PLEASE NOTE:
*
CCNet, 11 November 1999
------------------------------
POEM OF THE DAY
Panspermia
By Malcolm Miller
stellar2@actonline.com.au
Arrhenius and Hoyle shared this belief,
that life could spread though space,
braving the perils
of vacuum, cosmic rays, millennia spent
near zero K,
its only shelter a crust of rock in
which it huddled.
Neither scientist guessed the impulse of
its launch,
from shattered regolith in which it
lived,
nourished by scant traces of sulphur,
carbon, nitrogen,
and all the time protecting its core of
DNA.
Life might be ubiquitous within the
rocks
not only of our Earth but those of Mars
and even
underneath the tortured ice that
coats Europa's seas.
I wonder if we'll ever know if all life
shares one origin,
blasted off some primeval planet to
spread
its magic code thoughout the galaxy,
that self same code that makes us who we
are?
M.M. 11.11.99
(1) POSSIBLE REMEDIES FOR THE TORINO SCALE
EXPLOREZONE, 10 November 1999
(2) CRUSHABLE ASTEROIDS MAY ABSORB IMPACTS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) SYMPOSIUM TO HIGHLIGHT SOCIETAL IMPLICATIONS OF ASTROBIOLOGY
NASANEWS <nasanews@mail.arc.nasa.gov>
(4) SERIOUS DOUBTS ABOUT COMETARY DUST LOADING
Roy Tucker <tucker@noao.edu>
(5) ARTHUR C. CLARKE AND ALTERNATIVE UTOPIA MODELS
Andrew Glikson <geospectral@spirit.com.au>
(6) BBC REPORT ON ARTHUR C. CLARKE
David Whitehouse <Dr_D_Whitehouse@email.msn.com>
(7) LOOKING ON THE BRIGHT SIDE OF LIFE
Benny J Peiser <b.j.peiser@livjm.ac.uk>
(8) SPACE SETTLERS’ SUPPORT FOR SPACEGUARD UK
Andy Nimmo <andy.nimmo@net.ntl.com>
============
(1) POSSIBLE REMEDIES FOR THE TORINO SCALE
From EXPLOREZONE, 10 November 1999
http://explorezone.com/archives/99_11/10_marsden_comment.htm
In a recent explorezone.com story about the Torino Scale for
measuring
asteroid threats, director of the Minor Planet Center Brain
(sic!)
Marsden was quoted as saying the scale was "largely
irrelevant,"
charging that it does little to inform the public and is an
oversimplification for serious researchers. Here, Marsden expands
and
clarifies his views:
By Brian Marsden
Despite implications to the contrary, I am actually not opposed
to the
use of something like the Torino Scale for the purpose of
conveying to
the public information about specific predictions involving
possible
impacts by NEOs. At the meeting in Turin in June 1 in fact
remarked
that it was an improvement over the rejected proposal that Binzel
presented in 1995. The most important feature of the scale is the
way
it is built around level 1, or a "green alert", where
the impact
probability would be comparable to that of the
"background" population
of undiscovered objects -- or, at least, the undiscovered objects
at
the present time. Furthermore to define a level 0 (a "white
alert") for
smaller impact probabilities and a level 2 (a "yellow
alert") for
impact probabilities up to perhaps 100 times greater is also very
reasonable.
My problem is with the assignment of numbers to the higher
levels, all
the way up to a "red alert" level 10. I think this
degree of detail is
unnecessary and confusing to the general public. After all, we
really
don't know the diameters of the objects (and can only make
guesses from
often questionable observations of the brightness and an
assumption of
the albedo, or fraction of incident sunlight reflected by the
object's
surface), and the impact probability is not always as well
defined
as some might think. The way the "red alert" level 8
abuts the
"no-consequence" level 0 for an infinitesimal change in
size is quite
illogical, and the presence of a point on the diagram that is
ambiguously
level 2, 4, 5, 6 or 7 must have been remarked upon by others.
The scale would surely be much more satisfactory if the numbers
were
scrapped completely, and it utilized only the colors. For the
larger
impacting bodies, there are levels corresponding to an
"orange alert"
between the yellow and red. To have a sequence
white-green-yellow-orange-red is fine, except that I would adjust
the
probability-size relations such that this sequence is
consistently used
throughout the diagram, thereby eliminating the crazy white-red
boundary, as well as the yellow-red and white-yellow boundaries
of the
current version.
Use of colors, rather than numbers, could remove any tendency to
compare the scale to the Richter Scale. Although Binzel and
others have
stressed the similarity, it really makes no sense to compare a
scale
involving tentative predictions of impacts far into the future
with
that giving the well-defined Richter numbers of past earthquakes.
The
impact probabilities change continually as new observations are
obtained, and by using colors, rather than numbers, I think one
can
also better convey these changes, avoiding the precision that the
use
of numbers implies.
Although our experience to date is with four objects having
demonstrated impact possibilities over the course of the next
half-century, two never emerged beyond a white alert, one moved
up from
white to green, and one (1997 XF11 in 2040) just made it to a
yellow
alert. With the availability of further observations, three of
the four
dropped down to the extreme white region (i.e., essentially zero
impact
probability), while one of the white alerts remains a non-zero
white
alert because of the absence of further data. It is perhaps not
generally appreciated that, if the 1997 XF11 orbit relative to
the
earth had been shifted by something like 20,000 miles, there
would have
been an orange alert for this object in 2028. In Binzel's
notation this
would have been at level 6, verging on level 7. At such levels he
considers the object to have a "significant threat of a
collision
capable of causing a global catastrophe."
Would that therefore have been any cause for alarm? Of course
not! The
very next day, the recognition of the 1990 observations would
still
have sent the impact probability straight down to zero (for the
next
thousand years or more), just as actually happened. The actual
result
of reaching an orange alert would therefore have been no
different
whatsoever from reaching yellow, green or staying in the white!
The
public needs to be reassured that this kind of thing will happen
-- and
not frightened by explanations of the scale that speak of a
"significant threat."
In almost every case, at some point the acquisition of further
data
will eliminate all the danger. There might be some slight cause
for
worry until further data are acquired (either from observations
yet to
be made or from the examination of old records), but it is really
not
worth losing sleep over this. Nevertheless, observations are of
supreme
importance until the threat has completely gone. In this sense,
one
might in fact say that small objects are more troublesome than
the
larger objects, because the existence of past records of a
smaller
object would be less likely, and there would tend to be fewer
opportunities for further observations before the possible impact
is to
occur. Of course, if there is really going to be a hit, the
impact
probability will eventually reach 100 percent.
That brings up my final point, namely, that the scale needs to
have
built into it another parameter, and this is the amount of time
to
elapse between the present and the possible impact event. It
makes a
great deal of difference whether we are talking about an impact
event
that might occur in three decades, three days -- or somewhere in
between. As I have suggested, the public at large really does not
need
to get worked up if there is a lead time of several decades. And
that's
the way it will be -- most of the time. These are situations for
the
astronomers to monitor.
So how can we accommodate this in the scale? The obvious way
would be
to indicate the shade or intensity of the color. If the lead time
were
under one year, say, the color would be dark. Above one year, the
color
would be light. Very dark colors would apply under one-tenth of a
year
(37 days), very light colors beyond 10 years. If necessary, this
scheme
could be extended to extremely dark below 0.01 year (4 days),
extremely
light beyond a century. Thus 1997 XF11 made it to a "very
light yellow"
alert, 1999 AN10 to a "very light green"--before going
to white, the
shade of which does not apply. There is in fact still some slight
possibility that 1999 AN10 will be a danger a century or so from
now,
but at this stage it really does not matter whether it is
"extremely
light green" or "extremely light yellow". Of
course, the worry in all
of this is that we should find an imminent high-probability
impact
event that would qualify as "very dark red" or
"extremely dark orange".
