[extropy-chat] Not enough TNOs

[Terry W. Colvin]

Forwarding permission was given by William R. Corliss.

Science Frontiers, No. 151, Jan-Feb, 2004, p. 1
< http://www.science-frontiers.com >

ASTRONOMY

Not enough TNOs

TNOs (Trans-Neptunian Objects*) are large lumps of dirty ice orbiting the
sun in the so-called Kuiper Belt just beyond Neptune.  The Kuiper Belt with
its inventory of TNOs was not even recognized by astronomers until a few
decades ago.  By then, it was obvious to the comet-counters that the large
number of short-period (less than 20 years) comets they were tallying could
not come from the hypothesized Oort Cloud at the far fringes of the Solar
System.

Sure enough, when astronomers searched the Kuiper Belt region, they found
some fairly large objects, some almost planet-size.  Pluto, in fact, may
be a TNO.

A problem that has now arisen derives from a faint-object search of a small
section of the Kuiper Belt with the Hubble's Advanced Camera for Surveys by
a team led by G.M. Bernstein and D.E. Trilling.  What they saw and counted
is "wildly inconsistent" with the number of short-period comets that are
observed.  In fact, the team found only 4% of the number of objects that
theory had predicted.

Conclusion: the size distribution of TNOs deviates from theory because the
many expected larger TNOs were pulverized by some unrecognized event or
process at some time in the Solar System's long history.  Another possibility
is that the missing large TNOs were once merely loose rubble piles of ice
chunks that were gravitationally torn apart and dispersed.

A survey for even fainter TNOs may decide what really did happen.  In any case,
the history of that region of the Solar System needs some radical rewriting.

(Schilling, Govert; "Comet 'Factory' Found to Have Too Little Inventory,"
*Science*, 301:1304, 2003.  Cowen, R.; "Hubble Highlights a Riddle," *Science
News*, 164:148, 2003.)

*TNOs = KBOs (Kuiper-Belt Objects)


[Science Frontiers is a bimonthly collection of digests of scientific
anomalies in the current literature.  Published by the Sourcebook Project,
P.O. Box 107, Glen Arm, MD 21057.  Annual subscription: $8.00.]


-- 
"Only a zit on the wart on the heinie of progress." Copyright 1992, Frank Rice


Terry W. Colvin, Sierra Vista, Arizona (USA) < fortean1 at mindspring.com >
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