ريتشارد دوكنز's Blog, page 671

The Elephant in the Room

History

Banksy, The Elephant in the Room (2006). Photograph: Bit Boy, via Wikimedia Commons. Used under Attribution 2.0 Generic (CC BY 2.0) license, https://creativecommons.org/licenses/...

I was reading through Paul Johnson’s Darwin: Portrait of a Genius (2012) recently—not, I admit, with particularly high expectations. It's not just because there are plenty of excellent biographies of Darwin already, including Adrian Desmond and James Moore’s Darwin: The Life of a Tormented Evolutionist (1992) and Janet Browne’s Charles Darwin: Voyaging (1995) and Charles Darwin: The Power of Place (2002). The key reason: knowledgeable historians of science panned the book as shoddy and tendentious. In The Historian, for example, John van Wyhe complained of Johnson’s retelling “traditional legends” and inventing new ones, noting that, in discussing Darwin’s supposed influence on eugenics and imperialism, he offered “a guilt-by-association argument…normally made by creationists.” In Reports of the NCSE, John M. Lynch similarly complained (PDF) of “strange things” claimed by Johnson and noted the “not very subtle attempt to engage in polemic and guilt by association.”

I found myself agreeing. And here’s a single example, centering on a single passage from Darwin’s Origin, to show why. Johnson praises the Origin as “a cleverly written, superbly presented, and even a cunningly judged book”—but adds, “it was, and is, open to one objection.” What is the One Objection to Rule Them All? For Johnson, it is the unargued assumption of the cruelty of nature. Instead of providing evidence or even examples, Darwin elects “to use a selective, repetitive[,] and emotional vocabulary of strife.” One of Johnson’s examples of Darwin’s doing so involves the sentence “The elephant is reckoned to be the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase: it will be under the mark to assume that it breeds when thirty years old, and goes on breeding till ninety years old, bringing forth three pair of young in this interval; if this be so, at the end of the fifth century there would be alive fifteen million elephants, descended from the first pair.”

Darwin’s purpose here would seem to be to illustrate what he describes as “the rule that every organic being naturally increases at so high a rate, that if not destroyed, the earth would soon be covered by the progeny of a single pair,” even in the case of the slow-breeding elephant. But according to Johnson, Darwin “terrifies the reader with a vision of ‘fifteen million elephants’ suddenly appearing if these creatures—whom he picks as the slowest in procreating—are allowed to do so unchecked.” A moment’s thought reveals a few problems here. First, the adjective “suddenly” seems unwarranted: Darwin’s fifteen million elephants appear over the course of five centuries. Perhaps more to the point, it hardly seems credible that the reader of the Origin would be especially terrified by the prospect of millions of elephants. I don’t underestimate the destructiveness of elephants, but if Darwin were seeking to terrify his Victorian readers with ravening hordes of extrapolated beasts, why wouldn’t he have picked wolves or crocodiles or tigers?

Undeterred by such elementary considerations, Johnson returns to the elephant example a scant dozen pages later, when he discusses the later editions of the Origin: “To his consternation, he found that the ‘mathematical expert’ who had ‘worked out the number of elephants that would emerge under Malthusian theory at 15 million’ had got his sums wrong, and the figure had to be made less frightening.” Johnson is right that Darwin discovered that the figure was in error. In a letter to the Athenaeum in 1869, the pseudonymous Ponderer reported a different calculation—in five centuries, by Ponderer’s reckoning, a breeding pair would produce “85,524 elephants, less the number that would have died by reason of their age”—and asked how Darwin obtained the fifteen million figure. Darwin responded by acknowledging his error—he relied, he admits, on “some Cambridge mathematician” he could no longer recall—and revising his estimate: “after a period of 750 to 760 years” there would be more than fifteen million, “namely, 18,803,080,” elephants.