This has not yet happened, and we hope it remains that way ...
Brian G. Marsden
Harvard-Smithsonian Center for Astrophysics
November 7, 1999
Copyright © 1998,1999 Explorezone
MODERATOR’S NOTE: Brian Marsden should be commended for
converting his
well-known skepticism about the current format of the Torino
Scale into
a practical and persuasive proposal for modification. His
suggestions
are a sound basis for further deliberations of how the Torino
Scale can
be made both more logic and more usefulness. One would wish that
Richard Binzel and Brian Marsden could agree to cooperate in
refining
the Torino Scale and that some of the proposed improvements can
indeed be incorporated in an enhanced version that is less
disputed.
Benny J Peiser
==============
(2) CRUSHABLE ASTEROIDS MAY ABSORB IMPACTS
From Andrew Yee <ayee@nova.astro.utoronto.ca>
[http://www.academicpress.com/inscight/11101999/graphb.htm]
Wednesday, 10 November 1999, 5 pm PST
Crushable Asteroids May Absorb Impacts
By Robert Irion
Some asteroids may resemble squeezable slabs of Styrofoam instead
of
brittle, dense rocks that shatter on impact, according to a new
study.
Planetary scientists have found striking similarities between
craters
blasted in soft soils in the lab and the pattern of gouges on an
asteroid named Mathilde. They suggest that some asteroids absorb
energy
from collisions, growing smaller and denser over time rather than
breaking apart as other cosmic objects pummel them.
The Near Earth Asteroid Rendezvous (NEAR) spacecraft captured
images of
Mathilde in 1997, revealing a potato-shaped body 53 kilometers
across
and pocked by gigantic craters. The largest crater spans more
than 60%
of the width of the asteroid itself, raising questions about how
Mathilde survived the colossal impact. Gravitational data from
NEAR
also revealed that the asteroid is barely denser than water,
leading
researchers to speculate that it is a loosely consolidated
"rubble
pile" barely held together by its own gravity (Science, 4
July 1997, p.
30). NEAR exposed yet another curiosity: Mathilde's craters lack
the
fringe of rocky debris that typically litters the terrain around
large
impacts on other bodies.
To explore that oddity, planetary scientist Kevin Housen of
Boeing Co.
in Seattle, Washington, and his colleagues created miniature
craters in
the lab, they report in tomorrow's Nature. They smashed small
plastic
projectiles traveling 2 kilometers per second into loose clods of
sandy
material. The action took place inside a centrifuge to mimic the
gravitational forces that govern how crater debris would fly from
an
asteroid. The impacts simply compacted the material, ejecting
little or
no debris, they observed. The results imply that similarly
composed
asteroids would compress and become more dense as objects strike
them,
losing little mass in the process.
Housen's idea is provocative and plausible, says planetary
scientist
Erik Asphaug of the University of California, Santa Cruz. To test
the
hypothesis, he says, "We need experiments where we impact an
asteroid
and obtain seismic imaging of their interiors." NASA's
planned Deep
Impact mission, which will slam a projectile into the nucleus of
comet
Tempel 1 in 2005, may serve as a prototype for future studies of
porous
asteroids. Asphaug notes that such objects, which he calls
"flying Rice
Krispie treats," might swallow projectiles without breaking
apart or
significantly changing their orbits. That's potentially bad news,
Asphaug and Housen agree, if one of those rubble piles takes dead
aim
at Earth: The menacing asteroid might just shrug off efforts to
deflect it.
© 1999 The American Association for the Advancement of Science
[Extracted from INSCiGHT, Academic Press.]
==============
(3) SYMPOSIUM TO HIGHLIGHT SOCIETAL IMPLICATIONS OF ASTROBIOLOGY
From NASANEWS <nasanews@mail.arc.nasa.gov>
Nov. 10, 1999
Kathleen Burton
NASA Ames Research Center, Moffett Field, CA
(Phone: 650/604-1731 or 650/604-9000)
kburton@mail.arc.nasa.gov
NOTE TO EDITORS: 99-69AR
SYMPOSIUM TO HIGHLIGHT SOCIETAL IMPLICATIONS OF ASTROBIOLOGY
News media are invited to participate in a two-day symposium at
NASA
Ames Research Center, Moffett Field, CA, highlighting the
societal
implications of Astrobiology. The workshop will be held
November 16-17 in
the Moffett Training and Conference Center, Bldg. 3, both days
from 8:30
a.m. to 5:00 p.m. (PT).
The workshop will be structured around four basic astrobiology
questions: Why do we search for life? What are the
implications of
human exploration? How should we respond to the possible
discovery of
life elsewhere? What is the evolutionary fate of human
societies and
cultures beyond the home planet?
Speakers/panelists who will be available for interviews include
Nobel
Laureate Dr. Baruch Blumberg, NASA Astrobiology Institute
Director, author
Ben Bova and Charles Harper of the Templeton Foundation.
Astrobiology is the multi-disciplinary study of the origin,
evolution,
dissemination and future of life in the universe.
NASA Ames Research
Center is the NASA "nerve-center" for this research
effort, serving as the
agency's Astrobiology Center of Excellence and as the manager of
the NASA
Astrobiology Institute.
To attend the symposium, simply show your press credentials and
pick
up a visitor badge at the Visitor Badging Office, located to the
right of
the main gate. NASA Ames Research Center is located off
Highway 101 via
the Moffett Field exit.
==============
(4) SERIOUS DOUBTS ABOUT COMETARY DUST LOADING
From Roy Tucker <tucker@noao.edu>
At 12:32 PM 11/8/99 -0500, this was in CCNet:
"Actually his interpretation of the
evidence is more closely
aligned with the suggestion published by Fred
Hoyle and N. Chandra
Wickramasinghe in 1978 that the dinosaur
extinction was due not to
a cometary impact but rather to a dose call.
The logic is
impeccable. The Earth is a tiny target, so for
every strike there
are thousands of close approaches. For
asteroids, only impacts
count. But for comets, a flyby results in our
planet passing
through the cometary coma, which can be larger
than the Moon's
orbit. In such an event, we would accumulate a
mass of dust, which
takes years to settle out of the atmosphere.
These crossings must
occur on millennial time scales. (Napier and
Wickramasinghe are
currently investigating the climatic
effects.)"
Dear Dr. Peiser,
The notion that the passage of the earth through a cometary coma
can
deposit sufficient dust in the atmosphere to have significant
environmental consequences stretches credulity. A major volcanic
eruption can introduce many cubic kilometers of silicate
particles into
the atmosphere, perhaps a volume exceeding the dimensions of the
average cometary nucleus. Even if a cometary nucleus consisted
entirely
of silicate dust and was totally disrupted to fill the volume of
the
coma, the earth would sweep up only a tiny fraction of this
material
even during a central passage.
Let's assume a twenty kilometer diameter cometary nucleus made
entirely
of densely packed silicate particles with a mass of about 10^19
grams.
