- a study to find out if hormone therapy affects the immune response in patients with HIV
- a study looking at how steroid hormone administration affects fertility
- a study of the effects of testosterone on breast cancer susceptibility
- a study of how hormone administration affects the microbiome
- a study of how reproductive hormones affect neurological development in embryos
- a study of how reproductive hormones affect asthma
Saturday, March 8, 2025
The return of Lieutenant Kijé
Friday, March 7, 2025
Deep impact
It's remarkably hard to find evidence of impact craters on the Earth.
If you're thinking, "What's the difficulty? Just look for a big hole in the ground," you're probably thinking of one of two things -- either craters on the Moon, or Barringer Crater near Winslow, Arizona. The craters on the Moon stick around pretty much indefinitely because the airless, waterless surface experiences virtually no erosion; as far as Barringer, the impact that caused it only happened around fifty thousand years ago, which is the blink of an eye, geologically speaking. (Plus, it's in the high desert, with little vegetation to hide underneath.)
With older impact craters, the forces of erosion eat away at the telltale signs -- the raised, oval or circular ridges, especially. The oldest craters have been destroyed by subsequent tectonic shifts and faults, and (for ones in oceanic plates) because the damaged strata themselves were subducted and melted.
One massive impact crater that was only detected in 1983 -- despite the fact that tens of thousands of people live more or less right on top of it -- is the one left by the Chesapeake Bay Impact Event, which occurred during the Eocene Epoch, on the order of 35.5 million years ago. At that point, the impact site, on the southern tip of the Delmarva Peninsula, was coastal tropical rainforest; the global temperature was still dropping following the massive Paleocene-Eocene Thermal Maximum, but was still a good two degrees Celsius warmer than today. The mass of the impactor isn't known for certain -- it was completely vaporized -- but it's estimated to have been about three kilometers across and traveling at eighteen kilometers per second, and punched a hole eight kilometers deep into the crystalline basement rock, blasting the sediments on top to smithereens and creating a crater over eighty kilometers across. Because at least part of the impact was in the shallow ocean, it also created a massive tsunami that travelled inland as far as the foothills of the Blue Ridge Mountains.
Since the impact, it refilled -- first with unconsolidated, unsorted sediments, essentially broken up pieces of the rock that was blown out from the collision, then with eroded material as the whole place gradually settled down. Part of it was refilled with seawater. The only way it was discovered was the presence of an anomalous "fault" that turned out to be the edge of the crater wall, followed by the analysis of some rock cores that showed a huge, thick layer of jumbled junk that geologists figured out was the debris formed as the crater walls slumped inward. It also explained the North American Tektite Field, an enormous splatter field of what amounts to cooled droplets of melted rock.
But visiting the area today, you don't see much that would tell you that only thirty-five million years ago, the place got slammed by an enormous chunk of rock from outer space.
Even the much larger Chicxulub Impact Crater, near the Yucatán Peninsula, took a lot of work to identify. It's just shy of twice as old as the Chesapeake Bay site (about 66 million years), and is almost entirely underwater and filled with oceanic sediments. Today, the impact site that ended the 180-million-year hegemony of the dinosaurs is only visible to sensitive gravitometers and magnetometers.
Which makes the discovery of an impact crater 3.47 billion years old, in East Pilbarra, Western Australia, even more astonishing.
A paper in Nature Communications this week, authored by Christopher Kirkland of Curtin University et al., shows convincing evidence of an impact crater over a hundred kilometers wide near the northwestern coast of Australia. The center of the crater shows regions of shocked crystalline rock, along with layers of breccia (the same sort of jumble of debris found at the Chesapeake Bay site). Further stratigraphic work has confirmed that this was, indeed, the site of a "massive hypervelocity impact." This makes it the only Archaean-age crater known to have survived.
The authors write:
Despite the high modeled frequency of bolide impacts in the early Archaean, the rarity of verified impact craters of Archaean age suggests that: (a) the impact flux was much less than predicted by lunar data; (b) the evidence has been eradicated, or (c) that we have failed to recognise them. On a young Earth covered in primitive (mafic–ultramafic) crust, identifying shatter cones or impact breccias may represent the best chance of finding other large Archaean impact structures. However, these highly fractured rocks will be the first to undergo (presumably intense) weathering and erosion. Notwithstanding their fragility, we believe many more Archaean craters await discovery.
