Summer nights are not usually the best time for astronomy because the nights are shorter and the sky rarely gets totally dark. Fortunately, during the month of August, we are treated to one of the most reliable and spectacular meteor showers of the year.
The Perseid meteor shower is visible for a couple of weeks each August centered around 11th and 12th of the month and is a result of Earth crossing the orbit of Comet Swift-Tuttle.
Like all comets, Swift-Tuttle sheds bits of ice, dust and rock as it completes its relentless orbit around the sun. As the Earth orbits the sun at around 107,000 kilometers per hour (66,000 mph) it crosses the orbit, slamming into the debris that bombard us at around 60 kilometers per second (37 miles per second).
With each piece of rock that punches into our atmosphere we see a shooting star, or a meteor. The majority of the debris will burn up high in the atmosphere, but those that survive the fiery plunge to the surface are known as meteorites. It's a common misconception that the rocks get heated during the fall through the atmosphere but in reality it is the gas surrounding the rock that gets rapidly heated and glows brightly. We can see evidence of this in the bright meteor which leaves a trail of glowing gas behind it.
Catching a glimpse of meteors is a like trying to see lightening during a thunderstorm -- you never know when and where one will appear. The meteors making up the Perseid shower all come from a point (known as the radiant) in the constellation of Perseus.
The shower peaks at a specific point in time, estimated to be 10:00 UT (6:00 EDT/3:00 PDT) on 12 August and its at this time that the shower will peak with around 60 visible meteors per hour. Dark clear skies will be needed to see this level of activity, but unlike last year the light of the moon will not interfere with observation.
There is always a level of uncertainty around the time meteor showers will peak, so its best to keep an eye out on the nights either side. For most observers, the best time to look out is between midnight and dawn local time on Aug. 12 when you will be on the forward facing side of the Earth. Like a car driving through a swarm of flies, most will stick to the front; the back of the car will see very few and with meteors its the same. The forward face of Earth gets the best view.
The fabulous thing about meteor showers is that no equipment is required other than warm clothing and a comfortable chair. Binoculars and telescopes will be of no benefit as the trick is to simply get outside after midnight, get comfortable, sit back and watch (not in the direction of the radiant). If you're lucky and the conditions are right you might just catch a glimpse of one of our planet's most remarkable displays.