| Wednesday,
April 18, 2007 =
Subject: Overdue for an ice age
Jerry,
Regarding this: "We should have entered a new Ice Age
with glaciation, with Seattle and Chicago under half a mile of ice and
glaciers reaching almost to Olympia and Cairo, all of New England under ice,
about 5,000 years ago. The astronomical parameters are there. We have been
spared that for some reason or another."
While web surfing for information on the topic of
global warming, I happened to stumble on what appears to be a newer theory
regarding the glacial cycles:
http://www.seas.harvard.edu/climate/eli/reprints/Gildor-Tziperman-2003.pdf
The key idea is here:
> This `sea-ice switch' glacial cycle
mechanism may be briely described > as follows. Consider an interglacial
period as the beginning of a > glacial cycle. As the land ice begins to
grow from its minimum point, > the ocean is ice free and the atmospheric
and oceanic temperatures are rather mild. > Snow accumulation over
glaciers exceeds the ablation, melting and > calving term, and therefore
the ice sheets gradually grow. The > resulting slow increase in land
albedo slowly reduces the temperature > of the atmosphere and of the
ocean. After some 90 000 yr, when the > atmosphere is sufficiently
cooled and the high-latitude sea surface > temperature reaches the
freezing temperature, sea ice forms and > expands very rapidly. The
expansion of sea ice further increases the > albedo, induces a further
reduction in atmospheric temperature, and > results in the creation of
more sea ice (a positive feedback). In a > few decades, a large sea-ice
cover is created in the high latitudes. > Sea ice stops growing when it
insulates enough of the polar oceans > from the cold atmosphere,
reducing the air{sea cooling that leads to > the sea-ice formation. The
sea-ice `switch' is now turned to `on'.
> At this stage, the average global
temperature is lowest, sea-ice and > land-ice sheet extents are maximal,
and the system is at a glacial > maximum. The low atmospheric
temperature reduces the poleward > atmospheric moisture flux to about
half its maximum value. Similarly, > the sea-ice cover limits the
moisture extraction from the polar ocean > and the corresponding snow
accumulation over the land ice. As > ablation, glacier melting, calving
and run-off, being less sensitive > to temperature, proceed as before,
the glaciers start retreating. The > albedo decreases again, and the
atmospheric temperature rises slowly. > This is the beginning of the
termination stage of the glacial period. > After some 5000{10 000 yr,
the ocean warms sufficiently to allow the > sea ice to start melting,
again within a few decades, due to the sea > ice{albedo feedback working
this time to warm the atmosphere and > ocean. The sea-ice switch is now
turned to `off', the temperature of > both the atmosphere and the ocean
increases, and the system has completed a full glacial cycle.
The authors feel that this may have implications for
the impact of global warming:
> Whether sea ice is responsible for past
abrupt climate changes or > whether they were caused by the THC or by
atmospheric dynamics matters > quite a bit in the context of global
warming. If sea ice is to be > implicated for the abrupt past climate
transitions, then we cannot > expect future global warming to result in
as strong or as rapid > climate transitions as were observed during the
LGM.
That is encouraging, but I can't help wondering about
this: It looks like we didn't get quite as warm in this interglacial as we
did in the last (for whatever reason). Maybe that is why we didn't flip the
switch for the next ice age. Now suppose this latest bit of global warming,
be it man made or natural, is just the boost we need to flip the switch, and
kick off the next ice age? I guess we'd have "Fallen Angels", second
edition.....
CP, Connecticut
==========
Subject: If one guy had been packing
Jerry
I know our gun laws will take a lot of heat due to the
Virginia Tech shooting; but what struck me as I heard about this is that if
just one guy had been packing, he might have put an end to the slaughter
before the shooter had 32 victims.
Of course, I'm from the Cretaceous (which makes you,
my friend, a creature of the Jurassic).
Ed
========
Subject: Foreign OSINT Poised to Pounce
Jerry
Apparently US intelligence agencies are not terribly
open to "open source intelligence" - that is, gathering intelligence by
perusing the Internet:
http://www.strategypage.com/htmw/htintel/articles/20070417.aspx
Sad, really, but typical for the CIA. I would have
thought that DIA would be a bit more open, though.
Ed
=========
Subject: Burning Food
Jerry,
On one hand, I do not have a fundamental problem with burning food, i.e.
corn based ethanol. On the other hand, I do have concerns about burning
food while simultaneously paying people NOT TO grow food. On the
gripping hand, there will always be unforeseen consequences of the
government tinkering with the market.
