By David Ward
August is meteor shower month, and if the skies are still clear of smoke, it will be a great time to see lots of shooting stars. Last year’s show was spoiled by a large, bright moon that washed out the dark skies. This year the moon is out of the way and will not interfere with the show.
Most any night in mid August will produce more meteors than normal but the nights of Aug. 11-12 and 12-13 will probably be best. As always when looking for meteors, late at night is best, when we are peering into the direction in which the earth is traveling through space. I sometimes think of it as looking out the front windshield of a car. Driving through a snowstorm, are you going to see more snowflakes hit the rear window or the front?
The August meteors are called the Perseids because they appear to come from the constellation Perseus. Actually those stars are a zillion times farther away than the meteors, which are only 50 or 75 miles up. Most of the shooting stars we see are about the size of grape nut cereal kernels and are leftover debris from a comet that we run into every year in our journey around the sun.
These little bits of rocks are traveling fast, about 35 miles per second, and when they hit our atmosphere they heat up fast. What we see is an ionized column of super-heated air. The Perseids are also known for bolides, large fireballs with long glowing tails which sometime explode into several or more smaller pieces.
It does not take any special equipment or training to look for meteors. Just lay back in your favorite lounge chair with some bug spray and enjoy the show. While you are out there, there are plenty of other night sky sights to see.
Over in the east just after it gets dark, you cannot miss a very bright reddish, UFO-looking object. That is Mars, and we are closer to it than we have been for a while. To the right of Mars, dimmer Saturn glows with a yellowish color and bright Jupiter is farther right still. Just after sunset, brilliant Venus lights up the western sky.
Our cosmic home
August is a great time to take in the big picture out there, our home in the vast cosmos, the Milky Way Galaxy. The ancient Greeks thought it was breast milk of a goddess, hence its name, or a giant celestial river. On a dark moonless night, its dim glow can be seen traversing the sky from north to south going right over head. What you are looking at is a spiral arm composed of billions of suns. Down low in the south near Saturn, the center of the galaxy shines far, far beyond the ringed planet.
It is impossible for us to comprehend the size of our cosmic home. The closest part of it that we can see overhead is 6,000 light years distant. Want to translate that into miles? Multiply 6,000 times 6,000,000,000,000 and that may give you an idea of how far away from us it is. The whole thing, which is in the shape of a pinwheel, is 100,000 light years across.
Our sun was born here about 5 billion years ago and it is speeding across our home, tugging the earth along with it at 500,000 miles per hour. All the other stars we see in the sky are traveling along with us as in an immense merry-go-round. Why do we not notice the movement? The distance as are too vast and our lives are too short. It takes about 250 million years to make one spin around the galaxy. Have you ever sat with your child or grandchild on one of those merry-go-round horses that bobs up and down? We are actually doing that too, as we make our way around the galaxy. It takes millions of years to make one bob, but that is what is happening out there in the big picture.
Have fun out there looking at the very big and the very small. Does it all sound too confusing? Meet me up at Sun Mountain on the evening of Aug. 12 for the meteor shower and I will show you the planets through a telescope and explain it all to you. See you then!