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Nearly 6000 species and subspecies of earthworms have been identified by scientists – but the true number could top 30,000

Over at sapiens.org, an anthropology magazine, author Elaine Guevara (a lecturer in evolutionary anthropology at Duke) takes modern genetics education to task.  Making a number of assertions about what students from high school to college learn in their genetics courses, Guevara claims that this type of education imparts “zombie ideas”: outdated but perpetually revived notions that prop up biological racism.  Her main topic is race, and she does offer some insights that modern genetics has given us about differences between geographic populations (I prefer to use “populations” rather than “races”), but these insights have been known for a long time. By failing to tell us that the errors earlier biologists have made about race have been refined and, to a large degree, dispelled, Guevara is herself deficient in describing the state of modern genetics.

Click the screenshot to read:

Guevara makes several accusations that, I think, are misleading. I’ll group her misleading conclusions under bold headings (the wording of those is mine). Quotes from her paper, or my paper with Luana Maroja, are indented and identified

1.) Human populations are not as different as we think, and the concept of “race” is incorrect: classical “races” are not genetically distinguishable. Guevara first cites a famous 1972 paper by my Ph.D. advisor, Richard Lewontin, “The Apportionment of Human Diversity“. The paper looked at genetic variation of 17 proteins detected by gel electrophoresis, apportioning the worldwide variation of proteins among individuals within a population, among populations within a classical “race”, and then between seven “races”. He found that of the total genetic variation seen worldwide, 85% occurred among individuals within one geographic population, 8% among populations within a race, and only 6% was found among races.

Thus races were not as genetically different as some people assumed. Lewontin concluded this (bolding is mine):

It is clear that our perception of relatively large differences between human races and subgroups [JAC: note that Lewontin’s “subgroups” correspond to what I would call “populations’], as compared to the variation within these groups, is indeed a biased perception and that, based on randonly chosen genetic differences, human races and populations are remarkably similar to each other, with the largest part by far of human variation being accounted for by the differences between individuals.

Human racial classification is of no social value and is positively destructive of social and human relations. Since such racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance.

The first paragraph is correct. Later studies using better methods (DNA) have shown that yes, the apportionment of human diversity shows most of it within populations and only a fraction among populations or among “races”.  The classical view that races like “Caucasion”, “Asian” or “Black” showed large and diagnostic genetic differences at single genes was wrong

But the second paragraph is wrong, too, because Lewontin did not raise the possibility (as I’m sure he realized) that small differences among populations (or the groups of populations that constitute classical “races”) can, taken across many, many genes, add up to significant statistical and biological differences. The failure to recognize the power of using genetic data from many genes (we have three billion DNA nucleotides in our genome) is called “Lewontin’s fallacy.” This fallacy was pointed out in 2003 by A.W.F. Edwards and has its own Wikipedia page.

The power of using many genes instead of just an unweighted average of data from individual genes is shown by several things, as Luana Maroja and I pointed out in our paper published in Skeptical Inquirer last year. For one thing, if there were no meaningful genetic differences between populations, you couldn’t use genetic differences to diagnose someone’s ancestry. Yet you can, and with remarkable accuracy, as anyone knows who is aware of their family history and has taken a genetic test like those offered by 23andMe.  My test showed that I have complete Eastern European ancestry, with 98% of it from Ashkenazi Jews, which comports with what I know of my family history. (I also have a small percentage of genes from Neanderthals.)

Now this tells you the area of the world—the population—from which your ancestors probably came.  It doesn’t deal with “races” as classically defined. Yet a multiple-gene analysis using four races that Americans themselves use in self-identification (African-American, white, east Asian, or Hispanic) can indeed be diagnosed with remarkable accuracy. As Luana and I said in our paper (I’ve bolded the money quote):

Even the old and outmoded view of race is not devoid of biological meaning. A group of researchers compared a broad sample of genes in over 3,600 individuals who self-identified as either African American, white, East Asian, or Hispanic. DNA analysis showed that these groups fell into genetic clusters, and there was a 99.84 percent match between which cluster someone fell into and their self-designated racial classification. This surely shows that even the old concept of race is not “without biological meaning.” But that’s not surprising because, given restricted movement in the past, human populations evolved largely in geographic isolation from one another—apart from “Hispanic,” a recently admixed population never considered a race. As any evolutionary biologist knows, geographically isolated populations become genetically differentiated over time, and this is why we can use genes to make good guesses about where populations come from.