Let us disperse this material uniformly within a spherical volume
with
a diameter equal to the moon's orbit. The density of material
will be
about 2 x 10^-13 grams/cubic cm. A cylindrical 'core' with a
diameter
equal to that of the earth through the center of this spherical
volume
will contain a total of 2 x 10^16 grams of material. This equal
to
about 7.4 cubic kilometers of the original comet nucleus.
Mount Pinatubo injected about 5 cubic kilometers of material into
the
atmosphere and produced some beautiful twilight colors. Krakatau
produced 18 cubic kilometers. Long Valley spewed 600 cubic
kilometers
and the Yellowstone caldera dispersed 2000 cubic kilometers
(http://quake.usgs.gov/VOLCANOES/LongValley/sizes.html).
I think a little more information is required about their
hypothesis.
Simple introduction of dust into the atmosphere doesn't seem to
be a
compelling argument for environmental devastation from the skies.
Best regards,
- Roy Tucker
==============
(5) ARTHUR C. CLARKE AND ALTERNATIVE UTOPIA MODELS
From Andrew Glikson <geospectral@spirit.com.au>
Dear Benny,
In his early century novel "First and Last Man", which
predicted
world wars I and II, Olaf Stapledon portrays a future race
obsessed with the design of computers, which in turn take over
and
program a new human species. In revisiting the theme, Arthur
Clarke wrote: "The tool we have invented is our
successor.
Biological evolution has given way to a far more rapid process -
technological evolution. To put it bluntly and brutally, the
machine we have invented is going to take over" (Profiles of
the
Future, 1962).
In the wake of the realization this century of many of Jules
Verne's predictions, "conventional wisdom" suggests
that today's
science fiction is tomorrow's fact. However, since clearly not
everyone's imagination will become an actuality, reality tests
are
needed to evaluate the likelihood of future developments. The
central philosophical question is - does Homo Sapiens has any say
in the matter? Can it, for example, choose between
"green utopia"
(a return to nature) and "space utopia" (space
colonization), or
does it follow a deterministic trend of evolution?
Which is the factor underlying the optimism/pessimism debate
(CCNet 8.11.99). The authors are concerned with two different
kinds of "truth" - Malcolm Miller with the destruction
of the
planetary environment, while Benny Peiser emphasizes the
undeniable human need for hope, inspite of the odds!
Not having the answers, may I offer the following perspectives:
1. Neither "green utopia" models nor "space
utopia" models provide
an answer for the exponentially multiplying human population. A
pristine earth can only support a small number of pre-historic
nomads, nor would space fleets be ever large enough to take the
increasing billions to new green pastures ... such models appear
to be mostly concerned with the fate of small technological and
business elites.
2. In principle, the terrestrial environment itself can be
preserved, for example through reversal of population growth and
GNP rates, reforestation, arrest of soil erosion, sustainable
farming, application of renewable non-polluting energy - which
requires moral/ethical choices as much as technological choices
(an example of such choices - should trees be planted on comets,
as imagined by Freeman Dyson, or in the sub-Sahara and Australia
to arrest the advancing dunes?)
3. If the fundamental force which governs living systems is
growth
- whether proliferation of viruses, multiplication of rabbits, or
space colonization - such consciously self-imposed limits on
growth will constitute the first natural manifestation of free
will - conceivably as great an achievement as an adherence to
deterministic self-destructive expansion!
Andrew Glikson
10 November, 1999
Australian National University
andrew.glikson@anu.edu.au
<mailto:andrew.glikson@anu.edu.au>
===============
(6) BBC REPORT ON ARTHUR C. CLARKE
From David Whitehouse <Dr_D_Whitehouse@email.msn.com>
Dear Benny,
I think the reporter who put together the feature "The
future's not all
bright" slightly missed the point of Arthur's piece in
Nature which I
took as being slightly tongue in cheek to make a serious point
that we
humans may not be regarded as mature or desirable by any aliens
out
there. Although I believe that the reporter would have been
better
advised to say "alien civilisations COULD welcome the
annihilation of
the human race" rather than "alien civilisations
SHOULD..." I think the
article as a whole was OK though I do wish they had checked it
with me
first! Someone once said that journalism is literature in a
hurry,
sometimes in too much of a hurry.....
I too have read the article in Nature and don't think that the
Online
feature was too sinful. Arthur's comments were in the last two
paragraphs of a 24 paragraph feature that dealt with some of the
less
comforting predictions about the future. And having read the book
in
question I see nothing wrong in that even though some of the
contributions to the book were rather silly.
On other points raised recently in CCNet;
I'm not so sure that we are coming to realise the
"disastrous history
of life on Earth" although obviously we now accept that
cataclysmic
impacts occur, something that wasn't accepted 20 years ago. Even
with
these impacts life on Earth has not been a disaster, far from it.
The
history of life on Earth is certainly a far less disastrous story
than
the history of life on say, Mars (so far). Besides, what was a
disaster
for the dinosaurs certainly wasn't for us. I don't think that the
story
of a planet that has had some form of life on it for well over
four
billion years is disastrous.
It is likely that life arose on the primitive Earth which was
sterilised by giant impacts and then, after cooling, it arose
again.
Perhaps if life on Earth was wiped out tomorrow (and it doesn't
take
too large an asteroid to melt all the surface rocks on our planet
and
boil all the oceans) it would rise again, the Earth could spare
another
four billion years with ease.
I wonder. When the Sun has become a red giant and life on Earth
is a
distant memory, will it be the species that evolved from humans
that
will be the Earth's legacy to the intelligent universe?
It has been said on CCNet that there is no reason to suppose that
the
future will be as bleak as the past. Conversely it could be said
that
there is no reason to suppose that the future will be as good as
the
past.
As many in the book "Predictions" pointed out we are on
the cusp of a
new age where our capabilities will be unprecedented in the
history of
our species and our planet. These capabilities will not just be
straightforward extensions of abilities we have always had such
as
transport but of a fundamentally new nature - the ability to
manipulate
at a sophisticated level the building blocks of life, the
engineering
by electronic or biological (or both) means of
consciousness...unless
an asteroid comes our way and delays these events by a few
billion
years.
Regards,
David
Dr David Whitehouse
BBC
===============
(7) LOOKING ON THE BRIGHT SIDE OF LIFE
From Benny J Peiser <b.j.peiser@livjm.ac.uk>
Dear David
Many thanks for your clarification which is much appreciated. I
fully
understand that you are protecting your colleague from criticism,
but I do feel that the report may have misled many of your
readers to
believe that Arthur C Clarke has finally turned to cosmic
fatalism.
I must admit that I haven't yet read the "Predictions"
made by a number
of eminent scientists. But according to the BBC review of the
book, it
would appear that most of the quoted authors have a rather
pessimistic
view of the future. Is there any hard evidence for these dark
visions?
Hasn't it occurred to the authors that many similarly gloomy
fin-de-siecle prophecies in the past have also failed to
materialise?
Is there more starvation and poverty in the world then, say, 50
or 100
years ago? Are we dying younger? Are diseases on the increase? Is
there a regression in technological and societal development? Are
we
running out of our most vital resources? Obviously not! The fact
is
that most of the world's societies, in particular underdeveloped
countries, have become wealthier and healthier since the 1950s!
Don't get me wrong, I am far from being an optimist - the 20th
century
has proven to be too cruel and violent to be that naive! What I
object
to, however, are unsubstantiated predictions based on subjective
sentiments that convey the message that the human race is somehow
doomed in the next century, the next millennium, or whenever.