The sixth edition of the Origin updates the figures accordingly. But is “nearly nineteen million elephants” “after a period of from 740 to 750 years” (as in the sixth edition) really “less frightening” than “fifteen million elephants” after 500 years (as in the first through fifth editions), as Johnson asserts? Or is it simply more accurate? What seem less than accurate, in any case, are the quotation marks in Johnson’s claim, around “mathematical expert” and “worked out the number of elephants that would emerge under Malthusian theory at 15 millions.” There are no citations provided for these words in Darwin: Portrait of a Genius, but they are not taken from Darwin’s letter to the Athenaeum, or from anything Darwin wrote, as far as I can tell. The fact that the distinctive phrase “emerge under Malthusian theory” appears nowhere on the internet (including Google Books) except in Johnson’s book suggests that the phrases are Johnson’s own, mistakenly—and sloppily—indicated as verbatim quotations from a source.

Johnson returns again to the elephant passage in discussing The Descent of Man (1871), commenting, “One wonders whether Darwin put this sort of information [about communal marriage] in to titillate or frighten the reader, rather like the imaginary ‘fifteen million elephants’ of Origin.” Well, perhaps one would so wonder, if one were disposed to accept Johnson’s implausible judgment about the purpose of the elephant example. But then it would be odd for one not to observe that the Descent includes a frightening reference to the superfecundity of elephants (“The slowest breeder of all known animals, namely the elephant, would in a few thousand years stock the whole world”) or a titillating reference to their polygamy (“‘it is rare to find,’ as Dr. Campbell states, ‘more than one male with a whole herd of females’”): all grist to one’s mill, surely. Or one might instead conclude that in seeking a hidden rhetorical agenda in the Origin’s choice of examples, one is overlooking a large pachyderm in the immediate interior environment.

Christian group predicts the world will be ‘annihilated’ on Wednesday

Matt Hecht

By Adam Gabbatt

While our planet may have survived September’s “blood moon”, it will be permanently destroyed on Wednesday, 7 October, a Christian organization has warned.

The eBible Fellowship, an online affiliation headquartered near Philadelphia, has based its prediction of an October obliteration on a previous claim that the world would end on 21 May 2011. While that claim proved to be false, the organization is confident it has the correct date this time.

“According to what the Bible is presenting it does appear that 7 October will be the day that God has spoken of: in which, the world will pass away,” said Chris McCann, the leader and founder of the fellowship, an online gathering of Christians headquartered in Philadelphia.

“It’ll be gone forever. Annihilated.”

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First “Glowing” Sea Turtle Found

David Gruber

By Jane J. Lee

Yes, this sea turtle is glowing neon green and red. No, it’s not radioactive.

The critically endangered hawksbill sea turtle is the first reptile scientists have seen exhibiting biofluorescence—the ability to reflect the blue light hitting a surface and re-emit it as a different color. The most common colors are green, red, and orange.

Biofluorescence is different from bioluminescence, in which animals either produce their own light through a series of chemical reactions, or host bacteria that give off light.

Corals fluoresce, and recent research has found the ability in a number of fish, sharks, rays, tiny crustaceans called copepods, and mantis shrimp. But researchers never expected to find it in a marine reptile. (See pictures of other animals that glow.)

“I’ve been [studying turtles] for a long time and I don’t think anyone’s ever seen this,” says Alexander Gaos, director of the Eastern Pacific Hawksbill Initiative, who was not involved in the find. “This is really quite amazing.”

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The Gravest Threat to Colleges Comes From Within

Virginia Tech

By Scott A. Bass and Mary L. Clark

We are experiencing one of the greatest threats to the university as we know it. It is not about enrollments, revenues, regulation, rankings, or leadership. It is about the ability to engage in unfettered debate at American colleges. It is about the assurance of intellectual freedom, about what can and cannot be discussed.

Colleges face criticism from students and others uncomfortable with the points of view expressed in the classroom and by individual faculty members. Provocative art, revealing films, graphic literary portrayals, and controversial speech are understandably uncomfortable for those who find such work contrary to their beliefs. Yet it is this type of work — controversial at times — that has enlightened the world.

Throughout history, colleges have been sites for the creation of knowledge and its dissemination to new generations. The creative spirit of the scholars in higher education, along with the protection afforded by academic freedom, has ensured innovation. Basic research that appears to have little practical application has helped cure disease, led to breakthroughs in science, and fostered understanding of the world. Presentation of counterculture perspectives, art, and literature has contributed to the next generation of leaders’ understanding of social and political movements. Disclosures of business and government practices have increased transparency and improved quality of products and services.

