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Just yesterday I wrote about the drive in New Zealand to integrate indigenous medicine (Rongoā Māori, or RM) with modern (often called “Western”) medicine.  The problem is that RM not only uses  spiritual treatments (prayer, singing, dunking the sufferer in water) but also herbal remedies, and neither of these have been tested for efficacy using randomized, controlled, double-blind testing. This is the gold standard used in modern medicine to test the efficacy of drugs and (sometimes) surgery. Without such tests, we simply can’t say that a medical intervention actually works.

But the drive to sacralize indigenous “ways of knowing” is strong, and has spread from New Zealand across the Pacific, where it is growing in both Canada and the United States.  Although it’s one thing—and still a bad thing—to prevent scientists from examining bones and artifacts found on land claimed to be “owned” by indigenous people, it’s a different thing entirely to start treating people with indigenous medicine. Although everyone can decide whether or not they want to be treated with scientifically tried-and-true procedures versus quackery like homeopathy, or even seek religious “cures,” children can’t make such decisions. They are subject to the whims and faiths of their parents, and in Faith Versus Fact I document some horrible deaths of children  propagandized into religious healing by their parents.  (Jehovah’s Witnesses, for instance, are forbidden to receive blood transfusions because of a wonky interpretation of the Bible.) At least when you take your kids for their vaccinations, you can be almost certain that they’ll acquire immunity to infection.

As I said, this kind of harmful sacralization of medical “ways of knowing” is on our doorstep, and below is an op-ed from the WSJ (by the editorial board) reporting that the Biden Administration has approved funding for “traditional health care practices of Indigenous people.”  And it doesn’t seem to matter exactly what those healthcare practices are! It can be herbs, prayer, touch, chanting, and so on. The government will pay for it!

Click below to read the short piece, which I’ve reproduced almost in its entirety, or find it archived here.

The “housing” bit is tangential, reporting that “the Administration is letting states use federal Medicaid dollars to pay for low-income housing, mini-refrigerators and food. A Biden executive order last month gave states a green light to use Medicaid to pay for ‘gun violence prevention’ counseling.”  I don’t have such strong feelings about that, though it does seem a tad outisde the ambit of what Medicaid is for.

But main part of the article, given below, is about government funding for what seems like quackery.  And if you want to argue that this op-ed is “fake news” because it comes from the op-ed section of the paper (yes, that section leans right), you can find the same information in an NPR article from October 19 of this year.

A long excerpt (bolding is mine):

The Biden Administration is trying to woo Native Americans whose votes could be pivotal in Western states. One pre-election gambit is to let Medicaid pay for Native American “traditional medicine.”

The Health and Human Services Department last month approved requests by Arizona, California, New Mexico and Oregon to use federal Medicaid funds to cover “traditional health care practices” of indigenous people. “We are extending access to culturally appropriate, quality health care in Tribal communities,” said HHS Secretary Xavier Becerra.

HHS says the Medicaid approvals are “the latest action demonstrating the Biden-Harris Administration’s commitment to support and invest in Indigenous communities across the country.” In short, this looks like another income redistribution scheme.

HHS doesn’t plan to restrict the types of traditional medicine that Medicaid will cover, nor the types of “healers.” Each tribal “facility can tailor provider qualifications for their traditional health care practitioners,” HHS says.

An American Medical Association brief on the state Medicaid proposals says “traditional healers are often identified in their Tribal community by their innate gift of healing” and “typically work informally.” Their “healing services” could include sweat lodges, prayers, purification rituals, songs, dance, herbal remedies and shamanism.

One healer who advocated for Medicaid coverage told the Salt Lake Tribune in February that he sometimes prescribes a “special ceremony against the negative energy of diabetes.” Herbs, he said, are also a favorite remedy for chronic illnesses including cancer plus a “special expression of prayer to the deities that made those herbs.”