This view
of almost inherent failure of human nature is - it would appear -
nothing but a mirror image of the old Christian idea of man's
fall from
grace, i.e. the notion of original sin. I am only too aware that
this
is a deeply ingrained philosophy that is difficult to overcome.
But I
also know that there are many other scientists, myself included,
who
tend to look on the bright side of life.
Let me finish by congratulating you on managing a really
excellent
science website at the BBC. I am sure there will be many more
inspiring
BBC science reports in the future.
With best wishes,
Benny
===============
(8) SPACE SETTLERS’ SUPPORT FOR SPACEGUARD UK
From Andy Nimmo <andy.nimmo@net.ntl.com>
Dear Dr Peiser,
Just a short note to thank you for publishing Dr Michael
Martin-Smith's
very interesting essay. I was particularly interested in his
updating
of some of the facets of the Drake equation, but still leaving us
with
the mysterious "V". One of the dangers he mentions is
that of impact, a
matter of particular concern to members of CCNet. He also
mentions,
"Three organizations - Space Age Associates, the Greater
Earth
Initiative, and Technology of Frontiers" who are indeed
doing good work
to spread the idea of diaspora into space.
Some of your readers may be interested to know that there is
another
older UK-based organization that has been doing this for some
time, the
Space Settlers' Society. While we are a space-politics group, we
are
strictly non-party. Throughout November we are running a lead
campaign
item on the Space News pages of our website in favour of the
Spaceguard
UK Task Force. See http://www.soar.to/SpaceSettlers
.
As Jay Tate pointed out in his campaign letter, (available in
full on
the website) according to "Dr David Morrison of NASA, there
are more
people working in an average McDonalds outlet than there are
working on
the detection of Near Earth Objects."
We want to help Spaceguard get this UK Task Force up and running,
and
help get UK politicians sufficiently interested to put up the
funding.
Any CC Net reader may take part. You don't have to be a member of
either Spaceguard or Settlers. The more folk who write UK
politicians
the better, and Lembit Opik M.P., would be most grateful if those
resident in the UK would also send him a postcard telling him
they've
done so, as he will later be able to use the total number of
these as
campaign ammunition.
There is a saying that 'God helps those who help themselves'.
Whether
one believes in 'God' or not, politicians do pay attention to
letters,
particularly those from academics, and while I know CCNet is not
political I believe we should all do our utmost to help prolong
"V".
Best wishes,
Andy Nimmo (President: the Space Settlers' Society).
----------------------------------------
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----------------------------------------
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*
CCNet SPECIAL, 11 November 1999
WAITING FOR THE LEONIDS
-------------------------------
QUOTE OF THE DAY
"It is sometimes said that comets
are like cats: they have tails
and are unpredictable. If that's the
case, predicting a meteor
storm has to be about as easy as herding
cats! But Asher and
McNaught believe they have discovered
how to do it. The 1999
Leonids will be a serious test of their
method."
-- Mark Bailey, Armagh Observatory, 10 November 1999
(1) LOOK OUT FOR THE LEONID METEOR SHOWER
Jacqueline Mitton <aco01@dial.pipex.com>
(2) AIR FORCE SPACE COMMAND PREPARED TO WEATHER METEOR SHOWER
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) AROUND THE WORLD IN 8 DAYS - STUDYING THE LEONIDS
Ron Baalke <baalke@ssd.jpl.nasa.gov>
(4) HEADS UP! THE LEONIDS ARE COMING
NASA Science News <expressnews@sslab.msfc.nasa.gov>
(5) NASA ENGINEERS TO MONITOR LEONID METEOR SHOWER
Ron Baalke <baalke@ssd.jpl.nasa.gov>
(6) LEONID METEOR WATCH AN EXPANDED EFFORT
Ron Baalke <baalke@ssd.jpl.nasa.gov>
=============
(1) LOOK OUT FOR THE LEONID METEOR SHOWER
From Jacqueline Mitton <aco01@dial.pipex.com>
ROYAL ASTRONOMICAL SOCIETY
PRESS NOTICE
LOOK OUT FOR THE LEONID METEOR SHOWER
Date: 10 November 1999
For immediate release
Ref. PN 99/33
ISSUED BY:
Dr Jacqueline Mitton
RAS Press Officer
Office & home phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@dial.pipex.com
and
Peter Bond
RAS Press Officer (Space Science)
Phone: +44 (0)1483-268672
Fax: +44 (0)1483-274047
E-mail: 100604.1111@compuserve.com
RAS web: www.ras.org.uk/ras/press/press.htm
* * * * * * * * * * * * * * * * * * * * * * * *
CONTACTS FOR THIS RELEASE
Professor Mark Bailey (meb@star.arm.ac.uk)
Armagh Observatory, College Hill, Armagh, BT61 9DG
Tel: 028-3752-2928, Fax: 028-3752-7174
Professor Iwan Williams (I.P.Williams@qmw.ac.uk)
Queen Mary and Westfield College, London.
Tel: 020-7882-5452, Fax: 020-8983-3522
MORE INFORMATION
on the Armagh Observatory Leonid web site:
http://www.arm.ac.uk/leonid/index.html
* * * * * * * * * * * * * * * * * * * * * * * *
The 1999 Leonid meteor shower should produce a fine display in
the
early hours of the 18th of November, Professor Mark Bailey of
Armagh
Observatory will tell the Royal Astronomical Society's meeting on
Friday 12th November. Research done at Armagh, and by other
experts
around the world, suggests that an unusually strong shower is on
the
cards this year when Earth passes through streams of dust that
have
been shed by Comet Tempel-Tuttle.
Professor Bailey is putting his confidence in the work of his
colleague
at Armagh, Dr David Asher, who collaborated with Rob McNaught of
the
Australian National University. They believe they have discovered
enough about the location in space of the dust streams
responsible for
the meteors to give 2.08 a.m. on 18th November, give or take 5
minutes,
as the time for the peak of the display.
The number of meteors is more difficult to assess. Dr Asher says,
"It's
marginal as to whether the meteor activity will reach storm level
in
1999, but however strong it turns out to be, European longitudes
are
ideally placed for observing the outburst". His best
estimate is a
maximum of 20 meteors a minute visible to a single observer in
ideal
conditions under a clear, dark sky (conditions rarely experienced
by
casual observers). Professor Iwan Williams of Queen Mary and
Westfield
College, London, who has also done research on the Leonids, is
more
cautious, but said "Most models lead us to expect a better
display than
last year". Neither Asher nor Williams expects anything like
the
spectacular storm of 1966, when the rate reached 40 a second for
a
brief period.
Professor Bailey comments, "It is sometimes said that comets
are like
cats: they have tails and are unpredictable. If that's the case,
predicting a meteor storm has to be about as easy as herding
cats! But
Asher and McNaught believe they have discovered how to do it. The
1999
Leonids will be a serious test of their method."
Minimising the Danger to Satellites
A reliable method of predicting strong meteor showers such as the
Leonids has real practical value. The Leonids are the fastest of
all
meteors, plunging into the Earth's upper atmosphere at 71 km/s -
40
times the speed of a rifle bullet. Despite their small size, the
tremendous speed of the Leonids means they pack a mighty punch.
Apart from knocking a spacecraft off alignment or causing
physical
damage, such collisions can also generate a cloud of plasma which
may
cause electrical shorts or damage a spacecraft's sensitive
electronics.
