Necronomicon 2010
Hilton St. Pete.,
Lecture hall St. Pete 2
M. Linton Herbert
Exobiology
Update 2010.
This is a lecture on
exobiology. Why are aliens not
here? We start with:
The Dance of the Chromosomes
When somebody holds up a
finger like this, it’s a chromosome.
They replicate and you get two.
This foam model is also a chromosome.
It gets passed along.
Music: Seth Thomas mechanical
metronome, rate 96 beats/minute
Dress: Anything goes.
Steps: One step, any step or
nod or gesture per click. Turns are
good.
Once there was a green
valley. (Valley is arms up and out OR
down and in OR to the side and elbows bent.)
The sun
shown bright each day. (The sun
is a big smile and the face framed with the hands, fingers spread.)
In the valley were thousands
of rabbits. (Rabbits are fists with two
fingers up hopping around.)
One rabbit was named Old
Progenitor. (Decrepitude, cane, beard,
limp, hand on back or hip.)
Progenitor had a chromosome,
Progenitor 1. (Hold one finger up.)
Progenitor 1 the chromosome
replicated so there were two Progenitor 1’s. (Hold up finger next to the first and bump
the fingers together.)
Progenitor 1 the rabbit had
four children, Fred 1, Frank 1, Phillip
1 and Ferdinand 1. (Rabbits
hopping about.)
Fred 1 had two children, Fred
2 and Fed 2. (Rabbits hopping side by
side)
Fred 2 married Fred 2. This was inbreeding. This was bad.
(Rabbit ears droop. Frown.)
Frank 1 hung around and had
babies. (Rabbits
hopping about.)
Eventually Frank 5 married
Frank 5. (Rabbits
hopping side by side, then 5 fingers up.)
And there were lots of little
rabbits. (Rabbits
hopping about. Big
smile.)
Phillip 1, the rabbit was an
adventurer. He hopped all the way across
the valley. (Valley
and rabbit hopping across.)
While he was there it got
very cold and a glacier came down and separated the valley in two. (Hug self.
Shiver. Blow through pursed lips.)
The glacier was there a
thousand generations. (1
finger, then 3 zeroes.)
But then the sun shown bright again.
(Smiling sun face.)
And Phillip 1,000 hopped back
across the valley. (Rabbit
hopping across valley other direction.)
Phillip 1,000 the rabbit
married Phillip 1,000. (Rabbits hopping side by side.)
But Phillip 1,000 the
chromosome couldn’t recognize Phillip 1,000 the chromosome. It had been too long. They were different species, and that was
bad. (Droop eared rabbits. Frown.)
No little rabbits.
Ferdinand 1 just wandered
into the valley and got lost. (Rabbit hopping in valley.)
But there were 1,000 rabbits
in the valley. (1,000
again.)
Ferdinand did not meet
Ferdinand again until Ferdinand 1,000 the rabbit married Ferdinand 1,000. (Rabbits hopping side by
side.)
But
Ferdinand 1,000 the chromosome didn’t know whether there had been a glacier or
not. It hadn’t read the weather
report. (Point at
head. Frown and shake head.)
And
Ferdinand 1,000 could not recognize Ferdinand 10000. There were no little rabbits. (Drooping rabbits. Frown.)
So
the moral is (Halo over head.)
Keep your friends and family
close. (Smile. Rabbits all hopping close
together. Applause)
Not the first time in
history, cutting edge science presented by dancing girls. Graduate students have been doing it for
three years. The journal SCIENCE held a
competition last June, winners were to be announced on
the nineteenth of this month at the Imagine Science Film Festival in
Any high tech civilization in
order to get into space must face this problem.
If you have a tiny population, you can’t build a space ship. If you have a big population, you can’t have
babies. There are some possible ways
around this.
One way is to arrange to have
speciation be very slow. Then infertility
can’t set in until the population is very large. But this is a non-starter for evolution. Ecological niches are opening and closing all
the time. A species that cannot undergo
speciation reasonably quickly will be outpaced by species that can.