Herbal remedies may have their uses, but Medicaid is supposed to cover evidence-based treatments. HHS says “demonstration projects” can determine if traditional medicine improves health outcomes. But lack of access to modern medical care—not lack of traditional remedies—is why Native Americans suffer more disease and worse health outcomes.

The last paragraph is correct in both assertions: Medicaid isn’t supposed to pay for quackery (seriously: “sweat lodges, songs, dance and shamanism”?) and Native Americans do lack sufficient access to modern health care.  The first bit is documented here:

Alternative treatments that haven’t been proven in scientific studies usually aren’t covered by Medicaid. Some procedures, such as chiropractic treatments and acupuncture, are sometimes covered. These treatments are more likely to be covered if they are recommended or prescribed by a doctor. Other alternative treatments that are occasionally covered include massage, pain treatments, and nutrition therapy. Some treatments, such as herbal and homeopathic therapies, are usually not approved for Medicaid payment.

Well, I’m not so sure that many chiropractic therapies, or any form of acupuncture, has been “proven in scientific studies”. But your tax dollars are paying for it! Now get ready for your tax dollars to pay for sweat lodges, songs, dances, and ceremonies. And you don’t even have to live in Arizona, California, New Mexico and Oregon to be dunned for quackery. The fund for Medicaid comes from all of us.

 

h/t: Frau Katze

Experts predict that the number of cancer cases around the world will skyrocket, resulting in millions more fatalities by 2050

Our ancestors probably used a wide range of plant-based tools that have since been lost to history. Now we're finally getting a glimpse of this Botanic Age

One thing we’ve learned in recent decades is that exoplanets are surprisingly common. So far, we’ve confirmed nearly 6,000 planets, and we have evidence for thousands more. Most of these planets were discovered using the transit method. though we there are other methods as well. Many stars are known to have multiple planets, such as the TRAPPIST-1 system with seven Earth-sized worlds. But even within known planetary systems there could be planets we’ve overlooked. Perhaps their orbit doesn’t pass in front of the star from our vantage point, or the evidence of their presence is buried in data noise. How might we find them? A recent paper on the arXiv has an interesting approach.

Rather than combing through the observational data trying to extract more planets from the noise, the authors suggest that we look at the orbital dynamics of known systems to see if planets might be possible between the planets we know. Established systems are millions or billions of years old, so their planetary orbits must be stable on those timescales. If the planets of a system are “closely packed,” then adding new planets to the mix would cause the system to go all akilter. If the system is “loosely packed,” then we could add hypothetical planets between the others, and the system would still be dynamically stable.

The seven planetary systems considered. Credit: Horner, et al

To show how this would work, the authors consider seven planetary systems discovered by the Transiting Exoplanet Survey Satellite (TESS) known to have two planets. Since it isn’t likely that a system has only two planets, there is a good chance they have others. The team then ran thousands of simulations of these systems with hypothetical planets, calculating if they could remain stable over millions of years. They found that for two of the systems, extra planets (other than planets much more distant than the known ones) could be ruled out on dynamical grounds. Extra planets would almost certainly destabilize the systems. But five of the systems could remain stable with more planets. That doesn’t mean those systems have more planets, only that they could.

One of the things this work shows is that most of the currently known exoplanetary systems likely have yet-undiscovered worlds. This approach could also help us sort systems to determine which ones might deserve a further look. We are still in the early stages of discovery, and we are gathering data with incredible speed. We need tools like this so we aren’t overwhelmed by piles of new data.

Reference: Horner, Jonathan, et al. “The Search for the Inbetweeners: How packed are TESS planetary systems?” arXiv preprint arXiv:2411.00245 (2024).

The post How Many Additional Exoplanets are in Known Systems? appeared first on Universe Today.

