Return of the Lyrids
The waxing moon makes predawn skies your best bet for this annual meteor shower
The moon is at first-quarter phase Thursday the 18th. Even with only half its face illuminated, the moon washes out the stars of amid the constellation Cancer the crab, in which it rests that night. But if you look beyond the moon, you will see that it is juxtaposed between a triangle of three more or less equally bright stars: Procyon to the west, Regulus to the east and Pollux to the north.
Friday evening the moon is to the right of Regulus, and by Saturday it is just a few degrees below Leo the lion’s heart. One of the great constellations of the zodiac, Leo travels along the same apparent path as the sun, moon and planets and is one of the constellations that actually looks like its namesake. While Regulus marks the constellation’s heart, it appears like the dot at the bottom of a mirror-image question mark. Called the Sickle of Leo, this grouping of stars makes up the lion’s mane and face.
The waxing gibbous moon unfortunately interferes with this year’s annual Lyrid meteor shower. While modest in the number of meteors each hour, the Lyrids have staying power, lasting from April 16 to 25. The shower peaks in the late hours Sunday until dawn Monday, with 10 to 20 meteors an hour, many leaving bright trails that last several seconds.
Each year at this time, earth passes through a trail of interstellar debris left from the passing of Comet Thatcher. Like all comets, Thatcher orbits the sun, in this case every 415 years or so, each time shedding some of its mass in the warmth of the inner solar system. As earth passes through this debris, the tiny bits of ice and rock ignite upon impact with our atmosphere 70 miles high. The Lyrids were first recorded in ancient China nearly 3,000 years ago, but their parent comet was discovered only in 1861, Thatcher’s last close approach to sun and earth.