Myself, I think it's astonishing that they've found even one. For any traces to have survived for nearly three and a half billion years is staggering. At that point, life was only getting started; the first known microbes appeared 3.7 billion years ago, and when the impact occurred, it would still be another half a billion years before the first certain multicellular life. So unlike the Chesapeake Bay and Chicxulub Impacts, which were (respectively) regionally and globally devastating to life, the East Pilbarra collision probably didn't make much of... um... an impact.
But it definitely stirred things up, created an enormous crater and rain of debris, and would have been a dramatic thing to witness. From a safe distance. The fact that even today, 3.47 billion years later, geologists can detect the hole it left behind, indicates that it was one hell of a punch.
Thursday, March 6, 2025
Spin cycle
Well, The Daily Mail Fail is at it again, this time with a claim that the CIA has declassified a book predicting the end of the world (which is going to happen soon, of course). Illustrating the fact that there is no conspiracy theory so blatantly idiotic that there won't be people passionately espousing it, the whole thing has the End Times crowd running around making excited little squeaking noises, while the rest of us are wearing expressions like this:
My surmise is the fact that it languished after that because no one at the CIA took it seriously enough to bother reviewing.
Anyhow, Thomas's claim is that there have been cataclysms on the order of every six thousand years, and we're currently overdue. What happens during these catastrophes illustrates the fact that Thomas shoulda stuck with UFO research, or at least paid better attention during ninth grade Earth Science class, because the first thing that jumps out at me is that he does not understand the difference between the Earth's rotational axis and its magnetic poles. This leads him to conclude that when the magnetic poles flip -- something that happens around every three hundred thousand years, not six thousand, so he's off by a factor of fifty, but who's counting -- it somehow affects the rotational axis, throwing continents and oceans around like a washing machine on spin cycle.
The results are hella scary. Thomas writes:
In a fraction of a day all vestiges of civilization are gone, and the great cities — Los Angeles, San Francisco, Chicago, Dallas, New York — are nothing but legends. Barely a stone is left where millions walked just a few hours before... Winds with the force of a thousand armies will shred everything in sight with a supersonic bombardment, as a Pacific tsunami drowns Los Angeles and San Francisco as if they were but grains of sand... Calamity will overtake the entire North American continent within three hours, as an earthquake simultaneously creates massive cracks in the ground that allow magma to rise to the surface.
So I think we all can agree that this would be bad. By the time it's all over -- in seven days, he says -- everything will be rearranged, with Antarctica at the equator (melting its huge ice caps), and the Bay of Bengal at what is now the North Pole.
By now you may be wondering what historical cataclysms "every six thousand years" he's basing this on. I know I was. You ready?
The Flood of Noah, and six thousand years before that, something about Adam and Eve. (You might have guessed the latter based on the book's title; I have to admit by that point I'd already forgotten it, so this got an all-new eyeroll from me.)
Scholars of the Bible might be objecting by now that the Book of Genesis doesn't describe any kind of worldwide catastrophe centering around Adam and Eve, just some malarkey about a serpent and an apple and whatnot, and their being the ancestors of all humanity despite supposedly being the first people and having only sons. But Thomas seems sufficiently detached from reality that this is only a minor quibble compared to some of the other stuff he says.
Despite the fact that the claim is (in a word) ridiculous, I've already seen three videos on TikTok that seem to treat the whole thing as deadly serious, with the fact that three-quarters of the original manuscript is still classified being used as evidence that the CIA is "hiding something" and "they're trying to prevent mass panic."
Trust me, the only people out there panicking over this are ones who see messages from God on their grilled cheese sandwiches. And it hardly bears pointing out that you can't use pages you've never seen as proof of anything, given that by default we don't know what's in them.
Sometimes absence of evidence really is evidence of absence.
