Science shorts

Today, I want to look at some awesome shorts that were too good to pass up.

No, not that kind.

In the last couple of days I found three recent bits of research that are just plain cool, and I couldn't resist sharing them with you.

First, we have a new discovery out of China showing that flowering plants were around a great deal earlier than we'd thought -- the early Jurassic Period, 174 million years ago.  This pushes back the earliest evidence of flowering plants by a good fifty million years!

Called Nanjinganthus dendrostyla, this little flower grew during a time when we'd thought there was nothing much around, botanically speaking, but gymnosperms (relatives of today's spruces, firs, and pines), ferns, and other more primitive plants.  But a fantastically well-preserved group of fossils has shown that they shared the space with some of the earliest angiosperms, or flowering plants.

One of the Nanjinganthus dendrostyla fossils 

After careful microscopic analysis of the flower, the researchers put it together like this:

So cool, even if it's not something you'd necessarily want as the centerpiece of your garden.

The significance of the discovery goes beyond its age.  There are some other features that bear mention, as is described over at the blog In Defense of Plants (linked above):

Another surprising feature is the presence of an inferior ovary that, by its very definition, sits below the sepals and petals.  It has long been hypothesized that early angiosperms would exhibit superior ovaries so this discovery means that we must rethink our expectations of how flowers evolved.  For instance, it suggests we may not be able to make broad inferences on the past based on what we see in extant angiosperm lineages.  It could also suggest that the origin of flowering plants was not a single event but rather a series of individual occurrences.  It could also be the case that the origin of flowering plants occurred much earlier than the Jurassic and that Nanjinganthus represents one of many derived forms.  Only further study and more fossils can help us answer such questions.

The second story comes from zoology, and it concerns eyeless cave fish -- fish whose ancestors were trapped in dark caves, and evolved to lose their visual sense.  There's a fundamental misunderstanding that a lot of people have about these species, usually centering around the Lamarckian view that the fish lost their eyes "because they didn't need them any more."  The actual truth of the matter seems to be that if you're in perpetual darkness, using a lot of your energy to produce and maintain a structure as complex and delicate as the eye would be a waste, and diverting those resources to other, more useful purposes is a significant advantage.  It's a subtle point, but an important one.

In any case, this current research turns on two questions -- how cave fish navigate their habitat, and why they have asymmetrical faces -- a curiosity that they share with blind cave crickets.

It turns out that the two questions are related.  The convex side of the fish's skull contains more neuromasts, organs that are not only tactile sensors but give fish information about vibrations and water speed and direction.  All fish have these, but blind fish rely on them to create a mental map of their habitat.  Researchers found that most of the fish have skulls that bend slightly to the left, meaning they're getting tactile input mostly from the right.  And just as you expect, the fish whose skull bends to the left keep their right side in close contact to the walls, and tend to move counterclockwise around their habitat -- and the right-bending fish move the opposite way!

The whole thing brings to mind an article that appeared many years ago in the inimitable science spoof The Journal of Irreproducible Results, describing a little mammal called the Sidehill Gouger that has two short legs on one side and two long legs on the other, so it can stand upright on hillsides.  Thus, like our cave fish, some Sidehill Gougers always travel clockwise, and others counterclockwise.  The article goes into the genetics of the trait, describing how the offspring of a right and a left-handed Gouger produces some of each, but heterozygous individuals end up with diagonally opposite short legs.

They're called "Rockers."

I doubt there's any analog in the cave fish, but it's interesting and more than a little ironic that a piece from JIR actually ended up within hailing distance of reality.


The last story puts to rest the idea that scientists don't know how to have fun.  A couple of mechanical engineers from Boston University, Alexandros Oratis and James Bird, published some research this week in Physical Review Letters describing the physics of shooting a rubber band -- and how to optimize your strategy so it goes straight and doesn't smack your thumb on the way out.

After filming rubber band shooting with an ultra-high-speed camera, what Oratis and Bird found was that when it comes to tension, less is more.  When the rubber band is released, the release of tension in the band zooms forward, and the back end of the band follows, but at a slower speed.  When the tension release reaches your thumb, it allows your thumb to snap forward, dodging the band as it passes.  If you pull too hard, the speed of the tension release is higher, and it's simply too fast for your thumb to duck out of the way.  The result: you give yourself a nice stinging smack.

Wider rubber bands also work better, and for a similar reason; they have a higher tension, so when that's released, your thumb jerks forward more quickly.

Me, I wonder how many times Oratis and Bird popped each other with rubber bands while doing this research.