The British Heart Foundation’s Reflections of Research competition showcases beautiful images captured by researchers studying heart and circulatory disease

Reader Thomas Webber is a new contributor, but his photos of flowers are lovely. Tom’s captions and IDs are indented, and you can enlarge the photos by clicking on them.  The images have been stacked, but I removed that information from the captions.  On to Tom:

The University of Florida owns and manages a large pine forest near Gainesville for teaching and research. Much of it is a commercial-type pine plantation, with smallish trees all the same age growing in close-packed straight rows.

Another part is managed to restore something like the native pre-settlement forest; in this section the trees are relatively old and widely spaced, and the canopy is fairly open, allowing plenty of light to reach the understory. This forest type has evolved under the influence of fire, and the wildfires have now been replaced by managed burns. The understory is host to an impressive variety of shrubs, grasses, and forbs, many of which are adept at exploiting burned- or other periodically disturbed patches of the landscape. Here is a just a small sample of the wildflowers I’ve encountered there in late summer and early fall this year.

I think I’ve identified all of them correctly to genus, and most to species, but I have put the qualifier “cf.” before some of the species epithets I’m not so sure of. I invite corrections.

Prairie clover, Dalea cf. pinnata. 1 cm.:

Spurred butterfly pea, Centrosema virginianum. 3.5 cm across the long side:

Hempvine, Mikania cf. scandens. 2.5 cm. This one has not fully opened:

Blackroot, Pterocaulon pycnostachyum. 7 cm long. I was surprised to find these at this time of year; they are usually spring flowers, but a few emerged in one plot after the mid-summer burn:

Silkgrass, Pityopsis cf. graminifolia. 1.5 cm.:

Pineweed, Hypericum gentianoides. 3 mm. The flowers are tiny but the plants can be conspicuous; this year they covered a dirt road in one of the less-traveled parts of the forest:

Button eryngo, Eryngium yuccifolium. 1.5 cm.:

Azure sage, Salvia azurea. 1 cm across the lower lobe:

I especially like the next ones because they are uncommon, furtive, and take some finding.

Sensitive partridge pea, Chamaecrista nictitans. 7 mm across the lower lobe:

Ticktrefoil, Desmodium cf. paniculatum. 7 mm across the upper lobe:

Florida sensitive-briar, Mimosa quadrivalvis. 1 cm.:

Rustweed, Polypremum procumbens. 4 mm.:

Mouse melon, Melothria pendula. 3 mm.:

Axil-flower, Mecardonia acuminata. 5 mm.:

One day, doctors might be able to 3D print copies of your organs in order to test a variety of drugs, thanks to a new technique that uses light and sound for rapid printing

At CSICON this year I gave talk about topics over which skeptics have and continue to disagree with each other. My core theme was that these are the topics we absolutely should be discussing with each other, especially at skeptical conferences. Nothing should be taboo or too controversial. We are an intellectual community dedicated to science and reason, and have spent decades talking about how to find common ground and resolve differences, when it comes to empirical claims about reality. But the fact is we sometimes disagree, and this is a great learning opportunity. It’s also humbling, reminding ourselves that the journey toward critical thinking and reason never ends. On several topics self-identified skeptics disagree largely along political grounds, which is a pretty sure sign we are not immune to ideology and partisanship.

I spent most of the talk, however, discussing the issue of biological sex in humans, which I perceive as the currently most controversial topic within skepticism. My goal was to explore where it is we actually disagree. Generally speaking skeptics don’t disagree about the facts or about the proper role of science in determining what is likely to be true. We tend to disagree for more subtle reasons, although often the reason does come down to a lack of specific topic expertise on questions that are highly technical. The most important thing is that we actually engage with each-other’s arguments and positions, to make sure we truly understand what those who disagree with us are saying so that we can properly explore premises and logic.

Jerry Coyne, author of the book and blog Why Evolution is True, was also at CSICON and gave a talk essentially taking the opposing position to my own. His position is that biological sex in humans is binary, that this is the only scientific position, and anything else is simply ideology trumping science. His talk was after mine so I was very interested in how he would respond to my position. He essentially didn’t – he just gave the talk he was going to give and then included a single slide with his “responses” to my talk. Except, they weren’t responses at all, just a list of standard talking points that really had nothing to do with my talk.

