PLEASE NOTE:
*
CCNet DIGEST, 23 September 1998
-----------------------------------------------------
(1) POPULAR CULTURE & MAD ASTRONOMY
Michael Gerrad <Michael_Gerrard@aporter.com>
(2) THE NOVEMBER LEONIDS: WILL THEY ROAR?
Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
(3) DINOSAUR EXTINCTION: IMPACT VS VOLCANOES
Piper R.W. Hollier <piper@xs4all.nl>
(4) 800 BILLION $ WIPE-OUT: HAZARDS DUE TO ASTEROID IMPACTS IN
THE PACIFIC OCEAN
S. Yabushita, KYOTO UNIVERSITY
(5) ENVIRONMENTAL ENGENEERING & THE FUTURE COLONISATION OF
PLANET MARS
M.J. Fogg, PROBABILITY RESEARCH
GROUP, LONDON
(6) ESTABLISHING & MAINTAINING AN INHABITABLE ECOSYSTEM ON
MARS
R.L.S. Taylo, BRITISH
INTERPLANETARY SOCIETY
(7) TERRAFORMING & THE COMING 'CHARM' INDUSTRY
F. Turner, UNIVERSITY OF
TEXAS
(8) THERMAL DESTRUCTION OF SOLIDS NEAR THE SUN
L.I. Shestakova*) & L.V.
Tambovtseva, NATIONAL ACADEMY OF SCIENCE
(9) MYTHOLOGICAL NOTES
The Independent (London),
17th September 1998
(10) ON SWIFT-TUTTLE
Jens Kieffer-Olsen
<dstdba@post4.tele.dk>
===============
(1) POPULAR CULTURE & MAD ASTRONOMY
From Michael Gerrad <Michael_Gerrard@aporter.com>
Since it does not appear on most professional reading lists,
subscribers may have
missed the September 1998 special asteroid issue of Mad Magazine,
which was brought
to my attention by my 14-year-old son. It contains a
"Countdown to Armageddon"
with the following chronology. (I cannot reproduce the
illustrations, but will only
say that the astronomers are not drawn to resemble Robert
Redford.)
July 10, 1998 -- Astronomers announce they have observed a
huge asteroid
headed this way, and calculate it will collide with Earth in 30
years
July 10, 1998 -- Sales of 30-year Treasury Bonds plummet
July 12, 1998 -- Red-faced astronomers announce they forgot to
carry the
five, and now calculate the asteroid will miss Earth by several
million
miles
July 12, 1998 -- Every late night talk show host makes the
identical joke
["Turns out what they thought was going to destroy humanity
wasn't a
massive asteroid at all...it was just the shadow from Rosie
O'Donnell's
head!"]
October 3, 2008 -- Astronomers realize they were right about the
asteroid
the first time, only now Earth has a mere twenty years left
November 4, 2011 -- Las Vegas oddmakers begin posting odds for
the survival
of various species [e.g., whales, 6:1; cockroaches, 12:1]
September 6, 2016 -- Last health food store in the world closes
November 5, 2022 -- James Cameron is signed to produce a
$1billion movie
based on the impending disaster -- if he survives the collision.
January 29, 2023 -- Astronomers announce that previously
unavailable
technology has enabled them to make a more accurate calculation
of when the
asteroid will hit...and it's in three weeks
January 30, 2023 -- Nike sales skyrocket as various cult members
decide to
jump the gun and kill themselves.
February 2, 2023 -- IRS revenues dry up as a record percentage of
taxpayers
file extensions.
February 4, 2023 -- Increased attendance at churches, temples and
mosques
causes many houses of worship to structurally collapse, killing
thousands.
February 9, 2023 -- Nobody gives a #&@%! where they park
anymore.
February 14, 2023 -- The asteroid passes Earth, missing it by a
million miles.
Everyone goes back to their normal lives, embarrassed by their
behavior over the
past few weeks, but with a renewed passion for life and a sense
of brotherhood and
civility never before seen. It is truly the dawning of a
golden age.
March 3, 2023 -- A previously undetected comet destroys the
Earth.
The same issue includes scenes from an imaginary movie,
"Sleep Impact," including
an announcement by the President of the United States to a White
House audience
(including a beret-wearing intern) about "the Meshugginer
Space Shuttle, a joint
project between Russia and America! America provided the $5
trillion to build it
-- the Russians provided some neat T-shirts that say: 'My father
went to the comet
and all I got was this lousy T-shirt!'"
I don't know how this journal slipped through the peer review
process.