Another way around the
problem is to have a super competent population: everybody is brilliant,
healthy, lives for an exceedingly long time and so forth. But all those things require genes. And genes mutate. You can only have so many before your population
destabilizes. You are sacrificing more
offspring to keep bad mutations out than you can produce offspring. So the superman approach is a non-starter.
Third way would be not to
have whole chromosomes. You could break
them up into little bits, and maybe even in a big population you would share
some bits with everybody. Let’s try
it. We will build a population of 100
that can have 5 offspring per couple. We
give them a lethal mutation rate of 100 per forty thousand sites per
generation; just remember the 100. The
first run we’ll have no chance of recombination by punching in 100 here. Everything else is zeroed out. The population survives 500 generations with
a final number of offspring or it dies out on some generation. Then we repeat the run with an even chance of
recombination at any one site (we punch in 50), and the result is about the
same. So increasing
the number of chromosomes or the rate of recombination does not make much
difference at least with recessive lethal mutations.
Or you could give up on sex
altogether. Dandelions only fertilize
themselves, so it can be done. But it is
probably an evolutionary dead end.
So the only way your
population can survive and compete in the long run is to have multiple fairly
isolated small populations. And that is
going to be the case any where you have life because where there is life there
is going to be evolution. Here is how we
subdivide out populations here on earth.
On the Regulation of Populations of Mammals, Birds, Fish, and Insects, Richard M. Sibly et al. SCIENCE vol. 309 no. 5734 JULY 22, 2005 page 607 - 610
On the Regulation of Populations of Mammals, Birds, Fish, and Insects, Richard M. Sibly et al. SCIENCE vol. 309 no. 5734 JULY 22, 2005 page 607 - 610
It's with fertility. This graphs population growth rate against
population size for a typical animal. As
you see, if the population gets up to 1,000 nature pulls the plug and fertility drops below replacement. If the population were not limited or
eliminated, then it would endanger the whole species as we saw in the
dance.
Evolution cannot foresee the
future. (There is a cosmic reason for
that I hope we get to talk about in a year.)
But evolution does have a very long past. This limiting of the population size has
nothing to do with available food. It is
the result of a long process in which complex animals with populations that got
too large went extinct. Of course
according to the dance the process should take something like 1,000
generations. That’s not so long a time
for evolution. But nature does not even
wait that long. The best numbers are
actually from a study in
That’s right. Humans are like any other animal. Evolution prevents us having any population
that gets too big because it would endanger the whole species.
. This is what they found:
It’s the same story. Fertility is on the vertical axis, kinship on
the horizontal. When the population gets large enough so that
the average couple is separated by much more than 6th cousins, the
bottom falls out of fertility. Nature is
eliminating that population as a hazard.
This isn’t because of the environment.
It doesn’t happen in a single
generation. Here is how it plays out
over time.
In
(The Mouse in Biomedical
Research second edition Volume 1 History, Wild Mice and Genetics, chapter 3
“The Secret World of Wild Mice” section VI Population Dynamics part C.
Population Eruptions (Mouse Plagues in Australia; population eruptions in New
Zealand) Grant R. Singleton and Charles J. Krebs editors James G. Fox, Muriel T
Davisson, Fred W. Quimby, Stephen W. Barhold, Chritian E. Newcomer and
Abigail L. Smith Elsever Burlington 2007 page
39. The caption reads: House mouse
outbreaks in southeast
As you can see there are two
patterns. Either there is a single very
high peak or there is a lower double peak.
When there is a double peak, the second is generally higher and narrower
than the first, and they are skewed to the right. The double peak is hard to attribute to a
virus. If it is due to some sort of
genetic or epigenetic population control, then it is a complex system because
it is a complex pattern.
Here is a report on a
population of Anasazi Indians in a place called Long
House Valley. They did C14 on
every hearth in the valley and noted every year that house had been
occupied. That way they could get an
annual census that ran for centuries.