Many of the things we take for granted were once controversial, even heretical. Political dissent in the 1950s, which created a climate of fear for professors, serves as a not-too-distant example. Yet a key tenet of college has been the freedom to pursue novel questions. In the mid-12th century, the University of Bologna originated the concept of academic freedom such that scholars could pursue inquiry without risk of persecution. With 900 years of tradition, academic freedom is something to cherish and protect.

Our newest and greatest threat, however, comes not from external pressures, but from inside the university itself. Around the country, students have been rebelling against certain assignments, topics, or speakers. Some students object to material presented and readings assigned, asserting that assignments are upsetting, triggering anxieties or violating personal beliefs. After all, some argue, they are paying for the experience and should have a say in what they are exposed to and taught.

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bending truth

https://www.patreon.com/theramintrees

A reflection on the importance of acknowledging that we can all be manipulated.

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Studies:

Aronson, E. and Mills, J. (1959) The effects of severity of initiation on liking for a group. Journal of Abnormal and Social Psychology 59 (2), pp.177–181

Knox, R.E. and Inkster, J.A. (1968) Postdecisional dissonance at post time. Journal of Personality and Social Psychology 8 (4), pp.319-323

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music © theramintrees

Water on Mars

EvolutionGeneralHistoryScience Above: Pluto's mountains, photographed by the New Horizons spacecraft as the sun sets, 7/14/2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Below: "Recurring slope linae," identified as evidence of flowing liquid water on the surface of Mars. The dark streaks grow and shrink seasonally, as briny water liquifies and flows into the crater. Credit: NASA/JPL-Caltech/Univ. of Arizona

It’s been a big year for the late astronomer Percival Lowell. The New Horizons spacecraft is returning the first detailed images of Pluto, the dwarf planet whose existence he predicted, and for which he initiated a search which ultimately succeeded in 1930 (at the eponymous Lowell Observatory in Flagstaff, Arizona, thanks to Clyde Tombaugh’s careful observations).

And this week, NASA announced strong evidence of flowing liquid water on Mars. Lowell spent a lot of time and energy trying to chart what he believed were canals on Mars, evidence of a civilization on the planet. It turns out that he was wrong about canals, and pretty clearly wrong about a Martian civilization. But evidence of flowing water raises hopes that the planet hosts life.

It’s certainly true that life on Earth is dependent on water. Water has lots of handy chemical properties for life as we know it, which makes it likely that life elsewhere would also depend on (liquid) water. Finding liquid water on other planets would raise the odds of finding life as we know it elsewhere.

The qualifier “as we know it” carries a lot of weight in that analysis. How important water would be to any life on Mars (or elsewhere) is unclear, since we really only have one example of life—one big messy tree—to compare against. From what we know about the chemistry of life, it seems like water ought to be essential. By similar reasoning, carbon ought to be at the core of life on other planets. Once you have carbon chemistry and water, it’s likely that you’d wind up with a lipid bilayer containing proteins and nucleic acids for replication and metabolism. In other words, life as we know it (kinda).

Conveniently, many of those building blocks can be found in comets, and appear to be pretty easy to produce under the conditions that probably prevailed on Earth, Mars, and other planets (and some of the other moons in our solar system) in the solar system’s early days. Add in the observation that some of the earliest rocks on Earth that could plausibly contain evidence of life do indeed contain apparent microfossils and isotopic concentrations characteristic of biological metabolism, and it seems likely that life formed on Earth quite early. And if that’s true on Earth, why not Mars?

Even if life (somewhat like we know it) existed on Mars, there’s no guarantee it would still exist, let alone in any form we recognize. Earth’s surface was scoured by asteroid bombardment until about 3.8 billion years ago, then the surface nearly froze solid at least three times in a stretch between 850 million years ago and 635 million years ago. Any of those events could have wiped out life on Earth. Metazoan life was nearly obliterated in the waves of extinction around the Permian-Triassic border (other mass extinctions didn’t come quite as close, though they were pretty bad).

