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There are three problems with excessive use of acronyms:
1. It makes the writing more difficult to understand, and has the potential to mislead the reader. As the writer, your job is to do the work for the reader and eliminate barriers to understanding what it is you are writing about.
2. Even when the acronyms can be decoded (say using a glossary at the back), it is distracting, annoying, and conveys a leaden bureaucratic tone. The reading becomes a chore. It is not fun, and fun is one of the reasons I come to New Mars, not to practice my skills with secret codes.
3. Excessive use of acronyms is an impolite affectation showing a gross lack of respect for the reader. It stems from multiple motives: wanting to appear superior; showing that you are in the know and hip; a way to camouflage a message in jargon, covering up its foolishness; a secret handshake identifying those in the “club.” All motives that are most off-putting.
Aside from all that, it’s just bad writing style for anything meant for a general audience. The Associated Press Stylebook, for instance, commands that if an abbreviation is so unfamiliar as to require being identified within parentheses, it should be avoided altogether.
This is the zero mysterious acronym stance. A bit extreme, but there it is. Deviations require good reasons. Even with familiar acronyms, the AP (we all know AP, right?) requires that the abbreviation or acronym be used only on second reference. Of course there are always exceptions:
Certain abbreviations or acronyms are common enough to be used on first reference such as USA, UN, FBI, NASA or AP.
Some acronyms are better understood than the actual words, e.g., USB, HTLM
Sometimes texts contain repeated uses of a particular phrase that can be abbreviated to good effect. Writing out long expressions over and over again can break the flow of the text and actually impede understanding rather than improve it.
Obviously when not addressing a general audience, when preaching to the choir, the proper use of acronyms expands. Medical writing would be paralyzing if not for acronyms.
I don’t think the readers of New Mars can be categorized as any particular choir; we need to be addressed as a general audience. So, I find excessive use of acronyms in this context annoying because it is impolite, confusing, impedes communication, wastes my time and effort, and is frequently just plain belligerently presumptuous and rude.
What is this about Low-End Node Reduction? I didn't know Toyota was in the music business.
Oh, and a source would be nice. You know, there have also been innumerable reports of the end of the world.
"Dear B612 Friends,
"When we started B612 Foundation in 2002 our focus was on asteroid deflection research and advocacy. We developed several deflection concepts, which are accepted today as standard techniques to prevent an impact. However the key conditional phrase in preventing an impact is, “with adequate early warning.” Realizing that unless we act ourselves humanity is unlikely to have such adequate warning, B612 has significantly scaled up our operations and initiated the Sentinel Mission.
"Today I am asking many of you to join me in supporting B612’s year-end giving campaign. Since June of this year hundreds of individual donors have joined the B612 Board of Directors and Founding Circle members in support of the Sentinel Mission.
"Our goal before December 31st is to have 100 new individual donors join the B612 crew. Your gift of $1,000, $250, $100, or ANY amount meaningful to you will help make Sentinel’s next milestone...If you have already given THANK YOU and if you would, consider forwarding this to a friend and tell them why you supported B612.
"Remember, when you invest in B612 you’re helping to protect humanity from a devastating asteroid impact. Thank you for your support.
"My best,
"Rusty Schweickart
"B612 Foundation
"Co-founder, Chair Emeritus"
The next Mars Society Convention will be in Boulder Colorado from Thursday August 15 through Sunday August 18. Thursday is usually just registration and some committee meetings, and one can usually leave Sunday afternoon without missing much. But Friday and Saturday are very full - from 9 AM to late in the night.
You can arrive in Boulder sometime on Thursday the 15th and leave sometime after lunch on Sunday the 18th, driving or flying into Denver.
The RTD Skyride bus goes from the Denver airport right to the University of Colorado campus in Boulder, which is where the Mars Society Convention is held. The standard fare is $13 each way, which is pretty reasonable. Rental cars and cabs are ridiculously expensive. In 2008 the Mars Society hotel rate was $103 per night including a good continental breakfast and Wi-fi. Half price if you share a room with someone else. The hotel was an easy walk to the University.
Boulder is a very pleasant small college town, similar to Lawrence, KS, or Middletown, CT.
India plans to send a spacecraft to Mars in a giant leap forward for science and technology in the country. Prime Minister Manmohan Singh said the unmanned spacecraft will enter orbit around the planet and collect scientific information.
He announced the 4.5 billion rupee ($82 million) mission during a speech marking the 65th anniversary of India's independence from British rule. "This spaceship to Mars will be a huge step for us in the area of science and technology," he said. The spacecraft is to be launched in November 2013 on a frequently used rocket developed by the Indian Space Research Organization.
India has had an active space program since the 1960s. Since the 1970s it has launched scores of satellites for itself and for nearly two dozen other countries.