So there you have it.  Rubber band war strategy, lopsided cave fish, and extremely early flowers.  All of which illustrate what I've claimed all along: science is fun.

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Carl Zimmer has been a science writer for a long time, and his contributions -- mostly on the topic of evolution -- have been featured in National Geographic, Discover, and The New York Times, not to mention appearances on Fresh Air, This American Life, and Radiolab.  He's the author of this week's Skeptophilia book recommendation, which is about the connections between genetics, behavior, and human evolution -- She Has Her Mother's Laugh: The Powers, Perversions, and Potentials of Heredity.

Zimmer's lucid, eloquent style makes this book accessible to the layperson, and he not only looks at the science of genetics but its impact on society -- such as our current infatuation with personal DNA tests such as the ones offered by 23 & Me and Ancestry.  It's a brilliant read, and one in which you'll learn not only about our deep connection to our ancestry, but where humanity might be headed.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Postcards from deep space

It's way too easy to let yourself get caught up in all the ugliness in the news.

Scandals, allegations of crimes of all sorts by various public figures, humanitarian crises, ecological damage done by people who seem to have no real care for the long-term habitability of the Earth.  Hypocrisy, dishonesty, corruption.

Pretty dark stuff, and to judge by the news, it's about all humanity has to offer.

So today I'm going to write about something hopeful -- an indication that we have the capacity for a whole lot of positive things.  Curiosity, innovation, teamwork, and a deep-seated determination to understand the universe we live in.

Ultima Thule is the popular (but unofficial) designation of the object that is, much more prosaically, called MU-69.  It's far out in space by anyone's standards, circling the Sun at an average distance of 44 AU (astronomical units, the average distance from the Earth to the Sun).  By comparison, Neptune -- the outermost actual planet -- orbits at about 30 AU.  Even Pluto (which was downgraded from "planet" to "dwarf planet" status a few years back) orbits at an average 39.5 AU.

So if you reached Pluto, you'd still have a distance of four times the Earth to the Sun to cover before you'd be within hailing distance of Ultima Thule.

And it's not a large object, making me wonder how the hell anyone saw it in the first place.  It's highly oblong, with a long axis of about 33 kilometers and a short axis of 19 kilometers.  So that's the first amazing thing; using the Hubble Space Telescope, we spotted an object only a little more than twice the size of Manhattan Island from a distance of 6.5 trillion kilometers.

Then, astronomers decided it'd be a good place to visit, based on its position with respect to the trajectory of the New Horizons probe, which had sent back stunning photographs of Pluto in 2015.  So off the little spacecraft went, to visit one of the most distant objects known in the Solar System.

The photographs coming back are amazing.  It was known that Ultima Thule was oddly shaped, but as the probe approached, it became clearer and clearer that it was just an oval.  Some of the earliest photographs made it look like a spinning bowling pin.  When it got closer, we were able to see that it was shaped more like a snowman, leading to the inference that it was formed by the collision of two roughly-spherical bodies.  The impact must have been remarkably gentle; too fast, and it would have shattered one or both of the objects.  Instead, they appear to have spiraled in toward one another until finally they kissed -- and stuck together.

[Image courtesy of NASA/JPL]

Astronomers are understandably thrilled by this opportunity to study an object close-up that is observable only as a 26th-magnitude speck of light from our position here on Earth.  Astrophysicist and former member of Queen Brian May wrote a song for the occasion, called "New Horizons," celebrating our perpetual drive for extending what we know about the universe.  (This isn't the first time May has worked his scientific background into his music.  One of Queen's best, and most under-appreciated, songs is the bittersweet and poignant "'39," which has as its basis the bizarre effects of near-lightspeed travel -- especially time dilation, which describes how fast travel slows down the passage of time, so that if you were to leave behind your loved ones and travel near the speed of light, you'd age only a year while the loved ones you left behind would age decades.  If you haven't heard it, click the link -- it's fantastic.)

NASA has promised better photographs as more data comes streaming in from the probe, but the ones they've already gotten are pretty amazing.  When you're looking at them, keep in mind that you're looking at something out there spinning space, half again as far from the Sun as the planet Neptune, and be amazed.

So let's take a break from the constant stream of negativity and vitriol, and consider what incredible journeys we can take into wonderment and beauty, journeys that have taken us into the farthest reaches of the Solar System and beyond.  As we sit down here, engaged in our petty squabbles and petty rhetoric, an intrepid little probe is out there relaying back information about are on the very edges of what we know.  And that, I think, is something about which humanity should rightly be proud.

