85 lines
5.1 KiB
Plaintext
85 lines
5.1 KiB
Plaintext
SUBJECT: THE AGE OF THE PLEIADES FILE: UFO2654
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Ok... here's the information I have been able to dig out of various
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sources of astronomical data including "The Astronomy Databook",
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Gaposchkin's "Stars and Clusters" and Pasachoff's "Astronomy" From the
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Earth to the Universe" about the Pleiades.
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The age of the Pleiades:
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The age of star clusters and how we go about obtaining such data is
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probably best discussed in Cecila Payne-Gaposchkin's "Stars and
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Clusters" (Havard Univ. Press). Measuring the age of a cluster is a
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difficult chore and any figures must be taken as estimates rather than
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exact numbers. Basically, stars of different mass, spectral types and
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luminosities evolve at different rates. A blue-white O type supergiant
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is consuming its mass at a furious rate and only has a very short life
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expectancy measured in a few millions or tens of millions of years.
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Smaller, cooler stars like the Sun (G3 type) are much more sparing of
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their mass and the sun is estimated to have a lifespan of around 10
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billion years. Red dwarf type stars may last many more billions of
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years. The life of a star is measured not from the moment of its
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"birth" until the time it ceases to exist, but is a measure of how long
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that star will exist as a "main sequence" star - meaning how much of
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its life will be spent in a certain area on the Hertzsprung-Russell
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diagram. A star like the sun may spend millions of years forming out of
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the galactic gas, a short time as a proto-star, 10 billion years as a
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main sequence star, millions of years as a red giant...etc. However,
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its life is measured in terms of how long on the main sequence.
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The estimates of the age of the Pleiades rest right around 100,000,000
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years making it a very young cluster in terms of the age of the galaxy.
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Many of even the smaller, fainter stars have not even reached the main
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sequence yet, while the big, bright hot members have already expended
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much of their fuel and are moving off the main sequence. Such a cluster
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is a poor prospect for life based on the evolution of life on earth.
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The chances of life arising on any planets orbiting Pleiadian stars is
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probably good, but the chances of intelligent life arising in such a
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short period - again, based on the only model we have studied - is
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slim. It took 4 billion years for intelligent life to arise on earth,
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and the chances of it happening in less than 3% of that time is not
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considered likely.
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The Distance to the Pleiades:
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The most accurate means of measuring star distances is that of
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measuring the absolute parallax using the 186 million mile diameter of
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the earth's orbit as the base line. Obviously the closer a star, the
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more accurate the distance obtained. Such parallax measurements are
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considered very accurate out to about 100 light years and usable (with
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greatly increasing error) out to about 300 ly. Beyond 300 ly indirect
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measurements need be used. The most accurate of the indirect measure
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techniques involve the use of standard "candles" -objects of known
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brightness. The most effective standard candles are the Cephid variable
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stars. Other methods of indirect measurement include radial velocity
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studies, the orbits of double stars and, in many cases, flat out
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guessing! The best figures I can find for the distance of the Pleiades
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seems to be around 410 ly. Alcyone, the brightest star in the group, is
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listed as about 541 light years, but this apparent disparity only shows
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the wide margins for error of any indirect measurement. Of course, who
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knows what is actually being talked about when discussing the distance
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to a star cluster. Is it the mean distance to all the stars, the
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distance to the closest star or what? Determining which stars are evey
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part of a given cluster is not an easy job!
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Astronomer's lives would be so much simpler if these Pleiadians and
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other "star travelers" would stop with all their banal pronouncements
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about "peace and living together in harmony" (they ain't nothing new -
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our own philosophers and teachers have been saying the same thing for
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thousands of year) and start giving us basic scientific data.
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The fact that out of all the thousands of so-called abductions,
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channeled UFO information and the rest of the idle chatter there has
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never been a new, VERIFIABLE piece of information must lead one to
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doubt the veracity of these stories.
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**********************************************
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* THE U.F.O. BBS - http://www.ufobbs.com/ufo *
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