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Re: Lyrid Meteor Shower Reminder

In a message dated 98-04-19 12:20:59 EDT, you write:

<< 
 The point I made was that Bernd's railroad track example does not hold
 up in the case of cometary debris showers, because as you and others
 suggest the debris in fact radiates.  If this is true, then they are not
 travelling parallel to each other, merely in a similar course as the
 parent. >>

Whether you want to call them traveling parallel or a similar course, it's
obvious that the debris are related. The debris radiates from a region in the
sky....for an observer on earth, this radiating effect is an illusion. The
meteors aren't radiating from a point in the sky....but rather a region of sky
in so many degrees. A typical meteor shower radiant is about 5 degrees in
diameter. This means that any shower member can appear to radiate from
anywhere within this 5 degree diameter region. Some might radiate from dead
center while others on the outside edge of the 5 degree diameter circle. In
Space the meteoroids from a shower are traveling within a stream of certain
dimensions that are pretty much parallel. Not all will have the exact
characteristics. If they did, you would have a rope in space or a straight
line. They will be traveling in different regions of this stream simply
because not all particles left the parent comet with the exact same velocity.
Also not all particles will be of the same size. The smaller particles will be
easily influenced by the solar wind. The larger particles will be influenced
by a lesser amount.  Look at a River of water...such as the Mississippi river.
You scatter ping pong balls across the river at some point and they all float
downstream following pretty much the same general trajectory. But it's still
in the Mississippi river for the ping pong ball near the bank as for those in
the middle. 
George Zay