Now he has written a blog post discussing my talk. Here is his opening paragraph:

“I’ve been busy at the CSICon conference, which included giving my own 30-minute presentation this morning. I had to modify it to take into account the misguided views of Steve Novella, who gave a talk yesterday about “When Skeptics Disagree.” It turned out to be largely a diatribe about how sex in humans is not binary, and in fact isn’t even to be defined by morphology or physiology. As far as I can see, Novella’s view of sex is that one is born with a “brain module” (which of course is biological) that determines which sex you are. No, not gender, but actual biological sex. You can have a “female” module or a “male module”, and regardless of gametes, hormones, genitalia, and so on, you are whatever sex your module dictates to your self-identification.”

It’s difficult to convey how disappointing this response is, from someone I previously admired for his science communication about evolution and creationism. His summary of my position is completely and utterly wrong. Calling it a strawman does not do justice to how off it is. He sat through my talk (as I sat through his), and yet I have to wonder if he actually listened to it. We do agree on one thing – CSI will be making the recorded talks available and people can watch and decide for themselves – please do.

Here is my actual position, as articulated (quite clearly, if the overwhelming feedback I got was any indication) in the talk. Biological sex in humans is multifactorial and complicated, pretty much like all of biology. While there are two pathways of sexual development (we are a sexually dimorphic species), humanity is not “strictly” binary because not everyone fits cleanly or unambiguously into one of two sexes. Pretty much every aspect of biological sex has variations, or “differences in sexual development”, or ambiguous features in some individuals. These are the facts, and you cannot meaningfully disagree about this. So how do skeptics disagree? Largely due to semantics (or I guess making the other side into a one-dimensional strawman).

As an example I used archaeopteryx – a “transitional” species with morphological features that are pretty much half modern bird and half theropod dinosaur (the non-avian branch, if you are using cladistics, which of course is just another tradition of categorization). Creationist Duane Gish famously said that archaeopteryx is simply a bird. It had feathers and it flew, so it was a bird. When confronted about the fact that it also had teeth he say – well, some birds had teeth. He also, interestingly, said that you could look at archaeopteryx as a dinosaur with feathers. He was apparently blissfully unaware of the fact that he was just arbitrarily choosing a subset of morphological features as the “defining characteristics”. You could say feathers and flying equals bird, or teeth, claws, bony tail (and other features) equals dinosaur. Or – you could look at all the features and say it was transitional between these two groups. But that, of course, is exactly what he was trying to avoid and deny.

My larger point was that, in the end our labels are ultimately meaningless. They do not determine reality. Archaeopteryx is what it is regardless of what box we put it in. Saying that some birds have teeth or some dinosaurs have feathers are both equally correct, equally misleading, and equally just non sequiturs.

I then gave as an example of biological sex in humans those with CAIS (complete androgen insensitivity syndrome). These are people who are XY, produce male levels of testosterone, have undescended testes, produce sperm, and do not develop a uterus, but they do not respond to testosterone so they develop otherwise along the female body plan. They have vaginas, a complete (and often even more so than average) suite of female secondary sexual characteristics, and typical female neurological development. So they have male genetics, hormones, and gametes, but female genitalia, body and brain. So – are they male or female? Do some men have vaginas, or do some women have XY chromosomes?  You see the parallel?

There is no necessarily right or wrong answer. Categorization is ultimately arbitrary and context dependent. You  have to ask – why are we dividing humanity up into two categories of biological sex in the first place? Is this just an exercise in abstract biological science, is this for social reasons, medical purposes, designing public bathrooms, or making rules for competitive sports? The answer may differ depending on the context. Also, CAIS is just one example. There are differences in every feature of biological sex, and often those features are ambiguous (there are conditions that are literally referred to as ambiguous genitalia, for example).