In 2008, India successfully sent a probe to the moon that detected evidence of water on the lunar surface for the first time. India is also planning a rover mission to the moon and is awaiting budgetary approval for a manned space mission.
Terraformer worte, “I still don't get how human society could be in stasis for nearly two hundred millennia, before developing agriculture...”
I’ll suggest four reasons:
1. It is not known when the cognitive abilities of Homo Sapiens emerged. The earliest evidence of symbolic behavior dates to around 80,000 years ago, but there had to be much that went before.
2. It was hardly a time of stasis. There was the whole matter of developing language, a rather major project when there’s no one to teach you. The tool kits gradually changed through the Mousterian and Acheulean into the Solutrean and Magdalenian with a massive increase in the number of tool variants with innovation galore: heat treated stone, fluted projectile points, bow and arrow technology, bi-facial and micro blades, bone needles; including bone, antler, obsidean, quartz, and shell in the materials inventory. The arts of engraving, painting and sculpture were developed to very high levels. Artificial light in the form of oil lamps with wicks made their appearance as much as 35,000 years ago. And on and on; there was a lot to invent.
3. When anatomically modern humans emerged around 200,000 years ago, they were greeted with 70,000 years of the Illinoian glaciation. After about 30,000 years of inter-glacial, it was back to the Wisconsin glaciation which lasted till only about 10,000 years ago. During this time, very major volcanism occurred, killing all about a few tens of thousands of our species.
4. There were never more than a million humans on the whole planet until after the invention of agriculture, all existing in groups numbering a few hundred at most, frequently on the move, with very short life expectancies, and limited ability to defuse and preserve knowledge.
Evidence for the domestication of any species of animal, except dog, before the invention of agriculture is pretty sketchy. You have to feed the animals something. Dogs will eat human feces, which may be part of the reason they adopted us.
I know of no evidence of domestication of any species, except dog, before about 11,000 years ago.
If an agricultural society had been present in 100,000BC, how would one go about detecting it in the archaeological record? There are a whole lot of ways:
Pollen, spores and spore parts, cysts, egg cases, animal, insect and plant fossils,
Residual chemical effects. A simple and easily identifiable example is the soil discolorations produced by degraded wood, which remain accessible, potentially for millions of years depending on the environment.
One effect of agriculture is to enable a large increase in population, which will be evident in the quantity of dwelling spaces (which can be made of durable materials and are also detectable in a large variety of ways), middens (which will contain durable materials such as bone), and the prevalence of human and other fossils.
Changes in the landscape from terracing, storing and directing water flow, soil movement, and other effects determinable from analysis of organic remains in the soil, etc.
Agricultural effects human teeth in many different ways, and, with all those human remains, there will lots of teeth to examine.
Agriculture requires tools. Stone, bone and antler are better, and more likely, materials, but even wood may leave its traces.
Agriculture requires the storage of harvested food and of seed, which will be evident in various ways. Pottery, which is very durable, and which humans have been using since before the (known) invention of agriculture, would be extremely useful in storing and processing food. Pottery leaves all kinds of traces, can sometimes be fairly inexpensively dated and its manufacturing and materials origins determined. And the quantities of pottery, even in very small stone age communities, are absolutely enormous.
There are many other implements needed for processing agriculture products, and it is really hard to imagine a non-durable mano and metate.
Then there is this dilemma in the archaeological record: we do see many cultures that used stone, bone, and antler extensively in dwelling spaces, hunting, gathering, food storage and preparation, for decoration and other symbolic uses, and for many other purposes. But we do not see these cultures using any of these ubiquitous materials for agriculture. We do not see any transitions in the projectile points, knives, scrapers, etc. as they might be affected by agriculture.
So, we have a speculated agricultural society that left no traces of pollen, spores and spore parts, cysts, egg cases, animal, insect and plant fossils, soil effects, dwelling spaces, population changes, effects on the landscape or human teeth; did not leave traces of any tools, durable or otherwise, for growing, harvesting, storage or processing, and did not affect the existing stone, bone and antler tool kits.
Hmmmm. I wonder if they also had nuclear reactors, space flight and if they colonized Mars.
Of course, all things are possible. But do remember, “That all things are possible is no excuse for talking foolishly.”
Robert wrote: "The "ice free corridor" was never long enough, continuous, nor lasted long enough for humans to walk it's length before it closed."
That is one opinion. There are others. The ice free corridor has had numerous incarnations.
All of these and many new ideas, hypotheses, data, analysis which will be presented, discussed and debated at the Paleoamerican Odyssey Conference October 17-19,2013 in Santa Fe, New Mexico:
> The oldest sites in Siberia, teh cultural traditions of Beringia, routes taken by the first Americans, and the genetic record.
