{"id":43533,"date":"2023-04-03T08:45:11","date_gmt":"2023-04-03T08:45:11","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=51064"},"modified":"2023-04-03T09:32:33","modified_gmt":"2023-04-03T09:32:33","slug":"what-causes-a-meteor-shower","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/what-causes-a-meteor-shower\/","title":{"rendered":"What causes a meteor shower?"},"content":{"rendered":"

Where do meteors come from, and what causes a meteor shower? A guide to the science of shooting stars. <\/p>

By Penny Wozniakiewicz\n \t\t<\/p>

Published: Monday, 03 April 2023 at 12:00 am<\/p>

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2023 is set to be a great year for meteor showers<\/span><\/p>\n

One of the key indicators as to whether a meteor shower is worth observing during peak activity is whether there will be a bright full Moon high the sky, drowning out those meteor trails, or whether our lunar companion will be out of the way.<\/p>\n

Since 2023 is due to have a series of major Moon-free meteor showers<\/a>, between now and 2024 we\u2019ve got some great nights of meteor-spotting ahead of us. But what causes a meteor shower, and why do they happen at the same time every year?<\/p>\n

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Trails of the Lyrid Meteor Shower. Credit: Adventure Photo \/ Getty Images<\/span><\/figcaption><\/div>\n

A<\/span>lthough seemingly empty, the space between the planets of our Solar System is teeming with vast numbers of meteoroids, small pieces of rock and dust largely originating from comets and asteroids but also, to a lesser extent, from the terrestrial planets and rocky satellites.\u00a0<\/span>A small number even originate from outside our Solar System: so-called interstellar dust.<\/span><\/p>\n

Meteors are produced when particles of interstellar dust enter Earth\u2019s atmosphere at extremely high speeds (ranging from around 11km to 72km per second) causing them to burn up and leave a bright momentary streak across the sky.<\/span><\/p>\n

Earth encounters approximately 40,000 tonnes of extraterrestrial dust every year. <\/span><\/p>\n

Although this may sound like a lot, on a typical night it means you might see just a few meteors an hour streaking randomly across the sky. These are called sporadic meteors.<\/span><\/p>\n

At certain times of the year these numbers can increase to around 100 meteors an hour in events called meteor showers, as Earth ploughs through denser streams of particles on its orbit around the Sun.<\/span><\/p>\n

For more info, read our meteor shower<\/a> guide.<\/strong><\/em><\/p>\n

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Comet McNaught over South Australia. It\u2019s dust tail is an example of the debris streams that produce meteor showers. Credit: John White Photos \/ Getty Images<\/span><\/figcaption><\/div>\n

The oldest meteor shower<\/h3>\n

Of all meteor showers that occur today, one of the oldest known is the Lyrid meteor shower<\/a>.\u00a0 Observational records for it date back to 687 BC.<\/p>\n

In these ancient times, meteor showers were interpreted as portents and then later as phenomena of the upper atmosphere. Their extraterrestrial nature was not realised until the idea of an Earth-centred Universe lost favour and astronomers became intrigued with meteors.<\/p>\n

This was spurred on by the occurrence of spectacular meteor showers in the 19th and 20th centuries, as well as the findings from studies of meteorites \u2013 fragments of larger meteors that survive atmospheric entry and reach Earth\u2019s surface.<\/p>\n

We now know that the debris streams which produce meteors are left behind by comets \u2013 and occasionally asteroids, such as the Geminid meteor shower<\/a> \u2013 during their passage through the inner Solar System.<\/span><\/p>\n

The ice that binds the rocky and dusty constituents of comets is heated by the Sun and turns to vapour, flowing outwards from the nucleus and carrying these grains with it.<\/span><\/p>\n

These grains create a trail of particles that follows approximately the orbit of the parent comet.<\/span><\/p>\n