Celebrate Earth Day With The Lyrid Meteor Shower

The peak of the annual Lyrid meteor shower occurs tomorrow morning (Sunday, April 22) between about 2 a.m. and dawn local time. The meteors will stream from the constellation Hercules near the bright star Vega in Lyra. Vega is the brightest star in the Summer Triangle and stands high in the southeastern sky before dawn. Stellarium

Want to get an early start on Earth Day celebrations? Set your alarm for 3 a.m. tomorrow morning and spend an hour watching the annual Lyrid meteor shower. I’ll be out there — as long as the forecast holds. The moon sets around 1 a.m., so you can begin watching any time after. The closer to dawn, the more meteors you’ll see.

The Lyrids are the first meteor shower to pummel the sky since the touch-and-go Quadrantids in early January. That seems like an eternity ago. While not a rich downpour like the Perseids in August or December’s Geminids, the Lyrids are ever reliable, spitballing 10-20 meteors an hour across the pre-dawn sky from a dark site.

Before constellation boundaries were set, the Lyrids were associated with Lyra the Harp, the origin of their name. But in 1930, when boundaries were standardized, the shower radiant suddenly found itself in neighboring Hercules. We should be calling them Herculids, but tradition rules.

During its revolution around the Sun, the Earth intersects the orbit of Comet Thatcher every year in late April. As our planet plows into bits of rock and dust sloughed off by the comet, the particles burn up in the atmosphere as meteors 50 to 75 miles (80 km to 120 km) high. Click here for an interactive animation. Meteor data from Peter Jenniskens, visualization by Ian Webster

Like most meteor showers, the Lyrids originate from a particular comet with which it shares its orbit, in this case Comet Thatcher, discovered by amateur astronomer A. E. Thatcher on April 6, 1861. Thatcher — the comet not the man — orbits the sun every 415 years. When closest, solar heating vaporizes some of the comet’s dust-and-pebble-impregnated ice, sending the debris into space to form a tail. After many such passes, the material spreads out to pepper Thatcher’s orbit like a kid leaving a trail of dirt crumbs on the floor after playing outside. Each year in late April, Earth slams headlong into the comet debris. Bits of dust and rock flare into streaks of light when they strike the atmosphere at 46 kilometers a second (102,600 mph). One after another they arrive, emanating from a spot in the sky called the radiant.

Meteors appear to radiate from a point in the distance the same way snow striking your car windshield does when driving at night. Even though the snowflakes and meteors are generally parallel to each other, our eyes see them as converging in the distance. A similar illusion happens when looking down railroad tracks. Bob King

The radiant is a perspective effect caused by incoming meteoroids from Comet Thatcher arriving at Earth on parallel paths. Something similar happens when you drive through a heavy rain or snowstorm at night. Flakes and drops in the car’s headlights appear to stream in parallel from a point in the distance. Essentially, Earth’s a car driving into a cometary dust storm. Watching a meteor shower is one way to directly experience our planet orbiting the sun.

A Lyrid fireball over Ozark, Ark. against a Milky Way backdrop photographed in 2012 at the shower’s peak. Vega is at top. Click photo to visit Brian’s website for more photos.  Brian Emfinger

Meteor-shower-watching requires only the fortitude to get up for an hour or two in the middle of the night and a reclining chair. Since you’ll be lying still and April dawns can be chilly, dress as if it’s January: bomber hat, lined books, gloves and down coat. I grab a wool blanket or sleeping bag, crack open my squeaky recliner and get cozy under a blanket. The rest is pure relaxation. Night meditation. Simply lie back and wait for the meteors to come while soaking up the cosmic view.

The darker the sky, the more meteors you’ll see. Since most of us put up with some amount of light pollution, 10-12 Lyrids an hour might be a better estimate of how many you’ll see. In addition to shower members, you’ll notice sporadics. These are random meteors not associated with the Lyrids that appear at the rate of about 5-7 per hour. Lyrids can appear anywhere in the sky, but they all point back to the radiant; sporadics come from any direction.

NASA used an all-sky camera to photograph multiple Lyrids during the 2014 shower, composited into this single photo.  NASA

You may want to make an informal count during the night to keep track of how many you see. I do. And be prepared for times when not a single meteor shows for 5 minutes or longer. With smaller showers like the Lyrids, patience is a virtue. If you’d like go a step further and contribute to better understanding the shower’s long-term evolution,  register for free with the International Meteor Organization, then download a report form here.

To sum up:

* Set your clock for 2 or 3 a.m. Sunday morning and spend at least an hour watching.
* Dress warmly and observe from a comfortable chair.
* Face away from glaring electric lights to allow your eyes to adapt to the dark. You can look in any direction, but facing south or east allows you to see both the
“shorty” meteors near the radiant and longer ones that flash farther away from it.
* Keep your expectations low. The Lyrids have occasional outbursts when quadruple the normal number of meteors are seen, but the next flare-up isn’t expected until 2040.

Clear skies! If we’re lucky, maybe the aurora will return. Watching the shower on Earth Day reminds us that our planet is a full participant in the affairs of the solar system.

2 Responses

  1. Tomorrow, April 22nd marks the 6th anniversary since the 2012 Sutter’s Mill, California meteorites fall following a daytime fireball over northern Nevada

    1. astrobob

      BC,

      Thanks for the reminder. It was a unique meteorite – a type of carbonaceous chondrite. Even today, Sutter’s Mill has yet to be specifically classified: it’s only known as “C” for carbonaceous. A bit unusual for sure.

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