This threat is not simply theoretical. In 1993, a European Space
Agency
satellite called Olympus spun out of control, possibly as the
result of
an electrical disturbance caused by the impact of a particle from
the
Perseid meteor shower. There are currently more satellites in
orbit
around the Earth than ever before, all of which pose a tempting
target
for one of nature's miniature missiles.
Fortunately, impacts with spacecraft are quite rare, but
satellite
operators around the world will be monitoring the situation very
closely and taking a variety of precautions.
"There could be a lot of activity, but we just don't know
for sure,"
commented Dr Walter Flury of the European Space Operations Centre
(ESOC) at Darmstadt in Germany. "It's better to take
precautions now
than be sorry later."
The European Space Agency's Space Science Department will provide
information on meteor numbers to ESOC every 15 minutes. Using
this data
and radar counts from other sources, ESOC will be able to issue a
security alert, warning spacecraft operators to power down their
spacecraft or turn them away from the storm.
One of the largest targets, the NASA-ESA Hubble Space Telescope
will be
manoeuvred so that its mirrors face away from the incoming
meteors and
its solar arrays are aligned edge on to them during the Leonids'
predicted peak.
Apart from reducing the exposed area of giant solar arrays,
operators
may shut off power to vulnerable electrical components of
satellites.
In the case of ESA's two European Remote Sensing (ERS)
satellites, all
of the science instruments will be switched off during the peak
of the
Leonid activity.
Even spacecraft located some distance from the Earth may be at
risk.
ESA's Solar and Heliospheric Observatory (SOHO) studies the Sun
from a
vantage point 1.5 million kilometres away, but it, too, will be
turned
so that its main navigational aid, the star tracker, is pointing
out of
harm's way.
Expecting the unexpected
Since meteor showers - the Leonids especially - are given to
springing
surprises, it will definitely be worth watching out on the nights
of
both 16/17 and 17/18 November, any time between 11 p.m. and dawn,
though after midnight is best.
Meteor watchers awaiting the Leonid shower last year (1998) were
taken
by surprise when a spectacular display of bright meteors occurred
16
hours before the predicted time for the maximum of the shower.
However,
the explanation for this phenomenon was discovered afterwards by
David
Asher, Mark Bailey, and Professor Vacheslav Emel'yanenko of South
Ural
University, Chelyabinsk, Russia, and was published in April (see
RAS
Press Notice 99/09). They showed that the bright meteors were
seen when
Earth passed through a dense arc-shaped trail of particles shed
from
Comet Tempel-Tuttle in the year 1333.
NOTES
Meteors are caused by small fragments of material, mostly no
larger
than a grain of sand, which burn up as they enter Earth's
atmosphere at
high speed - around 71 kilometres (45 miles) per second in the
case of
the Leonids.
Leonid meteors are dust particles that have come off Comet
Tempel-Tuttle. Most of this dust is still following the comet
fairly
closely in space. The comet takes 33 years to complete an orbit
around
the Sun, and planet Earth ploughs through its main dust trail
when the
comet returns to our vicinity every 33 years. In the years when
this
happens, a strong shower or storm takes place. Particularly
intense
storms were recorded in 1833, 1866 and 1966. In the years between
returns of the comet, a very small number of Leonid meteors are
seen in
mid-November.
Some meteor showers produce about the same rate of meteors around
the
same date every year. Regular annual showers happen when the dust
from
a comet has spread around the whole of the comet's orbit,
something
that takes place gradually over a long period of time. An example
is
the Orionids, a shower in late October each year caused by dust
from
Halley's Comet.
The Leonids are so-called because the trails of the meteors
belonging
to the shower appear to radiate out from a point in the
constellation
Leo. But this is an effect of perspective. In reality, the meteor
particles enter the atmosphere along parallel tracks from the
same
direction in space.
People who wish to observe the Leonids are recommended to wrap up
in
warm clothes and find a cloud-free, dark site away from city
lights,
preferably with a good view towards the north-eastern horizon.
Between
about 11 p.m. and dawn, they can expect to see rapidly moving
shooting
stars anywhere in the north-eastern sky, emanating from the
'sickle' (a
backwards question mark) made up by the stars in the head of the
constellation Leo.
===============
(2) AIR FORCE SPACE COMMAND PREPARED TO WEATHER METEOR SHOWER
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Air Force Space Command News Service
Released: 10 Nov 1999
AFSPC prepares to weather Leonid meteor shower
By Nicole VanNatter, Air Force Space Command Public Affairs
PETERSON AIR FORCE BASE, Colo. (AFPN) -- Air Force satellites are
expected to sail through the potentially worst meteor shower in
33
years; however, Air Force Space Command people are not leaving
anything
to chance.
AFSPC and other national agencies have been diligently working on
a
host of plans and operations that will ensure critical
communication,
navigation and surveillance systems stay operational.
This year marks what is likely to be the last in the 33-year
cycle of
the comet Tempel-Tuttle that produces what is commonly known as
the
Leonid meteor shower. The height of the Leonid meteor shower will
be
the evening of Nov. 17 in most of North America.
Tempel-Tuttle has been orbiting the sun opposite the Earth for
nearly
2,500 years, but only poses a potential threat to the Earth three
years
out of each 33-year cycle said Lt. Col. Don Jewell, AFSPC's
deputy
chief scientist.
The comet travels 43 to 45 miles per second, relative to Earth's
orbit,
leaving a huge trail of dust through which the earth travels when
their
paths cross. The Temple-Tuttle is one of the fastest comets known
to man.
The increased speed makes the comet's particles more dangerous to
space
satellites. The debris trail of the comet contains particles from
0.04
to 0.40 of an inch in size.
Radiation hardening gives military satellites greater protection
than
civilian satellites from the flying debris. Although the comet
does
contain particles up to 0.40 of an inch in size, the chances of
one of
those hitting a satellite are very small, said Jewell.
"If one of those hit a satellite, it would be like a bullet
hitting a
satellite and certainly it would damage it," said Jewell.
"We don't
anticipate that happening, but we have to plan for it."
And planning is exactly what's been going on since last year's
Leonid
storm.
"This year we are focusing on refining the Leonid plan that
was
developed last year," said Lt. Col. Doug Hine, 14th Air
Force's chief,
space operations branch. "We took lessons learned and
ensured satellite
and ground systems are prepared to weather the storm."
The Leonid storm of 1966 was the last time the meteor shower
impacted
the nations' space assets. The potential harm was minimal though
because America only had 50 or 60 satellites in orbit then, said
Jewell.
The real concern came 32 years later, in 1998, when the United
States
had several hundred military satellites in orbit, operating
everything
from early missile warning to the Global Positioning System.
"Essentially, it was a non-event," said Jewell. Three
civilian
satellites were damaged, but all military space assets were left
unharmed.
There is not expected to be any damage to military satellites
this year
either, said Jewell, but the Air Force is prepared for the worst.
The Air Force began planning for the 1998 Leonid storm a full
year in
advance. Hundreds of thousands of dollars were allocated for
Leonid
preparation, but the money ran out and the analysis of the data
could
not be completed, said Hine.
This year, the Air Force and other sister agencies are poised to
spend
$2 million to proactively protect U.S. space assets, said Hine.
Special electro-optical video equipment will be set up at sites
in
Hawaii, Florida, the Canary Islands, Kwajalein Atoll in the
Marshall
Islands and at two sites in the Negev Desert, Israel, to record
the
storm as it develops. The video signals go to the Marshall Space
Flight
Center in Huntsville, Ala. The center will give real-time storm
warnings when necessary.