======================
(2) THE NOVEMBER LEONIDS: WILL THEY ROAR?
From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
The November Leonids: Will They Roar?
By Donald K. Yeomans
Jet Propulsion Laboratory/California Institute of Technology
August 7, 1998
Each November when the Earth runs into the dusty debris from
periodic comet
55P/Tempel-Tuttle, some Leonid meteor shower activity is noted.
These annual
displays of meteors, or shooting stars, seem to originate in the
constellation Leo
so they are termed Leonid meteors. Normally, the observed rate of
the Leonid
meteors is about 15 per hour under ideal observing conditions.
However, every 33
years or so when the parent comet Tempel-Tuttle returns to the
Earth's
neighborhood, there is a possibility that the Leonid meteors
rates can get
substantially higher. In some years such as 1799, 1833, and 1966,
when the Earth
passed particularly close to the tube of debris following in the
comet's wake,
there were Leonid meteor "storms" noted of up to
150,000 meteors per hour. Periodic
comet Tempel-Tuttle passed closest to the sun (reached
perihelion) most recently
on Feb. 28, 1998 and a month later on March 5, the comet passed
through the plane
of the Earth's orbit about the sun.
Another way of saying the same thing is to note that the comet
passed through the
ecliptic plane from north to south or it passed through its
descending node. We can
expect the maximum Leonid meteor shower activity when the Earth
arrives close to
this nodal crossing point on November 17, 1998 at 19 hours 43
minutes Universal
Time (UT). The peak Leonid meteor shower activity takes place
within one hour but
some activity can be observed for a few hours on either side of
this peak.
Unfortunately for observers located in the United States, the
Nov. 1998 shower
maximum will occur during daylight hours (2:43 pm local time on
the east coast and
11:43 am on the west coast). While some enhanced 1998 Leonid
activity may be
visible just before dawn for U.S. observers, the Leonid shower
maximum should be
best observed by those located near the regions of Japan and
eastern Asia. In
November 1999, the Leonid shower will be best observed from the
regions near Europe
and North Africa.
Table 1. Predicted Leonid Shower Circumstances. Although slightly
enhanced meteor
shower activity was evident in 1996 - 97, impressive meteor
showers are most likely
in 1998 and/or 1999.
Predicted time of Observed time
Leonid shower peak of shower peak
ZHR Good observing
Date (UTC) HH:MM
(Hours) meteors/hr
Locations
------------------ -------------- -----------
--------------------
1996-Nov-17 07:20 05 -
10
60 Eastern U.S.
1997-Nov-17 13:34 12 -
14
40 Western U.S., Hawaii
1998-Nov-17
19:43
200 - 5000? Japan, Asia
1999-Nov-18
01:48
200 - 5000? Europe, North Africa
As noted in Table 1, the predictions for the times of the 1996
and 1997 maximum
shower events were rather accurate and there is no obvious reason
to doubt that the
1998 and 1999 predictions will be seriously in error. What sort
of Leonid meteor
rates can we expect in 1998 and 1999? Meteor shower rates are
often expressed in
terms of the so-called zenith hourly rate (ZHR) or the hourly
rate of meteors an
observer would witness under ideal conditions with the meteors
appearing directly
overhead (at the zenith). The geometric circumstances between the
comet's orbit and
that of the Earth for 1998 and 1999 are most similar to those
circumstances during
the Leonid showers in 1866-67 and 1931-32. Since the observed
Leonid meteor rates
in 1866-67 and 1931-32 were approximately 5000 and 200 per hour
respectively, we
might anticipate a zenith hourly rate in 1998 and 1999 bounded by
the rates
witnessed in the earlier events - between 200 and 5000 meteors
per hour.
Like the weather, it is extremely difficult to predict the hourly
rates of meteor
showers. Table 1 is meant only as a rough guide. Peter Brown, a
respected
researcher of the Leonid meteor phenomena, has suggested a more
optimistic
prediction of between 1000 and 9000 meteors per hour in 1998
(zenith hourly rate).
In any case, it is well worth the effort to observe the upcoming
Leonid meteors
since it will be another century after the 1998-1999 events
before significant
Leonid meteor displays are once again likely.
Suggestions for further reading:
* Meteor Streams (http://ssd.jpl.nasa.gov/meteor_streams.html)
* Kronk, G.W. 1988. Meteor showers, a descriptive
catalog. Enslow
Publishers, Hillside, N.J.
* Mason, J.W. 1995. "The Leonid meteors and
comet 55P/Tempel-Tuttle".
