Sat April 21, 2012
Lights Off, Eyes Open: New Moon Darkens Skies For Meteor Shower
Originally published on Sat April 21, 2012 8:46 am
Tonight is a good night for a meteor shower. The Lyrids aren't known for their flashy shows, but this year they're getting help from a new moon.
The dark skies will be "ideal for meteor watching from the ground," NASA says.
Kelly Beatty, senior contributing editor for Sky and Telescope magazine, tells Weekend Edition host Scott Simon the best views are from the darkest places.
"For every bright [meteor] you see, there will be many more faint ones, and to see the faint ones, you need a dark sky," he says.
The relatively feeble light of a new moon will help hopeful meteor-watchers across the continent.
The frequency of the shower is unpredictable, Beatty says:
"Although ordinarily you might see one every five minutes or so, it's not unprecedented to see ... 40 or 50 an hour."
According to a Chinese chronicle, in 687 B.C. Lyrid meteors "dropped down like rain," Sky and Telescope reports.
The height of the shower is expected at about 1 or 2 a.m. EDT, according to the magazine. If you're standing outside, Beatty says the key is to turn your gaze to where it's darkest.
"But if you trace them back, they'll all appear to come from the constellation Lyra, which is rising over the eastern horizon in late evening ... and as Lyra gets higher up in the sky, the meteors should become a little bit more plentiful."
Astronomy Magazine suggests looking straight overhead and letting your eyes wander. Don't stare directly at the meteors' origin, it reports:
"All other things being equal, the farther away from the [point of origin] a meteor streaks, the longer its trail will be."
If you're not up for standing outside in the middle of the night, NASA will have a live video feed embedded on its site, along with a Web chat with three NASA meteor experts from 11 p.m. to 5 a.m.
During the chat, NASA says, they will cross-compare images from meteor cameras on the ground with images from a video camera attached to a rubber balloon, equipped with a GPS tracking system.
NASA says the hope for the flying camera, which will be launched by middle- and high-schoolers in Bishop, Calif., is to record meteors "from a vantage point well above the clouds."
"While not expected, the team hopes for the good luck to capture both a balloon-cam view and an meteor camera view of the same meteor, providing an unique perspective."
After about 2.5 hours, NASA says the balloon is expected to rise high enough that the atmospheric pressure will pop it, releasing a parachute that will float the camera back to Earth.
For those of you who need to brush up on your astronomy, Beatty has a reminder about what you're looking at when you see those streaks of light:
"There's a comet called Thatcher, which last came through this region of the solar system in 1861, and it's in an orbit that lasts more than 300 years. As it goes around, it spreads out debris, kind of like dust coming off of a truck, and it spreads around its orbit, and every April we plow through those little dust particles."
Those bits of dust are traveling fast, Beatty says, hitting the atmosphere at about 30 miles per second. They transfer all that energy to the air molecules around them.
"They get heated up to thousands of degrees, and that's that super hot air that gives off the light, more than the little particle itself," he says.
All meteor showers, Beatty says, are the result of Earth crossing the path of various comets.
The next shower to mark on your calendar is on May 5, according to a schedule of 2012 showers from Sky and Telescope.
That shower will be brought to you by the better-known Halley's Comet, although a full moon accompanies it this year.
SCOTT SIMON, HOST:
People have been observing the Lyrid meteor shower for more than 2,000 years. And tonight, watchers in North America will get their best chance when it peaks. While not as spectacular as the Perseid and some other meteor displays, the Lyrid can surprise you with its intensity. Joining us to help handicap this year's event is Kelly Beatty, senior contributing editor for Sky and Telescope magazine. He's at member station WBUR in Boston.
Thanks so much for being with us.
KELLY BEATTY: Oh, my pleasure, Scott.
SIMON: So this could be a good season for the Lyrid shower?
BEATTY: It can. The Lyrids, while not really strong, will benefit this year from the fact that the bright moon won't be in the sky and the skies will be nice and dark. And, you know, it's an unpredictable shower. Although ordinarily you might see one every five minutes or so, it's not unprecedented to see one, you know, 40 or 50 an hour.
SIMON: And where's the best view?
BEATTY: The best view is wherever you can get to where it's dark. For every bright one you see, there will be many more faint ones. And to see the faint ones you need a dark sky.
SIMON: The sky's a pretty big place. Where should we turn our head?
BEATTY: Well, the funny thing is that you can see these meteors in any part of the sky that's darkest for you. But if you trace them back, they'll all appear to come from the constellation Lyra, which is rising over the eastern horizon in late evening. And as Lyra gets higher up in the sky the meteors should be become a little bit more plentiful. So the best bet is actually to get up before dawn on Sunday morning and that's when they should be maximized.
SIMON: Could you remind us, what are we actually seeing when we see a meteor shower?
BEATTY: There's a comet called Thatcher, which last came through this region of the solar system in 1861. And it's in an orbit that lasts more than 300 years. As it goes around, it spreads out debris, kind of like dust coming off of a truck. And it spreads around its orbit and every April we plow through those little dust particles.
They flash in our atmosphere maybe 60 or 80 miles up and each one of those creates a little meteor when it goes through the atmosphere. So when these little particles hit the atmosphere they're traveling at 30 miles per second. And all of that energy gets transferred to the air molecules around them. They get heated up to thousands of degrees and it's that super hot air that gives off the light more than the little particle itself.
SIMON: Boy. Is there a next meteor shower to look forward to?
BEATTY: There are about eight or ten meteor showers every year that we can count on. All of these are places where Earth is passing through the path of a comet - one comet or another. Some meteor showers are from Halley's Comet. Others are from comets that no one's ever heard of, like the Perseus, but they are nonetheless very spectacular.
SIMON: Kelly Beatty, senior contributing editor for Sky and Telescope magazine. Thanks so much and good meteor shower watching to you, sir.
BEATTY: And to you, too, Scott. Thank you.
SIMON: This is NPR News. Transcript provided by NPR, Copyright National Public Radio.