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The average surface temperature varied more widely and was even hotter than previously thought during much of the past 500 million years, according to the most rigorous study so far

The Sun is midway through its life of fusion. It’s about five billion years old, and though its life is far from over, it will undergo some pronounced changes as it ages. Over the next billion years, the Sun will continue to brighten.

That means things will change here on Earth.

As the Sun goes about its business fusing helium into hydrogen, the ratio of hydrogen to helium in its core changes. Over time, the core slowly becomes more enriched in helium. As helium accumulates in its core, the core’s density increases, meaning protons are more closely packed together. That creates a situation where the Sun can fuse hydrogen more efficiently. After a chain reaction of processes and cause and effect, the end result is that the Sun’s luminosity increases. The Sun’s luminosity has already increased by about 30% since its formation, and the brightening will continue.

Any increase in the Sun’s luminosity can have a pronounced effect on Earth. Environmental cycles like the carbon, nitrogen, and phosphorous cycles sustain Earth’s biosphere. As the Sun becomes brighter, it will affect these cycles, including the carbonate-silicate cycle, which moderates the accumulation of carbon dioxide (CO2) in the planet’s atmosphere.

This schematic shows the relationship between the different physical and chemical processes that make up the carbonate-silicate cycle. In the upper panel, the specific processes are identified, and in the lower panel, the feedbacks associated are shown; green arrows indicate positive coupling, while yellow arrows indicate negative coupling. Image Credit: By Gretashum – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=79674633

Scientists think that over the next billion years, the brightening Sun will disrupt this cycle, leading to declining CO2 levels. Plants rely on CO2 and the levels are expected to plummet, which means that complex land life would end in the next billion years.

It’s a bleak prognosis, but new research suggests it might not happen.

The new research is “Substantial extension of the lifetime of the terrestrial biosphere,” and it’s been accepted for publication in the Planetary Science Journal. It’s in pre-print now, and the lead author is R.J. Graham, a postdoctoral researcher in the Department of Geophysical Sciences at the University of Chicago.

“Approximately one billion years (Gyr) in the future, as the Sun brightens, Earth’s carbonate-silicate cycle is expected to drive CO2 below the minimum level required by vascular land plants, eliminating most macroscopic land life,” the authors write.

As stars like our Sun age, they become brighter and warmer. Image Credit: ESO/L. Calçada

As the Sun brightens and warms the Earth’s surface, scientists expect the carbonate-silicate cycle to draw more CO2 out of the atmosphere because of carbonate-silicate weathering and carbonate burial. Rainwater is enriched with atmospheric carbon, which reacts with silicate rocks and breaks them down. The products of the chemical reactions that break them down find their way to the ocean floor, where they form carbonate minerals. As these minerals are buried, they effectively remove carbon from the atmosphere.

Normally, the cycle acts as Earth’s natural thermostat. However, higher temperatures make the reactions more efficient, meaning the carbonate-silicate cycle will remove more CO2 from the atmosphere. That’s what led scientists to conclude that the CO2 will become so low that planet life will perish. However, the authors examined these ideas and found that it may not quite work out that way.

“Here, we couple global-mean models of temperature- and CO2-dependent plant productivity for C3 and C4 plants, silicate weathering, and climate to re-examine the time remaining for terrestrial plants,” they write. C3 and C4 plants are two main plant groups that are classified based on how they perform photosynthesis and absorb carbon. They’re relevant because they respond differently to higher temperatures.

The researchers say recent data shows that the carbonate-silicate cycle isn’t as temperature-dependent as previously thought. Instead, it’s only weakly temperature-dependent and more strongly CO2-dependent. In that case, “we find that the interplay between climate, productivity, and weathering causes the future luminosity-driven CO2 decrease to slow and temporarily reverse, averting plant CO2 starvation,” they explain.

Instead of a one billion-year outlook for Earth’s plant life, the researchers say atmospheric CO2 levels will mean plants have another 1.6-1.86 billion years. When plants can no longer survive, it won’t be because of plummeting CO2 levels. Instead of CO2 starvation, it’ll be because of what scientists call the moist greenhouse transition.