Journal of the British Astronomical
Association 105(5):219-235.
* Rao, J. 1995. "The Leonids: king of the
meteor showers". Sky and
Telescope 90:24-31.
* Yeomans, D.K. 1991. Comets: A chronological
history of observation,
science, myth, and folklore. John Wiley
and Sons, N.Y.
* Yeomans, D.K., K, K. Yau, and P.R. Weissman 1996.
"The impending
appearance of comet Tempel-Tuttle and
the Leonid meteors". Icarus
124:407-413.
=======================
(3) DINOSAUR EXTINCTION: IMPACT VS VOLCANOES
Form Piper R.W. Hollier <piper@xs4all.nl>
For those who want a bit more detail, Channel 4 has an
illustrated summary of this
docu on their web site, with several useful external links at the
bottom of the
page and plenty of names and key phrases which could be used
as search arguments for further surfing. Go to:
http://www.channel4.co.uk/knowing/equinox/
This URL may be updated soon with the synopsis of next week's
program -- after this
happens, summaries of this and other past programs can be found
elsewhere on the
site using their search facility.
EQUINOX
From Channel 4
<http://www.channel4.co.uk/knowing/equinox/>
Sixty five million years ago, a mass extinction occurred on this
planet, with over
two thirds of all plant and animal life - including the dinosaurs
- dying out. What
caused this event has proved to be one of the most fundamental
and enduring
questions scientists have confronted.
Received scientific wisdom suggests a massive meteor struck the
earth around this
time, causing climatic change of catastrophic proportions,
leading to the mass
extinction. Case closed - or so it seemed. But there's a
significant number of
scientists from a variety of disciplines who subscribe to another
theory - and who
have compiled compelling evidence to back it up. They believe
that the dinosaurs
were killed off by the effects of a period of volcanic activity
of unthinkable
magnitude.
With testimony from experts in the fields of geology,
volcanology, palaeontology
and geophysics, Equinox tonight investigates this fascinating new
theory, a theory
that may solve the mystery of the dinosaurs once and for all.
Geophysicist Prof. VINCENT COURTILLOT is keen to re-open the
discussion: "Many
people think that the debate on what caused the mass extinctions
is over, and I
believe this is far from true."
The earth's core is made of iron, and burns hotter than the
surface of the sun.
Outside of it is the outer core of liquid iron and nickel, the
mantel, 3000 km of
hot, solid rock, and finally the lithosphere, the earth's crust.
Occasionally
(instances are tens of millions of years apart), a plume of
basalt up to 1000km
across will push upwards through the mantel and the lithosphere.
When this happens,
it reaches the earth's surface by means of an enormous fissure,
often hundreds of
kilometres in length. From this fissure emerges a sheet of flood
basalt, a slow
moving lava flow. Once a plume has reached the earth's surface,
it may continue to
erupt sporadically for millions of years, creating areas the size
of western Europe
where flood basalt has swallowed up the landscape.
The existence of these flood basalt eruptions is not
disputed. Vast flood basalt
provinces all over the world are testimony to this. The question
is, what effect
would they have had? Geologist Dr STEPHEN REIDEL explains the
flood basalt would
have been extraordinarily hot - over 1000°C - and resembling
"the closest thing we
could know to hell." But this would only effect those
organisms in the immediate
vicinity of the volcanic activity. Much more important would have
been the gases
produced from these fissures, which could have dramatically
altered climates around
the world.
In Iceland in 1783, a fissure of 12km cubic volume opened up,
producing thousands
of tonnes of gas daily. Despite the minimal size of the fissure,
it resulted in a
cooling in the Northern hemisphere of 1°C over a year long
period. A sizeable flood
basalt could produce over 3 million tonnes of gas every day. The
gases, sulphur
dioxide and carbon dioxide, cool and heat the earth respectively.
But the
two would not cancel each other out, as volcanologist Prof.
STEPHEN SPARKS
EXPLAINS: "You can get both cooling and warming depending on
exactly where the gas
goes in the earth's atmosphere." Indeed, the effects of the
two together would be
more, rather than less, devastating, says geochronologist Dr PAUL
RENNE: "If you
don't get it with one phenomenon, you get it with the other, and
it's really the
one-two punch."