And this:

More recent work, taking advantage of our ability to easily sequence whole genomes, confirms a high concordance between self-identified race and genetic groupings. One study of twenty-three ethnic groups found that they fell into seven broad “race/ethnicity” clusters, each associated with a different area of the world. On a finer scale, genetic analysis of Europeans show that, remarkably, a map of their genetic constitutions coincides almost perfectly with the map of Europe itself. In fact, the DNA of most Europeans can narrow down their birthplace to within roughly 500 miles. [See below for the European data.]

You can also identify the “classical” races used in self-identification using some morphological traits. As we wrote:

But you don’t even need DNA sequences to predict ethnicities quite accurately. Physical traits can sometimes do the job: AI programs can, for instance, predict self-reported race quite accurately from just X-ray scans of the chest.

Population differences summed across genes can tell us more, too:

On a broader scale, genetic analysis of worldwide populations has allowed us to not only trace the history of human expansions out of Africa (there were several), but to assign dates to when H. sapiens colonized different areas of the world. This has been made easier with recent techniques for sequencing human “fossil DNA.” On top of that, we have fossil DNA from groups such as Denisovans and Neanderthals, which, in conjunction with modern data, tells us these now-extinct groups bred in the past with the ancestors of “modern” Homo sapiens, producing at least some fertile offspring (most of us have some Neanderthal DNA in our genomes). Although archaeology and carbon dating have helped reconstruct the history of our species, these have largely been supplanted by sequencing the DNA of living and ancient humans.

Finally, there are nearly diagnostic differences between populations in genes that evolved in an adaptive way, like known genes for resistance to low oxygen, short stature or skin pigmentation. Here’s a figure from a 2015 Science paper by Sarah Tishkoff:

None of this would be possible if there were not significant genetic and biological differences between populations.  We did not maintain that there are always diagnostic differences between populations at single genes that can group them into races, but that there are statistical differences in frequencies of variable genes among populations that are biologically meaningful.  Nor did we claim that the classically-defined races are absolutely geographically distinct with little intermixing, or have nearly fixed differences in frequencies of variable genes. That’s not true, and all geneticists realize this now. (But note that even the classically defined “races” generally differ in gene frequencies and in some biological traits to an extent that they can be diagnosed.)

The reality is that we should be dealing with populations, and populations—roughly defined as geographically different groups of people that largely breed among themselves—show diagnostic genetic and morphological differences.

Yet Guevara misleads the reader by relying solely on Lewontin’s paper and neglecting all the work done since that showing that yes, there is diagnostic geographic variation among populations (note that Lewontin implied that the concept of “population” is about as meaningless as “race”). Here are cxcerpts from Guevara’s paper:

Lewontin published his calculations in a short paper in 1972 that ended with this definitive conclusion: “Since … racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance.” His results have been replicated time and again over the last 50 years, as datasets have ballooned from a handful of proteins to hundreds of thousands of human genomes.

But despite huge strides in genetics research—leaving no doubt about the validity of Lewontin’s conclusions—genetics curricula taught in U.S. secondary and post-secondary schools still largely reflect a pre-1970s view.

This lag in curricula is more than a worry for those in the ivory tower. Increasingly, genomics plays a leading role in health care, criminal justice, and our sense of identity and connection to others. At the same time, scientific racism is on the rise, reaching more people than ever thanks to social media. Outdated education fails to dispel this disinformation.

Leaving “no doubt about the validity of Lewontin’s conclusions”?  Nope.  The apportionment of variation is without doubt, but not his conclusion that populations or races are without biological meaning.

None of the critiques of Lewontin’s paper, including Edwards’s famous clarification, are even mentioned by Guevara. And, in fact, I don’t know of any biologists in post-secondary genetics education who still teach the view that “Race and ethnicity are social constructs, without scientific or biological meaning.” (This is a quote from JAMA reproduced in the Coyne and Maroja paper. And perhaps some people teach this erroneous view, but no biologist that I know of.) That JAMA statement is completely misleading, as I hope I’ve shown above. The delineation and definition of classical races was itself misleading and often tied to racism in the past, but, as we see, even self-identified classical races can be diagnosed through genes or morphology, and generally do fall into clusters using analysis of multiple genes.

