Explainer-The Eta Aquariid meteor shower: When is it and what to expect?


By Will Dunham

(Reuters) – Meteors will be streaking across the sky as Earth passes through dusty debris in space left by Halley’s Comet in the annual Eta Aquariid meteor shower, with peak activity in early May.

Here is an explanation of this meteor shower.

WHAT IS A METEOR?

Meteors are space rocks and other material that burn up as they plummet through Earth’s atmosphere, leaving a bright streak in the sky. They also are called shooting stars or falling stars, though they are not stars. Comets can be a source of meteor showers because they cast off dust and debris as they orbit the sun. Meteor showers happen annually or at regular intervals when our planet, during its orbit of the sun, journeys through trails of such debris.

WHY IS IT CALLED THE ETA AQUARIID METEOR SHOWER?

It gets its name because the origination point in the sky – called the radiant – for the debris that burns up in the atmosphere is in the constellation Aquarius – the “water bearer” – and close to Eta Aquarii, one of the constellation’s brightest stars and one of the four stars that comprise the top of its “water jar.” Eta Aquarii and the other stars in the constellation have nothing to do with causing the meteors.

WHEN AND WHERE CAN YOU VIEW THE METEOR SHOWER?

According to the American Meteor Society, the Eta Aquariids are active from April 16-May 27, with the highest meteor rates from May 1-10 and the peak on May 5. The meteors can be seen during pre-dawn hours in both the Northern and Southern hemispheres. The Southern Hemisphere offers an advantage because the Aquarius constellation is situated higher in the sky than in the Northern Hemisphere. Experts recommend viewing the shower in the darkest skies possible because most of the meteor activity is faint. During the peak, about 30 meteors can be viewed each hour, according to NASA.

WHAT DOES HALLEY’S COMET HAVE TO DO WITH THIS?

Comets are icy remnants from the time of the solar system’s formation, made up of rock, dust and ices. As they orbit nearer the sun, they release dust and gases. Halley’s Comet, named for English astronomer Edmond Halley (1656-1742) who studied it, is considered the most famous one. It takes a 76-year orbital lap around the sun. It was last seen in Earth’s skies in 1986 and will return in 2061, according to NASA. Debris released by Halley’s Comet causes the Eta Aquariid meteor shower. The Orionid meteor shower that peaks in mid-October each year also is driven by debris from Halley’s Comet.

HOW QUICKLY DO THESE METEORS TRAVEL?

According to NASA, Eta Aquariid meteors are particularly speedy, moving at about 148,000 miles per hour (238,000 km per hour) into Earth’s atmosphere. Such quickly moving meteors can produce glowing “trains” lasting for seconds to minutes. The American Meteor Society said meteor rates are expected to be enhanced this year by debris being perturbed by the gas giant planet Jupiter in a direction closer to Earth.

(Reporting by Will Dunham in Washington, Editing by Rosalba O’Brien)



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