In any case, I wouldn't lose any sleep over this. But I will appeal to the conspiracy theorists: can you please try and give me better material to work with? Because this one was kind of bottom-of-the-barrel. Time to step up your game, folks. It's positively making me pine for the good old days of HAARP and Nibiru and the Annunaki and "Birds Aren't Real."
Wednesday, March 5, 2025
Watch your tone!
You probably know that there are many languages -- the most commonly-cited are Mandarin and Thai -- that are tonal. The pitch, and pitch change across a syllable, alter its meaning. For example, in Mandarin, the syllable "ma" spoken with a high steady tone means "mother;" with a falling then rising tone, it means "horse."
If your mother is anything like mine was, confusing these is not a mistake you'd make twice.
English is not tonal, but there's no doubt that pitch and stress change can communicate meaning. The difference is that pitch alterations in English don't change the denotative (explicit) meaning, but can drastically change the connotative (implied) meaning. Consider the following sentence:
He told you he gave the package to her?
Spoken with a neutral tone, it's simply an inquiry about a person's words and actions. Now, one at a time, change which word is stressed:
- He told you he gave the package to her? (Implies the speaker was expecting someone else to do it.)
- He told you he gave the package to her? (Implies surprise that you were told about the action.)
- He told you he gave the package to her? (Implies surprise that you were the one told about it)
- He told you he gave the package to her? (Implies the speaker expected the package should have been paid for)
- He told you he gave the package to her? (Implies that some different item was expected to be given)
- He told you he gave the package to her? (Implies surprise at the recipient of the package)
Differences in word choice can also create sentences with identical denotative meanings and drastically different connotative meanings. Consider "Have a nice day" vs. "I hope you manage to enjoy your next twenty-four hours," and "Forgive me, Father, for I have sinned" vs. "I'm sorry, Daddy, I've been bad."
You get the idea.
All of this is why mastery of a language you weren't born to is a long, fraught affair.
The topic comes up because of some new research out of Northwestern University that identified the part of the brain responsible for recognizing and abstracting meaning from pitch and inflection -- what linguists call the prosody of a language. A paper this week in Nature Communications showed that Heschl's gyrus, a small structure in the superior temporal lobe, actively analyzes spoken language for subtleties of rhythm and tone and converts those perceived differences into meaning.
"Our study challenges the long-standing assumptions how and where the brain picks up on the natural melody in speech -- those subtle pitch changes that help convey meaning and intent," said G. Nike Gnanataja, who was co-first author of the study. "Even though these pitch patterns vary each time we speak, our brains create stable representations to understand them.""The results redefine our understanding of the architecture of speech perception," added Bharath Chandrasekaran, the other co-first author. "We've spent a few decades researching the nuances of how speech is abstracted in the brain, but this is the first study to investigate how subtle variations in pitch that also communicate meaning are processed in the brain."Tuesday, March 4, 2025
Birds, bees, etc.
Yesterday I was thinking about sex.
Not like that. My intention is to keep this blog PG-13. I meant sexual reproduction in general, and the topic comes up because I just finished reading Riley Black's lovely new book When the Earth Was Green: Plants, Animals, and Evolution's Greatest Romance, which looks at paleontology through the lens of botany. It's a brilliant read, the writing is evocative and often lyrical, and it needs to be added to your TBR list if you've even the slightest bit more than a passing interest in the past.
One of the topics she looks at in some detail is how sexual reproduction in plants -- better known as pollination -- led to an inseparable relationship between flowering plants and their pollinators. A famous example is Darwin's orchid (Angraecum sesquipedale), a Madagascar species with night-scented white flowers whose nectaries are at the base of an impossibly long tube:
Its discovery prompted Charles Darwin to predict that there must be a moth on the island whose mouthparts fit the flower, and which was responsible for pollinating it. Sure enough, in a few years, biologists discovered the Madagascar hawk moth (Xanthopan morganii):
The problem is, such dramatic specialization is risky. If something happens to either member of the partnership, the other is out of luck. In fact, sexual reproduction in general is a gamble, but its advantages outweigh the risk, and I'm not just talking about the fact that it's kind of fun.
