Summer nights, by the beach or in a countryside cottage, sounds of nature, a starry sky, and a light streaking across the horizon, a shooting star. Did something fall?
Despite their name, shooting stars are not actually stars (although they do fall)! In reality, they are small rocks or grains of dust—usually smaller than a fingernail—that break off from passing comets and fall towards the Earth, known as meteoroids. As they collide with the atmosphere, due to their high speed, they interact with air molecules and heat up—this results in them glowing, or radiating light! Their friction with the atmosphere causes them to ignite, similar to when we pass our finger rapidly over the surface of a desk, for example, and feel a “burning” sensation. The same happens to these grains, and they ignite!
When Earth passes very close to the path of a comet, many “shooting stars” appear to come from the same area of the sky (which we call a radiant point), and then we have a meteor shower.
Some “shooting stars” have colors. What the naked eye usually manages to see is a white streak running across the sky, but many times, it will also see other colors.
That happens because of the elements contained in the meteor. Iron, one of the most common elements found in a meteor, makes them glow yellowish, and it is this element that is used in various fireworks to give them a golden color. Some copper salts give meteors a red color, while a greenish glow indicates traces of copper.
Meteor showers are named according to the constellation or bright star closest to their radiant point (the “source”). For example, the “falling stars” near the constellation Lyra are called the Lyrids.
We don’t only have shooting stars in the summer!
Some of the most well-known meteor showers include:
- Perseids (constellation of Perseus), peak on August 12th (> one meteor per minute!)
- Leonids (constellation of Leo), peak on November 17th (several dozen meteors per hour)
- Geminids (constellation of Gemini), peak on December 13-14 (100-120 per hour)
- Lyrids (between the constellations of Lyra and Hercules), peak on April 22-23 (5-20 per hour)
The true nature of meteors was not known until the 19th century. So, from ancient times, there were many stories, myths, legends, and traditions regarding meteors, with one of the most well-known saying that if someone makes a wish when they see a shooting star, it will come true.
Ptolemy (an ancient Greek mathematician and astronomer) believed that shooting stars appear when the gods peek through the celestial spheres to see what mortals are doing on Earth. On the other hand, the Aboriginal Australians believed that shooting stars carry the souls of the dead to paradise, while according to Islam, shooting stars are angels conveying an important message to Earth. Finally, according to Romanian tradition, each star is a candle, and each person has their own candle that goes out when they die.
Next time you find yourself under a bright sky, look up high, and perhaps you’ll see the shooting stars that connect worlds, gods, and humans, Earth and space. And make a wish!
Photos: Constantine Themelis, shooting stars at the observatory of Helmos, in Pelion, and in Norway. www.constantinethemelis.com
Helen Koutsona & Katerinovi Triantafyllaki