The night sky will light up with a brilliant display of shooting stars over the next few days, as the annual Lyrid meteor shower makes its appearance for 2015. Considered the oldest-known meteor shower, the Lyrids will peak on 22 and 23 April, with stargazers able to spot between 10 to 20 meteors per hour.
Typically the first good meteor shower of the year, the Lyrids are visible from most parts of the world, although the timing this year may favour Europe. According to the Slooh Community Observatory, which will host a live stream of the event on Wednesday, 22 April 2015, it is set to be a good year for the Lyrids because the moon will be a slender waxing crescent and will not obscure the view of the meteor shower.
What are the Lyrids?
The April Lyrids have been observed for the past 2,600 years. They are the strongest annual shower of meteors from debris of a long-period comet, mainly because as far as other intermediate long-period comets go (between 200 and 10,000 years), this one has a relatively short orbital period of about 415 years.
The source of the shower is particles of dust shed by the long-period comet Comet C/1861 G1 Thatcher. As the comet sheds debris, the fragments of rock and dust strike the Earth's upper atmosphere at around 110,000 miles per hour, vaporising the debris and creating streaks of light. Sometimes, Earth may pass through a thick clump of comet debris, meaning more meteors will be visible.
Lyrid "fireballs" are created when brighter meteors cast shadows for a split second, leaving behind smoky debris. The radiant of the shower is located in the constellation Lyra, near the brightest star of the constellation, Alpha Lyrae, or Vega. The Lyrids can appear anywhere in the sky.
Why do the shooting stars leave behind a glowing trail?
Shooting stars are not actually stars but fast-moving fragments of rock and debris left behind by a comet, and as the Earth moves around the sun, some of these pieces are pulled toward Earth by gravity. Around a quarter of the meteors produced during the shower will leave behind an ionised gas trail that glows for just a few seconds.
When a meteor enters Earth's atmosphere it is moving so fast that its atoms collide with air molecules and electrons are 'knocked' loose - creating free electrons and positively charged ions. As the shooting star passes, the negatively charged free electrons are attracted to the positively charged ions and combine with them. When this happens energy is released in the form of light, creating the glowing trail behind shooting stars.