*******************************

Carl Zimmer has been a science writer for a long time, and his contributions -- mostly on the topic of evolution -- have been featured in National Geographic, Discover, and The New York Times, not to mention appearances on Fresh Air, This American Life, and Radiolab.  He's the author of this week's Skeptophilia book recommendation, which is about the connections between genetics, behavior, and human evolution -- She Has Her Mother's Laugh: The Powers, Perversions, and Potentials of Heredity.

Zimmer's lucid, eloquent style makes this book accessible to the layperson, and he not only looks at the science of genetics but its impact on society -- such as our current infatuation with personal DNA tests such as the ones offered by 23 & Me and Ancestry.  It's a brilliant read, and one in which you'll learn not only about our deep connection to our ancestry, but where humanity might be headed.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Runners' high

I am deeply ambivalent about running.

On the one hand, while I'm doing it, every fiber of my being is begging me to stop.  I'm short of breath, sweating, my legs ache.  It seems like I'll never be done, that this misery will go on forever.  My brain shouts at me with every step, demanding that I stop, asking me why the hell I'm doing this in the first place.  Voluntarily.  Without even a lion chasing me, or something, some circumstance that would make this reasonable behavior.

Me before the start of a race, experiencing deep ambivalence

However, a part of me craves it.  When I'm driving somewhere and I pass a guy out running, I immediately think, "I wish I was doing that right now."  I always feel better afterwards -- with the possible exception of the Montezuma 5K two years ago, when it was a good 95 F, and about 587% relative humidity.  But even then, when I got home -- and immediately went into my back yard, stripped, and jumped into my pond -- I had to admit I was glad I did it.

And crossing the finish line is itself a huge endorphin rush.  I'm a mediocre runner at best and will never be in contention for the top three slots, or even the top fifty, but when I finish -- usually in the middle of the pack -- I feel like a million bucks.  All the pain and misery are forgotten.  In fact, I have sometimes gone home from races, gotten online, and signed up for several more.

Crossing the finish line at the Fox Trot Trail Race, feeling far less ambivalent

The best part, though, is the racing community.  It's about as far from a cutthroat competition as you can get.  I'd guess the first four or five to cross are probably pushing to get ahead, but everyone else?  I can say that people at races are some of the friendliest folks around.  They honestly want everyone to do his/her best.  I've had people slow down, even turn around, when I'm lagging behind, and ask me if I was okay.  I've done the same for other runners.  The folks who have already finished cheer on the ones who follow them, urging them on to put on a final burst of speed as they approach the finish line, to "finish strong."  Afterwards, the question is never "what was your time?" or "what place did you finish in?", it's "did you have a good race?"

Most memorable was last year's Ithaca Twilight Race -- run on the solstice, when it's still light at nine PM.  It was a muggy evening, and after I finished, I got a bottle of water, plunked down onto the grass, and pulled my sweaty t-shirt off.  Shortly afterwards, a cute kid, maybe ten years old, came up to me with a big grin on his face, and gave me a double high-five.

He said, "Well done, Shirtless Tattoo Guy!"

Turns out I'm not alone in feeling this way.  New research in The Journal of Positive Psychology, just released last week and authored by Marzena Cypryańska and John Nezlek, looked at the attitudes of 404 recreational runners, and found something interesting -- but hardly surprising given my experience.  Not only were runners happier following a race, the high lasted throughout the following week.  They scored higher on just about every measure of well-being, including experiencing more positive emotions, having higher self-esteem and confidence, feeling more satisfied with life, and that their life had more meaning.

What's interesting is that the length of the race -- they looked at 5Ks all the way up to full marathons -- didn't matter.  Neither did what position the runner finished in.  The mere act of participating in a competitive run with a group of supportive people gave test subjects a boost that was remarkably long-lasting.

One thing that did seem to matter was how runners themselves felt about their performance.  If someone thought (s)he had "run well," the boost was significantly higher than if (s)he "didn't have a good race."  Again, it didn't matter where in the standings runners fell; a runner could come in 750th out of 1000, and if she felt like she'd run her best and was satisfied with the outcome, it was just as much of an endorphin rush as the woman who placed in the top fifty -- and a great deal more than the guy who came in #10 but felt like he hadn't done as well as he wanted.

I can vouch for this, too.  Last year, I ran the Trumansburg May Day 5K, and wasn't happy with my performance -- my time was high, my energy level low, and I ended up feeling kind of crummy.  I didn't do terribly -- I beat my time in the aforementioned Montezuma Sauna Race by a good three minutes -- but I just felt as if I hadn't met the standard I was shooting for.

And that cast a bit of gloom over running in general for quite some time afterward.