We know less about the geological history of Mars, but it’s surely a harsh environment today, and in the past it probably went through phases at least as bad as anything Earth experienced. Even if life had formed there, there’s no guarantee it would have survived. Mars seems to have been far less tectonically active, meaning that the refuges where life survived during eras of Snowball Earth may not have been available on Mars. It would also mean fewer of the energy-rich sites like hydrothermal vents where life probably started on Earth, making it less likely that life would survive or restart on Mars.

Or, at least, life as we know it. Even life based on water and carbon wouldn’t necessarily be easy to spot, or share the features we’re used to. One intriguing model for origin-of-life research draws heavily on iron-sulfur reactions for the early metabolic cycle of early life, using chemicals commonly found at hydrothermal vents (and which are notably common in the geology of Mars), and it doesn't have to be inside a cell. Robert Hazen, in his wonderful Genesis: The Scientific Quest for Life’s Origins, explains how that early life may not have been cellular at all:

The bold, heretical concept of flat life—a self-replicating chemical layer of molecules built on a solid mineral foundation—raises an intriguing geochemical possibility. A simple layered collection of molecules might be more tolerant of high temperatures and other environmental extremes than life based on nucleic acids, which break down close to 100ºC. If so, then colonies of flat life might exist today in deep zones of Earth’s crust. Such film-like molecular systems might persist for eons, because they survive at extreme conditions beyond the predation of more efficient cellular life.

If so, how would we know? Such a layer would be invisible under an ordinary light microscope and would appear as a nondescript film using more powerful atomic microscopes. Flat life would be undetectable in standard biological assays, which rely on the presence of DNA and proteins. Is it possible that layer life is abundant on Earth today, yet remains overlooked?

The idea that life-not-quite-as-we-know-it might still persist somewhere on Earth is fascinating enough. But more intriguing is the possibility that such life could exist on Mars. Many of the essential chemicals are common enough on Mars, and it seems likely that some version of the chemistry described by Hazen (drawing on Wächtershäuser’s work) could work on Mars, too. How reliant would such life be on water? How many assumptions that we usually make about what life needs would this chemistry force us to rethink?

All of this is a reminder of just how fundamental evolution is to our thinking about life. Life as we know it shares essential similarities thanks to its shared ancestry and to constraints inherent to chemistry, geology, and astronomy. When we look for life, we may well be focusing on the parts that owe to our common ancestry, and overlooking unfamiliar patterns. Percival Lowell was able to predict that something new was floating out past Neptune by understanding the constraints physics imposed on the Solar System (though, as it turns out, he based it on inaccurate information and basically got lucky). He was wrong about Martian canals because he saw what he wanted to see in the fuzzy and ambiguous surface markings of the planet. But it appears he was right that water flows on Mars, and we may yet find life there, if we can figure out how to see it.

20 Years Later–a Q&A with the first Astronomer to Detect an Exoplanet Around Another Sun

Twenty years ago this month the universe became a richer, stranger and decidedly less lonely place. For centuries, visionaries ranging from Isaac Newton to Gene Roddenberry had speculated about planets orbiting other suns, analogous to the worlds of our solar system—but it was only speculation. Then in October 1995 Michel Mayor, an astronomer at the University of Geneva, and his graduate student Didier Queloz discovered company: the first known planet orbiting a sunlike star.

Technologically, Mayor and Queloz’s work was a tour de force. They used a sensitive spectrograph to break up the star’s light and measure its minuscule back-and-forth motion due to the gravitational yank of the unseen world circling around it. Conceptually, their work was a white-hot firebomb. The planet, known simply as 51 Pegasi b, is as massive as Jupiter but orbits its star 100 times closer. Its “year” is just 4.2 days long and its cloud tops broil at about 1,000 degrees Celsius. It is utterly unlike anything in our solar system, so strange that it forced a wholesale rethink of where and how planets form.

In the two decades since, Mayor and his colleagues have deployed a variety of techniques to discover nearly 2,000 more exoplanets, worlds of staggering diversity. Researchers now estimate there are tens of billions of planets similar to Earth throughout our galaxy. Although Mayor’s breakthrough work helped kick-start what was then a new field of exploration, it did not exactly make him famous. His work was quickly overshadowed by findings from larger teams and big-budget satellite missions—and by more quotable, native-English-speaking researchers. Nevertheless, when Scientific American caught up with Mayor he was in high spirits, cheerfully describing his historic moment as well as his ongoing, boundary-pushing exoplanetary searches.

