News Feeds

Mining craters on the moon could be more practical than extracting precious metals from asteroids, but it might also introduce new legal difficulties

Surprising new fossil evidence undermines the idea that there was ever a mass extinction on land – and may force us to reframe the current biodiversity crisis

When dogs given spot treatments for fleas go swimming, they release levels of pesticides dangerous to aquatic life for at least a month after the treatment

Researchers have proposed a more accurate way to calculate the global surface air temperature, which suggests we are just three years away from breaching the 1.5°C climate goal

I was in Chicago this weekend attending the ASCO meeting, the largest oncology meeting in the world. Nary a talk or poster about "turbo cancer" was seen, but that doesn't mean there wasn't cancer quack fight online to distract me from the meeting.

The post No turbo cancer at ASCO: William Makis vs. Scott Adams and A Midwestern Doctor instead? first appeared on Science-Based Medicine.

As I say repeatedly, I find it very difficult to listen to long videos (and long podcasts without visuals are even worse). But I happened to click on the one below, part of the biweekly Glenn Show dialogue between Glenn Loury and John McWhorter, and found it quite worthwhile, even though it’s a bit more than an hour long (Loury gives an advertisement between 11:12 and 13:14). It’s interesting because of the topics: wokeness, race, and their intersection, and McWhorter (with whom I’m on a panel in three weeks) is particularly interesting.

The first thing we learn is that Loury has left (actually been fired from) the rightish-wing Manhattan Institute. He explains why in his website post “I was fired by the Manhattan Institute. Here’s why.”:

 In short, I think they disapproved of my opposition to the Gaza War, my criticisms of Israel’s prosecution of that war, and my praise of Ta-Nehisi Coates’s meditations on the West Bank settlements.

Well, I knew that Loury was a stringent critic of Israel, but praising Ta-Nehisi Coates’s “meditations” on the West Bank, meditations that followed just 10 days visit in the Middle East and did not even mention Palestinian terrorism, isn’t something to praise.  At any rate, since Loury retired from Brown, he’s contemplating his next move, and hints that the University of Austin (UATX) has been courting him.

That leads to a brief discussion of whether schools like UATX are the wave of the future: schools that can teach humanities courses without them being polluted by extreme “social justice” mentality. Both men ponder whether universities like that are the wave of the future, and whether regular universities will devolve into “STEM academies”.  That, in turn, leads to a discussion, mostly by McWhorter, about music theory and how that, one of his areas of expertise, has been polluted by wokeness.

The biggest segment of the discussion involves McWhorter’s recent visit to Washington’s National Museum of African American History and Culture, and his thoughts about it (read his long NYT op-ed piece, which is very good, here). McWhorter characterizes it as not a dolorous place but a “happy place,” and one that gives a balanced view of black history—a view in which black people are more than simple oppressed people who serve to remind the rest of us of their guilt. It portrays as well, he avers, the dignity and positive accomplishment of African Americans. (McWhorter compares the dolorous view of black history with the narrative pushed by Nikole Hannah-Jones of the 1619 Project.)  His description makes me want to visit that museum more than ever (I haven’t yet been but will, and I must also visit the United States Holocaust Memorial Museum).

Finally, they discuss the question of whether they were wrong to be so hard on DEI, given that some aspects of it (e.g., a call for equality) are positive. Here McWhorter is at his most eloquent, saying that, given the overreach of DEI, it was imperative for both of them to have criticized it. As McWhorter notes, the extreme construal of DEI did not “fight for the dignity of black people” and, he says, in the face of that extremist ideology, their silence would not have been appropriate. Loury agrees.  At this point McWhorter brings up Claudine Gay, ex-President of Harvard, claiming that she was hired simply because she was a black woman, which was “wrong and objectifying.” (Only McWhorter could get away from saying something like that.) The elevation of Gay, says McWhorter, was the sort of thing they were pushing back against when they opposed DEI.

This is worth a listen, and I’ve put the video below.

It’s time for a Sunday Duck Report. Esther’s brood hatched on May 6, and so today they are 26 days old, coming on to four weeks. As we’ll see at the bottom, in the last week or so they’ve started growing their feathers.

Here are some videos and pictures of the brood, most taken around May 20 when they were two weeks old.