> Clovis extinction of the megafauna, the Western stemmed tradition, and the archaeological record of South America
> The older-than-Clovis record at sites across the Americas.
This conference is the successor to and the most important event of its kind since the Clovis and Beyond Conference of 1999 (also in Santa Fe), which was the successor to the Clovis First, Clovis Everywhere Conference of 1940 (also in Santa Fe) at which the Clovis First, Clovis Everywhere paradigm gained a decades long consensus in the archaeological community.
While these are professional conferences, anyone has been welcome at all three, and the first two were more than spectacular. Register at www.paleoamericanodysey.com.
This is not a settled field, but one in great flux with new ideas, techniques and data emerging daily. Ex cathedra pronouncements are pretty silly.
Why did not Europeans, who lived through the worst parts of the Wisconsin glaciation, who hugged the glacier and turned white, develop flat noses with small tips and slited eyes?
Robert wrote: “I saw a documentary...”
TV shows are not the greatest place to obtain scientific information.
And, “genetic studies indicate exactly 5 distinct migrations of native people to the Americas.”
I think you will find that scientific opinion on this subject is not filled with the certainty these words suggest. I’m amused at the certainty with which these DNA numbers are bandied about. Just consider:
Identifying a partial (in many cases a very partial) skeleton as Neanderthal, Homo Sapiens or other hominins is not all that much of a sure thing.
The number of such partial skeletons containing recoverable DNA has been very limited.
The DNA is degraded and contaminated with DNA from bacteria, humans who handled the specimens, and god knows what else.
The commonly quoted studies (conducted on DNA from the SAME individuals) done in the US and Germany reach the conclusion that Neanderthal divergence from the common ancestor was 370,000 or 516,000 years ago, a rather yawning difference.
Homo Sapiens, since the diaspora from Africa, have interbreed with each other very extensively. In the case of the Australian Aboriginals, a lot of Polynesians visited even before the Dutch landed near Weipa in Queensland in 1606. In the case of North America, there was never complete isolation with Asia, and there is very considerable evidence for Polynesian contact at some points on the West Coast of the Americas as long ago as 1500 years, and, of course, the Viking contact more than a thousand years ago.
DNA comparisons are with people who lived in the 20th century, many of whom may still be alive.
So we have a few degraded, contaminated samples with somewhat uncertain species and sub-species identifications that are compared to populations with a very long and largely unknown quantity of cross breeding. Good luck with that. Or, to be more formal: I would not regard as very authoritative statements based on DNA analysis about the timing, origin and especially the exact number of migrations into the Americas.
Boats are not the only possibility as a means to reach North America. There was probably a route that opened about 14,000 years ago across Beringa (a truly huge six million square kilometer area), through what is now Alberta and eastern British Columbia in an ice free corridor between the Laurentide and Cordilleran ice sheets, and into lower North America.
Thomas Jefferson, more than 200 years ago, opined that American Indians came from somewhere in Asia a long time ago. The greatest mystery in archaeology is still very mysterious. It is a lesson in humility that 200 years of great scientific advances in this area have not moved our understanding too far from that of Jefferson.
Robert also wrote, “Asiatic people (the scientific term is Mongoloid) were not distinct until after the last ice age.”
The last glacial maximum did not occur until 15 to 20 thousand years ago. The retreat of the glaciers was mostly completed by about 10,000 years ago. I think the scientific consensus is that the Mongoloid subspecies had emerged by about 30,000 years ago – during the Wisconsin glaciation.
GW, you’re pushing the wishful thinking pretty far. There is no significant evidence that non-Homo Sapiens hominins had anything approaching the cognitive abilities of Home Sapiens.
The suggestion that the reason for this lack of evidence is because pre-Homo Sapiens used perishable materials is really not credible. Stone, bone and antler are superior materials for cutting, hammering, scraping, chopping, drilling, fire making, as projective points for spears and a host of other uses. You postulate that pre-Homo Sapiens used wood and fiber instead? And this indicates they were as smart as Homo Sapiens? I don’t think so.
There is no evidence for bow and arrow technology before about 64,000 years ago in Africa and clearly associated with Homo Sapiens. There is no evidence in Europe until about 16,000 years ago of bow and arrow technology. By then Neanderthal had been extinct for about 11,000 years.
“There's been some reports they might have clothed or cloaked themselves in feathers. Yet it appears from the trash middens they did not eat birds.” Does that really seem likely? These people frequently lived on or past the edge of starvation. They knew how to butcher many different kinds of animals. Yet they didn’t eat birds even though they had enough feathers around to show up in the archaeological record? Not likely.