The last paragraph of Guevara’s quote above shows the ideological motivation behind her paper: we must dismiss the existence of biological races and genetic differences between populations because it emphasizes differences between humans, and thus could lead to ranking of human populations, and thence to racism.  But, as Ernst Mayr recognized, accepting differences does not mean you have to view groups as being morally or legally unequal. We give a quote by evolutionist Ernst May quote in our Skeptical Inquirer paper:

Equality in spite of evident non-identity is a somewhat sophisticated concept and requires a moral stature of which many individuals seem to be incapable. They rather deny human variability and equate equality with identity. Or they claim that the human species is exceptional in the organic world in that only morphological characters are controlled by genes and all other traits of the mind or character are due to “conditioning” or other non-genetic factors. … An ideology based on such obviously wrong premises can only lead to disaster. Its championship of human equality is based on a claim of identity. As soon as it is proved that the latter does not exist, the support of equality is likewise lost. (Mayr 1963)

Thus, the second conclusion of Guevara is wrong:

2.) “High genetic variation exists within geographic regions, and little variation distinguishes geographic regions.”

Well, that’s sort-of true, but, as we said, that “little variation among geographic regions” can, when added up, diagnose populations sufficiently to not only tell you your geographic ancestry, but also to reconstruct the evolutionary and migratory history of human populations. Guevara dismisses these ancestry tests, though she doesn’t tell us why they are wrong:

Helping the zombie persist, direct-to-consumer genetic tests, like those offered by 23andMe and AncestryDNA, can reinforce misconceptions about human variation. These services have become many people’s primary reference point for human genetics information. To be marketable, the companies must communicate their results in simple, familiar ways that also appear meaningful and reliable. This usually entails simplifying genetic ancestry to bright, high-contrast colors, pinned definitively to geographic regions.

And yet, at the same time, Guevara admires the same kind of data—genetic differences between living populations (as well as “ancient fossil DNA”)—as being of value:

In addition to genomes from living humans, DNA extracted from ancient humans over the past two decades has revealed incredible insights. Across time, past humans frequently migrated, mated with, or displaced people they encountered in other regions—resulting in a tangled tree of human ancestry. The ancient DNA results refute any notion of deep, separate roots for humans in different geographic regions.

Well, there are deep roots for some groups (the Neanderthal lineage, for example, separated form the lineage leading to modern humans about 400,000 years ago), and this comes from both fossil and DNA evidence.  The “tangled tree” may be correct in some ways (we did hybridize with Neanderthals, and other populations exchanged genes to different degrees), but it’s not tangled enough to completely efface the evolutionary history of human populations.

All this leads to a third misleading conclusion:

3) Races are social constructs. Any differences between races are largely caused by racism rather than genes. As Guevara says:

As laid out by a major professional association for biological anthropologists, race is a social reality that affects our biology. For the last several hundred years in the U.S. and other colonized lands, racism has influenced people’s access to nutritious food, education, economic opportunities, health care, safety, and more. As a consequence, and precisely because of the environmental influence on most traits, the social construction of race is a risk factor for many health conditions and outcomes, including maternal and infant mortality, asthma, and COVID-19 severity.

This again shows both an ideological motivation and a misleading conclusion. Even the classical biological races (and even more so worldwide populations) are NOT social constructs, but are associated with genetic, morphological, and adaptive differences.  If races are purely socially constructed, how could you tell them apart in the first place? You need some kind of genetic marker. In the case of racism in America, the differences between African-Americans and whites were “constructed” based on skin pigmentation, hair texture, and other traits—traits based on genetic differences. Those differences served to mark out which people were considered different, and then “inferior”, though, as I said, genetic differences among people say nothing about moral or legal equality. THAT is the lesson that needs to be imparted, not the falsity that there are no genetic differences among groups.

Now Guevara may be correct that the “social construct” view is the one taught, erroneously, in high school and college.  But she’s wrong in thinking that Lewontin’s paper supports that “social construct” view.  In fact, the social construct view is largely wrong, with some exceptions centered on the outmoded view of “classical races”, but it appears to dominate anthropology and the social sciences. Anybody holding that view for either populations or groups of geographically contiguous populations needs to read the Coyne and Maroja paper.

4). Humans aren’t peas.  According to Guevara, Mendel’s work on peas, as taught in school, buttresses scientific racism, too:

I, along with others, am concerned that this focus instills and reinforces a false pre-Lewontin view that humans, like Mendel’s peas, come in discrete types. In reality, early studies of peas and other inbred, domesticated species have little relevance for human genetics.

Indeed, it is of little relevance to human genetics, but I’m not aware of any teacher who describes Mendel’s work—which served to show how genes sort themselves out during reproduction—and uses it to conclude, “See, human races are as distinct as round and wrinkled peas.”

In the end, both races and populations of humans show genetic and evolved morphological differences—less than we thought, say, a hundred years ago—but differences that are still significant in useful ways. To say that races or populations are purely social constructs is simply wrong, and to use Lewontin’s paper to reinforce that conclusion is doubly wrong.

