its movement around the Sun, crosses with them, these Cometary debris impact the atmosphere at such a speed that they literally burn and we can observe them as stars, spontaneous and fleeting.
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Several hundred meteor showers can be counted throughout the year, although around a hundred are considered well established.
Comets are objects composed primarily of water, dry ice, ammonia, methane, iron, magnesium, sodium, and silicates. It is sometimes said that a comet is made of dirty ice, due to this very particular mixture. They are also believed to be made up of the primitive remains that made up the formation of the Solar System.
Comets have different sizes and compositions and come mainly from the Kuiper belt and the Oort cloud, outside our Solar System. These objects orbit the Sun, with very different periods: sometimes only a few years and other times, when they pass close to the sun, they change their orbit and get lost in the confines of space.
From meteors to meteorites
The cometary variety leaves uneven remains, which means that the meteors that impact the atmosphere are also different in intensity, impact speed, color and even size. When a meteor is very bright and even exceeds the brightness of the planet Venus, it is called a fireball. Sometimes these objects have enough mass to survive the abrasion process produced by the atmosphere and fall to the ground in the form of meteorites.
To observe this meteor shower or any other, it is advisable to look for a place away from cities, with little or no light pollution. On days of maximum activity, the Moon will be on its way to a first quarter and will soon be on the horizon, so its brightness will not affect the observation.
It is recommended to adopt a lying or semi-lying position, since, although the radiant is in Perseus, meteors can be observed anywhere in the celestial sphere. As a last note, it must be said that it is not necessary to carry binoculars or telescopes. Meteor showers are best seen with the naked eye.
Francisco Ángel Espartero Briceño, Director Master Astrophysics, UNIR – International University of La Rioja
This article was originally published on The Conversation. Read the original.