The brood (still six):

A swimming duckling. They are starting to look like big ducks, though they still have their baby down:

A diving duckling. It’s learning a skill that will help it not only forage, but also escape predators:

They get fed two or three times a day and are coming quite close to us. (I whistle for them, a call that they recognize as “feeding time,” but all I really have to do is show up at the pond with my bag ‘o duck food, and they coming swimming towards me rapidly.)

By the way, they get a good diet: Mazuri duck chow, which is a complete diet. Esther and big ducks get big pellets (I get this in 50 lb. bags), while the babies get the same thing, but in smaller pellets since their bills are too small to engulf the big ones (this “waterfowl starter chow” I get in 25-lb bags).  As a special treat, they get freeze-dried mealworms, which are high in fats and protein. This is their favorite food, but it’s a dessert, not the main course.

They love to enter the plastic tubs that used to be used as supports for the “plant cages”. I think of it as a duck spa:

Here are two ducklings, their swollen craws making it obvious that they just ate. They store some of the foot they eat in their esophagus.

About a week ago, the ducklings and Esther climbed up the southern “ramp” on the east side of the pond, where they’d sun themselve and then, going further into the brush, would all rest together. Here they are approaching the ramp that leads to their resting spot.  Esther always leads the way, but sometimes the brood is reluctant to land as they still want to swim and play:

More recently, since the babies have gotten large enough to jump directly out of the pond onto its edge, they like to do that together and sun themselves on the cement. Esther, of course, is always nearby.

Having a good rest:

Sometimes they pile up a few feet away from mom, but she’s always nearby. The piling up keeps them warm, as it’s been a bit chilly lately.

A video showing their postprandial resting on the edge of the pond:

A pile o’ ducklings:

Finally, in the last eight days or so the babies have been sprouting their feathers.  Feather appearance starts at the tail, in which a few tiny feathers make the tail look like a paintbrush:

. . . then the feathers start sprouting on their wings (arrow). Next stop: scruffy-looking “punk ducks” with a mixture of feathers and fluff.  Stay tuned for that!

How can humanity use the developing Lunar Gateway as an appropriate starting point for advancing human space exploration beyond the Moon? This is what a recent study presented at the 56th Lunar and Planetary Science Conference (LPSC) hopes to address as a team of researchers evaluated a myriad of ways that Lunar Gateway could be used as a testbed for future technologies involving sending humans to Mars and Ceres. This study has the potential to help scientists, engineers, astronauts, and mission planners develop novel strategies for advancing long-term human space exploration.

The search for life on other worlds needs a way to sift through the chemistry of their atmospheres. If another species observed Earth to search for life, they'd look for "smoking gun" chemistry in the atmosphere. That includes looking for oxygen, since it is created through photosynthesis by plants and some bacteria. So, the key is to look for life-dependent chemical "signals" at exoplanets.

Here’s the latest comedy/news stint from Bill Maher’s “Real Time” show, a “New Rule” segment called “Freak-end update”, referring of course to Diddy’s “Freak offs,” his drug-fueled sex orgies often involving prostitutes. Diddy is very likely to be convicted (you’ve seen the tape, right?), and it will be a huge come-down from his status as music king to living in a cell sans sex and drugs.

Maher’s new rule is this: “If you’ve being abused, you gotta leave right away.” He understands why abused women and loath to report it, and will even send affectionate messages to their abusers, but Maher adds that we must understand these dynamics and not let them soften our attitudes towards abuse. He then recounts how laws and attitudes are changing to punish abusers more seriously, and advises abused women to go to the police immediately rather than just telling a few friends or writing about it in a journal.

This is far more serious than most of Maher’s other bits, but he feels strongly about it.  Yet he still manages to eke out a few laughs.

Quickie with Steve: Global Warming and Ocean Currents; News Items: Infrared Contact Lenses, Trees Respond to Solar Eclipse, Affective Polarization, The Brain's Motor Switchboard, New Dwarf Planet Candidate; Discussion: The Effect of Science Fiction; Your Questions and E-mails: HHS Cancels Vaccine Contract; Science or Fiction

Today we have a historical/natural history post by reader Lou Jost, who works as a naturalist and evolutionary biologist at a field station in Ecuador.

