The Geminids are among the most fascinating shows that gives us the winter sky: with the right tricks, you can see up to 150 shooting stars every hour
"If you have never yet seen a fiery Geminid ball draw an elegant arc across the expanse of the starry sky, you have never seen a meteor," write astronomers David Levy and Stephen Edberg in their famous "Observing Meteors."
The Geminids, also called "winter shooting stars" are indeed among the most fascinating spectacles among those that the sky gives every year. And we are very close to the time when they will reach the peak of visibility.
The Geminids, a meteor shower
The Geminids are a show not to be missed: they are among the brightest and most powerful meteor showers observable from our planet, and are the passion of astrophotographers around the world.
Una delle particolarità dello sciame meteorico è che le “stelle cadenti” possono sembrare provenire dalla luminosissima costellazione dei Gemelli – Gemini appunto – come se originassero tutte dallo stesso punto, anche se in realtà possono essere osservate in tutta la volta celeste, o quasi.
Le Geminidi sono “la coda” meteorica dell’asteroide 3200 Phaethon, e sono forse il prodotto dall’antichissima collisione dell’asteroide near-Earth con un altro oggetto celeste.
L’asteroide “madre” 3200 Phaethon orbita intorno al Sole ogni anno e mezzo circa, e nel corso della sua orbita si avvicina alla Terra e ancor di più al Sole, attraversando l’interno dell’orbita di Mercurio a solo 0,15 unità astronomiche di distanza dalla nostra stella (una unità astronomica è la distanza tra la Terra e il Sole).
The Geminid meteor shower was first observed in 1833, but is still very powerful, probably due to Jupiter's gravity pulling the particle swarm away from the "parent" asteroid, moving it closer to Earth over the years.
According to scientists, the Geminids meteor shower is evolving very rapidly and will probably become extinct in the next century: therefore, it is impossible to miss the opportunity to observe the brightest shooting stars of winter, in their last "golden years".
How to observe the Geminids
In this 2021, the bright full moon of December 18 disturbs not a little the vision of the most fascinating meteor show of the season, but you can still enjoy the Geminids at best by following a few tricks.
The peak of visibility of the meteor shower will occur between December 13 and 15, when the moon will be in its crescent phase and close to the maximum of its brightness. But knowing where and when to turn your eyes to the sky, you can fully enjoy the show.
To find the constellation Gemini in the sky, the easiest thing is to first locate Orion, with its well recognizable belt of stars. The constellation Gemini lies to the left of Orion, and slightly higher up: Castor and Pollux, the "heads" of Gemini, are visible. To help further, you can intercept the very bright Aldebaran, in the constellation Taurus: following an ideal horizontal straight line to the left, you meet Castor, the highest "head" of Gemini.
To have an epic view of the winter shooting stars, the best thing is to turn your gaze in the vicinity of the constellation of Gemini: the "stars" with the longest tail are those moving away from the constellation from which they seem to originate.
To be able to enjoy the incredible spectacle of the Geminids - with peaks of 150 "falling stars" every hour - the best time is around two o'clock in the morning, when the brightness of the crescent moon annoys less the view on the night sky.
The maximum peak of the meteor shower is expected between the night of Monday, December 13 and the morning of December 15: the time when the shower will be at its maximum power, when it will be possible to observe over one hundred "falling stars" every hour, is expected in the early hours of December 14.