The Air Force will also monitor the storm 24-hours a day Nov. 16
through 18 through mobile multi-frequency high-frequency radar
deployed
in Canada.
Additionally, aircraft are being deployed Nov. 16 to perform
high-altitude observation and collect data on the Leonid storm.
"We don't want to downplay this. We plan for the worst and
hope for the
best," said Hine. "Air Force Space Command has
experienced and
well-trained crews who are prepared and ready to respond to any
problems
that may surface during the storm."
The good news is, when Nov. 17th is over, so are the short-term
Leonid
worries. "We won't have any problems with it again for about
another 30
years," said Jewell.
So what's the advice for people Nov. 17? Sit back and enjoy
because "it
ought to be a beautiful show," said Jewell.
================
(3) AROUND THE WORLD IN 8 DAYS - STUDYING THE LEONIDS
From Ron Baalke <baalke@ssd.jpl.nasa.gov>
Air Force News Service
Released: 9 Nov 1999
Edwards to ferry NASA scientists around world in 8 days to study
Leonid
By Ray Johnson, Air Force Flight Test Center Public Affairs
EDWARDS AIR FORCE BASE, Calif. (AFPN) -- After a weak celestial
show in
1998, NASA's Peter Jenniskens dreamed of chasing Leonid meteor
storms
once again in 1999.
"This will be our last shot at it for a century," he
said after last
year's effort. "The mission we have in mind would circle the
world, and
do that in just a few days."
He's getting his wish with two Edwards airplanes: a modified
KC-135
tanker called the Flying Infrared Signature Technology Aircraft,
or
FISTA, and an EC-18 that normally serves as an Advanced Range
Instrumentation Aircraft, or ARIA.
Both aircraft, which belong to the 452nd Flight Test Squadron,
and 25
airmen will ferry 50 scientists on an eight-day, 18,000-mile
journey
that will take them from the Mojave Desert to Europe to the
Middle East
and back. The researchers' intent: to gather data during a
natural
fireworks show called Leonid.
A Leonid meteor shower occurs every November when Earth passes
close to
the orbit of comet Tempel-Tuttle. Usually not much happens,
according
to NASA officials. Earth plows through a diffuse cloud of old
comet
dust that shares Tempel-Tuttle's orbit, and debris burns up
harmlessly
in the atmosphere.
Typical Leonid meteor events consist of only 10 to 20 shooting
stars
per hour. But every 33 years, that meek shower surges into a
full-fledged storm, when thousands of shooting stars rain down
from the
sky hourly.
That's what Jenniskens and his crew hope to witness on this trip.
The two-ship formation leaves here Nov. 13 with the first stop
being a
"gas and go" at McGuire Air Force Base, N.J., said
Capt. Jeff Lampe,
aircraft commander for FISTA. From there it's on to Royal Air
Force
Mildenhall, England, where they'll launch late Nov. 16 for a
seven-hour
mission to Tel Aviv, Israel, hoping to capture a streaking light
display in clear, dark skies.
The next night they will leave on their main flight, an
eight-hour
mission to Lajes Field, the Azores, a small island several
hundred
miles off the coast of Portugal. It's there scientists believe
they
will follow a trail of thousands to tens of thousands of meteors
per
hour.
On this route, the two Edwards planes will fly 100 miles parallel
to
each other, giving researchers "an almost stereoscopic
(three-dimensional) viewing," said Maj. Tracy Phelps,
commander of the
EC-18.
Finally, the team will fly another seven-hour mission from Lajes
to
Patrick AFB, Fla., Nov 18-19, and then return home Nov. 20.
With powerful telescopes scattered throughout the world, some
people
might wonder why take such a time-consuming trip. The answer:
Only an
airborne mission can bring scientists to the right place at the
right
time to view Leonid, and guarantee clear weather. Moreover, using
both
the FISTA and C-18 allows scientists to measure meteor
trajectories and
orbits in space along with triangulating data.
Indeed, this mission centers on two Edwards aircraft serving as
observation platforms for cameras and investigative instruments.
Therefore, both planes have undergone modifications for the
journey,
including installation of optical windows, special camera gear
and
antenna mounts.
And besides helping collect data for NASA, the C-18 also will
downlink
real-time video for Air Force Space Command.
Capt. Jon Haser participated in last year's Leonid event and will
be
going again this year. He said the crews didn't get the expected
meteor
storm.
"It was sporadic, but they were some persistent trails that
lasted five
seconds or so. Hopefully, the sky's alive this time."
Maybe he will get to witness what James Young of the Jet
Propulsion
Laboratory's California Table Mountain Observatory did in 1966,
when
the last great Leonid storm occurred. He remembers a heaven
"absolutely
full" of meteors. Young called it a "sight never
imagined ... and never
seen since."
IMAGE CAPTIONS: [http://www.af.mil:80/news/Nov1999/n19991109_992056.html]
[Image 1]
An EC-18 aircraft from the 452nd Flight Test Squadron, Edwards
Air Force
Base, Calif., will transport NASA scientists overseas to study
the Leonid
meteor storm. The EC-18, which normally serves as an Advanced
Range
Instrumentation Aircraft, or ARIA, also will downlink real-time
information
to Air Force Space Command during the storm. (Courtesy photo)
[Image 2]
Capt. Jamie McKeon, left, Capt. Jon Hasser, Capt. Jeff Lampe and
Maj.
Tracy Phelps plan the 452nd Flight Test Squadron's eight-day
mission
for the Leonid meteor shower. The Edwards Air Force Base, Calif.,
unit
is flying NASA scientists overseas to study the Leonid meteor
storm in
modified EC-18 and KC-135 aircraft. (Photo by Dennis Taylor)
===============
(4) HEADS UP! THE LEONIDS ARE COMING
From NASA Science News <expressnews@sslab.msfc.nasa.gov>
NASA Science News for November 10, 1999:
Heads Up! - The upcoming Leonids meteor shower (Nov. 17-18)
is
predicted to be the biggest in decades and perhaps for the
next
century. While we are safe on the ground, satellite operators
are concerned that even small impacts could short-circuit
satellites.
NASA will coordinate a team that helps track changes in the
shower
that could be a storm. Full story:
http://science.nasa.gov/newhome/headlines/ast10nov99_1.htm
===============
(5) NASA ENGINEERS TO MONITOR LEONID METEOR SHOWER
From Ron Baalke <baalke@ssd.jpl.nasa.gov>
Steve Roy
Media Relations Department
Marshall Space Flight Center
Huntsville, AL
(256) 544-0034
Steve. Roy.@msfc.nasa.gov
http://www.msfc.nasa.gov/news
For Release: Nov. 9, 1999
RELEASE: 99-281
NASA Engineers to Operate Center for Monitoring Leonids Shower;
Scientists to Launch Balloon for Clear View of Leonids Meteors
To keep their satellites operating smoothly, NASA, the U.S. Air
Force
and the University of Western Ontario in London, Ontario, will
soon
open and operate the first center for monitoring the annual
Leonids
meteor shower around the clock.
In a separate effort to learn more about these dazzling
fireballs, NASA
scientists will launch a balloon to record meteor images and
sounds --
and maybe even catch a piece of a "shooting star."
