By David Ward
August is the month for celestial fireworks and we do not even have to worry about the pyrotechnics lighting any fires. At almost mid-month, simply look up for a show emanating from the heavens above, the Old Faithful of shooting stars, the Perseid meteor shower.
They are not really actual stars flying across the sky, of course, but shooting sand would be a more accurate description. Every August, the Earth’s path around the sun takes us through a debris field in space left over from a comet known as Swift Tuttle. All other astronomical phenomenon we see are big and far away. Their distances from us are so vast that zeros in their numbers run half way across the page. Their mammoth sizes make us feel like insignificant mosquitoes buzzing around on a summer evening.
Here is your chance to be dazzled by something that is very small and quite close to us. So what is all the fuss about mere sand? It is fast sand and it is slamming into our upper atmosphere at 70 times the speed of a bullet shot out of a high-powered rifle. When these sand grains encounter the first few molecules of air 100 miles or so up, they heat up instantly. Their high temperature ionizes a column of air and that is what we actually see streaking across the sky.
Starting in early August, you can start to see some of the meteors in the sky, but the nights of Aug. 11 and 12 will probably be the best. If at first you do not see much, try a little later. There are often smaller peaks and bursts in the show from time to time.
The best time of night to view these meteors is after midnight and just before dawn. Think about driving your car down a road in January during a snowstorm. More snowflakes hit the front windshield than the rear, right? So imagined our Earth is a giant car flying along at over 66,000 miles an hour. Early in the evening the Perseid meteors are hitting our rear window, but later the Earth has turned on its axis enough so they start hitting the front windshield and we see more.
The reason it is called the Perseid shower is because it appears to be coming out of the constellation Perseus, right near the famous double cluster in Perseus. While you are out there looking for meteors, see if you can find this little gem of stars between the constellations Cassiopeia and Perseus. Early in the evening it can be found low in the northeast but later the rotation of the Earth will carry it higher into the sky. The stars of Perseus are much farther away than the meteors themselves, and I will not bore you with zeros spreading across the page. At least not yet anyway.
To see the shooting stars, you don’t need binoculars or a telescope, just your eyes and some mosquito repellant. So have fun out there and enjoy the show.
Our neighborhood
Humankind has looked at the Milky Way as long as we have been able to crane our necks up to gaze at the sky. It has been called the backbone of the night. Ancient Greeks thought it was breast milk spilled across the heavens from the goddess Hera. Many cultures saw it as a giant celestial river flowing above. The philosopher Aristotle tried to give it a more scientific explanation. He thought it was gases from burning stars in the upper atmosphere of the Earth. Galileo was the first to point a telescope at it and he saw a multitude of otherwise unseen stars burst into view.
You too can see this amazing sight that people have looked at in wonder for thousands of years and the month of August is the time when it glows in all its glory. Most of the world cannot see it because of light pollution, but here in the Methow Valley with our dark night skies, we are the lucky ones.
Turn off your porch light and go out after it really gets dark. Fortunately, August nights are a little longer than June ones. A night with no moon is best, like the nights of the meteor shower. Look for a pale band of glowing light stretching across the sky from north to south arching up almost overhead.
It has only been quite recently that our advancing technology has enabled us to truly grasp what is up there — a vast system of hundreds of billions of stars of which our sun is just one. Imagine a giant pinwheel with two spiral arms wrapping out from the center tilted up at a crazy angle into the sky. The band of light overhead is one of the arms, the Perseus Arm, named for the same constellation as the meteors. Down in the south we can see the central hub of the pinwheel in the constellation Sagittarius. In winter when we look out in the other direction into the universe, we can see that other spiral arm but it is farther away and dimmer. Our sun resides between those two arms in a smaller structure of stars known as the Orion Spur. I know it is disappointing to learn we live on a spur, but actually it is a cool place to be with a great view of the big picture.
The Milky Way Galaxy is the name we have given to this vast collection of suns, our home in the vast cosmos. Home is huge, bigger than we can possibly imagine. In fact that band of light up there is the second-biggest thing in the universe that we can see with the naked eye.
The New Horizon spacecraft snooping around Pluto is so far away that it has taken almost 10 years to get there, and a radio signal traveling at the speed of light requires four-and-a-half hours to reach us back here on Earth. If you have not had a chance to see some of the pictures of Pluto, be sure to do so. They are awesome! If that piano-sized spacecraft were on the other side of the Milky Way Galaxy, a radio signal from it would take over 100,000 years to reach us. Now that is big!
If you look low in the west just after sunset in early August, you might catch a last glimpse of Jupiter and Venus, those two bright planets that have lit up our nights for months. By the middle of the month, they will have ridden off into the sunset. Look for them to return in the east just before dawn in September. Saturn is easy to spot in the south just above and to the right of the reddish star Antares.
I will be up at Sun Mountain Lodge on the night of Aug. 11 for the meteor shower. If the skies are not smoky, we should be able to see everything I have talked about and more.
You may have noticed that I mentioned that the Milky Way Galaxy is the second-biggest thing in the universe we can see with the naked eye. Check out this column in the fall to find how you can see the biggest.