Respectfully yours,
Mark E. Horning, Physicist,
========
Subject: China and Wheat -
Evening Jerry,
Just a note on the importation of grain from China
(i.e. the pet food scandal). From someone who used to work in the pet food
industry, I've learned that we import wheat gluten, not the whole grain. In
some cases, we export the whole grain (on the ships then sent us TV's
probably), they process it, and return the components to us.
Not that that's a good thing - if we're to be burdened
with OSHA, EPA, FDA and all the rest, the least we can expect is that they
keep the food supply safe. China has no such guidelines, and the import
inspections only test for bad chemicals that we expect to find - not for the
unknown ones. It's only a matter of time before this kind of thing impacts
the human food chain.
Maybe we can't have import duties...but perhaps import
regulations would serve the same purpose: level the playing field. If Japan
can do it with our beef, we can do it with Chinese grain. But then the
Clinton's would have to return all those campaign contributions.
Doug
=========
Subject: sci-fi futures
I just got back from a two week working retreat (lock
myself in a hotel room with a computer and no internet connection to do a
lot of work), and was going through what I missed on your site when I came
across this comment:
"Why do we always get the DARK version of Science
Fiction as OUR future? I want that OTHER worlds' future, the one over THERE
with the giant wheel space stations and Luna City! "
I while ago I recognized that I sort of have my feet
in both "sci-fi futures". I have spent 15 years working on computer
technologies at Id Software that lead towards a lot of the Matrix /
Neuromancer style dystopias, but in the last six years I have also been
pushing for the grand old future in space with
Armadillo
Aerospace. I often wish that I had time to try to put down some coherent
thoughts about it, but the time has never made itself available. I'm an
optimist about most things, and I think even the "plugged into the matrix"
sorts of futures can have all sorts of positive aspects, and all the trends
point towards that being a lot more likely than idyllic space colonies.
Still, more likely doesn't mean certain, and there is an appeal to going
down the road less traveled.
A lot of it does come down to how you look at the
world. We live in an age of wonders right NOW.
I am going to talk at the Heinlein Centennial in July,
hopefully I can flesh out a few thoughts by then. I would also love to hear
Neil Stephenson comment on the topic, as a seminal cyberpunk author and
special advisor to Blue Origin...
John Carmack
Well, you live in a world of wonders. Most of
us don't get to fly rockets on weekends...
==========
Subject: Rushing the VT Gunman
Dr. Pournelle
In response to your comment and John Derbyshire's
comment about not rushing the gunman I would add that on one of the
interviews from students I read, the student said that she and other class
mates debated whether or not to barricade the door. If my memory serves she
said this went on for quite some time, about 20 minutes. Finally one of the
other students got up and shoved the professor's desk against the door. Five
minutes later the gunman tried to enter the room, could not, and put two
bullets through the door but injured no one.
Do you think this could be another tragic example of
people not being having to be responsible for, well anything, anymore?
Ed C
Don't make more of my comments than I
intended. It's partly a matter of temperament. I wasn't there, and I can
hardly be critical of those who were. When I was in college there were a lot
of WW II and Korean War veterans in my classes, and I suspect we would have
reacted a bit differently; but that too is speculation. ========
Will there always be an England?
Dr. Pournelle:
Although multiple marriage is illegal in Britain, some
people are collecting for multiple spouses:
http://www.thisislondon.co.uk/news/article-
23393028-details/Polygamous%20husbands%
20can%20claim%20cash%20for%20their%
20harems/article.do
jomath
=========
"And young men, in particular, are not internalizing
the norms and values of our society."
http://www.cnn.com/2007/US/04/
17/Dobbs.April18/index.html
Roland Dobbins
==========
Subject: Quantum Gravity
Jerry check out the following I think you will find it
amusing.
http://groups.google.com/group/sci.physics/
browse_thread/thread/e5e86ae80125e359/
0ceed5329c5ef5ab?#0ceed5329c5ef5ab
Some years ago I asked a simple question related to
quantum gravity. The above are some of the results that the question stirred
up. The question came to be known as "The Ivie Conundrum"
Here was the question: Quantum gravity, if it can be
shown to exist, functions by means of the exchange of particles. These
particles may be gravitons, graviphotons, or gravitinos depending upon the
model. Consider that in GRT all of the mass of a black hole lies within the
event horizon What is the quantum gravitation model of a black hole that
allows the exchange of gravitons or other particles across the event horizon
without violating causality. Any solution must be consistent with the
predictions of general relativity at least to the first order.