A diatom sample from the HMS Challenger expedition of 1872-76

The Challenger in 1873, painting by Swine

The HMS Challenger was a British naval ship equipped with both sail and steam power. At the urging of scientists, and riding the wave of popular curiosity about our then-poorly-known planet, the ship was converted by the Royal Society of London to become the world’s first specialized oceanographic vessel. It went on a mission from 1872 to 1876 to systematically explore the world’s oceans, especially the scientifically almost completely unknown Southern Ocean near Antarctica. This mission was the 19th century equivalent of a trip to the moon or to Mars (except that this  HMS Challenger mission had a much more interesting and diverse subject region!).

One of the navigators, Herbert Swine, made contemporaneous drawings and paintings on site, including the two HMS Challenger images I have shared here (though these were probably polished somewhat for publication). He also published his lively diaries of his time on the expedition, in two volumes, just before he died of old age. He was the last survivor of the crew.

A map of the expedition

The voyage of exploration went 80,000 miles, lasted 1250 days, and circumnavigated the globe. They made systematic chemical, temperature, and depth readings across the globe, taking biological specimens along the way. They discovered over 4000 new species, from vertebrates to phytoplankton, and lost several lives along the way. They were the first to systematically explore the mid-Atlantic Ridge, and by pure chance they also discovered the Marianas Trench,  the deepest part of the Pacific Ocean. In 1950-1951 a modern vessel, again bearing the name Challenger in a homage to the original, found the deepest part of any ocean, the “Challenger Deep”, just 50 miles from the HMS Challenger’s deepest depth record.

The Challenger at work

The immense number of samples obtained by the crew of the Challenger took 19 years to analyze and publish, in 50 volumes. Specimens were sent to many scientists of the time, and some of these still circulate today. Among the most interesting organisms they sampled are diatoms. Diatoms are single-celled organisms that make up much of the oceans’ phytoplankton, and their most notable features are the finely sculpted glass cases called “frustules” that enclose them. These glass frustules are often preserved intact for tens of millions of years, sometimes forming enormous deposits of pure frustules known as “diatomaceous earth” on the beds of ancient lakes and oceans. Some of these deposits are so big that millions of tons of diatom frustules thousands of years old are whipped up by the wind in dry parts of Africa every year, and then cross the Atlantic by air and rain down on the Amazon basin in South America.

The expedition of the HMS Challenger launched the most systematic study of the 19th century on the diatoms of the Southern Ocean. They sampled at regular intervals during their voyage, and at multiple depths, including very deep water that had never before been studied, discovering new species of diatoms such as Asteromphalus challengerensis, named after the vessel (using bad Latin unfortunately). The samples were distributed to diatomists around the world, who carefully mounted them on microscope slides using special mountants of high-refractive-index liquid, designed to make the transparent diatom frustule more visible under standard microscopic illumination. Some of these Challenger diatom slides come up for sale periodically, and I could not resist buying one that appeared in eBay.

Increasing zooms of the diatoms on the slide:

This one slide, from 1873 during an Antarctic visit, has hundreds of individuals consisting of maybe a couple of dozen species. There are also many broken diatom fragments. Among the individuals, I was lucky enough to find several examples of what appear to be the aforementioned A. challengerensis. This is a rare species which is found only in water that is within 1 degree Centigrade of freezing. The taxonomy of this species and its relatives is in flux as we learn more about how the structures change with age.

Two slides of the species A. challengerensis:

Some of the taxonomic problems of these diatoms is caused by their weird way of replication. Diatoms can’t grow like a normal organism because they are in a glass case, so instead they shrink, each half of the frustule making a new matching half that is slightly smaller than the parent half-frustule, so that the two new halves each nest inside their parent half-frustule. Then they separate. Here is a nice illustration of this:

The population thus has a large spread of different sizes, and it appears that some frustule features may change as they get smaller, causing taxonomic confusions in the case of A. challengerensis and others.  By the way, eventually the smallest ones go through a sexual reproductive phase that builds a new full-sized frustule, so that the cycle can start over. This is really weird. Later I hope to write long post about the utterly astounding, almost unbelievable biology of diatoms.