Sixty five million years ago, a meteorite 10 km across landed in
Mexico, with
undoubtedly cataclysmic results. But for some time both before
and after the
impact, one of the biggest flood basalt eruptions was occurring
in what is now
western India. It was so large that today the flood basalt
province covers almost
one third of the Indian subcontinent. Fossils from this period
suggest that, far
from being instantaneous, many of the extinctions of this era
happened over a
million years. Such a lengthy process would be concurrent with
the effects of a
long period of volcanic activity rather than the sudden impact of
a meteor, whose
repercussions would last only a matter of decades. Furthermore,
sedimentologist
Prof. TOM YANCEY argues that the period of extinctions was almost
at an end by
the time the meteorite hit. Courtillot argues that the effects of
the meteorite may
have contributed to the extinction of some species, but maintains
that the primary
cause was the volcanic activity.
The volcanism theory is further reinforced by another period of
mass extinctions,
the most dramatic one of all, which occurred 250 million years
ago. Around this
time, the largest flood basalt province of all emerged, in
Siberia. Its emergence
coincided with, and almost certainly caused, the extinction of 95
per cent of life on
earth.
But after extinction comes evolution, as Prof. Sparks points out:
"It may well be
that the way life has evolved on earth has involved extinctions
due to these global
environmental catastrophes, but these extinctions in themselves
paved the way for
the flourishing of life and rapid evolution after a mass
extinction. So it could be that
maybe we wouldn't be sitting here talking to each other unless
there'd been flood
basalt eruptions in the past which had accelerated and triggered
evolution of life."
Copyright 1998, Channel 4
===============
(4) 800 BILLION $ WIPE-OUT: HAZARDS DUE TO ASTEROID IMPACTS IN
THE PACIFIC OCEAN
S. Yabushita: On the possible hazard on the major cities caused
by asteroid
impact in the Pacific Ocean - II. EARTH MOON AND PLANETS, 1997,
Vol.76, No.1-2,
pp.117-121
KYOTO UNIVERSITY, FACULTY OF ENGN, DEPT APPL MATH & PHYS,
KYOTO 606, JAPAN
Earlier, it was pointed out that asteroids with diameters close
to 200 m that hit
the Pacific Ocean once in 10(4) y create large tsunami waves
which could cause
serious hazards to the cities and countries lying along the
periphery. Here, a more
detailed investigation is carried out in relation to tsunami
hazards created by
earthquakes, it is shown that the energy involved in the asteroid
induced tsunami
wave is some 300 times greater than large tsunami waves and 100
times greater than
the Chile tsunami of 1960, the largest this century. Second, if
the impact should
take place in the Pacific south of Japan, so that the tsunami
wave enters Tokyo
Bay, the damage could cost 800 billion dollars, which is 6 times
greater than the
damage due to the Hanshin (Kobe-Osaka) earthquake of 1995.
Copyright 1998,
Institute for Scientific Information Inc.
===============
(5) ENVIRONMENTAL ENGENEERING & THE FUTURE COLONISATION OF
PLANET MARS
M.J. Fogg: Terraforming Mars: A review of current research.
ADVANCES IN
SPACE RESEARCH, 1998, Vol.22, No.3, pp.415-420
PROBABILITY RESEARCH GROUP ,C-O 44 HOGARTH COURT,FOUNTAIN
DR,LONDON
SE19 1UY, ENGLAND
It is possible in the future that Mars might be transformed into
a habitable planet
by a process of global environmental engineering known as
terraforming. This paper
provides a thumb-nail sketch of the terraforming concepts that
have appeared in the
technical literature, focussing on the steps required in order to
render Mars fit
for anaerobic life. Its intention is to provide a referenced
guide of progress to
date for any future researchers of the subject. (C) 1998 COSPAR.
Published by
Elsevier Science Ltd.
===============
(6) ESTABLISHING & MAINTAINING AN INHABITABLE ECOSYSTEM ON
MARS
R.L.S. Taylor: Why Mars? Even under the condition of critical
factor constraint
engineering technology may permit the establishment and
maintenance of an
inhabitable ecosystem on Mars. ADVANCES IN SPACE RESEARCH, 1998,
Vol.22, No.3,
pp.421-432
BRITISH INTERPLANETARY SOCIETY, 27-29 S LAMBETH RD, LONDON SW18
1SZ,
ENGLAND
There is significant evidence that the total volatiles inventory
of Mars is now
severely depleted, particularly so in the case of nitrogen. The
likely low
availability of nitrogen may constitute a 'critical limiting
factor' preventing the
establishment of a gravity-bound terraformed atmosphere of
terrestrial composition
and surface pressure. Even under the condition of critical factor
constraint
engineering technology could permit the establishment and
maintenance of an
inhabitable ecosystem on Mars. Under such conditions a fully
habitable environment
could still be achieved by constructing a deliberately restricted
ecospheric
environment (DREE) on the planet. This biosystem, enclosed within
a quasi-global
'Worldhouse', can mimic closely the free-running seasonal
biological and
geochemical cycles of the Earth and would function in an almost
completely
self-stable and self-regulatory manner. Constructing, creating
and maintaining a
habitable contained environment on Mars would be the greatest
architectural and
engineering challenge yet undertaken by mankind, although it
would require little
technology much in advance of that currently available. (C) 1998
COSPAR. Published
by Elsevier Science Ltd.