Now reader Lou Jost has argued that Lewontin couldn’t really mathematically partition genetic variation the way he did because Lewontin used the wrong method. Regardless, it’s clear that there is more genetic variation at a given locus within a population than between populations or the groups of populations once deemed “races”.  But in the end there is a tremendous amount of information of biological and evolutionary significance to be gained by adding up the small genetic differences we see between human populations.

To end, here’s a map of genetic variation among populations in Europe, showing how the genetic variation (grouped by principal components analysis) lines up nicely with the geographic variation in populations. That’s because genetic differences evolved between semi-isolated groups of people, and that is why we can tell with considerable accuracy where our ancestors came from

Paper: Gilbert et al. 2022

Geography (populations sampled are in black)

Genetics (grouping of individuals using two axes of a principal components analysis. Look how well the geography (identified by color above) matches the genetics!

 

It could be quite a night!

A powerful solar flare (an explosion on the Sun) about 36 hours ago created a large and fast coronal mass ejection (a cloud of subatomic particles heading away from the Sun) that is due to arrive at Earth in the next few hours (it will show up less than an hour before it arrives as chaos in this data.) UPDATE: IT HAS ARRIVED; IF IT’S DARK WHERE YOU ARE, GO LOOK. That could mean problems for the electrical grid. It could also mean strong auroras (northern and southern lights) far from the poles. The timing, if correctly predicted, is such that Asia and Europe may have the best chances, but the auroras could potentially last until it is dark in the Americas too.

Also, just after sunset tonight, we may with difficulty be able to see Comet A3 (short for Comet C/2023 A3 Tsuchinshan-ATLAS ). The comet is bright — some reports give it a brightness comparable to the planet Venus, although more diffuse — but so is twilight. UPDATE: I HAVE BEEN WARNED THAT THE RAPID BRIGHTNING PERIOD, DUE TO A LIGHT SCATTERING EFFECT, MAY ALREADY BE OVER. IF SO, THE STATEMENTS HERE MAY BE TOO OPTIMISTIC. The comet is roughly ten Sun-widths above and slightly to the right of the Sun, and should be visible 15-30 minutes after sunset if you have a low and mostly cloudless horizon. Best bet is to bring binoculars and scan the sky; you’ll notice it much more easily, even if it is visible to the naked eye.

Each day following, the comet will be higher in the sky at sunset, making it more visible in late twilight, but it will also become intrinsically dimmer. Experts seem to disagree about when it will be at its best, but this weekend should be good, if not before.

Thanks to a couple of readers who are helping fill my lacuna of wildlife photos. I now have more than a week’s worth, but please keep sending them in.

Today’s photos come from reader Mary Rasmussen, whose captions and IDs are indented. Click on the photos to enlarge them.

Birds Along the Northern Lake Michigan Shore

In Michigan’s Upper Peninsula, this shoreline serves as a crucial part of a migratory flyway for birds journeying from the southern U.S. and beyond, through Wisconsin, across an archipelago, and northward into Canada. Despite being 350 miles north of Chicago, this region falls within the same climatic zone.

Our cabin is perched on an ancient sand dune along this rugged coast:

Just a mile offshore, several small, uninhabited islands dot the landscape. These islands become nocturnal roosts for hundreds of Sandhill Cranes (Antigone canadensis) which then traverse the skies daily to and from nearby farm fields:

Occasionally, a pair of cranes chooses our shore for nesting, successfully raising a chick this season:

The Sandhill Cranes are known for their distinctive, almost prehistoric bugle call, which resonates loudly across the landscape (JAC: You can hear a variety of their calls here.)

A Great Blue Heron (Ardea herodias) wades along the shore, scanning the clear pools for small fish and tadpoles:

Killdeer (Charadrius vociferus), with their nearly perfect camouflage, blend into the rocky shore so well that I usually don’t see them until they move:

The Turkey Vulture (Cathartes aura) is a carrion feeder that is often here in groups soaring over the shore in search of dead fish, birds and other animals. It uses thermals to glide through the air and a keen sense of smell to find its food:

A nest of Bald Eagles (Haliaeetus leucocephalus) is situated nearby along the shoreline. Occasionally, a gathering of four or five juvenile and adult Bald Eagles can be observed on the shore.

