Poets talk about falling stars; astronomers talk about meteors. They’re the same thing, but the phenomenon resonates differently for scientists and regular people. For many of us, pretty much the most exciting thing about watching the night sky is catching sight of a falling or shooting star.
But What Is It Really?
A falling or shooting star is the visible path of a meteoroid (or debris from combusting meteoroids of any size) entering the Earth’s atmosphere. Upon entry it is referred to as a meteor; if it hits the Earth intact it is referred to as a meteorite. The bright light that even dust-sized falling stars emit as they heat up and disintegrate during their journey through the atmosphere can make them appear to be much larger than they are. If an actual star were ever to fall to earth, the planet would be instantly obliterated. Real stars (such as Earth’s sun) are enormous.
On a normal night, depending on location and the level of light pollution, most stargazers can expect to see a falling or shooting star every 20 minutes or so. They appear abruptly and arc briefly across the dome of the night sky. During a meteor shower, when meteors, debris and dust move in a cluster, the sky can seem full of falling or shooting stars.
A Brief History
People have always been excited, and often scared, by this celestial phenomenon. Ancient Greek philosophers such as Aristotle posited theories (incorrectly as it turned out) about what caused stars to fall and blaze so brightly, and historians and writers the world over have tracked and described these events — long before astronomy was even considered a science.
Arab historical accounts refer to the year of 902 AD as the Year of the Stars. At this time the Leonid meteors (the Leonids are a spectacular meteor shower event that occurs every 30 years or so) were especially active over Northern Africa and the Mediterranean.
In 1833, another Leonids event occurred over much of eastern North America, sparking renewed interest, both public and scientific, in falling stars and meteor showers. American astronomer Denison Olmstead correctly noted that the falling stars seemed to originate from the same part of the sky (which he called the radiant) and that gravity played a part in their fall. His work, which included many first hand accounts from non-scientists, ushered in a new era of observation and scientific research.
How to See Falling Stars Clearly
Some shooting stars can be seen as part of a seasonal phenomenon. The Perseid meteor shower, for example, derives from the debris stream of the periodic comet Swift-Tuttle, which takes 133 years to orbit the Earth. The Perseids appear in the skies across the Northern Hemisphere late each summer, and have since the mid-1800s. At the peak of this annual event, up to 60 falling stars can be seen between midnight and dawn, depending on light conditions. Generally, the less ambient light from homes or structures, or the moon, the better the chances of spotting a falling star. Some countries are establishing Dark Sky Preserves, to help amateur astronomers get the best possible falling star experience.
Whether we call them stars or simple comet debris, falling or shooting, the phenomenon triggers a special visual experience for children and adults around the world. So much so that a sweet ritual usually accompanies the sighting of a falling star. While in ancient Greece shooting or falling stars were believed to mark the passage of souls, in many modern societies the tradition is to make a wish when you see one.