Perseids Prominently Peaking

Yep, that time of year again. The Perseid meteor shower will peak early Tuesday morning, August 12th. The Perseids are one of the best meteor showers of the year (and the other one, the Geminids, are in December and most people think August nights are more comfortable to be outside than December nights!)

Meteors are best viewed under a dark sky away from the city, but brighter meteors do show up through city lights. They also are best viewed in the early morning before dawn. That's when Earth rotates and you are on the side plowing into all the meteors so you will see a lot more. This year, the Moon sets at about 1:18am in Racine, and that is just about the same time the rate will start picking up.

The best way to observe meteors in simply a nice lawn chair or blanket, lay down, and look up. These best place to look is near the constellation Perseus shown in the Sky and Telescope star map below.
The best bet is to find the familiar "w" of Cassiopea and look just slightly clockwise of it (imagine a big circle that passes through Cassiopea and the Big Dipper).

Simply lay back and look up. No telescope or even binoculars needed. Meteors move quickly and you don't know where the next one will appear, so you want to scan as much of the sky as you can. If you are lucky enough to catch a very bright meteor, you might see a smoke trail. If you see a smoke trail, then might be a good time to pick up the binoculars and watch the smoke trail disaapate.

Sometime people claim to hear hissing or crackling sounds associated with bright meteors. These sounds are not well understood. They cannot come directly from the meteor since sound travels so much faster than light, you would see the meteor and hear the sound later (just like you hear thunder after you see the lightning). An (unproven but plausible) idea is that the meteor gives off radio waves and some metal obect nearby is acting as an antenna and speaker, converting the radio waves to sound. Enough people have heard this phenomena, called electrophonic meteor sounds, that we are pretty sure you are not crazy if you hear one!

Meteor showers are usually associated with a comet. For the Perseids, it is comet Swift-Tuttle. When a comet nears the Sun, it heats up and lots of little bits break off. These little bits form the comets tail and they keep orbiting the Sun just like the comet does. Once a year, we pass the orbit of the comet and all these little bits (most the size of a grain of sand) are the meteors we see. Some meteor showers have a very narror debris area and Earth crosses them in a day or two. The Perseids are a very wide debris trail and it takes the Earth a couple of weeks to fully cross the debris trail. You will see qutie a few Perseids for the next several nights, but Tuesday morning is when we hit the most dense part of the debris trail.

The Perseids are not as much fun to watch down south. When I lived in Florida, warm humid nights and mosquitos dampened the fun. In Arizona we are in the rainy season now and the probability of clear weather is not that good (many observatories here shut down this time of year for annual maintenance.) That's why I like the Geminids in December...it's not too cold her and much better chances of clear weather. Still, I might go out here Tuesday morning if its clear (at least there aren't many mosquitos here!)