Jared M. Diamond,
“Life with the Artificial Anasazi,” NATURE, vol 419 no 6907,
The red line is the population
curve. The stepwise increases have to be
people moving in, since no natural increase could make such a big change in one
year. Since these people clearly migrate
in groups, we conclude that nobody ever moved away; there are no obvious
stepwise drops. The blue line is
population as calculated by tree ring thickness assuming this represented rainfall. Obviously the lines are parallel. But It is also
obvious that for many years the population was increasing, in fact people were
moving in, when the rainfall would not have supported them. It seems more likely that they were
cultivating the trees as they needed them.
Notice that the population
curve has two peaks, the second narrower and higher than the first just like
the mice. In case you were wondering, it
ends with extinction. Their numbers
never reached 1,000.
Compare that with the
survival curve of Japanese dynasties. We
assume that the dynasty survives as long as there are adequate numbers of young
people in the royal family and among their retainers.
The horizontal axis is the
ages of the dynasties. The vertical axis
is their chance at any 50 year increment of surviving the next 50 years. The second peak is not as high as the first,
but it is narrower, and the same notch occurs at the same time.
Here is
It is the same story. The notch is not so deep, but it occurs at
the same time.
So suppose we simply
construct a model of the curve, oversimplified.
This is not data. I just made it up. The population starts out stable, has a dip,
goes back up and then crashes. If you
take 7 populations with one starting out fresh, one 50 years
old, one 100 years old and so forth and then add up their experience you get
this:
:
Compare that with
There are other factors at
work, but you can see the plunge at 300 years.
Here is southern
Information taken from
R. H. Carling THE WORLD HISTORY CHART International Timeline Inc.
Nature, it seems, draws
cleaner lines than I do. Here is the
graph pooling
It’s the same curve.
And that is how nature
protects us from the danger of a population increasing until speciation effects
wipe it out. Nature is not sentimental,
and nature is very effective.
It is customary to refer to
infertility as prezygotic or postzygotic
depending on whether the cause happens before egg combines with sperm or
afterwards. The fact that the curve is
complex and stereotyped suggests that there are at least two mechanisms,
possibly one prezygotic and one post zygotic.
It has been found that the
sperm of deer mice can get together and form a sort of flying wedge. Male deer mice don’t fight over the females
like regular mice, but the sperm compete.
The flying wedge lets them swim faster and outrun other sperm.
Pictures from Competition
Drives Cooperation Among Closely Related Sperm of Deer
Mice, Heidi S. Fisher and Hopi
The sperm will only do this
if they are from related males. So the
sperm are able to recognize and bind to kin sperm. All you have to suppose is that they also
prefer to recognize and bind to kin eggs and you have a prezygotic
fertility effect.
There must be a prezygotic component to human infertility. Otherwise in vitro fertilization – directly
injecting the sperm into the egg – would never work. If it were all prezygotic,
injection should work just about all the time.
In fact it works about half the time.
So that is why we appear to
be alone. If there is any alien
civilization forming out there, it faces exactly the same barricade. Before it can attempt space travel nature
reacts to a population that has become too large for long term survival and
wipes it out. Judging from human history
it is just about impossible for any society to cooperate on a cultural level
without cooperating on a social level.
Here are the UN numbers for
the past 50 years. It is birth rates
broken down by developed, less developed and least developed regions.
The vertical axis is the
average number of children born per woman.
The horizontal axis gives the dates of the surveys.
At first glance, this is good
news. There are more people in the world
than we can support in the long run.
Birth rates are falling, the fastest among those who can least afford
children and very slowly among the rich.
But if we edit the graph, following one region until it overlaps the
next and then skipping to when that region had the same birth rate, we see
this.
We are all in the same
boat. We are all following the same
curve. Just some of us have been at it
longer. And nature has issued a death
warrant for essentially all of us.
Notice, by the way, at the beginning of the curve there is a time of
rising fertility. This is probably the
time when small bands are escaping from inbreeding. That is probably the way we have controlled
our populations over the ages, by inbreeding depression rather than by loss of
life of those already born.
