The Lyrid meteors are coming to skies near you, just in time to celebrate Mother Earth. This year, conditions are about at their best for a decent show. With a faint crescent moon not even peeking above the horizon until around 4 a.m., the night sky will be about as dark as it can get—especially if one is away from city lights.
“All in all the Lyrid meteor shower prospects look pretty good for 2017,” trumpets Earthsky.org, “though meteor showers are notorious for their fickle and not totally predictable nature!”
In a good year, says Astronomy magazine, up to 20 shooting stars may be visible hourly, about one every three minutes. A few showers have unexpectedly burst forth into 100 per hour—for instance, in the U.S. in 1982, Greece in 1922 and Japan in 1945, according to Earthsky.org—but that is not expected this year.
Remnants of Comet Thatcher (C/1861 G1), which orbits the sun every 415 years, cross Earth’s path every year at this time. When Earth intersects the comet's path in late April, “meteoric fireworks result,” as Sky and Telescope puts it.
Though they may look fierce, the meteors are nothing more than granules the size of Grape-nuts cereal, Sky and Telescope reports. Hitting the atmosphere at 30 miles per second, or 108,000 mph, changes everything.
“An encounter with our atmosphere at that speed vaporizes the comet fragment,” says Sky and Telescope. “As the particle crashes through the air, it leaves a linear trail of excited and ionized air molecules. A moment later, when each molecule returns to its ‘relaxed’ state, it releases a photon of light. The combined emission of billions of photons creates the temporary bright streak we call a meteor. If the streaks continue to glow for several seconds or longer, they're referred to as meteor trains.”
About 25 percent of Lyrid meteors leave these “persistent trains,” as Earthsky.org calls them. There have even known to be fireballs.
The Lyrids can be seen radiating from the southeast or south, because they appear to emerge from the constellation Lyra the Harp. The best viewing times are between 2 a.m. and dawn.
Assuming you're out when the radiant is high in the sky, face southeast or south, although truth be told, any direction will do. Vega, the bright star that’s the cornerstone of Lyra, is not the source of the meteors, though to our eye it looks that way. However, knowing the rising time of the radiant point gives a ballpark of what time it’s best to catch the show, as Earthsky.org notes. It’s not necessary to know the radiant point in order to make a wish on a shooting star.
“The idea that you must recognize a meteor shower’s radiant point in order to see any meteors is completely false,” says Earthsky.org. “Any meteors visible the sky often appear unexpectedly, in any and all parts of the sky.”