When that transition happens, a planet’s atmosphere becomes saturated with water vapour as the planet warms. Since water vapour is a potent greenhouse gas, it creates a feedback loop of increased warming. Eventually, it’s simply too hot for plants to survive. The consequences don’t end there. As the Earth’s upper atmosphere becomes more saturated with water vapour, UV energy splits water apart, and the hydrogen drifts off into space. In this situation, there’s a gradual and irreversible loss of water into space.

According to the authors, Earth won’t experience this transition for between about 1.6 and 1.86 billion years.

This astronaut photograph shows the sky over the Amazon Basin during the rainy season. Image Credit: NASA

“We show that recent data indicating weakly temperature-dependent silicate weathering lead to the prediction that biosphere death results from overheating, not CO2 starvation,” the authors write. “These findings suggest that the future lifespan of Earth’s complex biosphere may be nearly twice as long as previously thought.”

These results also affect our understanding of exoplanet habitability. It has to do with what are called ‘hard steps’ in the appearance and evolution of life. The hard steps model says that certain evolutionary transitions were difficult and unlikely to happen twice. Some examples are the appearance of multicellular organisms and the Cambrian explosion.

But if Earth’s biosphere has a much longer lifespan than thought, that affects the hard steps model.

“A longer future lifespan for the complex biosphere may also provide weak statistical evidence that there were fewer “hard steps” in the evolution of intelligent life than previously estimated and that the origin of life was not one of those hard steps,” the authors conclude.

If that’s the case, then exoplanet habitability could be less rare than thought.

The post Life Might Thrive on the Surface of Earth for an Extra Billion Years appeared first on Universe Today.

Genetic testing on samples collected during the earliest days of the covid-19 outbreak suggests it is likely that the virus spread from animals to humans at the Huanan seafood market

Divalent samarium compounds are important reagents for reductive transformations in organic chemistry. However, currently, a high amount of this reagent is required in most reactions, and it also necessitates the use of harmful chemicals. To address this issue, researchers have developed a visible-light-antenna ligand that coordinates with stable trivalent samarium compounds, which, upon exposure to visible light, are reduced to divalent samarium, enabling milder conditions and smaller amounts of samarium for reactions.

Researchers have developed an innovative new method for identifying biomarkers in wastewater using origami-paper sensors, enabling the tracking of infectious diseases using the camera in a mobile phone. The new test device is low-cost and fast and could dramatically change how public health measures are directed in any future pandemics.

Hydrogen is in great demand due to its promising role as a sustainable resource in the energy transition. Researchers have made an important breakthrough in the efficient and cost-effective provision of isotopes. These are the three forms in which hydrogen occurs in nature -- as protium, deuterium or tritium. The team has taken a big step towards realizing its dream of separating hydrogen isotopes at room temperature at low cost.

Scientists are now able to directly compare the different kinds of injury that mechanical ventilation causes to cells in the lungs. In a new study, using a ventilator-on-a-chip model, researchers found that shear stress from the collapse and reopening of the air sacs is the most injurious type of damage.

Researchers have developed a groundbreaking soft cortical device that could revolutionize the treatment of epilepsy and other neurological disorders.

A research team has successfully recreated the structure of wrinkles in biological tissue in vitro, uncovering the mechanisms behind their formation.

Can an immunoassay be created and selectively detect a virus in under 5 minutes? In a new study, researchers report that it can be done using a low-power laser like a laser pointer with a little liquid sample like a sesame seed.

Modern integrated microelectronic devices are often poorly repairable and difficult to recycle. Debondable adhesives play a key role in the transition to a circular economy with sustainable resources, less waste, and intelligent repair/recycling strategies. A research team has now introduced a method for making adhesives that can be deactivated 'on command'.

Researchers have developed a Martian atmospheric evolution model to propose a new theory about Mars's past.

Thermoelectric devices are devices that can convert heat into electrical energy. Researchers have now developed a thermoelectric device composed of organic materials that can generate electricity from ambient temperature alone. The device is made from copper phthalocyanine and copper hexadecafluoro phthalocyanine as charge transfer materials and was combined with fullerenes and BCP as electron transport layers.

