Earth is treating its inhabitants to quite a show for Earth Month. There was an April Fool's comet, an opposition of Jupiter and an asteroid flyby, and now comes the 2017 Lyrid meteor shower. The annual fireball show is already underway, and is expected to continue for about a week — with the peak arriving on Earth Day, April 22.
The Lyrids appear each year from about April 16 to 25, according to NASA, but activity is low until the peak night, so the 2017 show has just begun. This year's peak should begin late on April 21, and continue through the predawn hours of April 22. The true peak is forecast to hit about 17:00 UTC on Earth Day itself, but that's 1 p.m. EDT, so skies above the Americas will already be far too sunny by then.
Still, since the 2017 shower falls near the new moon (April 26), NASA says to "expect excellent, almost moonless viewing conditions" before dawn. The Lyrids normally produce about 15 meteors per hour during their peak, according to the American Meteor Society (AMS), and NASA says dark skies could raise this year's rate to 18.
And while this humble April shower isn't known for downpours like August's Perseids or November's Leonids, it has gone torrential a few times in recent centuries. As MNN's Michael D'Estries points out, up to 100 Lyrids per hour were reported in both 1982 and 1922, and the 1803 shower brought an amazing 700 per hour.
The Lyrids seem to radiate from the constellation Lyra the Harp, near the star Vega. (Photo: Islam Hassan/Flickr)
The Lyrids are named after the constellation Lyra, because that arrangement of stars — including Vega — marks the place in the sky where these meteors seem to originate, at least from our earthbound perspective. But Lyra is just a convenient reference point and namesake; Vega is 25 light-years away, for example, while meteors sizzle in our atmosphere only 60 miles above the surface.
The true source of the Lyrids is Comet Thatcher, a long-period comet that last visited the inner solar system in 1861. Earth passes through its orbital path every April, crashing into a cloud of comet debris left behind more than 150 years ago. As that rubble strikes Earth's upper atmosphere at 110,000 miles per hour, it vaporizes into visible streaks of light. Thatcher, meanwhile, is far away in its 415-year orbit around the sun, and won't return to our neck of the woods until 2276.
NASA astronaut Don Pettit caught this Lyrid in 2012 from the International Space Station, with city lights and thunderstorms illuminating Cuba, Florida and the Southeastern U.S. in the background. (Photo: Don Pettit/JSC/NASA)
Despite NASA's encouragement about viewing conditions, the waning crescent moon "will still be bright enough to be a nuisance," according to the AMS. Viewers in the Northern Hemisphere can boost their chances of seeing a Lyrid by fleeing urban areas, avoiding bright lights and being patient. The odds also improve as Lyra moves higher in the sky, which is why the best views occur around and after midnight.
The Lyrids are fairly fast meteors, unlike December's Geminids, but they tend to be bright. About a quarter also create glowing trails of ionized gas known as persistent trains, assisting skywatchers by leaving an ephemeral trace of their trajectory.
For more about the Lyrids, check out the infographic below, made in 2014 by the Giant Magellan Telescope Organization to promote the giant telescope it's building in Chile. Aside from the date and moon phase listed at top, the info is still up to date:
Editor's Note: This article has been updated since it was originally published in April 2014.