Watch out, Andromeda's on its way

As if we didn't have enough to worry about what with global warming, high gasoline prices, the energy crunch, and wars and rumors of wars, now we have this--the Andromeda Galaxy is going to crash into our own Milky Way Galaxy.

The Andromeda Galaxy, M31, is our closest neighbor in the local group of galaxies at 2.5 million light years away. It is rushing toward us at the calamitous speed of 270,000 miles per hour. At that speed we can expect the crash to begin in about, oh say, two billion years.

The Milky Way, Andromeda, and Pinwheel Galaxies, M33, are the three largest members of what is called the local group of galaxies. A close association about six million light years across which includes dozens of other smaller elliptical satellite galaxies.

There shouldn't be too much to worry about as the two giants begin to merge together. With all the distance involved in space, astronomers don't really expect anything to crash into anything else.

To get a perspective of the size of space let us say the sun was the size of a ping-pong ball and the nearest star to our sun (Proxima Centauri about four light years away) was another ping-pong ball, at that size it would be about 1,000 miles away. At that scale there is not much chance of anything hitting anything else.

What will happen is the galaxies will rush at each other (on galactic scales, 270,000 miles per hour is not fast) and as they pass, the gravity of each galaxy will pull stars and dust and other galactic matter out into long trails of material. They will pass each other and the gravity of both will pull them back together again.

This dance will go on for about another, oh say, three billion years until the galaxies have merged into one, very large, round, spheroid elliptical bunch of stars. The flat pinwheel of stars with which we all are so familiar will be no more, just a large ball of stars and gas and dust.

We know this because there are dozens of other elliptical galaxies that can be observed today and astronomers believe they are the product of other such galactic mergers.

If you would like to see our soon-to-be-neighbor you can find the Andromeda Galaxy in the east after about 10 p.m. local time. Find our old friend the constellation Pegasus, you remember, the big square standing up on one corner. Find the corner pointing north and follow the two lines of stars leading away from it toward the constellation Perseus. Count two stars out in the two lines, estimate the distance between those two stars and go that distance up and you will find a small, gray, fuzzy blob. That blob is the Andromeda Galaxy.

If you are looking from a dark sky place you should be able to see it without the aid of any optical device. Binoculars will help some and a telescope will give a much better look at what is coming at us.

SKY WATCH: First quarter moon, Aug. 8. The Perseid Meteor shower will be best observed in the early morning hours of Aug. 12, when the constellation Perseus is high in the northeastern sky and after the moon has gone down. From a dark sky place it could be possible to observe between 75 to 100 meteors per hour. On Tuesday, Aug. 12, look very low to the western horizon about a half hour after sunset for a close pairing of Saturn and Venus with very dim Mercury to the lower left of the pair. Watch over the next few evenings when Saturn dips toward the horizon and Mercury and Venus continue on in an upward trip to meet Mars. All of this will be taking place very low in the west just after sunset and will be in the bright glow of the sun. To see much of anything binoculars will be required. Just be careful being that close to the sun. One glimpse will destroy your vision forever.

NEXT TIME: More astronomical blathering.