The meteor shower known as the Leonids, originating from the comet 55P/Tempel-Tuttle, is primarily observable between November 17 and 18. This event, one of the most intense of the year, promises to illuminate the night sky and captivate patient observers with up to 15 meteors per hour.
Over the weekend, astronomy enthusiasts and the curious alike will direct their gaze towards the sky to witness one of the most anticipated meteor showers of the year—the Leonids. Renowned for its intensity and beauty, it will, as usual, transform the night sky into a luminous tableau of streaking stars.
According to the American Meteor Society, the Leonids’ activity will peak between Friday, November 17, and Saturday, November 18, with a potential second peak on Sunday, November 19. During these nights, conditions will be optimal for observing up to 15 meteors per hour, especially in areas with low light pollution (away from urban centers). These meteors are notable for their speed and brightness, providing an impressive visual spectacle. Additionally, this event presents an opportunity for scientists to gather information on the interaction between these celestial bodies and our planet.
The Origin of the Leonids
The comet 55P/Tempel-Tuttle is the source of the Leonids. It is a small celestial body with a nucleus measuring approximately 3.6 kilometers in diameter. The designation of the comet 55P/Tempel-Tuttle pays tribute to its discoverers, and the “P” indicates that it is a periodic comet with an orbital period of less than 200 years. Discovered independently by Ernst Tempel in 1865 and Horace Tuttle in 1866, this comet completes an orbit around the sun every 33 years. During its perihelion passage (closest point to the sun)—the last one occurring in 1998 and the next one scheduled for 2031—Temple-Tuttle releases debris into space.
These debris, composed of dust and small rocks, form a trail along the comet’s orbit. When the Earth traverses this debris field every November, some collide with our atmosphere at high speed, disintegrating and creating the luminous trails of the Leonids. Approximately every 33 years, this meteor shower transforms into a “meteor storm,” with rates reaching up to 1000 meteors per hour, as observed in 1966 and 2002. These storms provide an even more impressive spectacle, with meteors appearing to fall almost like rain.
The Leonid meteors are notable for their exceptional speed of about 71 kilometers per second. This velocity is significant in the context of meteoric phenomena as it directly influences the way these meteors interact with the Earth’s atmosphere. When these particles, traveling at such a high speed, enter the atmosphere, they undergo intense friction. This friction generates extreme heat, causing the vaporization of the meteors and creating luminous trails visible from the ground.
The size of the Leonid particles, often larger than those of meteors from other showers, also plays a major role in their spectacular appearance. These larger pieces of debris can survive longer and cover a greater distance in the atmosphere before completely disintegrating. Consequently, they produce very bright “fireballs” and “earth grazers”—meteors that appear to skim the horizon.
These unique characteristics of the Leonids—high speed and substantial debris size—contribute to its status as one of the most spectacular meteor showers.
Tips for Optimal Observation
To maximize the observation experience of the Leonids, several practical tips are essential. Firstly, it is recommended to move away from brightly lit urban areas. City light pollution significantly masks the visibility of meteors. A clear location, far from artificial lights, will enhance the appreciation of the spectacle.
The timing of the observation is also crucial. The ideal period is after midnight, extending into the early morning. During these hours, the constellation Leo, from which the Leonids appear to emanate, is well-positioned in the sky. This period coincides with the darkest hours of the night, providing an optimal background for observing the luminous trails. A crucial reminder: it takes approximately 20 to 30 minutes for the eyes to adapt to the darkness.
The current phase of the moon, in crescent form, favors observers. Its light will not be intense enough to hinder observation. The moon’s crescent will be illuminated at 23%, according to the American Meteor Society. Additionally, it will set relatively early in the evening, leaving the sky in almost total darkness.
Regarding equipment, observing the Leonids does not require specialized gear such as a telescope or binoculars. In fact, these instruments can limit the field of vision. Experts suggest lying on one’s back and observing the sky with the naked eye, thus covering a broad visual field. Although the meteors appear to radiate from the Leo constellation, it is advisable to direct one’s gaze to other parts of the sky. Meteors appearing far from the radiant point (the Leo constellation, in this case) tend to leave longer and more spectacular trails.
Featured Image: The Leonids appear to originate from the constellation Leo, but you can see them throughout the night sky. NASA / Ames Research Center / ISAS / Shinsuke Abe and Hajime Yano