Look Up! The Orionids Are Peaking!

The dusty debris from the tail of Halley's Comet will rain down on the Earth's atmosphere, producing around 30 meteors per hour.

THE GIST

Meteors are tiny pieces of debris dropped by comets as they orbit the sun.

The Orionid meteor shower is associated with Halley's Comet, which orbits the sun every 76 years.

A bright meteor streak isn't caused by friction with the atmosphere, but by the heating of the air via "ram pressure."

A few weeks ago, Discovery Space readers from Europe witnessed the peak of the Draconids meteor shower that produced around 300 meteors per hour. On Friday evening at around 21:00 GMT, another meteor shower peaks: the Orionids.

The meteors from this shower represent debris from the famous Halley's Comet that orbits the Earth every 76 years.

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Comets are lumps of rock and ice orbiting the sun. As they get closer, the heat from the sun causes the ice to turn straight into vapor -- a process called "sublimation" -- which leads to the formation of a coma surrounding the rocky nucleus.

As the comet heads even closer to the sun, a stream of electrically charged particles from the solar wind pushes against the coma, stretching it out into the comet's trademark tail.

In some of the more spectacular comets such as Hale Bopp, it's possible to see two tails, one made from gas and another at a slight angle made from dust. When you see this, it's easy to understand why we get meteor showers.

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As the comet travels around the sun it sheds debris along its path. If the Earth passes close by or even through the debris' orbit we will see a meteor shower as the tiny particles slam into our atmosphere.

Some meteors can be incredibly bright, but most of them -- which are the size of grains of sand -- burn up high in our atmosphere. If they do survive the fiery plunge (traveling over 60km per second) then they are classed as meteorites. It's unlikely that any meteorites will 'fall' during the Orionid shower this evening but there will be plenty to see high in the sky. The dusty debris from the tail of Halley's Comet will rain down on the Earth's atmosphere, producing around 30 meteors per minute.

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It's a popular misconception that meteors glow due to friction with the atmosphere, but in fact it's the 'ram pressure' causing the air in front of the falling meteor to get compressed. It heats to around 3,000 degrees causing the air ahead of the falling meteor to glow.

This year's Orionid display won't be anywhere near as impressive as the Draconids but at an estimated 30 meteors per hour it could still be worth checking out.

Unfortunately, the moon's phase is one day passed last quarter so its light will render many of the fainter meteors invisible. The best tip is to wrap up warm, get outside around 21:00 GMT (if you're in Europe), or any time during the night over the weekend before moonrise from your location. If it's dark, and the skies are clear, look up.

The great thing about looking for meteors is that no equipment is necessary other than warm clothing and perhaps a comfortable chair.