The eagles were landing at the end of our kayak ramp. I was able to get these shots because of the distraction of a large fish that had washed ashore:

Flocks of American White Pelicans (Pelecanus erythrorhynchos) frequent the islands and follow the fishing boats when the boats are heading in with their catch:

Pelicans are very large birds, having the second-largest wingspan of any North American bird. We found this skeleton on the shore. Here is the Pelican partial skeleton next to my dog Sylvie for scale. (55 lb. Golden Retriever) Sylvie looks unhappy because we would not let her keep the skeleton:

Equipment: I use a Nikon D500 camera with a NIKKOR 200-500mm lens.

The ion tail of C/2023 A3 (Tsuchinshan-ATLAS) could appear as a blue streak across the northern hemisphere sky during October, in a rare event thought to happen only every few decades

Meteorites strike Earth every day. It’s estimated that about 100 – 300 metric tonnes of material strike our planet every year. Most of it consists of sand-grain sized dust that burns up in the atmosphere, but each year a few thousand will reach Earth’s surface.

The vast majority of meteorites trace their origins to comets or the asteroid belt, but some of them come from the Moon or Mars. We know this by analyzing their chemical composition. While the Lunar meteorites have much to tell us, it is the Martian meteorites that are the greatest treasure for they are the only fragments of the Red Planet we currently have. By studying their chemistry and composition we have learned that Mars was once a warm and wet world similar to Earth.

There are about 200 meteorites we have confirmed as Martian in origin. There composition shows that they likely originated from about 10 large impacts on Mars. To be powerful enough to throw fragments of Mars into space, the impacts must have been large enough to make sizable craters, perhaps dozens of kilometers across. Which raises an interesting question. Which particular craters are connected to the meteorites we have? A new study in Science Advances explores this question.

A fragment of a Martian meteorite. Credit: Brian Koberlein

The team started by looking at the chemical similarities in each group of associated meteorites. From this they could get an idea of the age and geology of a particular impact site. They then compared this to the known age and composition of various regions of Mars, looking for craters that were a reasonable match. They were able to find an originating crater for about five of the groups.

This is important because knowing the precise origin gives us a more accurate picture of the evolution of Mars. We already have a good general understanding of the early history of Mars, but with specific impact sites we can compare regions. Perhaps early seas existed on Mars while other regions became deserts. Which regions were the last to dry, and therefore might be good sites for finding evidence of life. The study also found impact craters that are similar to the ones that produces meteorites but have no associated meteorites. As we find more Martian rocks, they might be part of new groups originating from these impacts.

Until we can recover rocks from Mars directly, the couple hundred Martian meteorites are our only physical link to our red neighbor. And thanks to this study we have a better idea of that link.

Reference: Herd, Christopher DK, et al. “The source craters of the martian meteorites: Implications for the igneous evolution of Mars.” Science Advances 10.33 (2024): eadn2378.

The post Most Mars Meteorites Came From Five Craters appeared first on Universe Today.

How certain are you of anything that you believe? Do you even think about your confidence level, and do you have a process for determining what your confidence level should be or do you just follow your gut feelings?

Thinking about confidence is a form of metacognition – thinking about thinking. It is something, in my opinion, that we should all do more of, and it is a cornerstone of scientific skepticism (and all good science and philosophy). As I like to say, our brains are powerful tools, and they are our most important and all-purpose tool for understanding the universe. So it’s extremely useful to understand how that tool works, including all its strengths, weaknesses, and flaws.

A recent study focuses in on one tiny slice of metacognition, but an important one – how we form confidence in our assessment of a situation or a question. More specifically, it highlights The illusion of information adequacy. This is yet another form of cognitive bias. The experiment divided subjects into three groups – one group was given one half of the information about a specific situation (the information that favored one side), while a second group was given the other half. The control group was given all the information. They were then asked to evaluate the situation and how confident they were in their conclusions. They were also asked if they thought other people would come to the same conclusion.

You can probably see this coming – the subjects in the test groups receiving only half the information felt that they had all the necessary information to make a judgement and were highly confident in their assessment. They also felt that other people would come to the same conclusion as they did. And of course, the two test groups came to the conclusion favored by the information they were given.

The researchers conclude (reasonably) that the main  problem here is that the test groups assumed that the information they had was adequate to judge the situation – the illusion of information adequacy. This, in turn, stems from the well documented phenomenon that people generally don’t notice what is not there, or at least it is a lot more difficult to notice the absence of something. Assuming they have all relevant information, it then seems obvious what the answer is – whichever position is favored by the information they are given. In fact, the test groups were more confident in their answers than the control group. The control group had to balance conflicting information, while the test groups were unburdened by any ambiguity.

