Monday, August 12, 2013

Perseids Meteor Shower

Monday, August 12, 2013
3:33 P.M.

Hello! I know many of you are waiting for a blog about our thunderstorms and all that wonderful stuff over the weekend. I've send out requests to certain photographers to use their pictures on my blog, and I've also sent out emails to some of the top meteorological minds around the area to learn more about this setup and why it happened.

Until then, we've got a meteor shower to go through. The following pictures should give the reader a rough idea of what I'm talking about.

Photo Credit: Dante Alighieri
Photo Credit: DO'Neil

On the left is the Willamette Meteorite at the American Museum of Natural History in New York City. On the right is a shower in a bathtub. Put these two together, and voila!: You've got a meteor shower.

Ok, so it's not quite that simple. Even if the plumbing throughout a region could allow meteorites to be used as showering material, I doubt one would actually want to take a shower in them. At the very least, these rocks could annoy you, and in extreme cases, such as the meteorite above, they could crush you. Meteor showers occur when meteoroids that have broken off from comets or asteroids enter the Earth's atmosphere at an angle roughly parallel to the surface of Earth. Most of these meteoroids can only be seen with a microscope, and they disintegrate completely as they encounter friction and ram pressure in the Earth's atmosphere, leaving donkeys, dolphins, dinoflagellates, and all of Earth's wonderful creatures intact. Of course, there is the occasional exception... search "Chicxulub" and you'll learn what I am talking about. 

Before we go any further, let's define the three similar-sounding terms I've thrown at you. Meteors, meteorites, and meteoroids are not the same thing.

Meteoroids: Most of us know what an asteroid is. According to Merriam-Webster, it is a rock going through space that you hope doesn't enter the Earth's atmosphere. In all seriousness, an asteroid is essentially a small planet. It does not have an icy core, and most of them are not spherical, though there are some exceptions. Ceres, the first and largest asteroid ever found, looks nearly spherical. Vesta, the second most massive asteroid, isn't quite as spherical, but it is the brightest asteroid in the solar system and the one we have been able to get the best photographs of.

1 Ceres. Photo Credit: NASA

4 Vespa. Photo credit: NASA

Meteoroids are basically smaller versions of asteroids. They are usually parts of asteroids or comets that have broken off, and but some can be fragments of planets that have been ejected into space by a bolide impact. On average, 33 million pounds of meteoroid matter enters Earth's atmosphere every year, so we are being bombarded by them all year long... some times more than others.

Meteors: Meteors are simply the flashes of light you see when a meteoroid enters Earth's atmosphere. As I said before, friction and ram pressure cause these meteoroids to disintegrate, and as they do so, they create these "shooting stars" that dart through the atmosphere for a second or so.

Meteorites: Meteorites are meteoroids that have survived the fall through Earth's atmosphere and have actually landed on the planet. I was curious to see if anybody got struck by a meteoroid (that was just billionths of a second before coming a meteorite), so I Googled it and found that it has actually happened. got struck by a meteoroid (that was just billionths of a second before coming a meteorite), so I Googled it and found that it has actually happened. Several people have been hit, but the most well-known one is the Sylacauga meteorite, which hit Ann Hodges on November 30, 1952. A grapefruit-sized fragment of the meteoroid smashed through her roof and hit her while she was sleeping. She survived - I have no idea how.

I'm not writing about these near-death-experiences just for kicks. Every year, Earth passes through a large cloud of meteoroids known as the Perseid Cloud. These meteoroids are from particles that have been ejected from comet Swift-Tuttle, a relatively short-period comet that orbits the sun every 133 years. Every year, Earth passes through this cloud. Perseid meteors streak across the sky from mid-July until late August, but they peak in early-to-mid August. Right now we are in the middle of this particular shower, but us Pacific Northwesterners have not been able to see the show because we've had a much more dramatic lightening show over our heads for the past couple of days. We should be able to get some great views tonight as skies will be clear.

2010 Perseid meteor over ESO’s Paranal Observatory in Chile. Photo Credit: ESO

The meteors will peak between midnight and 4 a.m. tomorrow morning with approximately 60 meteors per hour. Enjoy the show!


No comments:

Post a Comment