Then, there’s the leap that these hints of possible feather use indicate decorative and symbolic behavior. All based on a correlation between Neanderthal occupation and the presence of certain bird species, and some butchery marks on some bird bones. I’d tempted to call this whole line of reasoning bird brained.
Homo Sapiens probably reached Australia by boat. Whether they interbred with anybody on the way is kind of irrelevant and hardly based on a mountain of evidence. The Denisovan genome was constructed from a grand total of ONE bone fragment. In any case, So what? This was Homo Sapiens, the species that has been demonstrating symbolic behavior for at least 80,000 years.
The situation with Homo Floresiensis is not understood and is evidence of nothing at this point. None of the hypotheses explaining these fossils seems very likely, which is probably why no hypothesis has received scientific consensus – to put it mildly.
How is any of this evidence of “cognitive abilities more or less comparable to our own” going back a million years? All other hominin species likely exterminated in one way or another, a grossly inferior tool kit, no musical instruments, no cave paintings, no decorative arts, no statuettes and figurines, no engraved ochre, etc. All accomplishments of Homo Sapiens going back more than 80,000 years in some cases. All of it contemporary with hominins that were not Homo Sapiens; thus calling into question the preservation argument.
The evidence shows that there was some kind of evolutionary development that made us smart, and that it happened sometime more than 80,000 years ago in, or coincident with, the evolution of Homo Sapiens, i.e, less than 200,000 years ago.
The supposition that non-Homo Sapiens had cognitive abilities approaching those of Homo Sapiens is put very much in doubt by:
the extinction of all the other non-Homo Sapiens hominins
and the utter lack of significant archaeological evidence for symbolic behavior anywhere near the scale seen in Homo Sapiens
One can equally easily assert that extraterrestrial aliens walk among us in perfect disguise, or walked the Earth long ago but left no trace. As John Maynard Keynes put it, “That all things are possible is no excuse for talking foolishly.” About extraterrestrial aliens or smart Neanderthals.
It is my assertion that there is a very distinct difference between the cognitive abilities of Homo Sapiens and that of all other hominins.
Start with Neanderthal. Homo Sapiens arrived in Europe about 40,000 years ago; after hundreds of thousands of years, Neanderthal were edged out into extinction in the next 13,000 years. The same thing had happened to all other hominins in Africa, and had happened, or would happen, to all other hominins in Asia. I think that suggests something about the cognitive abilities of Homo Sapiens compared to other hominins.
Look at the Neanderthal tool kit: More varied and capable than most hominins excepting Homo Sapiens; and what a difference with Homo Sapiens. Neanderthal with less than 80 variants, no use of antler or bone, very rare hafting of stone points (if at all). Homo Sapiens with endless variety, using stone, antler, bone (as much as 80,000 years ago), hafting as a regular matter, and, very remarkably heat treating of stone 70,000 years ago in Southern Africa. Perhaps even the production of arrows more than 60,000 years ago.
And then there’s art and other symbolic behavior. Within the documented Neanderthal span, we very occasionally find a bone bearing incision marks, a tooth or bone with a hole, or a piece of stone with hollows, some deposits of ochre which might or might not have been used for body painting. Much of it may or may not have been intentional. The very scarcity of occurrence indicates that these possible examples of symbolic behavior were not a part of the cultural existence of Neanderthal.
Contrast that with Homo Sapiens with flutes, cave paintings, endless decorative arts, ubiquitous Venus and other figurines, engraved ochre, some dating to over 70,000 years ago,
The cave paintings demonstrate to me that the Homo Sapiens of more than 30,000 years ago were us. These paintings from the Aurignacian and Magdalenian periods are not one-off or rare affairs, but exist in hundreds, if not thousands, of places in Spain, France and Italy. Many of the caves complexes contain thousands of paintings Other cave paintings are known from Australia dating more than 40,000 years ago. I’m one of the last non-professionals to observe in awe some of the 2,000 cave paintings at Lascaux in 1983. I was amazed at the size, technique and sophistication of the paintings, but mostly at the realization these were not done by alien, or child-like people, or amateurs: This is great art that speaks directly to us. It is in the same line as the Egyptians, Romans, Michelangelo and Picasso. Excuse my unintentional Euro-centric biases.
It seems quite clear that something very distinctive in cognitive abilities emerged with the appearance of Homo Sapiens, a very distinct species with a very different set of cognitive abilities. The archaeological record clearly shows a sharp upward break in cognitive ability that occurred within Homo Sapiens; a break evidenced to 80,000 years ago, and which probably occurred much earlier, perhaps as early as with the advent of anatomically modern humans around 200,000 years ago in Africa.
But another question would be what has happened to those abilities within Homo Sapiens in the last 200,000 years or so. Or maybe just since:
the distinctive character of the cognitive abilities of Homo Sapiens became apparent in the archaeological record around 80,000 years ago?
