Galaxy hurtles toward Andromeda
Tonight, in the high eastern sky, you can see something that's truly out of this world. In fact, it's the farthest thing you can see with the naked eye — the Andromeda Galaxy.
It's a strain to see, though. It's easily camouflaged in areas with city lights. You really have to be in the countryside with a pitch-black sky on a moonless night to spot it. Look for a faint, misty patch of light just above the constellation Andromeda. Binoculars or a small telescope will really bring it in.
Our nearest next-door galaxy is about 2.5 million light-years away. Now if you're new to this column, a light-year is defined as the distance that light travels in one year.
The speed of light is about 186,300 miles a second and so one light-year would equal about 5,800,000,000,000 miles. If you do the math, that would put the Andromeda Galaxy 2.5 x 5.8 trillion miles away!
Remember the Apollo spacecraft that would take about three days to get to the moon and back in the late 1960s and early 1970s? Going at the same speed, it would take the Apollo capsule over 500 billion years to reach Andromeda Galaxy!
By the way, the Hubble Telescope has detected galaxies over 15 billion light-years away. It's no small universe, people!
Galaxies are vast islands of billions of stars. They come in all shapes and sizes. Our home galaxy, the Milky Way, is thought to have some 200 billion stars arranged in a giant spiral over 100,000 light-years in diameter.
All the stars we see in our sky are members of the Milky Way Galaxy. In fact, in really dark skies you can see a faint band of milky white that stretches roughly from the northeast to the southwest sky. That's the main plane and the thickest part of our galaxy.
The Andromeda Galaxy is a larger spiral galaxy than the Milky Way, with well over 200 billion stars in a diameter of more than 200,000 light-years.
In fact, Andromeda is the largest spiral galaxy within 50 million light-years. Just as it is with our Milky Way, all the stars in the Andromeda Galaxy are orbiting around a super- massive black hole at Andromeda's center. This mother of all black holes is believed to weigh as much as a million times more than our sun and 300,000 times more than our Earth.
It's the glue that gravitationally holds Andromeda together. In our own galaxy our sun obediently orbits around the black hole in the Milky Way's center every 225 million years.
When I gaze upon the stars in our own galaxy and when I look through the telescope at other distant galaxies, I can't help but think about other planets like our own going around other stars.
We know they're out there. Just in our part of the Milky Way alone, there are more than 70 stars that are known to have a planet or planets circling them. Where there are planets could there be life? Intelligent life? Are they watching their version of "American Idol" somewhere in the Andromeda Galaxy?
There are no final answers for now, but it's been said that even if there's only one star in a billion with a solar system capable of life somewhere within it, there would still be thousands and thousands of worlds hidden inside Andromeda.
Here's one more thing to think about when you gaze upon Andromeda. Every second we get 50 miles closer to Andromeda. The Milky Way and the Andromeda galaxies are on a collision course. Mark 4 to 6 billion years from now on your calendars or Palm Pilots. That's when the Milky Way and Andromeda will merge together.
Because of the vast distances between stars, the two galaxies may just slip through each other. There is a chance, though, the two star families could merge together permanently in a stellar marriage of galactic proportions!
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the book, "Pennsylvania Starwatch", available at bookstores and at his Web site www.lynchandthestars.com.
