Don’t let summer go by without a night under the stars. I’m not just talking about taking a few minutes to look upward on a warm summer evening. I’m talking about an extended stay under a starry sky, preferably in the countryside away from city lights.
Maybe you want to actually sleep under the stars, but even if you just lie back on a lawn chair for a couple of hours, I know it will be an inspiring experience. Also, keep it simple. You don’t need any fancy telescopes with you, just your two eyes, maybe a cheap pair of binoculars, and some friends or family to share in a very special night.
This is the time of year to spend time under the stars, not only because of the warmer weather, but because the Milky Way cuts across the entire summer sky. Every single star you see in the sky is part of the stellar family called the Milky Way galaxy, but what I’m talking about is that band of milky light we see in the sky, especially in the summertime. This time of year, when it finally gets dark enough, you can see that ribbon of ghostly light running from the northern horizon to nearly the southern horizon, cutting right across the top of the sky near the overhead zenith. Unfortunately, you’ll have a hard time seeing the Milky Way band if you are viewing the sky from a brightly lit urban area, but outside the city where the skies are dark, you’ll have no problem.
Determining how many stars are in our home Milky Way galaxy is extremely difficult, although many astronomers think the number may be more than 500 billion. It’s also believed that the Milky Way is a spiral galaxy, shaped like a colossal pancake, with a larger hump of stars in the middle and other stars, such as our sun, arranged in spiral arms. The Milky Way spiral is thought to be about 100,000 light-years in diameter and a few thousand light-years thick, although much thicker in the central region. Remember, a light-year equals nearly six trillion miles, the distance light travels in one year. Think about that while you’re lying under the wonderful canopy of stars.
When we gaze at the Milky Way band bisecting the sky, we’re actually looking into the plane of our own galaxy. There are so many stars, so far away, that all we see is the collective glow when we see the band. If you carefully look along the Milky Way, you can also see that it varies in width and there are dark splotches and rifts within, like boulders in a celestial stream. The dark patches are clouds of hydrogen gas, the primordial material in of the universe, and in those clouds new stars are developing and being born.
There are so many things you can contemplate when you look up into the stars. The distance of the stars really blows my mind, like the fact that even the closest stars to Earth, excluding the sun, are a rough average of 100 light-years away. That’s just under 600 trillion miles. Also, because the stars are so far away it takes the light a heck of a long time to reach our eyes. Since a light-year is based on the speed of light, it takes the light from a star 100 light-years away an entire century just to get here. The light we see from a star that’s 3,000 light-years away left that star around the time David was king of Israel and the Phoenician alphabet was invented. Even more amazing is that a star 3,000 light-years away is not all that far, when you remember that our Milky Way galaxy is 100,000 light-years across.
Another thing that’s bound to cross your mind when you spend time under the stars is whether there’s other life out there. Are there people like us out there? I certainly have no idea, and I’m not sure if we’ll ever answer that question, but without a doubt one of the most exciting discoveries in astronomy in the last twenty years has been the detection of other planets orbiting other relatively nearby stars in our galaxy. So far, more than 240 extrasolar planets have been discovered, and I believe we have just scratched the surface of what’s out there in the way of planets. I have to believe that in our Milky Way, or in one of the other billions and billions of galaxies, that there are planets like our Earth orbiting stars like our sun. Maybe someone on one of those possible worlds is lying back on their lawn chair looking up at the stars and wondering the same thing!
Enjoy your night under the stars … You’ll love it.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the new book “Washington Starwatch,” available at bookstores and on his Web site, www.lynchandthestars.com.