Asexually-reproducing organisms, like many bacteria and protists, some plants and fungi, and a handful of animals, have the advantages that it's fast, and only requires one parent. There's a major downside, however; a phenomenon called Muller's ratchet. Muller's ratchet has to do with the fact that the copying of DNA, and the passing of those copies on to offspring, is not mistake-proof. Errors -- called mutations -- do happen. Fortunately, they're infrequent, and we even have enzymatic systems that do what amounts to proofreading and error-correction to take care of most of them. A (very) few mutations actually lead to a code that works better than the original did, but the majority of the ones that slip by the safeguards cause the genetic message to malfunction.
It's called a "ratchet" because, like the handy tool, it only turns one way -- in this case, from order to chaos. Consider a sentence in English -- space and punctuation removed:
TOBEORNOTTOBETHATISTHEQUESTION
Now, let's say there's a random mutation on the letter in the fourth position, which converts it to:
TOBGORNOTTOBETHATISTHEQUESTION
The message is still pretty much readable, although the second word is now spelled wrong. But most of us would have been able to figure out what it was supposed to say.
Now, suppose a second mutation strikes. There is a chance that it would affect the fourth position again, and purely by accident convert the erroneous g back to an e, but that likelihood is vanishingly small. This is called a back mutation, and is more likely in DNA -- which, of course, is what this is an analogy to -- because there are only four letters (A, T, C, and G) in DNA's "alphabet," as compared to the 26 English letters. But it's still unlikely, even so. You can see that at each "generation," the mutations build up, every new one further corrupting the message, until you end up with a string of garbled letters from which not even a cryptographer could puzzle out what the original sentence had been.
Sexual reproduction is a step toward remedying Muller's ratchet. Having two copies of each gene (a condition known as diploidy) makes it more likely that at least one of them still works. Many genetic diseases -- especially the ones inherited as recessives -- are losses of function, where copying errors have caused that stretch of the DNA to malfunction. But if you inherited a good copy from your other parent, then lucky you, you're healthy (although you can still pass your "hidden" faulty copy on to your children).
This, incidentally, is why inbreeding -- both parents coming from the same genetic stock -- is a bad idea. It doesn't (in humans) cause problems in brain development, which a lot of people used to think. But what it does mean is that if both parents have a recent common ancestor, the faulty genes one of them carries are very likely the same ones the other does, and the offspring has a higher chance of inheriting both damaged copies and thus showing the effects of the loss of function. It's this mechanism that explains why a lot of human recessive genetic disorders are characteristic of particular ethnic groups, such as cystic fibrosis in northern Europeans, Tay-Sachs disease in Ashkenazic Jews, and malignant hyperthermia in French Canadians. It only happens when both parents are from the same heritage -- which is why "miscegenation laws," preventing intermarriage between people of different races or ethnic backgrounds, are exactly backwards. Mixed-race children are actually less likely to suffer from recessive genetic disorders -- the mom and dad each had their own "genetic load" of faulty genes, but there was no overlap between the two sets of errors. Result: healthy kid.
The difficulty, of course, is that despite its genetic advantages, sexual reproduction requires a genetic contribution from two parents. This is tough enough with mobile species, but with organisms that are stuck in place -- like plants -- it's a real problem. Thus the hijacking of animals as carriers for pollen, and the evolution of a host of mechanisms for preventing self-pollination (which cancels out the advantage of higher variation, given that once again, both sets of genes come from the same parent).
What's most curious about sexual reproduction is that we don't know how it started. Even some very simple organisms have genetic exchange mechanisms, such as conjugation in bacteria, which help them not to get clobbered by Muller's ratchet, and something like that is probably how it got going in the first place. We know sexual reproduction is evolutionarily very old, given that it's shared by the majority of life on Earth, but how the process of splitting up and recombining genetic material every generation first started is still a mystery.
Anyhow, that's our consideration of birds, bees, and others for the day. I'll end by saying again that you should buy Riley Black's book, because it's awesome, and gives you a vivid picture of life at various times on Earth, not from the usual Charismatic Megafauna viewpoint, but from the perspective of our green friends and neighbors. It's refreshing to consider how life is experienced from an entirely different angle every once in a while.