=================
(7) TERRAFORMING & THE COMING 'CHARM' INDUSTRY
F. Turner: Terraforming and the coming charm industries.
ADVANCES IN SPACE
RESEARCH, 1998, Vol.22, No.3, pp.433-439
UNIVERSITY OF TEXAS, SCH ARTS & HUMANITIES, RICHARDSON, TX,
75083
We will only begin to develop a truly spacefaring civilization
when it is in our
interest to do so. One key issue is what constitutes a human
''interest;'' and even
more important, how will human interests change during the coming
era in which
planetary engineering will become feasible. The European
exploration of the
Americas is a valuable analogy; the true beneficiaries of the
Columbian discovery
were not the aristocrats, sailors and warriors but the farmers
and planters that
followed them. If we are to get an accurate picture of the
potential wealth to be
gained from the solar system, we must recognize the successive
waves of economic
energy through which our civilization is passing. It is already
clear that the
shrinkage of employment and investment that occurred in farming
is already
happening to the extractive and manufacturing sectors and will
happen to the
information industries and the biotech/nanotech industries that
will succeed them.
Finally, we will be left with the irreducibly labor- and
capital-intensive human
industries of what we might call ''charm''. The chief natural
resources required
for these industries are empty space and empty time, which would
be plentiful in
the new planetary habitats opened up by terraforming. The paper
will explore a few
of the practical and visionary possibilities of such a
perspective. (C) 1998
COSPAR. Published by Elsevier Science Ltd.
======================
(8) THERMAL DESTRUCTION OF SOLIDS NEAR THE SUN
L.I. Shestakova*) & L.V. Tambovtseva: The thermal destruction
of solids near the
sun. EARTH MOON AND PLANETS, 1997, Vol.76, No.1-2, pp.19-45
*) NATIONAL ACADEMY OF SCIENCE, FESENKOV ASTROPHYS
INST, ALMATY 480068,
KAZAKHSTAN
We consider the thermal evolution of both icy and non-icy solids
moving in highly
eccentric orbits using an analytical solution of the heat
diffusion equation. The
thermal stresses which arise inside and at the surface of solids
can exceed by
several orders of magnitude the tidal stresses in the
neighbourhood of the Sun for
all material considered. This means that thermal disintegration
is the most
important factor in the evolution of cometary and meteorite-like
bodies. This
problem may be directly connected with the origin of the variable
part of the
infrared radiation excess in the F-corona observed at 4R(.) and
9R(.) from the
Sun. The possible scenario of the disintegration of the distant
solids due to the
thermal stresses is also given. Copyright 1998, Institute for
Scientific Information Inc.
=========================
(9) MYTHOLOGICAL NOTES
From: The Independent (London), 17th September 1998
By Alan F. Alford
Henny-Penny discovers Atlantis
In the English fairy tale, Henny-Penny was hit on the head by a
falling object, and
then set off with Cocky-Locky, Ducky-Daddles, and the rest of the
tongue-twisting
farmyard crew, to warn the king that the Skys "are going to
fall". What was the
reason for this paranoid behaviour? Surprisingly, the answer can
be found in the
famous legend of the lost island of Atlantis.
When the Greek philosopher Plato described Atlantis as an island,
which was struck
by an earthquake and sank into the sea, he inspired countless
generations of
explorers to search the deepest oceans and furthermost corners of
the Earth for the
remnants of a lost civilisation.
But my study of the ancient Egyptian texts now reveals that these
expeditions have
been wild goose chases, because the Egyptians - the source of
Platoıs Atlantis
legend - firmly believed that the lost island was up in the Sky.
It was a central tenet of ancient Egyptian religion that the Sky
had fallen to
Earth on more than one occasion. The oldest of these fallen
Sky-deities was Geb,
who was said to have laid a Great Egg out of which emerged the
Phoenix with a
blinding flash of light. Geb then let out a piercing scream and
fell to the Earthıs
surface, carrying out construction work in millions of places.