So the Cypryańska and Nezlek research shows a number of things -- it's important to participate in groups, critical to support each other, and perhaps most of all, necessary to be proud, not disparaging, of your own accomplishment.  After all, wherever you finished, you're still ahead of the people who are sitting on the sidelines.

Now, y'all'll have to excuse me.  I've got some races to sign up for.

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This week's Skeptophilia book recommendation is one of personal significance to me -- Michael Pollan's latest book, How to Change Your Mind.  Pollan's phenomenal writing in tours de force like The Omnivore's Dilemma and The Botany of Desire shines through here, where he takes on a controversial topic -- the use of psychedelic drugs to treat depression and anxiety.

Hallucinogens like DMT, LSD, ketamine, and psilocybin have long been classified as schedule-1 drugs -- chemicals which are off limits even for research except by a rigorous and time-consuming approval process that seldom results in a thumbs-up.  As a result, most researchers in mood disorders haven't even considered them, looking instead at more conventional antidepressants and anxiolytics.  It's only recently that there's been renewed interest, when it was found that one administration of drugs like ketamine, under controlled conditions, was enough to alleviate intractable depression, not just for hours or days but for months.

Pollan looks at the subject from all angles -- the history of psychedelics and why they've been taboo for so long, the psychopharmacology of the substances themselves, and the people whose lives have been changed by them.  It's a fascinating read -- and I hope it generates a sea change in our attitudes toward chemicals that could help literally millions of people deal with disorders that can rob their lives of pleasure, satisfaction, and motivation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Criticism bias

Following hard on the heels of yesterday's guardedly optimistic post about the potential malleability of people's views on such fraught topics as politics, today we have a recent and markedly less cheering study wherein we find that we don't apply the same moral lens to our own opinions as we do to other people's.

It may seem self-evident, but it's still kind of disappointing.  And the piece of research that showed this -- by Jack Cao, , Max Kleiman-Weiner, and Mahzarin R. Banaji of Harvard University's Department of Psychology -- is as elegant as it is incontrovertible.

In "People Make the Same Bayesian Judgments They Criticize in Others," which appeared in November's issue of Psychological Science, we find out that people are quick to use dispassionate evidence and logic to make their own decisions, but don't like it when other people do the same thing.

What Cao et al. did was to present test subjects with a simple scenario.  For example, a surgeon walks into the operating room to perform a procedure.  Is the surgeon more likely to be male or female?  Another one said that you're being attended by a doctor and a nurse.  One is male and one is female.  Which is which?

Clearly, just by statistics -- regardless what you think of issues of gender equality -- doctors and/or surgeons are more likely to be male and nurses more likely to be female.  And, in fact, almost everyone applied that logic to their own choices.  But then the researchers turned the tables.  Instead of asking the subjects what they thought about the question, they presented the answers given by a fictional stranger.  Jim answered that the surgeon and the doctor were more likely to be male and the nurse more likely to be female.  How does Jim rank on scales of morality, intelligence, and respect for equal rights?

Based on that one piece of information, respondents were harsh.  Almost across the board, people criticized Jim, saying he was less moral, less intelligent, and less likely to support equal rights than someone who had answered the other way.   "People don't like it when someone uses group averages to make judgments about individuals from different social groups who are otherwise identical.  They perceive that person as not only lacking in goodness, but also lacking in intelligence," Cao said, in a press release/interview in EurekAlert.  "But when it comes to making judgments themselves, these people make the same type of judgment that they had so harshly criticized in others...  This is important because it suggests that the distance between our values and the people we are is greater than we might think.  Otherwise, people would not have made judgments in a way that they found to be morally bankrupt and incompetent in others."

[Image licensed under the Creative Commons Deval Kulshrestha, Statua Iustitiae, CC BY-SA 4.0]

This is troubling in a couple of respects.  One is that we tend to give ourselves far more slack than we do other people.  Part of this, of course, is that we know our own internal state (at least insofar as it is possible).  We know our own attitudes and morals, while we're only guessing about other people's.  So when we apply purely statistical arguments to a question like the ones posed by Cao et al., we can say, "Okay, I know this sounds biased, but I'm not, actually.  I'm just basing my answer on the numbers, not what I think should be the case."

The other, though, is even worse.  It's how willing we are to be severely critical of other people based upon virtually nothing in the way of evidence.  How often do we find out one thing about someone -- he's a Catholic, she's a Republican, he's a lawyer, she's a teenager -- and decide we know a great many other things about them without any further information?  Worse still, once those decisions are made, we base our moral judgments on what we think we know, and they become very resistant to change.