There is one ray of hope for
us. It is quite possible that our high
tech civilization is doomed but tiny bands that have not and will not join
bigger populations may survive. What is
truly at stake is the survival of a rational, technological, literate
scientific culture. It is the survival
of the ability of the universe to be rational and to attempt to understand
itself. So there is just one, and so far
as I know so far, only one effective force that has the effect of increasing
the chance the universe will remain sane and self aware.
I have a web site
nobabies.net where I shall post this lecture along with hundreds of other
essays and letters and so forth. Here is
the experience over the lifetime of the site.
After an initial little burst
of growth the site settled down to over a year of few visitors – the red line –
very few returning visitors – the green line – and maybe a couple pages turned
per visitor – the blue line. The kindest
thing you can call my attempt to lay this out would be “ineffective.”
Then suddenly things started
to happen. More people, more returns and
a lot more pages turned. The moment of
the takeoff was just a year ago when I gave this lecture at Necronomicon.
So, my band of heroes, you
made progress where nobody else ever did, not since the beginning of time. You talked, you used the internet, you told
your friends and you got onto your social networks. Whatever you did, it worked. There will need to be a lot more attention if
we are to have a chance, so hit it again.
You have a chance.
I presented this subject last
year. I have added some new data and new
calculations. But there is much else
that is new in exobiology. There is a
great stirring in telescopes for planet discovery, which I will go over in the
next hour, which is on telescopes. For
what I presented last year, go to nobabies.net and click on the October 26 and
28 subjects.
There are a number of ways to
look for extraterrestrial life. One is
to look up and see whether they are flying overhead. Usually they aren’t. A couple of things have turned up this past
year. This article was published in
Atlantis Rising.
The Great
Airship of 1897 Alan Denelek ATLANTIS RISING # 80
March/April, 2010 page 46.
Many people saw something
flying slowly over
An event that happened this
year was in
A more rewarding way to look
for extraterrestrials is to look for compounds that you figure might be
evidence of life or provide the opportunity for life. Of these, the most
rewarding is water. That’s because there
is so much of it. The reason Jupiter is
so big is that it formed just outside the limits of liquid water. At the ice line, you are far enough from the
sun for water to freeze and persists. And water packs very nicely as you know if
you have ever made a snowball. The disc
from which the planets evolved was denser nearer the sun, so the biggest
snowball appeared not very far outside the ice line. They are starting to call some of the outer
planets “ice giants” rather than “gas giants” because they are mostly ice.
There’s lots of water.
Here is an artist’s rendition
of a geyser on Enceladus, one of the moons of
Jupiter, published in SCIENTIFIC AMERICAN.
Notice the distant sun and its sun dog; the spray is causing ice
crystals to form. The same article shows
things like another geyser on Triton, one of
8 Wonders of the Solar
System, Edward Bell, SCIENTIFIC AMERICAN, vol. 302, no. 4 April 2010 page
40. The other rewarding thing about
looking for water is that it’s so pretty.
They are interested in
finding water on the moon, not so much because it might support life – there’s
no air so surface water can’t be liquid at this distance from the sun or it
would evaporate – but it would be quite handy if there is ever a serious
attempt to spend a lot of time there or use it as a base for further space
voyages.
They have found that some
lunar rock – basalt – contains as much water as basalt here on earth. So there could be a lot of water deep below
the surface, much as here. (A Lunar Waterworld, Paul G. Lucey,
SCIENCE vol. 326 no. 5952 October 23, 2009 page 531) You remember the commandment not to make
images of anything, “In the waters under the earth.” Yep, there’s life in the water deep below us. Life may have originated there. Why not the moon? Of course they aren’t digging caverns down
there or we would have seen their mine tailings unless they were being very
sly. Other things are being studied
looking for lunar water with some success.
(Detection of Adsorbed Water and Hydroxyl on the Moon, Rorger N. Clark, page 562, Temporal and Spatial Variability
of Lunar Hydration As Observed by the Deep Impact Spacecraft, Jessica M.