There are some obvious parallels to the real world here. There is a lot of discussion about how polarized the US has become in recent years. Both sides appear highly confident that they are right, that the other side has lost their collective mind, and nothing short of total political victory and any cost will suffice. This is obviously a toxic situation for any democracy. Experts debate over the exact causes of this polarization, but there is one very common theme – the two sides are largely siloed in different “information ecosystems”. This is the echochamber effect. If you listen mainly or only to partisan news, then you are getting one half of the story, the half that supports your side. You will have the illusion that you have all the information, and in light of that information the conclusion is obvious, and anyone who disagrees must have dark motives, or be mentally defective in some way.

I have seen this effect in many skeptical contexts as well. After watching or reading a work that presents only half the story – the case for one side of a controversy – many people are convinced. They think they now understand the situation, and feel that such a large amount of information has to add up to something. I have had many discussions, for example, with people who have rad books like The Aquatic Ape, that argues that humans went through an evolutionary period of adaptation to an aquatic life. It’s all nonsense and wild speculation, without any actual science, but it’s hard not to be persuaded by a book-length argument if you don’t already have the background to put it into context. The same happened with many people who watched the movie Loose Change.

This is why it is a good rule of thumb to suspend judgement when you encounter such claims and arguments. Professionals in investigative professions learn to do this as part of their deliberate analytical process. What am I not being told? What information is missing? What do those who disagree with this position have to say? What’s the other side of the story?

This is a good intellectual habit to have, and is also a cornerstone of good skepticism. Who disagrees with this claim and why? In everyday life it is a good idea to have diverse sources of information, and in fact to seek out information from the “other side”. For political news, no one source can be adequate, although some sources are better than others. Not all news sources are equally partisan and biased. It’s a good idea to seek out news sources that are generally considered to be, and may have been rated, to be less partisan and are balanced in their reporting. But it is also a good idea to utilize multiple sources of news, and to specifically consume news that is of reasonable quality but comes from a different position than your own. What is the other side saying and why? It may be painful and uncomfortable sometimes, but that is a good reason to do it.

It’s good to know that there is a bias towards the illusion of information adequacy, because with that knowledge you can work against it. In the study, when the test subjects were given the other half of the information that they were initially missing, many of them did change their minds. This is something else we often see in psychological studies – humans are generally rational by default, and will listen to information. But this is true only as long as there is no large emotional stake. If their identity, tribe, ego, or fundamental world view is at stake, then rationality gives way to motivated reasoning.

This is why it is extremely useful (although also extremely difficult) to have no emotional stake in any claim. The only stake a rational person should have is in the truth. Your identity should be as an objective truth-seeker,  not as a partisan of any kind. Also there should be no loss in ego from being wrong, only from failing to change your mind in light of new evidence. This is a rational ideal, and no one achieves it perfectly, but it’s good to have a goal.

At least it’s good to be engaged in metacognition, and to think about your thought process and everything that might be biasing it. This includes information and perspective that might be missing. This is the most difficult to detect, so it requires special attention.

The post Confidently Wrong first appeared on NeuroLogica Blog.

Accumulated evidence does not demonstrate that elderberry has meaningful beneficial effects.

The post Elderberry (What is it good for) first appeared on Science-Based Medicine.

We often talk about Jupiter’s Great Red Spot quite candidly but forget that hurricanes can be devastating, destructive forces here on Earth. Hurricane Milton is a reminder of the awful effects here on Earth. It came out of nowhere, appearing in the Gulf of Mexico as a tropical storm and two days later was a category 5 hurricane. It tracked a course and hit land near Siesta Key in Florida. NASA have been tracking the storm from space, recording high sea temperatures that fuelled the storm allowing it to grow. Images have been released from the ISS showing the sheer enormity of the hurricane.

Hurricanes form over warm oceans, typically in tropical regions of Earth. Their formation tends to start as a collection of thunderstorms over bodies of water where the temperature is at least 26.5 degrees celsius. The warm, moist air over the ocean rises creating a region of lower pressure at the surface.

Hurricanes Gordon and Helene

The low pressure causes air to flow inward, warming and rising as it goes. It then cools and condenses to form clouds that release the heat. The heat then warms the surrounding air creating a continuous cycle of rising warm air and an inward movement of air. The system grows and eventually takes on a rotational movement due to the rotation of the Earth. When the winds are recorded to be sustained above 119 kilometres per hour, it is classed as a hurricane. They can continue to grow as long as their is a source of warm moist air so typically they hit landfall and start to weaken. 