Or the invention of agriculture around 10,000 years ago?
Or the industrial revolution?
After my experiences in Lascaux, I would opine that those abilities have not changed much in more than 30,000 years.
About the suggestion that hominins other than Homo Sapiens engaged in sea faring.
First, I’m amused at the certainty with which these DNA numbers are bandied about. Just consider:
Identifying a partial (in many cases a very partial) skeleton as Neanderthal is not all that much of a sure thing.
The number of such partial skeletons containing recoverable DNA has been very limited, less than ten.
The DNA is degraded and contaminated with DNA from bacteria, humans who handled the specimens, and god knows what else.
The commonly quoted studies (conducted on DNA from the SAME individuals) done in the US and Germany reach the conclusion that Neanderthal divergence from the common ancestor was 370,000 or 516,000 years ago, a rather yawning difference.
Homo Sapiens, since the diaspora from Africa, have interbreed with each other very extensively. In the case of the Australian Aboriginals, a lot of Polynesians visited even before the Dutch landed near Weipa in Queensland in 1606. The comparisons are from people who lived in the 20th century, many of whom may still be alive. And who knows with whom their ancestors may have mated? Captain Cook? Captain Bligh? Captain Hook? No wonder they have Neanderthal DNA.
In brief, I would not regard statements about the percentage of Neanderthal in Aboriginals, Africans or Irishman as Holy Writ.
There is no evidence whatever – none – of any occupation of any part of Greater Australia (Australia, Tasmania, New Guinea and some other islands were all part of an extended continent for much of the Pleistocene) by any hominin other than Homo Sapiens. The supposed greater concentration of Neanderthal DNA in Australian Aborignals is not suggestive of a Neanderthal occupation of Greater Australia; such a concentration, if it exists, has many other possible explanations.
The total lack of any anthropological or archaeological evidence of Neanderthal over the 10 million square kilometers of Greater Australia should gave some pause to enthusiastic assertions that the presence of Neanderthal in Australia proves a steady state in cognitive abilities for hominins over the last million years.
"What kind of cognitive abilities were required for homo erectus to spread from Africa through Asia all the way into Indonesia?"
One could as easily ask: What kind of cognitive abilities were required for ants to spread from Africa through Asia all the way into Indonesia? Or rats. Range is not related to IQ.
By the way, a complete barrier to reproduction is not necessary for speculation – consider dogs, wolves, coyotes. While it is true that if two populations that reproduce sexually can NOT interbreed, they are NOT the same species, there is NO criteria that says that two distinct species CAN'T interbreed, or that if two populations can interbreed they are the SAME species. Species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups. The "reproductive isolation" can be genetic (non-fertility), geographic, or behavioral.
GW wrote, "we think Neanderthals got their start around 100,000 years ago in the middle east and Europe."
Neanderthal are undoubtedly much older than 100 kyb.
For instance, from Journal of Archaeological Science, Volume 30, Issue 3, March 2003, Pages 275–280, Abstract:
"The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320 kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling. We report here on a new discovery within the Sima de los Huesos of human bones stratigraphically underlying an in situ speleothem. U-series analyses of the speleothem shows the lower part to be at isotopic U/Th equilibrium, translating to a firm lower limit of 350 kyr for the SH hominids. Finite dates on the upper part suggest a speleothem growth rate of c. 1 cm/32 kyr. This rate, along with paleontological constraints, place the likely age of the hominids in the interval of 400 to 600 kyr."
Also, there was another glacial maximum during the Illinoian (or Wolstonian) glaciation at about 170,000 years ago. What were sea levels then? The dates of glacial maximums, and of short, sharp glaciation episodes (like the Younger Dryas of a much, much later period) are not all that firm, leaving lots of room for maneuver when it comes to sea levels.
What I know about radiometric dating suggests to me that there are usually considerable ranges, especially (as noted above) with contamination and other issues. We have uncertainty piled on uncertainty, and from this we're to draw some conclusions about the evolution of human intelligence. I say pure nonsense.
Even with respect to the anthropology, one needs say, "There is much work to do before the community will accept this result" or refute it.
I know of no evidence that any hominin group reached Australia other then Homo Sapiens - ever. As for Flores, there is evidence of the presence of elephants and Homo Errectus on Flores 840,000 years ago. No one suggests that either elephants or Homo Errectus had sea faring 840,000 years ago, but it is truly remarkable.
Lemurs originated in Africa about 60 million years ago, although today they inhabit Madagascar almost exclusively. But Madagascar separated from the Africa/South America landmass about 135 million years and has been located hundreds of kilometers off the African coast for at least 100 million years, far out of sight of any other land and across deep ocean. How did the lemurs get to Madagascar? It wasn't by sea faring.