Darwin published his theory of evolution just 13 years before this expedition, and evolution was on everyone’s mind, and the commander of the ship was an “early adopter” of the theory. At the time there was still not much clarity about the predictions of the theory. It was widely believed that the cold dark oceans would preserve “living fossils” similar to the earliest forms of life on earth. The expedition did not find this to be true, and so it actually was a slight setback for evolutionary theory. They unfortunately missed the hydrothermal vents which do indeed shed light on the origins of life.

I wrote at the beginning of this post that the HMS Challenger expedition was the 19th Century analogue of space exploration. So it was fitting that NASA decided to name one of the space shuttles “Challenger”, after the two scientific ships which carried that name. The photo above shows Challenger orbiting over the ocean 110 years after the original HMS Challenger sailed that same ocean. Unfortunately, as in the original Challenger expedition, people died on that space shuttle in the name of science, a reminder that exploration on the margins of what is known will always be risky, and the participants are real heroes of their age.

Solar storms have the potential to cause catastrophic damage. One that occurred around the end of October 2003 (now called the 2003 Halloween Storm) caused an estimated $27B in damages. That number will only increase as humanity has become more reliant on space-based and electrical infrastructure. However, if we could predict when storms would hit with some accuracy and adjust our use of the technologies that could be affected, we could avoid the worst damage. But, as of now, we don't have such a system that could help predict the types of events that could cause that damage accurately enough. That is where a new Sun activity monitoring system, described in a recent paper by Leonidas Askianakis of the Technical University of Munich, would help.

How can fission-powered propulsion help advance deep space exploration, specifically to the outer planets like Jupiter, Saturn, Uranus, and Neptune? This is what a recent study presented at the 56th Lunar and Planetary Science Conference (LPSC) hopes to address as a pair of researchers from India investigated the financial, logistical, and reliability of using fission power for future deep space missions. This study has the potential to help scientists, engineers, and future astronauts develop next-generation technologies as humanity continues to expand its presence in space.

Students recently unveiled their invention of a robotic actuator -- the 'muscle' that converts energy into a robot's physical movement -- that has the ability to detect punctures or pressure, heal the injury and repair its damage-detecting 'skin.'

Students recently unveiled their invention of a robotic actuator -- the 'muscle' that converts energy into a robot's physical movement -- that has the ability to detect punctures or pressure, heal the injury and repair its damage-detecting 'skin.'

Researchers proposed a novel strategy for using a magnetic field to boost the efficiency of single-atom catalysts -- thus speeding up helpful reactions used for ammonia production and wastewater treatment.

A series of studies sheds light on the origins and characteristics of intermediate-mass black holes.

A new method for predicting underwater landslides may improve the resilience of offshore facilities.

Today we have a guest post from reader Coel Hellier, who does this kind of stuff for a living. His text deals with the recent kerfuffle about whether a nearby planet shows an atmospheric gas indicative of life.  I particularly like the details about how scientists go about analyzing a question like this. His text is indented, and he’s added the illustrations.

Is the dimethyl sulphide in the atmosphere of exoplanet K2-18b real?

Everyone is interested in whether there is life on other planets. Thus the recent claim of a detection of a biomarker molecule in the atmosphere of an exoplanet has attracted both widespread attention and some skepticism from other scientists.

The claim is that planet K2-18b, 124 light years from Earth, shows evidence of dimethyl sulfide (DMS), a molecule that on Earth arises from biological activity. Below is an account of the claim; I try to include more science than the does mainstream media, but do so largely with pictures in the hope that the non-expert can follow the argument.

Transiting exoplanets such as K2-18b are discovered owing to the periodic dips they cause in the light of the host star:

And here is the lightcurve of K2-18b, as observed by the James Webb Space Telescope, showing the transit that led to the claim of DMS by Madhusudhan et al.:

If we know the size of the star (deduced from knowing the type of star from its spectrum), the fraction of light that is blocked then tells you the size of the planet.

But we also need to know its mass. One gets that from measuring how much the host star is tugged around by the planet’s gravity, and that is obtained from the Doppler shift of the star’s light.

The black wiggly line in the plot below is the periodic motion of the star caused by the orbiting planet. Quantifying this is made harder by lots of additional variation in the measurements (blue points with error bars), which is the result of magnetic activity on the star (“star spots”). But nevertheless, if one phases all the data on the planet’s orbital period (lower panel), then one can measure the planet’s mass (plot by Ryan Cloutier et al):

So now we have the mass and the size of the planet (and we also know its surface temperature since we know how far it is from its star, and thus how much heating it gets).  Combining that with some understanding of proto-planetary disks and planet formation. we can thus dervise models of the internal composition and structure of the planet.

