Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site utastro.UUCP Path: utzoo!linus!decvax!genrad!panda!talcott!harvard!seismo!ut-sally!utastro!bill From: bill@utastro.UUCP (William H. Jefferys) Newsgroups: net.origins Subject: Re: The Scientific Case for Creation: (Part 45) Message-ID: <347@utastro.UUCP> Date: Sat, 13-Jul-85 09:11:36 EDT Article-I.D.: utastro.347 Posted: Sat Jul 13 09:11:36 1985 Date-Received: Mon, 15-Jul-85 02:15:21 EDT References: <403@iham1.UUCP> <799@sphinx.UChicago.UUCP> Organization: U. Texas, Astronomy, Austin, TX Lines: 59 > From: rck@iham1.UUCP (Ron Kukuk), Message-ID: <403@iham1.UUCP>: > > 86. Stars that are moving in the same direction at > > significantly different speeds frequently travel in > > closely-spaced clusters [a]. This would not be the case if > > they had been traveling for billions of years because even > > the slightest difference in their velocities would cause > > their dispersal after such great periods of time. Similar > > observations have been made of galaxy and of galaxy-quasar > > combinations that apparently have vastly different > > velocities but which appear to be connected [b-d]. > > Cars travelling on interstates in the same direction at significantly > different speeds tend to travel in closely-space clusters. This would not > be the case if they had been travelling for hundreds of miles because even > the slightest difference in their velocities would cause their dispersal > after such great periods of time/distance. Obviously the cars have only > been travelling a few minutes. > > Despite the sarcasm, the above statement is true: cars DO tend to travel > in clusters. But nobody believes that the members of a cluster are the same > across "vast periods of time". > Not true. The stars in both open clusters and globular clusters are known to be physically associated and in fact to have been born at the same place and time. The automobile analogy isn't true in this case. Which is not to say that Kukuk's argument has any validity. It doesn't. The mutual gravitational field of the stars in the cluster is quite sufficient to keep them together for extended periods of time. The stars in such a cluster have different velocities, but travel in orbits around the cluster center, just as planets have different velocities but travel around the center of the Solar System (the Sun). Also, many (open) clusters are quite young - only tens to hundreds of millions of years old. Globulars are very old - around ten billion years - but they have many more stars and the time it would take for them to dissolve is orders of magnitude larger than that. As for the apparently connected quasar-galaxy associations, it is clear that there is no physical association among the members of such groups. Stephan's Quintet, for example, has five apparent members, only four of which are physically associated. Arp has tried to find anomalous situations where galaxies with physical associations have greatly differing velocities; so far, he has been unsuccessful in persuading most astronomers that he has found such evidence. However, even if he were to succeed, it would not help the Creationist cause, because Arp's explanation (the one he is working towards) is that the quasar has been ejected rather recently from the center of the galaxy at high velocity. According to this hypothesis, this sort of thing goes on all the time, so the fact that we see such situations is by no means evidence that the universe is young. It is disingenuous for Creationists to claim otherwise. -- "Men never do evil so cheerfully and so completely as when they do so from religious conviction." -- Blaise Pascal Bill Jefferys 8-% Astronomy Dept, University of Texas, Austin TX 78712 (USnail) {allegra,ihnp4}!{ut-sally,noao}!utastro!bill (uucp) bill%utastro.UTEXAS@ut-sally.ARPA (ARPANET)