A new way of making ammonia by harnessing the unique power of liquid metal could lead to significant cuts in carbon emissions caused by production of the widely-used chemical. Ammonia is used in fertilizer to grow much of our food, but also plays a role in clean energy as a carrier to safely transport hydrogen.

Abigail Shrier has a new book out, and it’s doing quite well despite the vitriol she received for her first book, Irreversible Damage, the Transgender Craze Seducing our Daughters. I read the latter one, and thought it was quite good—not nearly as inflammatory as the gender activists deemed it. But of course the topic—that social media was contributing to a desire of young women to identify as men, a
“rapid-onset” change that was unnecessary and generally harmful—was tailor-made to anger gender activists. Remember this tweet by ACLU LAWYER Chase Strangio about that book?

An ACLU lawyer advocating censorship! What has the world come to? Well, Strangio, a biological woman who identifies as male, deleted that tweet, but the Internet is forever.

Now Shrier has a somewhat related book, in that it’s about children’s psychological difficulties, but this one isn’t directly related to gender. Click on the icon to go to the Amazon link.

I haven’t yet read it, but have ordered it by interlibrary loan (I can no longer buy books because I have no space on my shelves), and will report my take forthwith.  But Greg Lukianoff, President of FIRE and coauthor of two books (one a blockbuster bestseller), has reviewed Shrier’s new book on his website, The Eternally Radical Idea. He pronounces Bad Therapy a “masterpiece,” which is high praise. But he also takes up about 70% the review listing the varieties of opprobrium that Shrier will meet.  Click to read Lukianoff’s review; I’ll just give a couple of excerpts:

First, Lukianoff’s assessment and brief summary. Bolding is mine:

“Bad Therapy” is simply a masterpiece — easily the most important book of the year. Unfortunately, it most desperately needs to be read by the very people who are likely most hostile to Shrier’s work. The book focuses on the harms of the therapeutic approach to raising our children and how the generation treated with the most psychological therapy and psychiatric drugs has become the most miserable, anxious, and disempowered generation on record. (“Disempowered,” by the way, was the original title of the book I wrote with Jonathan Haidt, which became “The Coddling of The American Mind.”)

Shrier comes to many of the same conclusions that Haidt and I came to in “Coddling,” which I’d sum up like this: As a culture, we seem to be teaching young people the mental habits of anxious and depressed people — encouraging them, often through example, to engage in negative mental exaggerations called cognitive distortions. It’s a kind of reverse-cognitive behavioral therapy. I’ve talked about this problem for the last decade, beginning with Haidt’s and my original 2015 article for The Atlantic, “The Coddling of the American Mind,” and most recently with my piece, “What’s behind the campus mental health crisis?” for UnHerd.

Shrier’s book also focuses on how parenting in the K-12 environment is informed by an ideology that completely undermines students’ sense of an internalized locus of control. Indeed, if you really want to make someone despondent, just persuade them that all important decisions are out of their hands and that they are essentially powerless in their own lives.

Haidt and I — and more recently a Substacker named Gurwinder Bhogal — have pointed out that the current campus left ideology inherently tells young women in particular that they are unavoidably simultaneously both oppressors and oppressed; that their life is determined by their immutable characteristics; that the planet is doomed; that fascists are everywhere; and that there’s not much that can be done about this other than consciousness-raising and feeling guilt, shame, and despair.

What I’ve been emphasizing more recently is that, in many cases, teaching people these cognitive distortions was largely done in the name of motivating them towards some positive social action. This is a terrible strategy, of course, because depressed and anxious people make terrible activists. Depression and anxiety more often result in fatalism and despair than an attitude capable of bringing about positive social change, so it’s a weird way to build a movement.

Here are the three conclusions from Haidt and Lukianoff’s best-selling and influential book:

1.)  We young people are fragile (“What doesn’t kill you makes you weaker.”)

2.) We are prone to emotional reasoning and confirmation bias (“Always trust your feelings.”)