Another fallen god was Osiris, who was born in the Sky but was
then laid low by the
evil god Seth. Osiris was said to have split open the Earth, and
come to rest in
the deep dark caverns of the underworld.
What is the connection to Atlantis? Well the Egyptians believed
that the gods had
descended to the Earth from a place in the Sky, known variously
as the Homeland of
the Primeval Ones, the eastern Horizon of Heaven (the Land of
Light) or the
Mountain-Land of the God. But underlying all of these epithets
was the image of an
island floating in an infinite abyss of primeval waters (which we
nowadays call
space).
How did this island come to be lost? The Egyptians claimed that
Osiris had drowned
(compare the sinking of Atlantis), but they also said that Osiris
had been
dismembered i.e. chopped into pieces - a close parallel to the
earthquake which
destroyed Atlantis.
The myth of the Sky falling to Earth reflected an Egyptian belief
in a catastrophic
act of creation, a day when the Sky-goddess Nut gave birth to her
children of
chaos, and the Sky became choked and stifled. The Earth was said
to have become an
"Island of Fire" as a result of impacts from heaven.
Was ancient Egyptian religion inspired by a meteorite which fell
from the asteroid
belt?
The idea seems plausible in view of the meteorite-cults which are
well-attested in
Egypt. However, whereas modern astronomers claim the asteroid
belt is nothing more
than space debris, the Egyptians believed that asteroids and
meteorites were parts
of the body of their Sky-deity, who had been dismembered.
Remarkably, this
Sky-deity was described in the same terms as used for the Earth
herself - an
island, a mountain, a throne, and a horizon. In other words, the
Egyptians believed
that their "God" was a planet.
The same idea is found in depictions of the god Atlas, supposedly
the first king of
Atlantis, who was shown supporting the heavens in the form of a
planetary globe. The
Greek meaning of his name tells us that Atlas failed to withstand
the Sky, which
came crashing down to the Earth.
Atlantis was thus conceived as a planet which suffered a
catastrophe and sank into
the waters of space. But might there be a reality behind this
myth? The notion that
one or more planets have actually exploded in our solar system is
not without its
supporters in the science of astronomy. If their predictions
concerning the
explosive origins of asteroids and comets are proved correct (and
we should find out
in 1999), the ancient Egyptian myths will become due for a
re-assessment. And
Henny-Penny wonıt be the only one to wake up with a sore head.
Alan F. Alford is the author of The Phoenix Solution: Secrets of
a Lost
Civilisation (Hodder & Stoughton £18.99). His website is http://www.eridu.co.uk and
his email address is alford@eridu.co.uk.
Copyright 1998, The Independent
=======================
(10) ON SWIFT-TUTTLE
From Jens Kieffer-Olsen <dstdba@post4.tele.dk>
> Earth is still being accreted, albeit slowly. It is
estimated
> that every year some 30000 metric tons of cosmic dust are
being
> added. The annually accreted volume of larger
extraterrestrial
> bodies is more difficult to estimate. Astronomical
observations of
> near-Earth asteroids (NEA) suggest that the chances of
impact by a
> body about 1 km-large are about 1 in 200 000 to 300 000
years.
> The probability of a collision on the scale which ended the
> Mesozoic world is 1 in several tens of million years. An
even
> bigger potential event is represented by the comet Swift
Tuttle -
> a 24 km behemoth twice the size of the dinosaur-killer -
which
> crossed the Earth orbit in A.D. 1737, 1862 and 1992 and is
> calculated to pass within about 14 days flight from the
planet in
> A.D. 2126.
Dear Dr. Peiser,
The prospect of Swift Tuttle paying us earthlings a visit some
time during the next
millennium highlights the fact that close asteroid encounters are
bound to be of
great benefit to mankind ONCE THE NECESSARY TECHNOLOGY is in
place.
If asteroids are properly tamed and brought into Earth orbits
they are worth
fortunes, much more than their redirection could possibly cost.
If Swift-Tuttle were placed in synchronous orbit I gather it
would form the perfect
anchor point for a space elevator. Mars, as you know,
already has the moonlet
Deimos in almost the right orbit.
Has anybody suggested so far how to go about building an actual
space elevator? I
presume it should be lowered down into the gravity well rather
than lifted out of
it. A sizeable base such as provided by Swift-Tuttle would
of course greatly
facilitate this endeavour, especially when compared to a
free-floating space
elevator anchored through the use of contra weights stretching
far beyond
synchronous orbit.
Yours sincerely
Jens Kieffer-Olsen, M.Sc.(Elec.Eng.)
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