As a high school teacher, I can't tell you the number of times I've been asked questions like, "How do you handle dealing with being disrespected by surly teenagers every day?"  Well, the truth is, the vast majority of the kids in my classes aren't surly at all, and the last time I was seriously disrespected by a student was a very long time ago.  But that knee-jerk judgment that if a person is a teenager, (s)he must be a pain in the ass, is automatic, widespread, and pervasive -- and remarkably difficult to challenge.

I think what this demands is a little bit of humility about our own fallibility.  We can't help making judgments, but we need to step back and examine them for what they are before we simply accept them.  Eradicating this kind of on-the-fly evaluation is the key to eliminating racism, sexism, and various other forms of bigotry that are based not on any kind of empirical evidence, but on our tendency to use one or two facts to infer complex understanding.

As Oliver Wendell Holmes put it, "No generalization is worth a damn, including this one."  Or, to quote skeptic and writer Michael Shermer, "Don't believe everything you think."

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This week's Skeptophilia book recommendation is one of personal significance to me -- Michael Pollan's latest book, How to Change Your Mind.  Pollan's phenomenal writing in tours de force like The Omnivore's Dilemma and The Botany of Desire shines through here, where he takes on a controversial topic -- the use of psychedelic drugs to treat depression and anxiety.

Hallucinogens like DMT, LSD, ketamine, and psilocybin have long been classified as schedule-1 drugs -- chemicals which are off limits even for research except by a rigorous and time-consuming approval process that seldom results in a thumbs-up.  As a result, most researchers in mood disorders haven't even considered them, looking instead at more conventional antidepressants and anxiolytics.  It's only recently that there's been renewed interest, when it was found that one administration of drugs like ketamine, under controlled conditions, was enough to alleviate intractable depression, not just for hours or days but for months.

Pollan looks at the subject from all angles -- the history of psychedelics and why they've been taboo for so long, the psychopharmacology of the substances themselves, and the people whose lives have been changed by them.  It's a fascinating read -- and I hope it generates a sea change in our attitudes toward chemicals that could help literally millions of people deal with disorders that can rob their lives of pleasure, satisfaction, and motivation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Political change blindness

Like many of my fellow Americans, I had hoped to get through the holiday season without conflict, but was thwarted by the acrimonious times we live in.  As these things go, the conflict I was in was pretty mild.  No dishes were thrown, no fists pounded on tables, no ugly epithets hurled, and we all parted still more or less as friends.

Even so, it wasn't what I would call pleasant.  As someone who despises conflict, and doesn't enjoy either politics or argument for their own sakes, I would very much have liked to avoid it.  One of the things that struck me -- this always strikes me in these situations -- was the sheer immovability of the participants.  No one budged one iota from their positions, not after an hour of heated discussion.  To be fair, neither did I.  But the fact that no one changed even the smallest bit of their opinion brought home how utterly pointless it all was.

We're all rock-solid-sure of our views, pretty much all the time, aren't we?  Well, maybe not as much as we think, to judge from new research out of Lund University (Sweden), by cognitive scientists Lars Hall, Petter Johansson, Andreas Lind, Philip Pärnamets, and Thomas Strandberg.  In their paper that came out recently in the Journal of Experimental Psychology, "False Beliefs and Confabulation Can Lead to Lasting Changes in Political Attitudes," they showed that a simple trick -- a bit of sleight-of-hand -- can lead people to defend a view they originally argued against.

[Image licensed under the Creative Commons David Shankbone, Anger during a protest by David Shankbone, CC BY-SA 3.0]

What they did was striking in its simplicity.  First, they showed test subjects various photographs of human faces, asking them to decide between pairs of them which was the more attractive.  The researchers surreptitiously exchanged the higher-rated photograph for the lower-rated one, and went back through the choices, saying, "This is the one you chose.  Do you still feel that way, or do you want to reconsider your decision?"

Two-thirds of the subjects never caught on.

Well, you might be thinking, that's just about physical attraction, which can change pretty fluidly, and isn't that critical anyhow.  But the researchers went a step further -- pulling the same kind of trick, but this time with political statements (for example, "It is more important for a society to promote the welfare of the citizens than to protect their personal integrity").  The review-your-decision phase of the test took one of the statements they'd agreed with and made it diametrically opposite to what they'd chosen.

Once again, two-thirds never noticed the change, and they were just as articulate in defending their position -- the one that, minutes earlier, had been the opposite of what they believed -- as they were opinions they'd held all along.

The real kicker: they were retested a week and then three weeks later, and most of them stuck with the view they didn't intend but had been forced to justify.

And didn't even know they'd changed.