[An edited transcript of the interview follows.]

What were you expecting to find when you started searching for companions around nearby stars two decades ago?

An important thing to realize is that it was a sad time to search for planets. Gordon Walker and Bruce Campbell [at the University of British Columbia] had been searching for 10 years and concluded that there were no Jupiter-type planets orbiting solar-type stars. A second team, Geoff Marcy and Paul Butler [at San Francisco State University], mimicked that study and in August ‘94 they reported the same result. But we were not troubled by these negative results. We had started construction of a new spectrograph in ‘90 and were not about to stop.

Given those dismal results, what made you optimistic you would discover something?

In ’89, with our old spectrograph, we found an interesting object with 11 times the mass of Jupiter and realized, we are not far from detecting planets. Then in ’94 we had “first light” [inaugural observations] with our new spectrograph, ELODIE, at Haute–Provence Observatory in France. It was fantastic; it could measure stellar motions as small as 15 meters per second, 20 times better than we had with our old instrument. We decided to conduct a large survey of 142 single stars.

I applied for telescope time with Antoine Duquennoy, one of my postdocs, and Didier Queloz, one of my graduate students. We started our measurements, but then Antoine died in a car accident. Didier and I continued. After only a few months we had enough measurements of 51 Pegasi to see something very special, a periodic signal [back-and-forth motion of the star] of 150 meters per second. We fed our data into the computer and saw we had something going around 51 Peg with a period of 4.2 days, meaning it had to be in a very close orbit. This was a surprise, because at the time the idea was that giant planets had to be more than five AUs [five times the distance from Earth to sun] from their star. That was in fall of ’94.

Why didn’t you announce your big discovery until a full year later?

It was so unusual, so unexpected, that we decided to wait for the next season of visibility for 51 Peg. We wanted to be sure the amplitude of the variability was the same, the phase was correct and the period was the same [proving that it was a real planet in a stable orbit]. We didn’t have telescope time again until July 1995. We saw that all the parameters matched up—that was the time when we opened a bottle of champagne. On August 25, we submitted our paper to Nature. [Scientific American is part of Nature Publishing Group.]

51 Pegasi b went against all contemporary thinking about what a planet should be. Did you run into a lot of skepticism?

We were going to a conference on solar-type stars in Florence in October. Just before, I received information from Nature that only two of the three referees voted to accept the paper. It was up to the editor at that point. Fortunately, he decided to accept! Some people at the meeting were really intrigued: “Now we have to look for the reason why we have such a short-period planet.” Other colleagues were looking for arguments: “It’s not a real object, you don’t have enough precision.” But we were 100 percent sure of our measurements.

In contrast, it seems like the theorists were fully ready to embrace the idea that a Jupiter-size world could migrate extremely close to its star.

Yes, in fact the answer had already existed for 15 years. The first paper published on orbital migration by Peter Goldreich and Scott Tremaine—two very important men in astronomy—was devoted to the study of a small body embedded in a disk. The body could be a small galaxy in the disk of a large galaxy or a planet in an accretion disk [the dusty structure around a newborn star]. In the abstract of this paper the last sentence read: “Jupiter was not born where it is today.” That was in 1980.

Still, you must have wondered if 51 Pegasi b was a freak, or whether it was normal and our solar system was perhaps the oddball.

We had only 51 Peg, one object with an orbital period of four days. What would be the impact of a single discovery? Absolutely nothing. Things changed when Geoff Marcy went on his telescope to see if 51 Peg b is real. He realized our observation was correct, and then he and Paul Butler reanalyzed a lot of measurements they had accumulated during the previous years. On January 17, 1996, [at the American Astronomical Society meeting] in San Antonio, Texas, they announced two new exoplanets. Several more objects with short periods were discovered in the first six months of ’96. It was only after we discovered a lot of other planets that we realized 51 Peg b is actually a normal object.

And yet the later discoveries by other teams also overshadowed your early work, at least in the English-speaking media.

It’s true, we don’t have so many callers from the U.S. I’m just sorry my English is so bad.

