Pondering the Milky Way
By: Steve Roark
I hope each of you have had the opportunity to be in a really dark place on a clear night and caught a glimpse of a shimmering, sort of thin fog like band of light across the sky. This time of year it runs high overhead. It helps to let your eyes adjust to the dark before trying to see it, and any street lights or the moon ruin your chances.
What you are looking at is the edge-on view of your home galaxy. The stars of our galaxy form a broad, flat disk, in which the Sun and Earth are located about two thirds of the way out from the center. When we look into the disk, we see the combined glow of millions of stars, which make up the band of light called the Milky Way.
The number of stars in the Milky Way can only be estimated at best, but it could be as high as 300 billion. Discovering planets around other stars (over 2000 so far) have led to speculation that most stars have planets around them, upping the chances I suppose of there being other life out there looking at our star and wondering if there’s life on it. The bigness of Milky Way Galaxy is beyond comprehension. The book answer is that the disc is 100,000 light years across, and since a light year is roughly 6 trillion miles, let’s keep it simple and say it’s really big.
The Milky Way galaxy is rotating around its center, and at our location the disk is rotating at around 140 miles per second. In the time it takes you to finish this sentence, you will have been moved through space 750 miles. In the time it takes you to ponder that, you will have moved another 700 miles.
All of this pondering can make one feel pretty small. But rejoice in the fact that the Earth and all of its life forms are unique… in the galaxy at least. In the entire Universe is another matter. You see there are 60 known galaxies in existence for every human being on the planet, with each galaxy containing at least 100 billion stars each. So with those kind of numbers there may be planet out there with someone on it that looks just like you… only maybe with a green complexion….or maybe a third arm. Who knows?