Astronomy

Perseids and star showers

Perseids and star showers

The Perseids are a meteor shower visible in August from the northern hemisphere. The so-called "star rains" are flashes produced by materials from a comet that disintegrate due to friction as they enter the Earth's atmosphere.

The Perseids are known as "the Tears of St. Lawrence" because they occur every year around August 10 and, in medieval Christian tradition, they were associated with the tears shed by St. Lawrence, who died burned on a grill and whose saint It is celebrated that day.

The Earth crosses at this time the area where there are some remains left by the tail of the Swift-Tuttle comet when approaching the Sun. These fragments, most of them very small, collide with our atmosphere at speeds of more than 200,000 km / h and disintegrate emitting flashes of light, short but intense. They can appear anywhere in the sky, although most seem to leave the constellation Perseus, and that is why they are called Perseids. Its maximum occurs from August 11 to 13

He Swift-Tuttle kite It is about 26 kilometers in diameter and a very elliptical orbit that takes it close to Earth every 133 years. He was here at the end of 1992 and will return in July 2126.

What is a meteor shower?

Perseids are not the only star showers of the year. All comets that enter the Solar System lose part of their surface material because of the solar wind and, therefore, they form a tail. The gases and materials of that tail remain in the comet's orbit forming what is called a "meteor swarm."

The Earth's orbit crosses some of these swarms of meteors every year, always on the same dates, then producing a meteor shower that is named according to the constellation from which they appear to emerge.

The following table shows the main star rains that occur at the end of the year with periods of maximum activity. In the "Hemisphere" column, the one with the greatest intensity is named first, if they are visible from both:

Meteor shower DatesConstellationHemisphere
QuadrantidsJanuary 1 - 5BootesNorth
LyridsApril 19-24LiraNorth and south
Eta AquaridsMay 5-8AquariusSouth and North
Delta AquaridsJuly 28 - 31AquariusSouth and North
LostAugust 11-13PerseusNorth
DraconidsOctober 6-10DracoNorth
OrionidsOctober 19 - 23OrionBoth of them
LeonidasNovember 16-21LeoBoth of them
GeminidsDecember 11-15GeminiNorth South

Some meteor showers, such as the Geminids, seem to have their origin in an asteroid and not in a comet. However, it is believed that these asteroids are "spent" comets that lost their volatile elements.

Materials scattered throughout space are called meteoroids. Upon entering the Earth's atmosphere, they become a meteors leaving a light trail or Shooting Star, produced by ionizing by friction with air. Shooting stars, therefore, are not stars, although shooting stars.

The vast majority of meteors are very small and disintegrate at high altitude, 80 kilometers or more. Some larger ones shine brighter for longer. These are called racing cars. If they can get to the ground we would call them meteorites.

Where and how to observe the rain of stars

To observe a meteor shower, such as the Perseids or any other, it is advisable to find a place where you can cover a lot of sky, away from cities and light pollution. If there is no choice, we will try to find a place where artificial light does not directly affect. The lighter and darker, the better.

You also have to have some luck. If there are clouds, for example, we can see little. If there is a moon, we will have to look to the opposite side, although, even then, we will miss the weakest meteors.

It is not necessary to use telescopes, binoculars or any other optical material, since they would prevent us from covering the whole sky. Nor is it necessary to look in a specific direction. Meteors can appear anywhere.

In general, meteor observation usually takes considerable time. Therefore, it is necessary to look for a certain comfort to look at the sky. It is a good idea to have a beach chair, sunbed or even a mattress. Warm clothes should also be worn, even in summer, because the motionless body, at night, in the open air and for a long time, tends to cool down.

Finally, it is worth knowing that, despite its fame, the Perseids are not the most active star shower of the year. The Quadrantids and the Geminids show more meteors per hour. And the Leonidas, despite having an irregular behavior, they can be as spectacular as the Perseids.

Discover more:
• Difference between meteoroid, meteor, meteor, asteroid and bolid
• What are comets and where do they come from?
• A Perseid crossing the sky


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