I don't know about you, but I find this kind of hopeful.  It shows that human perception and memory are even more unreliable than I'd realized, which is rather humbling.  But it does mean that we can shift our views.  I suspect that the most powerful aspect was that the subjects were asked to defend the position they'd initially disagreed with, and that forced them to consider the opposite side's views without engaging the emotional side of the brain by identifying them as contrary to their own beliefs ahead of time.  This squares with an experience I had long ago.  A teacher in a high school English class had us all write position papers, and then debate them -- but we had to research and defend the opposite stance.  If your paper was about strengthening gun control laws, you had to argue in the debate on the side of loosening them.

It was an intensely uncomfortable experience, but it did make me aware of the fact that my opponents' views did have support, that they weren't simply unfounded and unjustified opinions.  I don't think the exercise changed my particular viewpoint, but it did make me appreciate that there was another defensible side.

So maybe political discourse isn't as hopeless as it seems.  It remains to be seen, however, how to engage this mental plasticity without the emotional brain screaming it down -- which it did with the argument I was in over the holidays.  But if we could, we might find that the acrimony largely vanishes -- and that our opinions may not be as far apart as they'd seemed.

****************************************

This week's Skeptophilia book recommendation is one of personal significance to me -- Michael Pollan's latest book, How to Change Your Mind.  Pollan's phenomenal writing in tours de force like The Omnivore's Dilemma and The Botany of Desire shines through here, where he takes on a controversial topic -- the use of psychedelic drugs to treat depression and anxiety.

Hallucinogens like DMT, LSD, ketamine, and psilocybin have long been classified as schedule-1 drugs -- chemicals which are off limits even for research except by a rigorous and time-consuming approval process that seldom results in a thumbs-up.  As a result, most researchers in mood disorders haven't even considered them, looking instead at more conventional antidepressants and anxiolytics.  It's only recently that there's been renewed interest, when it was found that one administration of drugs like ketamine, under controlled conditions, was enough to alleviate intractable depression, not just for hours or days but for months.

Pollan looks at the subject from all angles -- the history of psychedelics and why they've been taboo for so long, the psychopharmacology of the substances themselves, and the people whose lives have been changed by them.  It's a fascinating read -- and I hope it generates a sea change in our attitudes toward chemicals that could help literally millions of people deal with disorders that can rob their lives of pleasure, satisfaction, and motivation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Paradoxes within paradoxes

Sometimes the simplest, most innocuous-seeming questions can lead toward mind-blowingly profound answers.

I remember distinctly running into one of these when I was in -- I think -- 8th grade science class.  It was certainly pre-high-school; whether it was from Mrs. Guerin at Paul Breaux Junior High School, or another of my teachers, is a memory that has been lost in the sands of time and middle-aged forgetfulness.

What I have never forgotten is the sudden, pulled-up-short response I had to what has been nicknamed Olbers' Paradox, named after 18th century German astronomer Heinrich Wilhelm Matthias Olbers, who first thought to ask the question -- if the universe is infinite, as it certainly seems to be, why isn't the night sky uniformly and dazzlingly bright?

I mean, think about it.  If the universe really is infinite, then no matter what direction you look, your line of sight is bound to intersect with a star eventually.  So there should be light coming from every direction at once, and the night sky shouldn't be dark.  Why isn't it?

The first thought was that there was something absorptive in the way -- cosmic dust, microscopic or submicroscopic debris left behind by stars and blown outward by stellar wind.  The problem is, there doesn't seem to be enough of it; the average density of cosmic dust in interstellar space is less than a millionth of a gram per cubic meter.

When the answer was discovered, it was nothing short of mind-boggling.  It turns out Olbers' paradox isn't a paradox at all, because there is light coming at us from all directions, and the night sky is uniformly bright -- it's just that it's shining in a region of the spectrum our eyes can't detect.  It's called the three-degree cosmic microwave background radiation, and it appears to be pretty well isotropic (at equal intensities no matter where you look).  It's one of the most persuasive arguments for the Big Bang model, and in fact what scientists have theorized about the conditions in the early universe added to what we know about the phenomenon of red-shifting (the stretching of wavelengths of light if the space in between the source and the detector is expanding) gives a number that is precisely what we see -- light peaking at a wavelength of around one millimeter (putting it in the microwave region of the spectrum) coming from all directions.

[Image licensed under the Creative Commons Original: Drbogdan Vector: Yinweichen, History of the Universe, CC BY-SA 3.0]

So, okay.  Olbers' paradox isn't a paradox, and its explanation led to powerful support for the Big Bang model.  But in science, one thing leads to another, and the resolution of Olbers' paradox led to another paradox -- the horizon problem.

