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Is a falling star really a star?
No, it’s not. In fact, it’s way too small to be a star. A falling star, also known as a shooting star, is just the colloquial term used to describe the visible trajectory of a meteoroid. In scientific circles, this visible path or trajectory is called a meteor.
Meteoroids are much smaller than their giant cousins, the asteroids. Although their diameters can go as high as 10 m, most meteoroids are only as small as dust particles or sand grains. The really small meteoroids are aptly called micrometeoroids. Most of these tiny particles weigh less than a gram.
These dimensions are very small that, when a typical shooting star enters the atmosphere, the atmospheric ram pressure allows the shooting star to glow. This glow can last for about a second – just enough time for you to observe the streak across the sky … and to wish upon it if you care to.
During some nights, shooting stars or meteors can appear at intervals from as high as a few minutes to as low as a few seconds. This phenomena is called a meteor shower, which occurs when the Earth comes across a stream of debris in the trail of a comet. When the debris, which are small enough to undergo disintegration, enter the atmosphere, they ignite – which we then observe as streaks of light.
Some of the popular meteor showers are the Quadrantids of January, Lyrids of April, Arietids of June, Perseids of August, Orionids of October, Leonids of November, and Ursids of December. Perseids, the most visible of them all, can treat observers to a torrential shower of shooting stars. During its peak every August 12, an observer may spot at least one shooting star per minute.
If, by some stroke of luck, you haven’t seen an actual shooting star, you can try going out (assuming the night sky is clear, of course) on the night of August 12. Although they’re best seen in the northern hemisphere, you can catch them practically from anywhere on the surface of the Earth.
Shooting stars will be so prominent on that night, that you won’t need a telescope to see them. Actually, it’s easier to spot them without a telescope.
Now that you know what a shooting star really is, you can breathe easy the next time you see one knowing that, most likely, they can be no larger than yourself.
Allow us to share previous announcements here at Universe Today regarding the Perseid Meteor Shower:
2009 Perseid Meteor Shower – Double Peaks This Year!
Perseid Radio Astronomy from the Fourth Plinth With Chris Lintott
From NASA, there’s a very recently published article entitled: The Perseids are coming. Another informative article, published in 2007 and titled: Great Perseids, can also be found there.
Astronomy Cast has the following related episodes:
Meteor Showers. Yes, the sky is falling.
Getting Started in Amateur Astronomy
Source: NASA
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