Sunshine et al page 565 and Character and Spatial Distribution of OH/H20 on the Surface of
the Moon Seen my M3 on Chandrayaan-1, C. M. Pieters
et all page 568 all in the same issue)
They had a stroke of
luck. The plan was to crash something
into the permanently shadowed interior of the crater Cabeus near a lunar pole. The models assumed that the impactor would be solid and that it would throw debris
mostly to the sides. But they used a
spent rocket segment, which was hollow, and as it turned out it threw stuff
high enough to be visible to instruments on the earth. Sure enough, water was there, 2% of the
material by weight. (Lucky Glimpses of a
Weirdly Wetter Moon SCIENCE vol. 327 no. 5972
Of course water is vital to
life. (How to Find a Habitable Planet, James Kasting
Princeton University Press, 2010 and its review Signatures of life on other
worlds Debra Fisher NATURE vol. 464 no. 7293 April 29, 2010 page 1276) This is a book you might be interested in.
The author came up with the
notion of a habitable zone around a star.
Here’s another book I liked:
The author notes that our
lack of contact off planet is troubling and I say with good reason, as we
discussed in the first half hour.
As for liquid water on Mars,
there is a lot of evidence for it in the past, but the place should have been
warmer than it is now. (Did a Deep Sea
once Cover Mars SCIENCE vol. 328 no. 5985 June 18, 2010 page 1467 reviewing
work by Gaetano Di Achille and Brian Hynek of the
University of Colorado also Detection of Hydrated Silicates in Crustal-Outcrops in the Northern Planes of Mars, J. Carter
et al SCIENCE vol. 328. no. 5986 June 25, 2010 page 1692) The going theory is that there was a lot more
CO2 in the past. It now
appears that this was the case, and the CO2 was removed by becoming
carbonates in Martian rock. (Carbonates
and Martian Climate, Ralph P. Harvey SCIENCE vol. 329 no. 5990 July 23, 2010
page 400 and Identification of Carbonate-Rich Outcrops on Mars by Sprit Rover,
Richard V. Morris et al on page 421 of the same issue.) Currently it’s too cold there.
And thereby hangs a small puzzle
that I must have missed in my reading.
If Jupiter is so big because it’s just outside the ice line, then Mars
should be inside the ice line and ought to have water. The sun has been getting hotter, so the ice
line must be moving out. I suppose somebody
mentioned that the planet migrated or something, but I missed it.
As for ice at present, well
of course we have seen it as mentioned last year. It may also be trapped in volcanic
tubes. (Martian Cold Traps NATURE vol.
464. no. 7293
For more exotic ideas I am
indebted to Don Oremland. I wrote him and he was kind enough to send
some things to share with you. He has
delved deeper into possible exobiology and in particular exobiochemistry
than anyone else I know of and probably of anybody else ever.
Acetylene is produced by the
action of ultraviolet light on methane and may have been abundant in the early
earth’s atmosphere. There is a microbe Pelobacter acetylenicus that
is able to metabolize acetylene, and the key enzyme is very specific,
suggesting it evolved when there was a lot of acetylene. So this could be part of the origin of life
on earth and could be happening elsewhere.
(Ronald S. Oremland and Mary A. Votek, ASTROBIOLOGY vol. 8 no.1 2008) The metabolism of
acetylene does not require oxygen, and it may be going on under the ice on Enceladus, Europa, Ganemede and/or Titan.
Yes, one could spend the entire two hours talking about any of the
papers by Oremland.
Another possibility for
exotic biochemistry is arsenic metabolism.
(Arsenic and the Evolution of Earth and Extraterrestrial Ecosystems,
Ronald S. Oremland et al GEOMICROBIOLOGY JOURNAL,
26:522-536, 2009) Arsenic supports
diverse microbial life here on earth and it can under certain circumstances
accumulate in high concentrations, and that would include the early earth. Of course it is a poison. (See also The Arsenic Century – How Victorian
Britain was Poisoned at Home, Work and Play by James
C. Whorton, Oxford University Press, 2010 and a
review by W. F. Bynum, NATURE vol. 466. no. 7306
Chemically arsenic is related
to phosphorus, which is why it is so toxic.