The problem is that multiple different internal structures can add up to the same overall mass and radius. One has flexibility to invoke a heavy core (iron, nickel), a rocky mantle (silicates), perhaps a layer of ice (methane?), perhaps a liquid ocean (water?), and also an atmosphere.

This “degeneracy” is why Nikku Madhusudhan can argue that K2-18b is a “hycean” planet (hydrogen atmosphere over a liquid-water ocean) while others argue that it is instead a mini-Neptune, or that it has an ocean of molten magma.

But one can hope to get more information from the detection of molecules in the planet’s atmosphere, a task that is one of the main design goals of the James Webb Space Telescope [JWST]. The basic idea is straightforward: During transit, some of the starlight will shine through the thin smear of atmosphere surrounding the planet, and the different molecules absorb different wavelengths of light in a pattern characteristic of that molecule (figure by ESA):

So one observes the star both during the transit and out of transit, and then subtracts the two, and the result is a spectrum of the planet’s atmosphere.

If the planet is a large gas giant with a fluffy, extended atmosphere and is orbiting a bright star (so that a lot of photons pass through the atmosphere), the results can be readily convincing. For example, here is a spectrum of exoplanet WASP-39b with features from different molecules labelled (figure by Tonmoy Deka et al):

[I include a plot of WASP-39b partly because I was part of the discovery team for the Wide Angle Search for Planets survey, but also because it is pretty amazing that we can now obtain a spectrum like that of the atmosphere of an exoplanet that is 700 light-years away, even while the planet itself is so small and dim and distant that we cannot even see it.]

The problem with K2-18b is that the star is vastly fainter and the planet much smaller than WASP-39b. This is at the limit of what even the $10-billion JWST can do.

When you’re subtracting two very-similar spectra (the in- and out-of-transit spectra)  to look for a rather small signal, any “instrumental systematics” matter a lot. Here is the same spectrum of K2-18b, as processed by several different “data reduction pipelines”, and as you can see the differences between them (effectively, the limits of how well we understand the data processing) are similar in size to the signal (plot by Rafael Luque et al):

The next problem is that there are a lot of different molecules that one could potentially invoke (with the constraint of making the atmospheric chemistry self-consistent). For example, here are the expected spectral features from eight different possible molecules (figure by Madhusudhan):

To finally get to the point, I show is the crucial figure below. Nikku Madhusudhan and colleagues argue — based on an understanding of planet formation, and on arguments that planets like K2-18b are hycean worlds [with a liquid water ocean under a hydrogen-rich atmosphere], and from considerations of atmospheric chemistry, in addition to careful processing and modelling of the spectrum itself — that the JWST spectrum of K2-18b is best interpreted as follows (the blue line is the model, the red error bars are the data):

This interpretation involves large contributions from DMS (dimethyl sulphide) and also DMDS (dimethyl disulphide) — the plot below shows the different contributions separated — and if so that would be notable, since on Earth those compounds are products of biological activity—mainly from algae.

In contrast, Jake Taylor analysed the same spectrum and argues that he can fit it adequately with a straight line, and that the spectral features are not statistically significant. Others point out that the fitted model contains roughly as many free parameters as data points. Meanwhile, a team led by Rafael Luque reports that they can fit the spectrum without invoking DMS or DMDS, and suggest that observations of another 25 transits of K2-18b would be needed to properly settle the matter.

There are several distinct questions here: Are the details of the data processing sufficiently understood? (perhaps, but not certainly); are the relevant spectral features statistically significant? (that’s borderline);  and, if the features are indeed real, are they properly interpreted as DMS? (theorists can usually think of alternative possibilities). Perhaps a fourth question is whether there are abiotic mechanisms for producing DMS.

This is science at the cutting edge (and Madhusudhan has been among those emphasizing the lack of certainty, though the doubts have not always been in news stories), and so the only real answer to these questions is that things are currently unclear. This is a fast-moving area of astrophysics and we’ll know a lot more in a few years.