The horizon problem hinges on Einstein's discovery that nothing, including information, can travel faster than the speed of light.  So if two objects are separated by a distance so great that there hasn't been time for light to travel from one to the other, then they are causally disconnected -- they can't have had any contact with each other, ever.

The problem is, we know lots of such pairs of objects.  There are quasars that are ten billion light years away -- and other quasars ten billion light years away in the opposite direction.  Therefore, those quasars are twenty billion light years from each other, so light hasn't had time to travel from one to the other in the 13.8 billion years since they were created.

Okay, so what?  They can't talk to each other.  But it runs deeper than that.  When the aforementioned cosmic microwave background radiation formed, on the order of 300,000 years after the Big Bang, those objects were already causally disconnected.  And the process that produced the radiation is thought to have been essentially random (it's called decoupling, and it occurred when the average temperature of the universe decreased enough to free photons from the plasma and send them streaming across space).

The key here is the word average.  Just as a microwaved cup of coffee could have an average temperature of 80 C but have spots that are cooler and spots that are hotter, the fact that the average temperature of the universe had cooled sufficiently to release photons doesn't mean it happened everywhere simultaneously, leaving everything at exactly the same temperature.  In fact, the great likelihood is that it wouldn't.  And since at that point there were already causally disconnected regions of space, there is no possible way they could interact in such a way as to smooth out the temperature distribution -- sort of like what happens when you stir a cup of coffee.

And yet one of the most striking things about the cosmic microwave background radiation is that it is very nearly isotropic.  The horizon problem points out how astronomically unlikely that is (pun intended) if our current understanding is correct.

One possible explanation is called cosmic inflation -- that a spectacularly huge expansion, in the first fraction of a second after the Big Bang, smoothed out any irregularities so much that everywhere did pretty much decouple at the same time.    The problem is, we still don't know if inflation happened, although work by Alan Guth (M.I.T.), Andrei Linde (Stanford), and Paul Steinhardt (Princeton) has certainly added a great deal to its credibility.

So as is so often the case with science, solving one question just led to several other, bigger questions.  But that's what's cool about it.  If you're interested in the way the universe works, you'll never run out of things to learn -- and ways to blow your mind.

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This week's Skeptophilia book recommendation is one of personal significance to me -- Michael Pollan's latest book, How to Change Your Mind.  Pollan's phenomenal writing in tours de force like The Omnivore's Dilemma and The Botany of Desire shines through here, where he takes on a controversial topic -- the use of psychedelic drugs to treat depression and anxiety.

Hallucinogens like DMT, LSD, ketamine, and psilocybin have long been classified as schedule-1 drugs -- chemicals which are off limits even for research except by a rigorous and time-consuming approval process that seldom results in a thumbs-up.  As a result, most researchers in mood disorders haven't even considered them, looking instead at more conventional antidepressants and anxiolytics.  It's only recently that there's been renewed interest, when it was found that one administration of drugs like ketamine, under controlled conditions, was enough to alleviate intractable depression, not just for hours or days but for months.

Pollan looks at the subject from all angles -- the history of psychedelics and why they've been taboo for so long, the psychopharmacology of the substances themselves, and the people whose lives have been changed by them.  It's a fascinating read -- and I hope it generates a sea change in our attitudes toward chemicals that could help literally millions of people deal with disorders that can rob their lives of pleasure, satisfaction, and motivation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Myths, mammals, and extinctions

It's interesting how the scientific version of urban legends can be incorporated into people's knowledge of how things work, and become so entwined that most folks don't even know which bits are true and which aren't.

Stephen Jay Gould riffed on this theme in his essay "The Case of the Creeping Fox Terrier Clone," which appeared first in Natural History and was later published in his essay collection Bully for Brontosaurus.  He looks at the claim that an early horse species, Hyracotherium, was "the size of a fox terrier" -- something that Gould found quoted in dozens of books on prehistoric animals (and which has therefore been used as a gauge of the animal's size in countless classrooms).  It turns out that it originated with a paleontologist, O. C. Marsh, who said Hyracotherium was the "size of a fox" -- a significant underestimate, as both foxes and fox terriers top out at around twenty pounds, and Hyracotherium weighed in at something closer to sixty.  But the analogy stuck, and people continued to pass it along without checking its veracity -- giving us the impression of tiny dog-sized horses, lo unto this very day.