Do keep in mind that it is not only the Curiosity observations, but also the Mars Express and ground based observations that are all compatible with zero methane. All three are also compatible with a non-biological origin for the methane.
It is not hard to imagine a geologic process taking place on Mars that would emit some methane periodically or continuously.
I wouldn't get your hopes up on, at most, a trace amount of methane which could easily have a non-biological origin.
I think you have to say Spanish, French and Portuguese, who all got to the new world before the English.
So, we have 4 relatively unsuccessful colonial powers that allegedly do not share the common characteristic of "creating a mutual trade network that would persist through independence." And one that does share this trait with one of the unsuccessful one. That does not seem like strong evidence. Also, mutual trade networks with Spain, France and Portugal did persist past colonial independence.
There are many, many varied reasons why Canada and the US are more successful, in some ways, than Latin American countries, e.g., the Mexicans didn't mostly exterminate the indigenous peoples, and the English didn't discover gold till much later.
At least as important, the US and Canada benefited very greatly from inheriting the English understandings and approaches to governance and economics. The fact that free trade amongst the former colonies is required in the US Constitution is an example. Canada's continued use of the Queen as head of state is another. The use of the Common Law in both the US and Canada - to this day - is still another.
History has a lot to teach, but it's not an easy study.
Would the survival value of intelligence decrease with the invention of agriculture around 10,000 years ago? Doesn't seem likely to me. People living in cities didn't happen until modern times. In 1900 the urban population of the US was around 40%, in 1850 15% in 1800 6%.
Even in Britain, the most industrialized country in the world, over half the population lived in rural areas as late as 1831.
Also:
> There are relationships today between schooling, financial achievement, and reproductive success which could favor intelligence
> The domestication of animals required a range of skills mostly aided by intelligence; machinery, of course, does the same to a higher degree. Unintelligent handling of machinery causes large reductions in reproductive success due to deaths and disabilities. Intelligent handling of automobiles has been shown to increase reproductive success.
> Formal schooling, a more stimulating environment, better nutrition, control of infectious diseases, and more out-breeding should all enhance intellectual skills.
Where's the evidence for a decline in intelligence? The Flynn effect says the opposite.
I'd question the dating.
And Crete may be 100 miles out of sight of land now, but what about when sea levels were 100 meters lower, say 15,000 years ago?
I've read about this stabilizing moon idea for awhile. I don't buy it. Our Moon disturbing the delicate things taking place (maybe) in the tidal pools that lead to life. It does other things like lengthen the day.
As for climatic instability, how relevant could that be in the oceans? And assuredly those climatic instabilities would be less extreme than the more or less periodic glaciations Earth has experienced in the last 3 million years. The other non-periodic glaciations, including snowball Earth of six hundred million years ago and maybe other times in the past. It's effects less extreme than the numerous impacts Earth has experienced producing mass extinction events.
Then there are the moons of gas giants as potential homes for life. They wouldn't need a moon.
I think more likely explanations are the rarity of abiogenesis (if it is rare), and the barriers imposed by the necessity to invent photosynthesis, multicellar structures and ridiculously sized brains. Last, and hopefully least likely, that the life span of technological civilizations is very brief even accounting for robots, beacons, probes and other artifacts.
The Great Silence implies that contemporary technological civilizations more advanced than ours must be rare. I think we have enough data about exo-planets to be able to say that a lack of habitable planets and moons is probably not the reason for the Great Silence. Even assuming that super-luminal travel, communication and observation are not practical, I still emphatically reject the idea that ETs would be uniformly uncommunicative.
They will certainly know we are here from the atmospheric gases that life has produced in very great quantities for the last four billion years. For those within a few thousand light years of Earth, the effects of large scale agriculture and metal working will have signaled the presence of a technological species on Earth for the last ten thousand years.
At least some ETs will not be monolithic, which means many groups within each ET civilization will provide evidence observable by us from engineering, altruistic, religious, ideological, academic or numerous other motives, many of which I haven’t thought of.
All of this suggests that the probability of a contemporary technological civilization must be considerably less than one per million star systems. One per million would leave about 400,000 contemporary technological civilizations in the Milky Way Galaxy. There would be about a thousand such civilizations within five thousand light years of Earth; a 90% probability of one such a civilization within 800 light years. It seems inconceivable that many of these would not be noticed.
That leaves three reasons for the Great Silence, for the rarity of contemporary technological civilizations:
1. Abiogenesis and interstellar transport of life are rare
2. Overcoming all of the numerous hurdles after abiogenesis and before a contemporary technological civilization emerges is rare. Hurdles such as the invention of photosynthesis, the development of multi-celled organisms, brain growth gone wild (as with Homo Sapiens), etc.
