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.
(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.
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
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.
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
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
along with other evidence.
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