August 11 – Pretty But Deadly

Today’s factismal: Meteor showers are named after the constellation that they appear to come from.

If you go outside tonight or tomorrow night, you’ll be treated to not one but two astronomical amazements. The first is the sight of the Saturn and Mars lying less than a hand’s breath away from the Moon in the sky; if you go out just after sunset you’ll also be able to see Jupiter, Mercury, and Venus down low in the west. And beautiful as that set of planets is, it won’t be the most amazingly beautiful thing in the sky. That’s because tonight and tomorrow are the peak of the annual Perseid meteor shower.

Tonight's astronomical wonder (Image courtesy NASA)

One of tonight’s astronomical wonders
(Image courtesy NASA)

The Perseids happen when the Earth crosses the path of the comet Swift-Tuttle every year. Like a car getting hit by gravel flung off of the truck ahead, the Earth runs into the bits of dust and rock thrown off by Swift-Tuttle on its 130 year long journey around the Sun. The comet last passed by the Earth in 1992 (we’ll see it again in 2026) and left lots and lots of junk on our cosmic road. When that a piece of that junk hits the windscreen that is the Earth’s atmosphere, it heats up and forms the long, glowing trail that we call a “shooting star”. Thanks to the recent close encounter, we expect to see up to 200 meteors each hour in darker places. But even if you live in the city, you can expect to see some of the brighter meteors.

A meteor shower radiating (Image courtesy NASA)

A meteor shower “radiating”
(Image courtesy NASA)

To catch the light show, just go outside and look up. If you’d like a better chance at catching the falling stars, turn to the northeast at about 10 PM. Using your fist at arm’s length, count up two fists. That puts you right in the middle of the constellation of Perseus; if you hit the “W” of Cassiopeia, you are too high. And now just watch. The meteors will appear to radiate out of the center of Perseus which is why they are called the  Perseids.

Where to look tonight and tomorrow night (Image courtesy NASA)

Where to look tonight and tomorrow night
(Image courtesy NASA)

And meteors are more than just pretty; they can tell us a lot about comets and planets. And you can help! If you download NASA’s Meteor Counter App (available for iPad, iPhone, and iWannaMeteor), then you’ll be able to send NASA scientists valuable information on the number of meteors that hit during the shower. They’ll then use that information to help us understand how likely it is that we’ll get hit. To learn more, go to NASA’s web site:
http://science.nasa.gov/science-news/science-at-nasa/2011/13dec_meteorcounter/

One thought on “August 11 – Pretty But Deadly

  1. Pingback: December 31 – Hairy Situation | Little facts about science

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