3.) We are prone to “dichotomous thinking and tribalism” (“Life is a battle between good people and evil people.”)

So what’s the difference between Shrier’s book and the earlier one? I’m sure they are quite different, but Lukianoff says very little about this issue. In fact, he says nothing about what Shrier add’s to the Haidt and Lukianoff book:

But Shrier’s book goes far beyond what Haidt and I did in “Coddling,” and that is why every single parent and K-12 teacher must read it. Despite being steeped in this stuff for the better part of two decades, I still learned a great deal from it — including that the research behind the health harms of growing up with “adverse childhood experiences” is far weaker than I understood it to be.

The book is gorgeously written, thoughtful, compassionate, and has gobs of both research and common sense. It also features some of my favorite experts, including my friend Camilo Ortiz, a professor and clinical psychologist who specializes in CBT. Other friends who make an appearance include Jonathan Haidt, Lenore Skenazy, Rob Henderson, Richard J. McNally, Paul Bloom, and Peter Gray.

And that first paragraph is all you’ll get. The review and assessment of the book takes up only a third of Lukianoff’s piece. Now I don’t mind someone using a review as a platform to launch their own ideas into the ether (H. L. Mencken was famous for that), but Lukianoff uses the book as a way to list all the potential criticisms that Shrier’s book will face, criticisms that he outlined in another book with Rikki Schlott: The Canceling of the American Mind: Cancel Culture Undermines Trust and Threatens Us All—But There is a Solution. The review leaves me, at least, not knowing what Shrier’s book is really about.

The criticisms that Lukianoff says that Shrier will face fall into three categories: “The Obstacle Course” (“rhetorical doges and logical fallacies” like strawmanning and misrepresenting the book’s arguments); “The Minefield” (dissing the book by attacking the author, a tactic with which we’re quite familiar), and “The Perfect Rhetorical Fortress” (raising guilt by association, labeling people as bad because of their politics, and so on). If you read Shrier’s earlier book, you’ll see all of these tactics were indeed used to dismiss it. It turns out that Shrier had a good point, as we now know as European countries dismantle their use of “affirmative treatment” and puberty blockers for gender-dysphoric youth, most of whom would come out as gay (and not lose body parts nor get sterilized) if they were treated less “affirmatively” and they deep-sixed the hormones for adolescents. But now that Shrier has been labeled a Bad Person and guilty of Ideological Wrongthink, that label can be used to discredit everything she writes in the future.

At any rate, and despite the digressions by Lukianoff that are aimed at pushing his own platform, this is certainly a book worth investigating. I haven’t read any other reviews, but just found on on Slate that is quite critical.  We shall see if the author of that one, Anna Nordberg, engages in the bad-faith criticisms described by Lukianoff. (Nordberg does have expertise in the area of parenting and child psychology.)

A meta-analysis of 137 clinical trials finds triptan drugs are among the most effective for treating migraines, while newer ditan and gepant drugs were rated less highly

Most of the exoplanets we’ve discovered orbit red dwarf stars. This isn’t because red dwarfs are somehow special, simply that they are common. About 75% of the stars in the Milky Way are red dwarfs, so you would expect red dwarf planets to be the most abundant. This also means that most habitable worlds are going to orbit these small, cool stars, and that has some significant consequences for our search for life.

To begin with, any potentially habitable red dwarf world will need to orbit their star closely, just to be warm enough for things like liquid water. The TRAPPIST-1 system I talked about yesterday is a good example of this. The three potentially habitable planets of the system orbit at a small fraction of the distance between Mercury and the Sun. This means they are at risk of things such as stellar flares, but it also means they are almost certainly tidally locked.

Tidal locking occurs when a planet or moon is so close to its companion that tidal forces cause its rotation to sync with its orbital motion. When a planet is tidally locked, one side always faces its star while the other side is forever in darkness. As you might imagine, this would mean the warm side fries while the other freezes. That’s true unless the planet were to have a good atmosphere. With a water-rich Earth-like atmosphere heat could move between the day and night sides. Weather would be strange on such a world, but a tidally locked world could be habitable, with fairly even day-side and night-side temperatures.