Watch this video of Hurricane Milton from the International Space Station

The inhabitants of Florida only just recovered from the effects of Hurricane Helene before warnings were received from another hurricane brewing over the Gulf of Mexico. Hurricane Milton started to form on 5 October and two days later had become a category 5 hurricane. Fuelling this leviathan of a hurricane are the higher than average sea temperatures in the Gulf of Mexico. Milton’s wind speeds rapidly increased from 28 to 281 kilometres per hour in 24 hours as the hurricane strengthened. 

It wasn’t just warm oceans that intensified Milton so rapidly though, vertical wind shear was also a vital component. This change in winds with height interacts with the brewing thunderstorms to usually diminish a hurricanes ferocity. In the case of Milton, it was in a low-shear environment which means with changing altitude, there is usually very little difference in wind speed or direction. This allowed the storm to grown without being checked. 

Thunderstorms over Brazil

The National Hurricane Centre (part of the National Oceanic and Atmospheric Administration) have been tracking Milton since its formation, paying particular attention to where it was likely to hit land and what path it was likely to follow. They were also able to determine (largely from imagery and data from orbiting infrastructure) that an eye-wall replacement cycle had completed. This process occurs when a new eye begins to develop around the old eye. The new eye slowly decreases in size and eventually replaces the old eye. Events such as these can cause the hurricane to grow but reduce wind speed. It can happen several times but then grow in intensity again if the conditions permit.

The eye of Hurricane Milton can be clearly seen in this image from the International Space Station 

International Space Station. Credit: NASA

With astronauts on board the space station and the remote sensing technology available to them, NASA are a key part of disaster management teams. Their Disasters Response Coordination System has been used to support agencies dealing with the storm on the ground. They provide maps, images and data to help manage flooding, power outages and rain fall levels. 

Our thoughts go out to all those effected by Hurricane Milton from all the team at Universe Today. 

Source : Fuel for Hurricane Milton

The post NASA Reveals the Mind-Boggling Scale of Hurricane Milton seen from Space appeared first on Universe Today.

Ancient volcanic rock from South Africa has been found to harbour primitive bacteria, which may shed light on some of the earliest forms of life on Earth

The total number of exoplanets discovered to date totals 5,288. Among them are a host of rocky, Earth-like exoplanets but none of them seem to have atmospheres. It’s a fairly challenging observation to make but a team of researchers think they’ve come up with a new, simpler technique. It involves measuring the combined temperature of a star and the exoplanet just before the planet passes behind. If it’s lower than expected, the planet is likely to have an atmosphere regulating its temperature!

The search for alien worlds has of course in itself an exciting journey. Finding other planets around distant stars helps us to understand more about possibility of life in the Universe. Finding other planets that could sustain life is perhaps one of the most exciting goals in modern science. Before we can get to that stage however, we need to first find worlds with atmospheres. 

Coronagraph allowing the direct imaging of exoplanets

Atmospheres around Earth-like planets are key components for the development of life (I should add life like us since there could be a whole host of different biologies out there!) The layer of gas surrounding rocky worlds insulates the planet and acts to regulate its temperature to. Our own atmosphere warms during the day and cools at night but it redistributes the heat of the Sun around the planet keeping it a moderately temperate climate for life. 

A view of Earth’s atmosphere from space. Credit: NASA

A new study led by PhD student Qiao Xue from the University of Chicago has developed an intriguing new way to hunt for Earth-like planets with an atmosphere. Typically we we have relied upon the study of the light from the host star as the planet passes in front to reveal the presence of an atmosphere. It’s an approach which turns out to be far more efficient and simpler than previous methods. 

The idea was first proposed in 2019 by Bean and Megan Mansfield to analyse the temperatures of the exoplanet and the star. More accurately the difference between the temperature of the exoplanet when at its hottest and the predicted temperature at its coldest. An atmosphere around an exoplanet would disperse the heat around the surface, reducing the day time temperature. The team theorised that if the actual temperature of an exoplanet is not as hot as it could be then an atmosphere must be present and redistributing the warmth. Until now thought, the technology was not sensitive enough. The James Webb Space telescope has changed that though.

Artist impression of the James Webb Space Telescope

As an exoplanet passes in front of the host star, some of the star’s light is blocked and so the overall brightness decreases. As the planet passes almost behind the star then the light from the star and a little from the exoplanet allows for a measure of the brightness of the full system. As the planet passes behind then we can measure stellar brightness alone and, analysing the changes in light, the brightness and hence temperature of the planet can be deduced. 

Using this technique, the team applied their attention to planet known as GJ1132 b 41 light years away. They concluded that it does not have an atmosphere because its measured temperature is too close to the calculated maximum temperature. It therefore cannot have an atmosphere redistributing the energy from its host star. It is therefore not a suitable candidate for live!