3. The lifetime of technological civilizations is short even considering that after the extinction of the biological entities, observable signs of the civilization may remain for eons in various artifacts such as legacy beacons, robots or interstellar probes in our solar system.
I hope that the third reason is not THE reason. What Mars has to say, to date, about abiogenesis and interstellar transport of life is comforting.
There is no constraint on the lower limit of the probability of a contemporary technological civilization per star system. There’s nothing to say it has to be more than one per billion, one per trillion, or one per google. This concept is a bit frightening since it leaves open the possibility that we are the ONLY one.
A new type of information about this issue will be produced before the end of the next decade; analysis of the atmospheric gases of habitable exo-planets will tell us if abundant life exists around other stars. If we find no such evidence, the data about Mars (and the rest of our solar system) will reinforce the idea that abiogenesis and interstellar transport of life is rare. The lifetime of technological civilizations will not necessarily be short. If we do find life, Mars will be an anomaly, and either the hurdles to technological civilization or the life span of such civilizations will be the answer to the Great Silence.
I’ll be 90 years old when this new data is flowing, and that will be my last glimpse of these questions – unless ET pops in for my hundredth.
It would be helpful for the uninitiated, such as myself, if some explanation were given for the acronyms. I think I've got NASA, ICBM and LEO down pretty well, but what is
BEO - Banquet Event Order?
SLS - Society of Laparoendoscopic Surgeons?
LSS - Lutheran Social Services?
Then there's all the other stuff, even though it's defined once, one has to construct a glossary to keep tract: ELA, SEV. Fortunately RTTM was used just once and defined at the time.
Do you guys also have a secret handshake?
We know on Earth there are lots of microenvironments - sub oceanic hot springs, deep caves etc - where there are isolated ecologies that carry on happily for billions of years.
I'm not aware of any such that have lasted for billions of years. Could you enlighten me?
You contend that we do know enough to say with a reasonable degree of certainty that life does not exist on Mars.
I do not make that assertion. I suggest an educated assessment based only on what is now known. We make such assessments all the time. In life we rarely have the luxury of “a reasonable degree of certainty.” We very frequently have to make decisions based on incomplete, imperfect data. Would we make money advertising on the radio? Should we market porous point pens? Should we arm anybody in Syria? Who?
So, at this point in time, what do you think? Not based on wishes or fantasies, but on the observations, theory, logic and experience we currently possess. Life on Mars now? In the past?
I have problems with life existing on Mars now.
It’s hard to imagine finding much life on the surface of Mars, even bacteria. On Earth bacteria and algae leave unmistakable signs: changing the color of rocks, changes that last thousands of years even in Earth’s active climate. The entire surface of Mars has been examined rather closely from orbit, and millions of square meters at multiple locations by eight landers. Couple that with the hostile radiation, desiccation and chemical environment on the surface, and my educated assessment is that we are just not going to find life on the surface of Mars.
(Nearly?) all life on Earth produces identifiable gases. The Curiosity observation constrains the upper limit of methane at about 1,000th that on Earth. Earth has more robust means of eliminating methane; not all Earth life produces methane. There’s also a considerable probability that methane may be produced through non-biological processes on Mars. Even with this added boost, still methane on Mars is less than 1,000th that on Earth.
In more than a century no other gas (such as oxygen, ozone, or nitric oxides) has been observed out of thermal equilibrium by orders of magnitude. Mars life would have to produce gases at a rate many orders of magnitude less than life on Earth for this to be the case.
That leaves life limited to the sub-surface, producing no gases detectable in the atmosphere, using energy sources other than the Sun, and leaving no evidence in any of the samples and geologic structures we’ve studied to date. There could be redoubts in which small colonies of life have existed for the billions of years that Mars has been in its current inhospitable condition. But SMALL POCKETS OF LIFE ISOLATED FOR VERY LONG PERIODS OF TIME TEND TO DISAPPEAR; they use up their resources; things change; the nest gets fouled; the ecological niche collapses; they can’t move.
So my educated assessment is that WE WILL NOT FIND LIFE CURRENTLY EXTANT ON MARS BECAUSE IT’S NOT THERE. This could be because it was never there, or because it died out.
There have been a few observations that could detect extinct microbial life: effects on the Martian surface or in geologic formations, meteorites, and what landers may have examined. No signs of extinct life that the scientific community accepts.
If life ever did exist on Mars, how long will it be before a comprehensive search is mounted for microbial life that died out a few billion years ago? Not for a long time, I venture. Which means that, for the foreseeable future what we know now is what we will know for the next few decades.