To me it is an unavoidable and simple fact that biological sex in humans is not strictly binary. I always use the modifier “strictly” to be as clear as possible. Even critics of this position admit humans are only “mostly” binary when it comes to sex. But they say – “mostly” binary equals binary. But this is nonsensical – it is a purely semantic argument.

What they are saying (pretty directly) is that biological sex in humans is binary, and anyone who does not fit into this binary simply doesn’t count. They also say that some features of sexual dimorphism in humans don’t count. Coyne’s position is that we should categorize biological sex by gametes and gametes only. Why? He only said during his talk that this is how it is done, so an appeal to tradition, I guess. He seems to be engaged in a bit of circular logic – biological sex is binary because of gametes, and we use gametes to define biological sex because they are essentially binary (with rare exceptions). I have also seen him make the justification (which I find ironic coming from an evolutionary biologist) that biological sex is about reproduction, and reproduction is all about gametes. But biological features, even if they evolved mainly for a specific purpose, often take on other purposes and aspects. I would argue that people are more than their gametes. Again – context matters. Should we have sperm and egg leagues in competitive sports? Should we just have pictures of sperms and eggs on signs outside public bathrooms?

Coyne argued that the percentage of people with differences of sexual development is too small to count. He used the very low end of estimates (without disclosing or discussing this fact), but even with this estimate we are talking about millions of people. And also where you draw the line is yet another arbitrary choice of categorization.

He also explicitly argues that the brain does not count. He ridicules this notion in his response, again creating a shallow strawman, and uses quotation marks inappropriately. I never said, for example, “male module” and yet his use of quotes made it seem as if I did. He states that it is my position that only the brain counts – which is pretty close to the exact opposite of my position, which is that everything counts. All sexual dimorphism, from genes to neurological development, are part of biological sex. It is a complex, dynamic, and multifactorial system, with lots of variation. There is no one “correct” way to categorize male and female. Sure, you can make rules that are true for most people. There are typical schemes of development. But whatever system you come up with, there will be people who do not fit. And yet all people count, and not just because they are actual people. Even in the abstract – all data counts.

My final point was that I don’t think we would even be having this discussion were it not for the political controversy around the trans issue. The point, in my opinion, of saying that only gametes count is to argue that the brain specifically does not count. But the brain is a biological organ, and brain development is absolutely influenced by sex genes and hormones. The brain is a sexual organ, and part of sexual dimorphism. Why wouldn’t it count as part of biological sex? I specifically said that at this time we have not identified the specific neuroanatomic correlates of gender identity (which are likely to be complex). But the early research so far is pointing in the direction that gender identity is both real and a neurological trait. It has the features of other neurological traits – like core personality features, and sexual orientation. Most people who identify as trans knew their gender identity from a very young age, and their identity is remarkably persistent over their lives. They are likely not a homogenous group, which is to be expected for a complex phenomenon like gender identity. But again, most show clear signs of gender identity being a persistent neurological trait (something Coyne dismisses as mere “feelings”).

The best analogy here is sexual orientation, which also behaves like a stable neurological trait. People cannot be “turned” gay, nor converted from being gay. Sexual orientation is basically a brain phenomenon, influenced by biological sex, including genetics and the hormonal environment of the womb. And yet, all the same arguments against the claim that gender identity is real and neurological were used against sexual orientation being a neurological trait, including the lack of a “gay gene” (analogous so saying their is no “gender module” in the brain).

This is the basic science, and we should be able to find common ground here. We can have meaningful discussions about what all this means for sports, bathrooms, and medical care for those identifying as trans. That is the social, medical, and political debate we should be having, because this is a complex topic. The claim that biological sex is simply binary, and any other thought is (as Coyne writes) “full-out progressive woke” is just not true. It strikes me as a rhetorical strategy to win the debate by semantic fiat. Biological sex is binary (because gametes) therefore all other discussions about sports and medical care is merely an exercise is delusion.