Another example of this, from the same field, is that mammals were small, few in number, and low in biodiversity until along came a meteorite that for some reason selectively killed all the dinosaurs, leaving the mammals to throw a great big party and evolve like mad into the species we have around today.  This is incorrect on a variety of levels:

1. The K-T (Cretaceous/Tertiary) Extinction of 66 million years ago seems to have been caused by a double whammy -- the aforementioned meteorite, which left the Chicxulub Crater in what is now the Gulf of Mexico, and the formation of the Deccan Traps, a lava field from a colossal supervolcano eruption, all the way around the Earth in what is now India.
2. Dinosaur biodiversity had been decreasing for some time before the K-T Extinction, and in fact by some estimates was already down 40% from its peak during the mid-Cretaceous.
3. ...however...  All the dinosaurs didn't go extinct 66 million years ago, and I'm not talking about Nessie, Ogopogo, and Mokélé-Mbembe.  We still have dinosaurs around, we just call 'em birds.  The evidence is now incontrovertible.  Think about that next time you're putting out sunflower seeds for the chickadees.
4. The extinction hit pretty much every taxon that existed at the time.  The hardest-hit were large carnivores -- a vulnerable spot in the food chain at the best of times -- but no one escaped unscathed.  In fact, one group that got wiped out completely were the ammonites, a cephalopod mollusk that had thrived for 350 million years before getting clobbered during the K-T Extinction.
5. Most pertinent to this post, the mammals weren't just skulking around waiting for their opportunity; they'd been thriving alongside dinosaurs since the Triassic Period, 154 million years earlier.  This was the topic of a paper released a couple of months ago in Biology Letters by Tiago Bosisio Quental of the University of São Paulo and Mathias Pires of the University of Campinas.

What Quental and Pires did is a thorough survey of mammalian fossils, analyzing biodiversity as a function of time in three of the four big lineages of mammals -- Eutherians (most of the mammals you're familiar with), Metatherians (marsupials), and Multituberculates (an odd group of rodent-like mammals that were only distantly related to the rest of Class Mammalia, and which were one of the most common groups of mammals for almost two hundred million years).  They didn't include the fourth lineage -- the Monotremes, or egg-laying mammals -- only because they are extremely rare in the fossil record.

A late Cretaceous multituberculate, Catopsbaatar [Image licensed under the Creative Commons, Artwork by Bogusław Waksmundzki. Article by Zofia Kielan-Jaworowska and Jørn H. Hurum, Catopsbaatar, CC BY 2.0]

What they found -- predictably -- is that the dynamics of the extinction, and the years following it, is far more complex than it's usually represented.  "All these mass extinction episodes are heterogeneous," study co-author Pires said.  "They occurred for different reasons and unfolded in different ways.  Their impact on life forms was not absolute but relative.  Some groups suffered more, others less.  Some disappeared, while others took advantage of the new environmental conditions after the catastrophe to diversify rapidly."

Even within groups, the extinction didn't have uniform effects.  "Extinctions were concentrated among the specialized carnivorous metatherians and insectivorous eutherians," Pires said, "whereas more generalized eutherians and multituberculates survived and maintained higher diversity."

He added, "This means that studies of macroevolutionary phenomena focusing on broad taxonomic groups may miss a much richer macroevolutionary history, which can be perceived only at finer taxonomic scales."

Which can more generally be summed up as "the simple explanation is usually wrong."  It'd be nice if things weren't so complex, especially for we non-scientists.  But like Gould's fox-terrier-horse, many of these oversimplifications are flat-out incorrect -- and the truth is so much more interesting.

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This week's Skeptophilia book recommendation is one of personal significance to me -- Michael Pollan's latest book, How to Change Your Mind.  Pollan's phenomenal writing in tours de force like The Omnivore's Dilemma and The Botany of Desire shines through here, where he takes on a controversial topic -- the use of psychedelic drugs to treat depression and anxiety.

Hallucinogens like DMT, LSD, ketamine, and psilocybin have long been classified as schedule-1 drugs -- chemicals which are off limits even for research except by a rigorous and time-consuming approval process that seldom results in a thumbs-up.  As a result, most researchers in mood disorders haven't even considered them, looking instead at more conventional antidepressants and anxiolytics.  It's only recently that there's been renewed interest, when it was found that one administration of drugs like ketamine, under controlled conditions, was enough to alleviate intractable depression, not just for hours or days but for months.

Pollan looks at the subject from all angles -- the history of psychedelics and why they've been taboo for so long, the psychopharmacology of the substances themselves, and the people whose lives have been changed by them.  It's a fascinating read -- and I hope it generates a sea change in our attitudes toward chemicals that could help literally millions of people deal with disorders that can rob their lives of pleasure, satisfaction, and motivation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]