Of course, after 10,000 scientists of various stripes have diligently searched for extinct life in ten million places on Mars, we still will not be able to say, “This proves no life ever existed on Mars.” While this proposition can never be proved, we might consider John Maynard Keyes admonition, “That all things are possible is no excuse for talking foolishly.”
Available today:
Some evidence that no life currently exists on Mars, because it’s effects, if any, are not detectable, and small quantities of life would probably have died out billions of years ago.
No extinct life in the places we’ve been able to look.
The simpler idea is that there is currently no life on Mars because there never was any. This implies that interplanetary (and even more so interstellar) transport of life is unlikely and that abiogenesis is rare.
Both implications supported by, and explaining, the Great Silence.
No certainly implied; just an educated assessment based only on our current state of knowledge.
If life were discovered on Mars (other than that introduced by our instruments), it would demonstrate one of two possibilities depending on whether Martian life shared a common origin with Earth life:
INTERPLANETARY TRANSFER OF LIFE had happened, which would suggest that interstellar transfer of life was also possible.
Or
ABIOGENESIS occurred more than once in our solar system, which would suggest that abiogenesis was a probable outcome of a favorable environment in the rest of the universe.
Finding life anywhere else in our solar system would lead to similar conclusions.
The question as to whether life exists on Mars can be answered in the affirmative by one example of such life. Until such an example emerges, it is an open question. The negative cannot be proven by observation, and a theory that would preclude life on Mars does not seem to be anywhere in sight. Nonetheless, with no example of life on Mars and no proof of the negative, we can still make an EDUCATED ASSESSMENT.
We make such assessments all the time in the face of uncertainty and incomplete information. Will that store have soy free, vegetable butter? Is that Clint Eastwood movie worth seeing? Will Iran get the Bomb?
Back to Mars: At this point the observation is fairly robust that any life on Mars must not have been very successful; at least its effects on the Martian environment are minute compared to life on Earth. To review the observations:
Until the middle of the 20th century observations of the surface of Mars did not provide much evidence of anything, but for the last half century, increasingly sophisticated observations of the surface have been made from Earth, space and Mars itself. So far about two dozen spacecraft have successfully flown by or orbited Mars, and almost a dozen have landed on Mars. They have at least partially fulfilled the role of geologist over hundreds of kilometers of Martian surface. For over a century increasingly sophisticated observations of atmospheric gases have been made, now including those of Curiosity. Observations of the sub-surface have been made from an analysis of geologic structures currently on the surface, minor digging operations, Martian meteorites, and various remote imaging techniques applied to the sub-subsurface.
To summarize these observations:
ATMOSPHERIC GASES display no evidence of life. From Curiosity, “The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.” On the Earth it’s 2 parts per million even with our higher temperatures and 21% oxygen. No other gaseous product of life is evident.
SURFACE. For decades there have been orbiters photographing the entire Martian surface with resolutions down to sub-meters. On the Earth, of course, life is observed everywhere except in glacial areas, parts of the most extreme deserts, and most water covered areas (even there algae blooms and marine phosphorescence display in large parts of the water cover). A random sample of Earth’s surface has about one chance in three of observing life at a one meter square scale; on Mars the result is zero out of hundreds of trillions of observations.
SUB-SURFACE. Sedimentary layers observed from orbit and from the surface show no signs of fossils, no actions of life, no layers of calcium carbonate formed by planktonic algae, no other hint of the action of life. Martian meteorites display no evidence of life that convinces the scientific community. Our landers don’t find anything with their digging. Evidence of life is ubiquitous from such observations on Earth.
For over a century we've looked for life in increasingly capable ways that would have revealed its presence if that life had affected its environment within four or more orders of magnitude of the effects of Earth life. There has been no meaningful evidence of such life. Given these observations and the generally inhospitable environment of Mars, I would make the somewhat educated assessment that NO EXAMPLE OF INDIGENOUS LIFE WILL BE FOUND ON MARS.
Given that assessment, the lack of indigenous life on Mars is a bit surprising considering:
> the huge reservoir of very diverse life that has existed on Earth for the last four billion years
> that a lot of Earth material has landed on Mars in that time
> and that Mars had a more friendly environment for life in the past, which should have given life imported from Earth a chance to establish itself, evolve and adapt.
That life has not migrated to Mars, with four billion years of very substantial opportunity, implies that interplanetary transport of life is not all that easy, and that INTERSTELLAR TRANSPORT OF LIFE IS UNLIKELY.
Given that assessment, the lack of abiogenesis in such a favorable environment implies that ABIOGENESIS IS NOT ALL THAT COMMON.
The implications that interstellar transport of life is unlikely, and that abiogenesis is uncommon, are reinforced by the observation that we have also seen no evidence of ET beyond our solar system. These implications may also serve as an explanation for this Great Silence.