distances

Paul Arveson (arveson@oasys.dt.navy.mil)
Thu, 26 Dec 96 15:41:35 EST

John Burgeson, referring to M. Lubenow's book, says:

On page 201 he makes the argument (in connection with the YEC position) that
triangulation techniques can only be done to measure out to about 300 light
years. I seem to remember (perhaps recently) an argument that this technique
could be used further out than that; don't see how, as the earth's orbit seems
to be a limiting factor. Does anyone here know about this? Of course, Lubenow is
not an expert in astronomy, so if he is in error here, it does not invalidate
the rest of the book particularly.

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There are many ways astronomers have developed for measuring distances in space.
Apparently Lubenow is implying that parallax is the only valid one. This is
standard young-earth creationist nonsense.

There is a carefully-developed sequence of distance yardsticks that has been
constructed, based on thousands of observations of Cepheid variables, cluster
motion, local and cosmological red shifts, supernova brightness, light
absorption, etc. All these yardsticks fit together in an interlocking system of
physical theories that offers numerous ways for independent cross-checking.
For instance, the supernova 1987A in the Large Magellanic Cloud was found
to be about 160,000 light years away, and this distance is consistent with
the neutrino flux observed from that supernova in light of the theories of
nucleosynthesis -- theories that are totally independent of distance to a
star. For another instance, numerous recent Cepheid variable measurements
using the Hubble telescope have given a distance to the Andromeda galaxy of
1.74 million light years (note the number of decimal places). For another
instance, the Hubble has taken some remarkable pictures of arcs caused by
gravitational bending of light from distant galaxies; Einstein's quantative
theory of general relativity accounts for the existence and dimensions of these
features.

True, this system is based on inference. But so is parallax, and so is
everything else in life. You can't walk down the street without inferring that
what you see is a solid sidewalk, and not a hole in the ground. YEC's invoke
"selective skepticism" sometimes when inferences get in their way. They really
reject this mass of quantitative data because it interferes with their own
mistaken beliefs, a habit which Francis Bacon called "the blind and immoderate
zeal of religion."

Paul Arveson, Research Physicist
Code 724, NSWC, Bethesda, MD 20817-5700
73367.1236@compuserve.com arveson@oasys.dt.navy.mil
(301) 227-3831 (W) (301) 227-1914 (FAX) (301) 816-9459 (H)