The position is one giant non-sequitur. What do we do in this specific context with people who do not unambiguously fit into a biological sex binary? Well, the answers seems to be, they don’t count because biological sex is binary because gametes. And they are a small percentage of humanity. But they exist and we still need to decide how best to accommodate them. Insisting sex is strictly binary is not only wrong, it doesn’t even address the issue.

Coyne makes some other claims (as if they are a rebuttal to my position) that are not based in reality (but are suspiciously similar to right-wing talking points and propaganda). He says, for example,

“And what about those people—yes, they exist—who think they really are in the wrong body, and should be a member of another species, like a horse or a cat? Does that actually make them a cat or horse? Of course not.”

First, reports of this phenomenon (called therians) is greatly exaggerated. They are often conflated with other groups (like furries). This is pretty clearly a social and psychological phenomenon, not a neurological trait, and having nothing to do with a system of neurological development (influenced by hormones, for example). He is making some sort of slippery slope argument, which does not hold up to examination. Some people have a strong psychological identity with an animal archetype, just like some people think they are aliens, or that they were reincarnated. This has literally nothing to do with gender identity and is not the same kind of phenomenon.

He also writes:

“One more example. There are people who are nonbinary, but are that way on a temporal basis: they change from feeling male to feeling female on a daily or even hourly basis.”

There are some people who are “gender fluid”. So what? What does that say about people who are not fluid, but remarkably stable in their gender identity (ie, most people)? Nothing. It’s irrelevant. It’s similar to arguing that we cannot treat people with MS because a subset of people with MS have a type that does not respond to treatment.

I think this statement by Coyne highlights his misunderstanding:

“Does a full biological man, with the right genitalia, hormones and chromosomes, but who feels that he’s a woman, actually become a woman (or vice versa for women)? Of course not, unless you think that words mean whatever you want them to. This is why I believe that people can claim to be of any gender, but they can’t actually change their biological sex.”

This is a non sequitur, and has nothing to do with my actual position. It shows that he completely does not get it. Notice that he thinks there is a “right” genitalia. This is a strangely essentialist formulation for an evolutionary biologist. Notice also that he dismisses how someone “feels” as if this is not, in some cases, a function of developmental neurology. But the core fallacy here is the straw man that gender identity changes biological reality. Rather, it is just part of biological reality. The entire point of the “trans” identity is that gender identity (which behaves in most people like a neurological trait) does not align with aspects of sexual morphology. They are not delusional about their genitalia – otherwise they would not identify as trans. Every aspect of biological sex may line up or not line up in some people. That is just reality. Coyne’s entire framing, however, is as a conflict between subjective feelings (which are not real) and anatomy (which is real). And in people where the more tangible anatomy does not line up (like in CAIS)? Well, they don’t count. Only gametes count.

I don’t expect we will agree on the broader issues here. But at the very least we should be able to agree on the basic science. This means getting past pointless semantic arguments and confidently mischaracterizing the “other side”. If I have misstated his position in any way I will happily make corrections, but I tried to fairly and with the principle of charity reflect what he has written. You can read it for yourself and see. My summary here is pretty much exactly what I said during my CISCON talk and have written elsewhere.

 

The post A Discussion about Biological Sex first appeared on NeuroLogica Blog.

Fibres in wet wipes and clothes often make their way into soil - and natural versions could be more damaging than synthetic ones

A mysterious man is said to have arrived in Japan in 1959 from a country that never existed.

Many people think of the James Webb Space Telescope as a sort of Hubble 2. They understand that the Hubble Space Telescope (HST) has served us well but is now old, and overdue for replacement. NASA seems to agree, as they have not sent a maintenance mission in over fifteen years, and are already preparing to wind down operations. But a recent paper argues that this is a mistake. Despite its age, HST still performs extremely well and continues to produce an avalanche of valuable scientific results. And given that JWST was never designed as a replacement for HST — it is an infrared (IR) telescope) — we would best be served by operating both telescopes in tandem, to maximize coverage of all observations.