A Leonids shower happens every year when Earth passes close to
the
orbit of the comet Tempel-Tuttle and the debris left in the
comet's
path. As Earth travels through the comet dust, the debris burns
up in
Earth's atmosphere, and observers typically see about 10 to 20
shooting
stars an hour. But some experts predict this year's annual shower
may
turn into a "storm" -- a spectacular display of 1,000
meteors per hour
or more.
To monitor any increases in meteor activity, the Leonid
Environment
Operations Center at NASA's Marshall Space Flight Center in
Huntsville,
Ala., will be staffed 24-hours a day from the afternoon of Nov.
15
until the shower has passed on Nov. 19.
Marshall Center engineers will coordinate and distribute
pre-Leonid
storm information and real-time observations about Leonid
activity,
intensity and potential threat to NASA and U.S. Air Force
spacecraft. A
worldwide network of radar and optical observation sites
sponsored by
the Air Force and operated by the University of Western Ontario
will
send information to the Leonid Environment Operations Center at
Marshall, where scientists and engineers will analyze the
information
and distribute it to satellite operators.
"NASA, the Air Force, the University of Western Ontario and
several
other organizations have teamed together to provide these space
weather
updates to keep spacecraft operators well informed so they can
best
protect our satellites," said Dr. Jeff Anderson of the
Marshall
Center's Engineering Directorate. "Monitoring the Leonid
meteor stream
also provides a rare look at a natural phenomenon that will
continue to
grow in importance as more and more satellites orbit our planet,
and we
venture deeper into space."
Although a typical meteor is smaller than a grain of sand, it
travels
more than 40 times the speed of a bullet. The Leonids are the
fastest
of all the meteor streams, fast enough to circle the globe in
less than
10 minutes. Meteor impacts can impair satellites and their
sensitive
sensors.
Space weather forecasts are not something one hears on the
nightly news
because they are tricky at best. Will this year's annual Leonids
display be just a shower -- a few to a few hundred shooting stars
per
hour? Or will it be a storm -- a few thousand to a few hundred
thousand
meteors an hour?
"In 1998, the world watched and nothing happened," said
Anderson. "But
in 1966, most folks in the western U.S. were sleeping while one
of the
most spectacular displays in history was going on over their
heads."
It is because many experts are predicting a storm this year that
the
Marshall Leonid Operations Center is being staffed around the
clock
during the shower. Just last year, the comet Tempel-Tuttle
visited our
inner solar system, depositing a dense cloud of debris. But
because
Earth crossed the comet's orbit too soon after the comet's
passage,
there was no storm -- just a strong shower.
In 1999, the Earth will pass only 68,200 miles (110,000
kilometers)
from the comet debris cloud, making a storm more likely.
In another activity, Marshall scientists will work to give the
public a
clearer view of the streaking fireballs. Weather permitting, they
will
launch a 10-foot (3-meter) diameter weather balloon from
Marshall's
Atmospheric Research Facility at approximately 12:30 a.m. CST,
early
Thursday morning Nov. 18. The balloon will ascend approximately
20
miles (32 kilometers), carrying a sensitive camera for capturing
pictures of the meteors. During the flight from around 12:30 a.m.
to
3:30 a.m. CST, both still and low-resolution television from the
onboard camera can be viewed online at the Science Directorate's
Web
site at
http://www.leonidslive.com
Last year, more than one million people tuned into the live Web
cast or
saw the replay the next day on the Web site. This year a new
feature
will be a recording device that sends back sounds of meteors from
space. Visitors to the Web site will be able to hear the
"whistlers"
and other bizarre noises that meteors make as they interact with
ionized gas or plasma in the Earth's atmosphere. Scientists hope
to use
this radio receiver to record very low frequency electromagnetic
emissions below 10 kHz emitted by the meteors.
A capture device on the balloon may even bring back a meteor
particle.
Scientists are still analyzing data from an aerogel-collecting
device
that was flown last year to capture bits of comet Tempel-Tuttle.
The
meteoroid capture device on the upcoming flight uses xerogel, a
close
relative of aerogel, and a variety of low-density acrylic
materials.
"It works like flypaper," said Dr. John Horack, an
astronomer at the
Marshall Center. "We expose these materials to the air up in
the
stratosphere while the meteor shower is under way. When tiny
particles
strike the exposed xerogel, they stick."
Note to Editors / News Directors: Media are invited to schedule a
visit
to view the Leonid Environment Operations Center during
operations from
Nov. 16-19. Media also may watch the balloon launch scheduled for
approximately 12:30 a.m. CST, Thursday, Nov. 18, weather
permitting. To
attend the balloon launch or visit the Leonid Center, media
should
contact Steve Roy of the Marshall Media Relations Department at
(256)
544-0034.
Interviews, photos and video supporting this release are
available to
media representatives by contacting Roy. For an electronic
version of
this release, digital images or more information, visit
Marshall's News
Center on the Web at:
http://www.msfc.nasa.gov/news
For information about the U.S. Air Force role during the Leonid
storm, contact
Lt. Col. Don Miles at (719) 554-3842.
IMAGE:
NASA Photo #9906509 : To keep their satellites safe, this month
NASA,
the U.S. Air Force and the University of Western Ontario will
operate
the first center for around-the-clock monitoring of the annual
Leonids
meteor shower. From left, NASA engineers Dr. Bill Cooke, Dr. Jeff
Anderson and Dr. Rob Suggs discuss the meteoroid approach angles
at the
Leonid Environment Operations Center at NASA's Marshall Space
Flight
Center in Huntsville, Ala. Engineers will coordinate and
distribute
pre-Leonid storm information and provide pdates to satellite
operators
about Leonid activity, intensity and potential threat to
spacecraft.
(NASA Marshall Space Flight Center Photo by Emmett Given)
This print-quality photo may be downloaded at:
http://www1.msfc.nasa.gov/NEWSROOM/news/photos/1999/photos99-281.htm
==============
(6) LEONID METEOR WATCH AN EXPANDED EFFORT
From Ron Baalke <baalke@ssd.jpl.nasa.gov>
Dept. of Communications and Public Affairs
University of Western Ontario (UWO)
London, Ontario, Canada N6A 5B8
Tel. (519)661-2045 Fax: (519)661-3921
http://www.uwo.ca
FOR IMMEDIATE RELEASE: October 25, 1999
'99 LEONID METEOR WATCH AN EXPANDED EFFORT
A team of UWO researchers is stepping up its efforts this year to
monitor November's rare and potentially-hazardous Leonid meteor
stream.
The stream, scheduled to pass through the Earth's atmosphere on
Nov. 17
and 18, could produce hundreds to thousands of meteors per hour.
A
potential storm component may result in much higher rates --
causing a
spectacular display of faint meteors in some parts of the world
but
also a potential risk to any of the close to 600 operational
satellites
orbiting Earth.
"The Leonid shower hits its peak every 33 years and this is
the peak
year," says team member Margaret Campbell, a PhD student in
physics and
astronomy.
The UWO team led a monitoring effort from Mongolia and Australia
last
year as a lead-up to this year's anticipated larger storm.
With financial and logistical backing from the U.S. Air Force,
NASA,
the Canadian Space Agency, Canada's Department of National
Defence, and
the European Space Agency, the researchers are setting up
monitoring
sites in seven locations around the world.
