Friday, August 13, 2010

Perseid Bombardment under way

Meteor streaks among the stars.

Recently the Earth has moved along in its orbit around the sun to encounter the orbital trail of debris left behind by comet Swift-Tuttle. As the small bits of rock and dust encounter the Earth's atmosphere, they heat up to an incandescent glow in a mere instant, leaving behind a trail of fading light for us to enjoy. Some particles are large enough to become "fireballs," a meteor that ends in a flash of explosion that is quite noticeable. These meteors in last night's showers are called the Perseids because they seem to come from the same point in the sky (the radiant), located in the constellation of Perseus.

We've actually been entering the area of the comet trail since about late July. The peak of the encounter would have been last night, so I managed to wake up at about 12:30 am and go outside for a gander. For the best view, you really need to get away from the city lights which cause the sky to brighten enough so that the faintest meteors will not be seen. I was a bit lazy, so I just set up a lawn chair on the driveway, adjusted it's position so I could face the constellations of Cassiopeia and Perseus, and moved it enough so a nearby tree would block the very annoying bright streetlight half a block away. To the east, Mt. Timpanogos blocked the horizon up to about 30 degrees. I could see a couple of cars or atv's working their way up the hillsides to reach a better viewing position, I supposed. It wouldn't help them, that position was still way too close to the city lights.

I could hear people's muffled voices eminating from several nearby backyards as my neighbors stayed out for the show as well. Every now and then cars would zoom up the streets. Evidently a lot of my neighbors don't come home till after midnight! It also got a bit chilly during my stay outdoors, as the drop from our daytime high to a nighttime low made it feel colder than it was. Fortunately, there were no annoying clouds of mosquitos or other disturbing bugs.

As time passed, I could easily notice the rotation of the Earth as the constellations slowly rose from the horizon into the eastern sky. Perseus was hidden at first by the top of Timpanogos, but gradually the top half rose above the mountain into a prominent position.

I didn't have to wait long. Within a couple minutes the first meteor flashed overhead as if on it's way to California. Because I couldn't see the dimmer meteors, it meant the ones I would see would be fairly bright (although some were dimmer to me, about half I think). After five minutes a very bright meteor streaked overhead and I knew the show had already started! While I kept count and checked my watch, I calculated my personal observation rate was about 20-30 per hour. Not bad for a city-light-polluted location. I noticed streaks in many different areas: to the north, to the southeast, from the north east, and overhead. Almost all seemed to have come from the same point in the sky. From my view it looked more as if they were radiating from the eastward edge of Cassiopeia, rather than Perseus.

I was very tired however, and knew I wouldn't stay up long. I called it quits after a medium-bright flash sighting about 1:30 am. I would have seen more meteors if I hadn't been distracted. You see, I also had my astronomy binoculars with me, and I couldn't help but also take the opportunity to view Jupiter with a couple of Moons showing, the Andromeda galaxy, the Double Cluster in Perseus, and various other star clusters and stars. What I found surprising was the lack of satellites. Normally I can spot traveling satellites about once every twenty minutes. Then I realized that at that time, we were well into the shadow of the Earth, and there would be no reflecting sunlight to reveal their locations!

Overall a very enjoyable experience and I'll plan better for the next one.

The bombardment of projectiles was spectacular but the Bunker remained safe. The enemy bomber Swift-Tuttle has laid these particulate mines for us to run into, but they are so small they can't penetrate our atmospheric shields. Oh, the occasional large one may smite the Earth, but no reports of damage or casualties have been heard. The danger is not over yet, though- we won't pass the minefield until about August 24th.

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