This section is from the book "Time Out for Living", by Ernest DeAlton Partridge and Catherine Mooney. Also available from Amazon: Time Out for Living.
When astronomers are photographing the sky, they sometimes accidentally photograph a meteor. A meteor, or "shooting star," is in the upper center of this picture. The cluster near the lower edge is the Pleiades.
If people in different parts of the earth do this and send their records to the Fowler Observatory, University of Pennsylvania, Philadelphia, Pennsylvania, the astronomers by comparing all the observations can tell just what path the meteors are following.
When observing a meteor shower, it is necessary to distinguish between meteors which belong to the shower and those that just happen to have collided with the earth that evening. The shower-meteors appear to radiate from one point in the sky. If the meteors of a shower came suddenly and all at once, they would look like the bursting head of a rocket on the Fourth of July. It would be a beautiful sight, but unfortunately that isn't the way a shower behaves. The meteors do radiate from a particular part of the sky, but usually they come only one or two a minute throughout the night.
One way to distinguish between the shower-meteors and the ordinary meteors is to have a star chart with you. Then, when you see a meteor, draw a line on the chart in the exact position in which you saw the streak of light. After you have made several of these lines, you will find, if you extend them by a ruler, that they all meet in nearly one point in the sky. This is known as the radiant point of the meteor shower. Usually the shower is named for the constellation in which this point is located. An example is a famous shower that occurs near November 14. The radiant point is in the constellation of Leo, the Lion. The shower, is, therefore, called the Leonids.
The Leonids have been colliding with the earth for hundreds of years. On the night of November 12 to 13, 1833, there were so many Leonids dashing through the sky that some people were terrified. They thought all the stars were falling. In some towns the church bells were rung to wake the people so that they could see the amazing display. Again, in 1866 there was a fairly brilliant shower, not visible in North America. The many European observers called the display extremely impressive. The historical records indicate that the Leonids are extraordinarily numerous about every 33 years. The brilliant display anticipated for 1899 was very disappointing. The observers counted 500 to 1,000 meteors but not the thousands which they had expected to see. The 1932 show was equally disappointing.
On an autumn night in 1833, so many meteors darted through the sky that some people said that they were as thick as snow-flakes. Perhaps the sky looked the way this picture shows it.
This radiant point that was mentioned above is merely a "vanishing point." In a certain sense it is our imaginary place from which the meteors appear to come. The two rails of a long straight railroad track apparently meet in a point far off toward the horizon. We all know that no matter how far we walk on the track the two rails are always the same distance apart - four feet, eight and one-half inches. The place where these parallel rails seem to meet wc call the vanishing point.
The meteors in a shower enter our atmosphere in paths which are parallel to each other. So, when their brilliant trails are extended across the sky, they seem to come from one point - the vanishing point.
Sometimes, when the sun is setting, the clouds will cause long narrow bands of shadow to radiate from the point on the horizon where the sun is setting. These shadow-bands spread sometimes over the western sky like the ribs of a fan. As a matter of fact all these shadow-bands are parallel to each other. The sun is so far off that its rays of light for all practical purposes come to us in parallel lines. So the long narrow shadows made by the cloud appear to radiate from the "vanishing point."
During the hours an observer watches for the meteors of a shower, he may record a number of ordinary meteors, which just happened to collide with the earth during that interval. These ordinary meteors may come from any direction. It will be obvious that they have no connection with the shower. Some of these ordinary meteors may be extremely brilliant, perhaps more brilliant than any member of the shower. Occasionally a meteor will be so bright as to cast a shadow, but as far as we know no such brilliant shooting star has ever been associated with a shower.
Some meteors leave a long trail of light, which may remain visible for more than a minute. While such a trail is disappearing, it may bend and twist like a wisp of cloud. Occasionally a meteor will be slightly red or brilliantly green. Of course, the observer will record all meteors which have a brilliant color and all trails which last any appreciable length of time.
 
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