S&T News Bulletin - Nov 26



According to a study by astronomer William Bottke at the University of
Arizona, some fraction of the tiny asteroids discovered whizzing past
Earth in recent years may have been blasted into space from the Moon. 
Many of these asteroids have orbits very similar to Earth's, and Bottke's
computer simulations show that some of objects flying off the Moon after a
major impact within the last 10 or 20 million years would have gone into
heliocentric orbits quite like those of the Earth and Moon. Also, such
objects only survive for about that long before colliding with us or being
flung from the solar system.


After an absence of 275 years, the clock used in establishing Greenwich
Mean Time is being returned to its original home.  Made by Thomas Tompion,
known as the father of English clockmaking, the clock will be restored to
its original setting in the Octagon Room of the Royal Greenwich
Observatory near London.  In the late 17th century it was used to
determine that the Earth rotated at an even rate.  Those findings formed
the basis of all measurements of time and space more than 2 1/2 centuries.
 The clock was sold in 1719 and wound up in the ancestral home of the Earl
of Leicester before its return to the observatory.


Those of you up before dawn on November 30th will be treated to a stunning
pairing of dazzling Venus and the thin crescent of a Moon just three days
from new.  You'll find them about 10 to 15 degrees up in the southeast.


The nearly new Moon gives you a chance to resume the hunt for Periodic
Comet Borrelly, which reached perihelion on November 1st.  The comet is
well up in the eastern sky late at night, parked among the stars of Gemini
and Cancer and headed north toward Ursa Major.  Some observers have
commented that the comet had an obvious fan-shaped anti-tail, pointed
*toward* the Sun, the second week of November.  Its total brightness is
estimated near 8th magnitude at present.  A detailed chart for finder
chart appears in December's S&T on page 76, but here are positions for the
coming week, given for 0h Universal time.

          R.A. (2000) Dec.
Nov 27   8h 47m   +33.4 deg.
Nov 29   8  51    +35.0
Dec  1   8  56    +36.6


If anyone has visual reports or photographs of last week's Leonid meteor
shower, we'd love to hear from you.  Contact SKY & TELESCOPE via Internet
e-mail at skytel@cfa.harvard.edu. 

The News Bulletin is provided as a service to the amateur-astronomer
community by Sky & Telescope magazine.  Electronic distribution is
engouraged; however, this text may not be published without permission of
Sky Publishing Corp. At the present time, the News Bulletin is not
available via electronic mailing list.

   | Stuart Goldman         Internet: sgoldman@cfa.harvard.edu  |
   * Associate Editor                 mrastro@aol.com           *
   | Sky & Telescope                                            |
   * P. O. Box 9111           Sky & Telescope: The Essential    *
   | Belmont, MA  02178           Magazine of Astronomy         |