Kathmandu, May 1:

Eta Aquarid meteor shower will light up the pre-dawn sky on May 5. Meteor shower occurs when up to 40 shooting stars fall in the night sky per hour.

The Eta Aquarids are active between April 24 and May 9, but the strongest activity will be seen on May 5, when rates of the shower could reach up to 40 meteors per hour, said Suresh Bhattarai of the Nepal Astronomical Society.

Unlike most major annual meteor showers, there is no sharp peak for this shower, but rather a plateau of good rates would last approximately three days from May 4-6, he added, “The best time to view the shower would be between 3 am to 4 am.”

Contrasting other meteor showers which are seen in the north-east sky, the Eta Aquarids will be seen in the south-east horizon, Bhattarai said.

Eta Aquarids are seen when the radiant, the point from where entire meteors shoot outward from one place in the sky, is low in the horizon. They strike the Earth on a nearly head-on direction, thus a majority of these meteors will appear swift. This situation allows these meteors to leave very long streaks in the sky, often lasting up to five seconds.

The best part of the Eta Aquarids this year is the moon will be new on the day and there will be no lunar interference and the shower would be clearly visible. These meteors are likely to strike earth’s atmosphere at a speed of 66 km per second.

A meteor shower is the result of an interaction between the earth and Comets that are like ‘dirty snowballs’ made up of ice and rock, orbiting the sun. Each time a comet swings by Sun in its orbit, some of its ice melts and it sheds a large amount of debris. As the debris streams from the comet, it forms the comet’s visible tail. If the earth travels parallel to this stream, a meteor shower is visible.

The Eta Aquarids are leftover bits of Comet Halley making contact with our atmosphere, which last passed through the inner solar system in 1986.