Kerry Ellis, a UWO graduate, will operate an Australian-built
radar
that uses high-tech Canadian-designed and constructed radar
antennas
that will monitor the Leonid stream from Alert, Nunavut. Special
electro-optical video equipment will be set up at sites in
Hawaii,
Florida, the Canary Islands, Kwajalain Atoll in the Marshall
Islands
and at two sites in the Negev Desert, Israel to record the storm
as it
develops. The data collected from these seven sites will be
transferred
to a communications centre at NASA's Marshall Space Flight Centre
in
Huntsville, Alabama. From Alabama, NASA and UWO researchers will
compile and profile the data so government, military and
commercial
satellite operators can access it.
Physics and astronomy professor Jim Jones together with
engineering
professor Alan Webster and UWO graduate Bruce McIntosh will help
lead
the NASA team in Alabama. Professor Robert Hawkes of Mount
Allison
University and UWO physics and astronomy graduate students
Margaret
Campbell and Simona Nikolova will manage the sites in Israel.
Peter Brown, a physics and astronomy research associate at
Western, is
the overall project manager for the monitoring effort. He will be
at
the observation site in the Canary Islands during the storm.
Brown stresses the long-term objective of the meteor watch is to
gain
better insight into how comets and meteoroids streams form and
evolve.
"Comets are made of materials formed long before life
existed on
Earth," he says. "Understanding them may help us
understand how life
evolved on our planet."
The monitoring sites were chosen because they lie along what is
expected to be the best longitude for viewing. The storm is
predicted
to peak at approximately 9:20 p.m. EST on Nov. 17.
Sky watchers shouldn't expect to see much activity in southern
Ontario
however, says Brown.
"We're not in a good location for viewing," he says.
"While this year's
storm is expected to present a higher risk to satellites, it is
largely
because there are more small particles. That means fewer bright
fireballs,
even for people in the best geographical location."
Campbell will travel to Israel on Nov. 10 to set up the sites
there.
Brown will depart for the Canary Islands on Nov. 11. Other
scientists
from around the world will be involved at all sites.
For more information, Margaret Campbell can be reached until Nov.
10 at
(519) 850-2385. Peter Brown can be reached between Oct. 29 and
Nov. 11
at (519) 661-2111 ext. 86458. Judy Noordermeer, Communications
and
Public Affairs, can be contacted at (519) 661-2111 ext. 85468.
Attention Broadcasters: Western has installed Bell's VideoROUTE
service
that allows for live or pre-taped broadcast interviews with
television
studios. To arrange to interview the experts on this story using
this
service, please call (519) 661-2111 ext. 85468 or ext. 85165. A
30-second Betacam animation clip of the comet and storm is also
available.
***
QUESTIONS AND ANSWERS
What is the difference between a meteor, a meteoroid and a
meteorite?
A meteoroid is any solid particle larger than a molecule and
smaller
than an asteroid which is in orbit about the sun. When a
meteoroid
collides with the Earth, the frictional heating with the Earth's
upper
atmosphere produces light, heat and (for deeply penetrating
meteoroids)
sound phenomena called a meteor. If a meteoroid is large enough
to
survive its passage through the atmosphere as a ponderable mass
it is
termed a meteorite. The Leonid shower does not produce meteorites
as
the meteoroids move too fast to allow any material to survive.
What is a meteor shower?
A meteor shower occurs when the Earth, in its annual journey
around the
Sun, passes through a stream of dust particles (called a
meteoroid
stream) strewn along the path of a comet. Dust particles from the
stream collide with the Earth's upper atmosphere at speeds of up
to 72
kilometres per second (260 times the speed of sound) and are
rapidly
vaporized at heights between 80 and 120 kilometres above the
ground,
producing the brief streaks of light that we call a meteor
shower.
What is the Leonid Meteor Shower?
First reported by Chinese astronomers in 902 A.D., the Leonid
meteor
shower is so named because it appears to radiate from the
constellation
Leo. It is normally observed every year between November 14 and
20
during which time as many as 20 meteors are visible each hour.
However,
the shower is most famous for the periods of much greater
activity that
have, with a few exceptions, occurred at intervals of about 33
years.
This is a year in which greater activity is possible.
At its peak this year on Nov. 17, hundreds to thousands of
meteors an
hour could hurtle through the sky. Although most meteoroids will
be no
larger than a grain of sand, the shower has been so active in the
past
that it has taken on the appearance of falling snow.
What's the difference between the '99 Leonid storm and the '98
Leonid storm?
This year's storm will almost certainly be as intense, or more
intense
than last year -- this is the peak of its 33-year cycle. While
the
meteoroids will be smaller this year, the risk to satellites will
be
greater because of their greatly increased numbers. Smaller
particles
also mean there will be fewer bright fireballs than were seen
last
year.
What's the danger?
Although small, the meteoroids are moving so fast that they
possess a
great deal of energy. They could poke holes in solar panels, pit
lenses, blast reflective coating off mirrors, short out
electronics
with a burst of electromagnetic energy, or even damage computers
on
satellites. While some military satellites are better shielded
because
they are built to withstand nuclear assault, other spacecraft are
not
as protected.
In Canada, for example, damage to any of the Anik satellites
might shut
down TV transmission, some telephone service, electronic banking,
and
airline and travel reservation systems. The Leonids could also
harm the
American Hubble space telescope and the Russian space station
Mir, for
example.
Why monitor the shower from Israel, Hawaii, Florida, the Marshall
Islands and the Canary Islands?
The Leonid meteor shower will be most intense across the
longitudes of
Israel and the Canary Islands. The other sites cover a wide
spread in
longitudes, allowing observation of the shower for 18 continuous
hours,
even though it will be up in darkness for only about six hours
from any
individual site. These locations also have a good probability of
clear
skies -- necessary for the electro-optical equipment. The radar
has been
set up in Alert because the shower will be visible 24 hours a day
there.
Alert is also too far north for aurora, which interfere strongly
with radar
observations.
Will we see the Leonids in Southern Ontario?
Southern Ontario is not a good viewing location for the Leonid
meteor
shower. The shower will be strongest around the longitudes of
Europe
and the Middle East; however, Europe has a low chance of clear
skies in
mid-November, so it is not the best observing location.
What scientific questions can meteor monitoring answer?
The long-term objective of the Leonid meteor watch is to gain
better
insight into how comets and meteoroid streams form and evolve.
Comets
are made up of material originating from a halo of ice and dust
that
has surrounded the solar system long before life existed on
Earth.
Understanding them may help scientists understand how life
evolved on
our planet.
How will we know if satellites are at risk of being hit?
The real-time reporting system being coordinated through NASA's
Marshall Space Flight Centre in Huntsville, Alabama will be the
only
coordinated, multi-instrument means of providing immediate
warning
about the shower strength and severity. By analyzing the strength
of
the shower in real-time, scientists will be able to provide some
advanced warning about the most probable time for the showers
peak and,
less reliably, its peak strength.
Who are the members of the research team at The University of
Western
Ontario?
* Dr. Peter Brown, research associate, physics and astronomy --
project
manager
* Dr. Jim Jones, professor of physics and astronomy -- principal
investigator
* Dr. Alan Webster, professor of engineering science --
co-investigator
* Margaret Campbell, PhD student in physics and astronomy
* Simona Nikolova, master's student in physics and astronomy
* Dr. Wayne Hocking, professor of physics and astronomy
With help from:
* Dr. Kerry Ellis, Communications Research Centre, Ottawa
* Dr. Bruce McIntosh, formerly of the National Research Council,
Ottawa
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