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(meteorobs) Excerpt from "CCNet SPECIAL: BRITISH ASTRONOMERS MAKE HISTORY..."
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: BRITISH ASTRONOMERS MAKE HISTORY: LEONIDS PREDICTION CONFIRMED
Date: Thu, 18 Nov 1999 10:44:19 -0500 (EST)
CCNet SPECIAL: BRITISH ASTRONOMERS MAKE HISTORY: LEONIDS PREDICTION=20
CONFIRMED - 11 November 1999
(1) BRITISH ASTRONOMERS MAKE HISTORY: LEONIDS PREDICTION=20
CONFIRMED
Benny J Peiser <b.j.peiser@livjm.acdot uk>
[...]
========================================================================
(1) BRITISH ASTRONOMERS MAKE HISTORY: LEONIDS PREDICTION
CONFIRMED
>From Benny J Peiser <b.j.peiser@livjm.acdot uk>
Britain woke up this morning to the usual lamentation about the=20
weather. What made things worse, however, was the fact that most people =
in the country weren=92t able to enjoy the display of the Leonids =
meteor=20
storm. Bad weather had hampered the view. Yet instead of moaning, we=20
should celebrate a remarkable accomplishment by two young British=20
astronomers.
David Asher, an English astronomer based at the Armagh Observatory =20
(Northern Ireland) and Robert McNaught, a Scottish astronomer based in =
Siding Spring Observatory (Coonabarabran, Australia) have made history=20
by solving a scientific puzzle that has bewildered the astronomical=20
community for exactly one hundred years: How to forecast the seemingly=20
irregular Leonids meteor storms.=20
Ever since the widely predicted Leonids failed to appear in the morning =
of November 16, 1899, their erratic behaviour has been viewed as=20
somewhat of an enigma that seemed difficult to elucidate. Looking back, =
the unsuccessful prediction of 1899 led to a public relations fiasco=20
for the astronomical community: "... the failure of the Leonids to=20
return in 1899 was the worst blow ever suffered by astronomy in the=20
eyes of the public, and has indirectly done immense harm to the spread=20
of the science among our citizens." (Charles Olivier, Meteors, 1925)
After one hundred years of endeavours to get a grip on the capricious=20
Leonids, Asher and McNaught have pulled off a major success! Their=20
prediction for the 1999 Leonids, based on their "dust trail theory" has =
been confirmed - at least regarding the exact timing of the peak=20
activity. McNaught & Asher predicted (see CCNet 10 November 1999) the=20
peak activity of the Leonids to occur this morning at about 2.08 am UT. =
"For the 3-rev trail encounter in 1999, the time of maximum is=20
predicted to be at Nov 18, 02:08 UT in the Mediterranean region, with=20
an uncertainty of around 5 minutes. The time of maximum is dependent on =
location, with the peak predicted at 01:58 in South Africa and 02:14 in =
northern Scandinavia."
As Marc Gyssens from the International Meteor Organization points out
in the IMO press release (see below), the observed peak time coincides=20
almost perfectly with the peak time of 2:08 am Greenwich Mean Time=20
predicted by Asher and McNaught, "indicating that the activity was due=20
to the dust trail created the Leonids' parent comet, Tempel-Tuttle,=20
about 100 years ago (i.e., 3 revolutions ago of the Comet around the=20
Sun)."=20
While this is an impressive confirmation of their theory, it is=20
interesting to note that their prediction of the highest hourly rate
(Zenithal Hourly Rate, or ZHR), expected to be in the 500 range,=20
could not be validated: In fact, early reports suggest that the peak=20
activity corresponded with an hourly rate up to ten times higher than=20
the predicted number. Evidently, the Leonids never fail to surprise us.
The historical achievement by Asher & McNaught should not be=20
depreciated by this minor drawback. What their success proves is that=20
astronomical predictions are progressively improving. The time will=20
come when we will be able to sufficiently understand, and ultimately=20
yield control over, the dynamics of cometary and meteoric activity that =
affect our cosmic environment.
Well done, David and Rob!
Benny J Peiser
[...]
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