How clouds could make a planet appear airless. Credit: Powell, et al

Observing the atmospheres of tidally locked planets is difficult, but astronomers have a trick to see whether an atmosphere exists. Rather than trying to capture an atmospheric spectra, they can simply measure the surface temperature of the planet on opposite sides. So, look at the star as the planet moves in front of it to determine the temperature of the dark side, and look at it again as the planet moves behind the star to get the light side temperature. If the dark and light sides have dramatically different temperatures, then it must not have an atmosphere. Easy-peasy. But a new study shows that isn’t necessarily true.

In this paper the authors argue that clouds on the dark side of a world could skew our data. To show this, they considered a tidally locked world with a thick atmosphere. Based on their models, the atmosphere would moderate global temperatures on the planet so that the day side is only a few dozen degrees warmer than the dark side. This is similar to the day and night extremes of a dry region on Earth. While moderate, the temperature shift would be enough to trigger the formation of thick clouds on the dark side.

In this scenario, the day side would be mostly cloudless and we would measure the warm temperature of the planet’s surface. But with a cloudy dark side we would measure temperature of the upper layer of clouds, which would be much colder. So even though surface temperatures of the planet are fairly uniform, it would appear to have an extreme temperature shift like an airless world. The authors go on to look at how observations from the JWST could distinguish between cloudy planets and those without an atmosphere, but it is clear that one simple trick in the search for habitable planets isn’t quite so simple.

Reference: Powell, Diana, Robin Wordsworth, and Karin Öberg. “Nightside Clouds on Tidally-locked Terrestrial Planets Mimic Atmosphere-Free Scenarios.” arXiv preprint arXiv:2409.07542 (2024).

The post Exoplanets Could be Hiding Their Atmospheres appeared first on Universe Today.

Today we have LEOPARD photos taken by Phil Frymire, whom I met in the line for the plane from Newark to Johannesburg. Someone said, as I perused the line, “Are you Jerry Coyne?” I was shocked, but it turned out that Phil and his brother read this site and recognized me. My 5 minutes of fame!  Phil’s IDs captions are indented, and you can enlarge the photos by clicking on them.

My brother and I visited South Africa at the same time as our host. We stayed at Kambaku River Sands lodge in the Timbavati Nature Preserve and at Mala Mala Sable Camp. Kambaku River Sands is about 35 miles northwest of Manyeleti (where Jerry visited) and Mala Mala is about 12 miles south of Manyeleti. The routine at both lodges was very similar to what Jerry described for Manyeleti. Here are a selection of leopard (Panthera pardus) photos which also include some unfortunate impalas (Aepyceros melampus). The first six photos are from Timbavati and the last five are from Mala Mala.

This leopard was eating an impala she had killed and cached up a tree when part of the carcass fell onto some lower limbs. She slipped briefly when retrieving it, hence the expression. A lone hyena was lurking below, hoping in vain for scraps.

Another Timbavati female:

The same cat in a different pose:

This cub was stashed up a tree about 30 yards away from its mother:

This female was relaxing in between bites of impala. What is she thinking?:

This is a screenshot of a video I took. We missed this leopard’s taking of an impala by only a couple of minutes. When we came upon the scene, it was dragging its prey, looking for a suitable tree to store the kill. We found out later that hyenas had stolen the carcass.

Closeup of another Mala Mala female:

She was part of a mating pair. The larger male is on the right:

A Mala Mala female:

Her nearby cub:

Just above the mother and cub, in a dense tree, you can see the disembodied head of her impala victim:

Back in April 2022, the CDF experiment, which operated at the long-ago-closed Tevatron particle collider. presented the world’s most precise measurement of the mass of the particle known as the “W boson“. Their result generated some excited commentary, because it disagreed by 0.1% with the prediction of the Standard Model of particle physics. Even though the mismatch was tiny, it was significant, because the CDF measurement was so exceptionally precise. Any disagreement of such high significance would imply that something has to give: either the Standard Model is missing something, or the CDF measurement is incorrect.