It is intriguing to me that at least one arsenic pathway can run in
reverse. That just sort of feels like
something a very old biochemical pathway could do. It is speculated that as Mars dried out,
brine concentrations rose so that arsenic concentrations may have risen high enough to support life.
Oremland, himself quite readable considering the highly
technical material he works with, has pointed out a novel about an
extraterrestrial life form that uses arsenic.
It is Brain Plague by Joan Slonczewski, Tom Dougherty Associates,
Then there is nitric
oxide. A microbe has been found (NO
Connection with Methane, Ronald S. Oremland NATURE
vol. 464 no. 7288 March 25 2010 page 500 and Nitrite-driven Anaerobic Methane
Oxidation by Oxygenic Bacteria, Katharina F. Ettwig page 543 in the same issue) that metabolizes methane
by making its own oxygen out of NO. I am
getting the feeling that if nature is as smart as Ron Oremland,
the solar system teams with life.
That brings us to
methane.
There are
methane producing microbes in hypersaline
environments. (Radiotracer Studies of
Bacterial Methanogenesis in Sediments from the Dead
Sea and Solar Lake (Sinai) Mark Marvin DiPasquale, Aharon Oren, Yehuda Cohen and
Ronald S. Oremland © 1999 by
Methane using microbes use an
enzyme that is now thought to include two copper atoms linked together. (Getting the Metal Right, J. Martin Bollinger
Jr. NATURE vol. 465 no.7294
Some methane comes from
microbes; some comes from photochemical effects, like the methane on
Jupiter. So people study methane in
various places looking for its characteristic residences. (Fluorescent Methane Spotted, Seth Redfield
NATRE vol. 463 no. 7281
Sea floor vents release
methane, but it appears to be produced by microbes at the vent. (Expanding the Limits of
Life, Alexander S. Bradley SCIENTIFIC AMERICAN vol. 301 no. 6, December 2009
page 62. Most of the methane
released from the ocean floor gets metabolized by anaerobic microbes on the way
up. (The Ongoing Mystery of Sea-Floor Methane, Marc Alperin
and Tori Hoehler SCIENCE
vol. 329 no. 5989 July 16, 2010 page 288)
The take home message is that
there are a lot of bugs out there that eat methane or release methane, so when
you see methane, the notion of life does occur to you. For instance, as we mentioned last year,
there is methane on Mars and whether it is of biological origin remains a
question of great interest. (A Whiff of
Mystery on Mars, Katherine Sanderson NATURE vol. 463 no. 7280
If you want really big time
methane, or at least hydrocarbon, using microbe activity, consider the Gulf oil
spill of a few months ago. For the first
five days, the microbes appeared to be ignoring the oil, but then they started
to make up for lost time.
(Bacteria are Gobbling Gulf
Oil, SCIENCE vol. 329 August 2010 page 1005) Yes the picture is upside down. I kind of like it that way.
There was a bit of a puzzle
because the oil was disappearing without any detected fall in the amount of
oxygen. (The Mystery of the Missing Oil
Plume, Amanda Mascarelii, NATURE vol. 467 no. 7311
September 2, 2010 page 16) But by now we
know that microbes can deal with methane without needing oxygen, why not oil?
So is there a danger that
some sample returned from Mars will bring back a microbe that can digest
methane? If it can do that, it or something
like, it can digest any organic material.
(The definition of an organic chemical is any compound that includes a
carbon linked to a hydrogen atom, and methane contains no other kind of bond.)
That includes us. Well there are tons of
hydrocarbon eating microbes in the Gulf, the Gulf washes in and out of
Another exotic as far as life
goes is nitrous oxide, as distinct from nitric oxide we mentioned before. There is a place called Don Juan Pond in
The Mystery of Don Juan Pond,
Andrew Mitchinson, NATURE vol. 464 no. 7293 April 29,
2010 page 1290. (Does is seem to you
that the word “mystery crops up a lot in this subject?)