Monday, March 3, 2025
Lost horizon
Saturday, March 1, 2025
The undiscoverable country
After Thursday's post about nonexistent islands, a loyal reader of Skeptophilia asked me if I'd ever heard of the country of Listenbourg.
I said, "Do you mean Luxembourg?" but he assured me he was spelling it right.
"Islands aren't the only thing that can be nonexistent," he said, which is true, but when you think about it too hard is a very peculiar statement.
So I looked into Listenbourg, and it's quite a story -- especially since the whole thing started as a way to ridicule Americans for their ignorance about anything outside the borders of the United States.
In October of 2022, a French guy named Gaspard Hoelscher posted a doctored map of Europe on Twitter that looked like this:
You'd think anyone who'd ever given more than a ten-second look at an actual map of Europe would immediately know this was a joke, but no. Even a closer look at this map would have revealed the curious fact that "Listenbourg" is actually a resized and inverted copy of the outline of France itself, simply pasted onto (and partially covering) the northwest corners of Spain and Portugal.
Apparently, this was not the case, as the original post caused a number of irate Americans to jump up and defend our superior knowledge -- almost none of whom, however, came right out and said that they recognized it was a prank. You could tell that some of them had actually come damn close to saying, "Of course I know where Listenbourg is," but held back at the last minute.
This prompted a flood of hilarity online that the prank's originator, Hoelscher, said "totally overwhelmed" him. Amused Europeans invented a flag, capital city ("Lurenberg"), culture, history, language, and even a national anthem for Listenbourg. It has five regions, they said: Flußerde, Kusterde, Mitteland, Adrias and Caséière. A post saying that Hoelscher himself was the president was met by universal acclaim. Then it escaped social media into the wider world:
- An announcement prior to the Paris Olympics of 2024 stated that "The number of Olympic delegations has risen from 206 to 207 with the arrival of Listenbourg."
- Amazon Prime in Europe announced that a documentary on the history of Listenbourg was in production -- only careful watchers noticed that the projected release date was "February 31, 2025."
- Ryanair said in a press release that they were "Proud to be announcing their new base in Listenbourg."
- The French television network TF1 aired a realistic-sounding weather report for the country.
- French politician Jean Lassalle said in a speech that he was "just returned from a visit to an agricultural seminar in Lurenberg."
- The city of Nice said that they were happy to announce their intention to become a sister city to Lurenberg, and that there would be new inexpensive flights between the two.
I have to admit that as an American, my laughter over all this is coupled with a distinct edge of cringe. I mean, being global dumbasses is not exactly the reputation I'd like my country to have. Sadly, though, I can't really argue with the assessment. You don't have to dig very hard to find highly embarrassing videos of interviewers stopping people in crowds in the United States to ask them tough questions like "What is the capital of England?" and finding numerous Americans who can't come up with the answer. And with the Republicans currently doing everything in their power to destroy our system of public education, the situation is only going to get worse.
Oh, but don't worry. At least we'll have the Ten Commandments on the wall of every classroom, and students will get Bible lessons every day and won't be exposed to scary books like Heather Has Two Mommies.
Hey, I wonder what would happen if you asked Donald Trump to find Listenbourg on a map? I bet he'd never realize he was being pranked, considering that he once gave a speech to African leaders and confidently talked about the proud country of "Nambia."
Look, I know we all have holes in our knowledge; all of us are ignorant about some subjects. The important thing is not to make ignorance a permanent condition -- or to flaunt it. Stubbornly persisting in your state of ignorance has a name.
It's called "stupidity."
What's worse is when people think they are experts on stuff when they're clearly not, and publicly trumpet their own idiocy. (Donald Trump is absolutely the poster child for this phenomenon.) As Stephen Hawking trenchantly put it, "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." Because if you're convinced you already know everything you need to know -- and that, I'm afraid, is the state of many Americans, including the majority of our elected officials -- you have no incentive to learn more, or worse, to find out you're actually wrong about something.
My dad used to say "there's nothing as dangerous as confident stupidity." I think that's spot-on. And sad that the Listenbourg incident -- funny as it is -- pointed out that in the eyes of many people in the world, that's what the United States represents.




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