Re: how do you know that the planets will align on 5-5-2000?

Dear Melissa:

You have asked a very good question.

The motions around the sun are all controlled by the action of gravity.

Since our Sun is so very heavy, it has a lot of gravity and it also has a lot of control over the motion of the planets.

One of the results of this gravity is that the planets move around the sun in pathways, or orbits, in well known mathematical shapes called ellipses. These ellipses are sort of shaped like a circle that has been streatched out. Maybe your teacher can show you what an ellipse looks like.

These ellipses are so well known and they have such exact mathematical properties that the orbits of the planets can be calculated out with a lot of accuracy.

Today we use calculators and computers to figure out these orbits. Then all we have to do is compare the planets orbits and then we can see when they will allign.

Some people place great importance to alignments and they say that all kinds of things will happen to the Earth because of alignments. I have lived long enough to see many alignments and nothing has ever happened to the Earth because of an alignment. Alignments are very interesting to look at, I hope you will enjoy the 5-5-2000 alignment!

[There was a recent article in Sky & Telescope about alignments during the current millennium. There have been quite a number. Unfortunately, the alignment of 2000 May 5 will occur mostly on the other side of the Sun, i.e., during the day, so we won't really see much. TJWL.]