Source :  UChicago researchers use new method of finding atmospheres in distant planets

The post A New Way to Detect Rocky Exoplanet Atmospheres appeared first on Universe Today.

Two of the three science Nobel prizes in 2024 have been won by people working in AI, but does this mean that AI models are now vital for science?

Mars has captured our imagination for centuries. Ever since the invention of the telescope our imagination has often drifted toward the possibility of life on Mars. Exploration of the red planet has often revealed that Mars once had plenty of water on its surface but it’s no longer there. Now NASA’s Curiosity rover has found deposits of carbon-rich minerals that could give us a much needed clue.  

Mars Curiosity Rover was launched by NASA to the red planet in 2011. It’s part of the Mars Science Laboratory mission and, like many of the explorers, is a robotic mission. It arrived at Gale Crater on 6 August 2012 and was designed to explore the geological and climatic environments of Mars, search for signs that it was once a habitable world and to that end, was essentially a sampling and analysis mission. Originally it was a two year mission but Curiosity has continued long passed the intended duration, operating now for over a decade.

New simulations are helping inform the Curiosity rover’s ongoing sampling campaign. Credit:NASA/JPL-Caltech/MSSS

Mars, the fourth planet from the Sun, has been known to be a fairly hostile world devoid of any signs of life. Gale Crater was chosen as the target for Curiosity because it’s an impact crater formed just under 4 billion years ago. The layered rock formations found on the crater walls make it an ideal location to study the red planets geological history. The analysis is completed using the on board instruments SAM (Sample Analysis at Mars) and TLS (Tunable Laser Spectrometer) that heat up the samples to almost 900 degrees Celsius with the resultant gasses being analysed.

There’s methane on Mars, but only in Gale Crater, and only sporadically. Image Credit:

As Curiosity explores Mars it has been measuring the isotopic composition (the ratios of different isotopes) of the minerals found in the crater. Isotopes are elements that have different masses than usual for example as water evaporates, lighter version of carbon  and oxygen were likely to evaporate leaving heavier ones behind. Eventually, over time, the heavier versions (isotopes) became an integral part of the rocks that Curiosity is analysing. The minerals are largely carbon rich but they point toward high levels of evaporation suggesting they could only have formed when Mars could support liquid water. 

David Burtt from NASA’s Goddard Space Flight Centre and lead author of the paper that describes the findings do not rule out ancient life either. He said “Our samples are not consistent with an ancient environment with life on the surface of Mars, although this does not rule out the possibility of an underground biosphere or a surface biosphere that began and ended before the carbonates formed.”

Their paper that was published in the National Academy of Sciences suggests there may have been two possible formation processes for the carbonates. A series of wet-dry cycles within the Gale Crater are one such possibility with the formation of carbonates in highly salty water under cold temperatures the other. 

The two possible formation scenarios point to two different climate models and different habitability.  The wet-dry cycling suggests an alternating climate between more and less habitable conditions. Alternatively the salty water process with cold temperatures would indicate a less habitable environment with most water locked up in ice and the rocks. Neither scenario is ideal for the establishment of complex life forms but as Burtt highlighted, it doesn’t rule out the possibility further back in the history of Mars. 

Source : NASA: New Insights Into How Mars Became Uninhabitable

The post How Did Mars Become Uninhabitable? appeared first on Universe Today.

Researchers have significantly improved a new joining technology, interlocking metasurfaces (ILMs), designed to increase the strength and stability of a structure in comparison to traditional techniques like bolts and adhesives, using shape memory alloys (SMAs). ILMs offer the potential to transform mechanical joint design in manufacturing for aerospace, robotics and biomedical devices.

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Artificial Intelligence has learned to master language, generate art, and even beat grandmasters at chess. But can it crack the code of abstract reasoning --t hose tricky visual puzzles that leave humans scratching their heads? Researchers are putting AI's cognitive abilities to the test, pushing the multi-modal large language models (MLLMs) to solve visual problems once reserved for human IQ tests. The result? A glimpse into how far AI has come -- and where it still stumbles.

Astronomers have observed Jupiter's legendary Great Red Spot (GRS), an anticyclone large enough to swallow Earth, for at least 150 years. But there are always new surprises -- especially when NASA's Hubble Space Telescope takes a close-up look at it. Hubble's new observations of the famous red storm, collected 90 days between December 2023 to March 2024, reveal that the GRS is not as stable as it might look. The recent data show the GRS jiggling like a bowl of gelatin. The combined Hubble images allowed astronomers to assemble a time-lapse movie of the squiggly behavior of the GRS.