Like most of my colleagues, I was more than a little skeptical about CDF’s measurement. This was partly because it disagreed with the average of earlier, less precise measurements, but mainly because of the measurement’s extreme challenges. To quote a commentary that I wrote at the time,

• “A natural and persistent question has been: “How likely do you think it is that this W boson mass result is wrong?” Obviously I can’t put a number on it, but I’d say the chance that it’s wrong is substantial. Why? This measurement, which took several many years of work, is probably among the most difficult ever performed in particle physics. Only first-rate physicists with complete dedication to the task could attempt it, carry it out, convince their many colleagues on the CDF experiment that they’d done it right, and get it through external peer review into Science magazine. But even first-rate physicists can get a measurement like this one wrong. The tiniest of subtle mistakes will undo it.”

In the weeks following CDF’s announcement, I attended a detailed presentation about the measurement. The physicist who gave it tried to convince us that everything in the measurement had been checked, cross-checked, and understood. However, I did not find the presentation exceptionally persuasive, so my confidence in it did not increase.

But so what? It doesn’t matter what I think. All a theorist like me can do, seeing a measurement like this, is check to see if it is logically possible and conceptually reasonable for the W boson mass to shift slightly without messing up other existing measurements. And it is.

(In showing this is true, I took the opportunity to explain more about how the Standard Model works, and specifically how the W boson’s mass arises from simple math, before showing how the mass could be shifted upwards. Some of you may still find these technical details interesting, even though the original motivation for this series of articles is no longer what it was.)

Instead, what really matters is for other experimental physicists to make the same measurement, to see if they get the same answer as CDF or not. Because of the intricacy of the measurement, this was far easier said than done. But it has now happened.

In the past year, the ATLAS collaboration at the Large Hadron Collider [LHC] presented a new W boson mass measurement consistent with the Standard Model. But because their uncertainties were 60% larger than CDF’s result, it didn’t entirely settle the issue.

Now the CMS collaboration, ATLAS’s competitor at the LHC, has presented their measurement. They have managed to be almost as precise at that of CDF — a truly impressive achievement. And what do they find? Their result, in red below, is fully consistent with the Standard Model, shown as the vertical grey band, and with ATLAS, the bar line just above the red one. The CDF measurement is the bar outlying to the right; it is the only one in disagreement with the Standard Model.

Measurements of the W boson mass made by several different experiments, with names listed at left. In each case, the dot represents the measurement and the horizontal band represents its uncertainty. The vertical grey band represents the Standard Model prediction and its own uncertainty. The ATLAS and CMS measurements, shown at the bottom, agree with each other and with the Standard Model, while both disagree with the CDF measurement. Note that the uncertainty in the CMS measurement is about the same as in the CDF measurement.

Since the ATLAS and CMS results are both consistent with all other previous measurements as well as with the Standard Model, and since CMS has even reached the same level of uncertainty obtained by CDF, this makes CDF by far the outlier, as you can see above. The tentative but reasonable conclusion is that the CDF measurement is not correct.

Of course, the CDF experimentalists may argue that it is ATLAS and CMS that have made an error, not CDF. One shouldn’t instantly dismiss that out of hand. It’s worth remembering that ATLAS and CMS use the same accelerator to gather their data, and might have used similar logic in the design of their analysis, so it’s not completely impossible for them to have made correlated mistakes. Still, this is far from plausible, so the onus will be on CDF to directly pinpoint an error in their competitors’ work.

Even if the mistake is CDF’s, it’s worth noting that we still have no idea what exactly it might have been. A long chain of measurements and calibrations are required to determine the W boson mass at this level of precision (about one part in ten thousand). It would be great if the error within this chain could be tracked down, but no one may have the stamina to do that, and it is possible that we will never know what went wrong.

But the bottom line is that the discrepancy suggested by the CDF measurement was always a long shot. I don’t think many particle physicists are surprised to see its plausibility fading away.

African giant pouched rats proved adept at detecting four commonly trafficked products derived from endangered species including rhino horn and elephant ivory