You remained very active in exoplanet research. What were your most exciting discoveries in the years after 51 Pegasi b?

A very important step was our new spectrograph, HARPS, at La Silla [Paranal] Observatory in Chile. It has a precision of about three meters per second [the smallest back-and-forth stellar motion it can measure]. We’ve improved by a factor of 1,000 in 30 years. Starting in 2004, HARPS [for High Accuracy Radial velocity Planet Searcher] has detected a population of super-Earths, objects with a mass between one and 10 times the mass of Earth. We do not have any planets in this range in our solar system but they are extremely frequent around other sunlike stars. We built another version of HARPS on La Palma in the Canary Islands for the northern sky. This past July HARPS–North found HD 219134 b, one of the closest super-Earth planets, just six parsecs [about 20 light-years] away.

What about the ultimate goal: directly observing a true Earth twin around another star?

Detecting an Earth-type planet that’s habitable is really tough. Earth is a small planet. It will take a new generation of instruments on the new, bigger telescopes [like the Giant Magellan Telescope and Thirty Meter Telescope] to have a chance to observe them directly. To learn about the physics of Earth-like planets—atmospheres and such—we need close, bright stars. At some point, people will try to build a spacecraft to make direct images of other Earths. They will have to know which are the interesting stars to look at. My ambition now is to set up such a list. The planet we announced in July—HD 219134 b—will be a very important target for the future.

Largest dinosaur population growth study ever shows how Maiasaura lived and died

Holly Woodward

By Montana State University

Decades of research on Montana’s state fossil — the “good mother lizard” Maiasaura peeblesorum — has resulted in the most detailed life history of any dinosaur known and created a model to which all other dinosaurs can be compared, according to new research published recently in the journal Paleobiology.

Researchers from Oklahoma State University, Montana State University and Indiana Purdue University used fossils collected from a huge bonebed in western Montana for their study.

“This is one of the most important pieces of paleontology involving MSU in the past 20 years,” said Jack Horner, curator of the Museum of the Rockies at MSU. “This is a dramatic step forward from studying fossilized creatures as single individuals to understanding their life cycle. We are moving away from the novelty of a single instance to looking at a population of dinosaurs in the same way we look at populations of animals today.”

The study was led by Holly Woodward, who did the research as her doctoral thesis in paleontology at MSU. Woodward is now professor of anatomy at Oklahoma State University Center for Health Sciences.

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Scientists to bypass brain damage by re-encoding memories

© ra2 studio / Fotolia

By University of Southern California

Researchers at USC and Wake Forest Baptist Medical Center have developed a brain prosthesis that is designed to help individuals suffering from memory loss.

The prosthesis, which includes a small array of electrodes implanted into the brain, has performed well in laboratory testing in animals and is currently being evaluated in human patients.

Designed originally at USC and tested at Wake Forest Baptist, the device builds on decades of research by Ted Berger and relies on a new algorithm created by Dong Song, both of the USC Viterbi School of Engineering. The development also builds on more than a decade of collaboration with Sam Deadwyler and Robert Hampson of the Department of Physiology & Pharmacology of Wake Forest Baptist who have collected the neural data used to construct the models and algorithms.

When your brain receives the sensory input, it creates a memory in the form of a complex electrical signal that travels through multiple regions of the hippocampus, the memory center of the brain. At each region, the signal is re-encoded until it reaches the final region as a wholly different signal that is sent off for long-term storage.

If there’s damage at any region that prevents this translation, then there is the possibility that long-term memory will not be formed. That’s why an individual with hippocampal damage (for example, due to Alzheimer’s disease) can recall events from a long time ago — things that were already translated into long-term memories before the brain damage occurred — but have difficulty forming new long-term memories.

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Sweden Plans To Become World’s First Fossil Fuel-Free Nation

Environment





Photo credit:

TTstudio/Shutterstock

Recently, there seems to be an uptick in small nations or islands setting their sights on becoming increasingly, or completely, powered by non-fossil fuel energy sources, particularly renewables such as solar, wind and hydroelectric power. This is welcomed news in a world that – despite recent advances in tackling climate change by the U.S. and China – remains relatively paralyzed in its ability to make substantial changes to how it deals with climate change.