Leonids in the 1999 shower above the Torre de la Guaita, an observation tower used during the 12th century in Girona, Spain (Image: Juan Carlos Casado/GSFC)

Well-placed skywatchers could see hundreds of meteors an hour on Tuesday, at the peak of the annual Leonid meteor shower.

Meteors are bits of dust or rock that collide with Earth’s atmosphere. The friction heats up gas particles that produce a glowing trail. A handful of meteors can be seen each hour on any clear night, but this number can spike significantly during a meteor shower.

The Leonid shower occurs each year when the Earth passes through streams of debris ejected by the comet 55P/Tempel-Tuttle, which often leaves behind dusty trails as it passes through the inner solar system every 33 years.


Earth will cut across the first such stream around 0900 GMT on 17 November, an event that is expected to produce dozens of meteors an hour. But the spectacle will reach its peak between 2100 and 2200 GMT, as Earth passes through two debris trails left by Tempel-Tuttle in 1466 and 1533.

Leonids rising

These stream crossings could create as many as 300 Leonid meteors per hour, according to NASA’s Meteoroid Environment Office. Skywatchers in Asia and the easternmost parts of Europe will have the best view of these intense showers, because the sky will be dark and the apparent point of origin of the meteors – called the radiant – will be over the horizon.

The Leonid shower is so called because the radiant is in the northern constellation Leo. The best time to view the shower is after this spot rises, around 2400 GMT.

North American observers may be able catch a glimpse of dozens of meteors before dawn on 17 November, but an elevated number of meteors may also be visible on the following night. European observers will get their best glimpse of the shower after the peak, in the early hours of 18 November.

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