The pond is so salty that it
does not usually freeze even in the cold Antarctic winter, and that’s really
cold, far colder than what is generally considered to be the habitable
zone. It’s a lot like Mars. The soil around the pond emits nitrous
oxide. So the question was whether there
were living organisms in it that were doing it, or was it some sort of chemical
reaction. So they (V. Samarkin et al NATURE GEOSIENCE doi:
10.1038/NGO847; 2010 as reported in the Mitchinson
article) took a sample of water from the pond, sterilized it, and mixed it with
some soil from around the pond. Sure
enough, out came nitrous oxide. It had
to be a non-biological process. So far
as I know, however, they didn’t sterilize the soil sample. Oh well.
Paul Davies recounts in The Erie Silence that the Viking
expedition, as he points out the only scientific probe actually to look for
life on Mars, carried some experiments.
One was to look for organic molecules, one sniffed for gasses that might
be given off by living things, a third looked for photosynthesis and a final
one mixed a nutrient broth with dirt (I almost said “earth” but it would be
“mars” wouldn’t it?) to
see if anything would metabolize it.
Well the spectrometer that
was looking for organic matter found less
than was expected – comets for instance deliver organic
matter – and was deemed negative.
I would say if it was not at equilibrium, the test was positive. The test for metabolic activity was positive
and indeed the reaction stopped when the broth was heated, as if something had
been killed. Apparently the
photosynthesis experiment was negative as well as the gas sniffer. Well the score was deemed to be three to one
against and the conclusion was “no life.”
I would say at the time that it was a tie, and since methane plumes on
Mars exist and the methane is being destroyed faster than known non-living
processes could do that, I would say that just now the weight of the evidence
is for there being life. Besides, if the
place is thick with things that gobble anything in sight, the negative results
from the experiment to detect the emitted gases does not carry much
weight. The only thing that is
convincing is that there is no photosynthesis on Mars. Of course that is a big negative. Without using sunlight, the energy available
for life on Mars would be quite limited.
Look at the earth. Most of the
energy life uses comes from the sun, and we have other energy sources such as
volcanic activity that Mars lacks in similar degree.
Davies has another nifty
idea. It invokes the concept of
stereoisomerism. Things can have mirror
images. Your right hand is more like
your left hand than is anything else in the world, unless you decide it is
important that one is the mirror image of the other. In that case your right hand is more like the
right hoof of a horse than it is like your left hand.
Well chemicals also have
reflections called stereoisomers. Amino acids in your body exist in one form
but not the reflection. So Davies
proposes that if a compound is found that exists in one form but not its
reflection, then it must by of biological origin.
And we might have a mirror
world right here. There might be living
organisms, microbes of course, that use the other handedness. If you could look around and find them, you
would have demonstrated an utterly alien life form here on earth, one that
arose and evolved independently from our own.
So I had an idea. I would get hold of a nutrient broth that was
the mirror image of what ordinary life would prefer. Then I would get a grant and travel around
looking for soil samples that contained something to digest it. Since I would have no idea where to look, I
could go anywhere … the British Museum, the Alhambra, the Taj
Mahal, the Red Lion Pub in Avebury,
my best buddy’s house in Boston.
There is a little critter
called Caenohabditis elegans. It is a chordate, but so primitive it does
not have a head. For many years most of
the papers published about the animal used ones captured in
Well my dreams of becoming a
jet setter were dashed. There are indeed
D-amino acids around, the reflection of our usual L-amino acids. They apparently are a significant carbon sink. (Invisible Carbon Pumps, ECONOMIST vol. 396
no. 8699
I have not seen the primary
source, but there is a report that a group has published in EARTH
So that has been the year in
exobiology. Perhaps next year I can get
even farther from the main stream and talk about the fitness of the universe to
support life. My view is, shall we say,
not the standard one. And there is
recent relevant work I would like to see mature for a while before commenting
on it.
So get out there and save the
universe. This lecture will be posted on
Nobabies.net
along with other evidence.
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