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From: TerryMoselat signaol.com
Date: 30 November 2006 00:12:38 GMT
Subject: Greenwich job, Geminid Meteors

Hi all,
  1. ROYAL OBSERVATORY GREENWICH: Job Vacancy - Astronomer - Public
Engagement:    Astronomer - Public Engagement. Starting salary #27,000 -
#35,000 p.a. + benefits depending on skills and experience.    The
National Maritime Museum is currently developing 'Time & Space', a #15M
project at the Royal Observatory, Greenwich. This will be fully open in
April 2007 and will make a major contribution to the Museum's overall
mission. The ROG homepage is at www.rog.nmm.ac.uk.   
 We are currently seeking an
Astronomer- Public Engagement to play a key role in delivering the ROG's
vision to be a centre of excellence for all audiences, to represent the
ROG, and to sustain its reputation nationally and internationally. The
postholder will have research experience in astronomy or space science,
to lead in maintaining modern aspects of these subjects accurately in
the ROG's public engagement work including the planetarium, galleries,
displays and education programmes.     As a member of the Learning and
Interpretation Department they will liaise closely with the Press Office
and the Curatorial team. They will be expected to keep in touch with
current astronomy and space research. The post is funded by PPARC as
part of its Science and Society programme. PPARC will also be an
advocate for activity and programmes connected with the post.    The
successful candidate will hold a PhD in astronomy or space science
together with at least 2 years research experience in those or a related
field. They will have excellent communication skills, including the
ability to represent scientific ideas in a clear and accessible style
and a proven track record at working in a team and with people at all
levels. Previous experience of public engagement work in a University,
science centre or museum would be an advantage.    For a full job
description please visit www.nmm.ac.uk/jobs.
To apply, please send a CV and covering
letter to Closing date for the receipt of applications: 15 December 2006
The Museum upholds equal opportunities for all staff. [Thanks to Mario
di Maggio for the above. T.M.]

  2. GEMINID METEORS SET TO DAZZLE The Geminids are almost always the
best of the annual meteor showers. As the name implies, they appear to
come from the constellation Gemini, which is high up in the SE late on
December evenings. The radiant, or point in the sky from which they
appear to come if you trace their paths backwards, lies just above the
star Castor, the fainter of the two  Heavenly Twins.   You can start to
see the first Geminids in the late evenings from about December 8, but
activity starts to pick up about the 10th, building to the maximum which
this year will be in the early hours of December 14. In other words,
you'll see most meteors late on the night - in fact just before dawn!
- of December 13-14. Activity will then decrease sharply, with few being
seen after the 15th.     Meteors are tiny specks of debris from comets,
and become visible only when they collide with Earth's upper atmosphere
at very high speed, and burn away in a streak of light. But the Geminids
are unusual, because they appear to come from an asteroid, 3200 Phaethon
*, not a comet. They are also slightly unusual in two other respects:  
(a) They have relatively low collision speeds with the Earth - 'only'
about 35 km/sec.   (b) they have a higher than average particle density
- about 2g/cm3, compared with about 0.3 g/cm3 for the Perseids. That
perhaps reflects their 'rocky (?) origin....    The Earth only started
to encounter the Geminid meteor stream in the mid-19th century. It was
first reported by Robert P Greg of Manchester in 1862. Acticity
gradually increased over the years with hourly rates of 50-60 in the
1930s. Recently, Zenithal Hourly Rates have sometimes exceeded 100. The
Earth will no longer encounter the Geminids in about another 100 years,
so observe them while you can! It could be that the shower will get
richer still before starting to decline, or it may already be at or near
its peak - there's only one way to find out!      The low collision
speed, and higher density, means that Geminids often last longer than
other meteors before extinction, and that, combined with their slow
speed, makes them good photographic candidates. Bright ones sometimes
break up unto a chain of fragments all travelling along the same path.
Geminids are, on average, brighter than most shower meetors, so they're
a great shower to watch in good conditions.    Moonlight does not
interfere this year, so if we are blessed with a clear sky that night we
will see some nice free celestial fireworks! But please note that you
will see very few meteors from brightly lit city areas, and even the
light from moderate sized towns will spoil the view significantly. To
see them at their best you must get well away from all bright lighting -
the darker the sky the better. If you can see the Milky Way really
clearly, that's a good indication.     Some Geminids will be visible
from about 7 or 8 p.m. onwards each night, mainly from 10 - 15 December,
but the real peak will be just before the first glimmer of dawn on
Thursday 14th. If you have very clear dark skies then, you might see as
many as 100 meteors per hour!    So keep the night of 13/14 December
free just in case it's clear!

* Prof Alan Fitzsimmons of QUB provided this latest, more technical
info: "Spectra  show Phaethon to have a carbonaceous/silicate
composition that has been altered by water. So it looks different to the
known cometary nuclei, and could be a primitive asteroid that was
activated by being moved into its present orbit.    Another new piece of
info is that 2005 UD discovered last year has almost the same orbit and
the same spectral type as Phaethon, rare for NEOs. So it could have been
a proper weak comet for a short time, rather like the main-belt comets
like 133P/Elst-Pizzaro." Clear skies,

Terry Moseley


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