I have seen lots of arm waving but never a satisfying
explanation.
Chuck Ivie
==
On Reactionless Drives and Mach's
Principle
Jerry
re your questions.
I would very much like to follow up on how you might
get reactionless drive as a plausible system (after all I write science
fiction); and of course any such thing would be the key to the solar system
if not to the stars. And I'd be interested in how the explosion of the Mach
platform (my name for your inertia independent device) is covered by
Newton...
Let me cover the "Mach Platform" first. By the way I
like that name, if the thing had worked it would have definitely shed some
light on Mach's Principle.
We never built another one but we think we know what
happened. Precession forces were coupled through the structure that held the
three gyros together. The wheels were large, 10 inches in diameter, and
heavy, over 20 lb. each. The motors spun them at over 8000 rpm. Side loads
on the shafts holding the wheels were calculated to be several thousand
pounds but because, Again according to Newton, the sum of the moments in a
closed system is always zero we could not detect these forces externally.
The transverse load had to be carried by bearings, which were never designed
to sustain such a force. The bearings failed, pretty much simultaneously,
freeing the wheels and motor parts to go where ever they wanted which was
just about everywhere. One tech suffered minor injures from flying debris
and it took a couple of days to clean up the lab and find all the pieces. We
got unambiguous instructions from upper management to not build such a
device again without approval.
With regard to the reactionless drive idea I am not
sure that is the best way to characterize it but on the other hand I don't
know what else to call it.
Mechanical gravitational wave generator
The concept is derived from another device that I
proposed a number of years ago that being a means of producing measurable
gravitational waves. The basic idea is as follows.
A pair of wheels loaded with a pattern of very heavy
pellets, tungsten or heavier, located at the periphery are rotated in close
proximity to one another. The wheels rotate in opposite directions so that
the pellets form minute gravitational perturbations as they pass one
another. Because all of the pellets on one wheel encounter their
corresponding fellows on the other wheel simultaneously there is
constructive interference that produces a very weak oscillating
gravitational dipole that propagates along the spin axis of the wheels. Now
if we build several such wheel assemblies and arrange them along their
common spin axis and synchronize their rotation rates constructive
interference again acts to strengthen the magnitude of the gravitational
wave and to narrow the width of the beam. Calculations indicate that if
tungsten were used it would take several thousand such wheels in an assembly
a kilometer or so long to produce minimally detectable waves. If depleted
uranium were used those numbers could be cut approximately in half.
Detection could be performed using a Forward Gravitational Gradiometer
(Robert Forward's invention) operating at the same frequency as the
generator. The advantage of this device is that the frequency and
orientation of the gravitational waves are known in advance making detection
much easier.
What does such a device buy you? First it would
demonstrate that gravitational waves do exist. Then, if it worked, it would
permit the direct measurement of the propagation velocity of gravitational
waves. The general relativity theory predicts that G waves propagate at C
but this has never been demonstrated. This device would provide yet another
confirmation of Einstein's GRT. It would also provide a general-purpose tool
for analysis of G waves and a means to explore their properties.
The closest analog to this device in electronics is a
traveling wave amplifier. I like to think of it as a "GRAZER" or
Gravitational Laser.
Needless to say the device was never built primarily
because of cost and a certain amount of legitimate skepticism that the thing
could ever work. Also, I had gained a reputation for inventing things that
blew up in the laboratory resulting in great cost, questionable results, and
potential injury to everyone near.
So what does all this have to do with a space drive?
Consider this.
Lets assume that we can build one of these things but
instead of using pellets of dense ordinary material like tungsten or uranium
we use relativisticly degenerate matter or even quantum black holes. Now I
admit that the components have now moved from "hardtogetium" to "unobtainium"
but calculations indicate that if such a device were to be built very
powerful gravitational waves could be produced. Powerful enough to warp
space time and to create a warp bubble as described by Alcubierre (See
Alcubierre drive in Wikipedia and elsewhere).
So as you can see, now that I am retired I have far
too much time on my hands.
Chuck Ivie, Apple Valley, Ca
========
Dhimmitude in Minnesota.
http://www.startribune.com/191/story/1115081.html
- Roland Dobbins
========
Tree warming, talk about your unintended consequences!
Regards, Paul
http://www.ncpa.org/sub/dpd/index.php?Article_ID=14445
Russell strikes again...
TOP
CURRENT
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