The Eta Aquarid Meteors.

The Eta Aquarid Meteor Shower will be at a peak on Monday 6 May 2013, with up to 55 meteors per hour at it's peak, radiating from the constellation of Aquarius. This does not spend long above the horizon in the northern hemisphere at this time of year, but potentially could produce good shows before dawn on the 4-6 May, with longer displays in the southern hemisphere.

The radiant point of the Eta Aquarid Meteors. Astronomy Central.

The meteor shower is caused by the Earth passing through the trail of Halley's Comet, where it encounters thousands of tiny dust particles shed from the comet as its icy surface is melted (strictly sublimated) by the heat of the Sun. Halley's Comet only visits the inner Solar System every 75 years (most recently in 1986 and next in 2061), but the trail of particles shed by it forms a constant flow, which the Earth crosses twice each year; in May when it causes the Eta Aquarid Meteor Shower and in October when it causes the Orionids.

Diagram showing the orbit and current path of Halley's Comet relative to the rest of the Solar System. Image created using the JPL Small-Body Database Browser.

See also Connecticut house struck by meteorite, The Lyrid Meteors, Fireball over Wyoming, Fireball over the northeastern United States, and Comet C/2011 L4 (PANSTARRS) to reach its closest point to Earth this week.

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The eta Aquarid Meteors.

The eta Aquarid Meteor Shower peaks on (or about) 6 April each year, when the Earth passes through the orbital path of Halley's Comet; the meteor shower is caused by material from the comet's tail hitting the planets atmosphere and burning up. This occurs even though the comet is not currently close to us - it last visited the Inner Solar System in February 1986 and will not return until July 2061. The comet has been on its current orbit for at least 16 000 years (possibly as long as 200 000 years), and during this time a lot of material has been shed from its tail, and continues to follow roughly the same orbital path.

The orbit of Halley's Comet. University of Alaska Fairbanks.

Halley's Comet visits the Inner Solar system every 75-76 years, making it a short period comet; long period comets return to the Inner System less than once every 200 years. At its closest to the Sun it reaches a distance of 0.6 AU, 60% of the distance at which the Earth orbits the Sun, between the orbits of Venus and Mercury. At its furthest it reaches 35 AU, roughly the average orbital distance of Pluto. During each visit it crosses the orbital path of the Earth twice, creating two yearly meteor showers, the eta Aquarids in May and the Orionids in October.

The eta Aquarids are named for the point in the sky at which they originate, close to the star Eta Aquarii. They are best seen from the Southern Hemisphere, as the point of origin is close to the horizon in the Northern Hemisphere, though the display is likely to be poor in 2012, due to a bright Moon. At the peak of the shower about 30 meteors an hour should be visible. The visible meteors are tiny particles burning up high in the atmosphere, it is highly unlikely that any material from the shower could ever reach the ground (a meteor is a shooting star, an object visible in the sky; a meteorite is a piece of rock on the ground of extra-terrestrial origin).

The point of origin of the eta Aquarid Meteor Shower. NASA/Space.com.

See also Fragments of 22 April meteor found in California, Fireball over Nevada and California, The Lyrid Meteors, Images of Vesta and Asteroid 2012 DA14 may pass within 21 000 km of the Earth.

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