Let’s not fool ourselves: the Hubble Space Telescope (HST) is old, and is eventually going to fall back to Earth. Although it was designed to be repairable and upgradable, there have been no servicing missions since 2009. Those missions relied on the Space Shuttle, which could capture the telescope and provide a working base for astronauts. Servicing missions could last weeks, and only the Space Shuttle could transport the six astronauts to the telescope and house them for the duration of the mission.

Without those servicing missions, failing components can no longer be replaced, and the overall health of HST will keep declining. If nothing is done, HST will eventually stop working altogether. To avoid it becoming just another piece of space junk, plans are already being developed to de-orbit it and send it crashing into the Pacific Ocean. But that’s no reason to give up on it. It still has as clear a view of the cosmos as ever, and mission scientists are doing an excellent job of working around technical problems as they arise.

The James Webb Space Telescope was launched into space on Christmas dat in 2021. Its system of foldable hexagonal mirrors give it an effective diameter some 2.7 times larger than HST, and it is designed to see down into the mid-IR range. Within months of deployment, it had already seen things that clashed with existing models of how the Universe formed, creating a mini-crisis in some fields and leading unscrupulous news editors to write headlines questioning whether the “Big Bang Theory” was under threat!

This image of NASA’s Hubble Space Telescope was taken on May 19, 2009 after deployment during Servicing Mission 4. NASA

The reason JWST was able to capture such ancient galaxies is that it is primarily an IR telescope: As the Universe expands, photons from distant objects get red-shifted until stars that originally shone in visible light can now only be seen in the IR. But these IR views are proving extremely valuable in other scientific fields apart from cosmology. In fact, many of the most striking images released by JWST’s press team are IR images of familiar objects, revealing hidden complexities that had not been seen before.

This is a key difference between the two telescopes: While HST’s range overlaps slightly with JWST, it can see all the way up into ultraviolet (UV) wavelengths. HST was launched in 1990, seven years late and billions of dollars over budget. Its 2.4 meter primary element needed to be one of the most precisely ground mirrors ever made, because it was intended to be diffraction limited at UV wavelengths. Famously, avoidable problems in the testing process led to it being very precisely figured to a slightly wrong shape, leading to spherical aberration preventing it from coming to sharp focus.

Fortunately the telescope was designed from the start to be serviceable, and even returned to Earth for repairs by the Space Shuttle if necessary. In the end though, NASA opticians were able to design and build a set of corrective optics to solve the problem, and the COSTAR system was installed by astronauts on the first servicing mission. Over the years, NASA sent up three more servicing missions, to upgrade or repair components, and install new instruments.

Illustration of NASA’s James Webb Space Telescope. Credits: NASA

HST could be one of the most successful scientific instruments ever built. Since 1990, it has been the subject of approximately 1200 science press releases, each of which was read more than 400 million times. The more than 46,000 scientific papers written using HST data have been cited more than 900,000 times! And even in its current degraded state, it still provided data for 1435 papers in 2023 alone.

JWST also ran over time and over budget, but had a far more successful deployment. Despite having a much larger mirror, with more than six times the collecting area of HST, the entire observatory only weighs half as much as HST. Because of its greater sensitivity, and the fact that it can see ancient light redshifted into IR wavelengths, it can see far deeper into the Universe than HST. It is these observations, of galaxies formed when the Universe was extremely young (100 – 180 million years), that created such excitement shortly after it was deployed.

As valuable as these telescopes are, they will not last forever. JWST is located deep in space, some 1.5 million kilometers from Earth near the L2 Lagrange point. When it eventually fails, it will become just another piece of Solar System debris orbiting the Sun in the vast emptiness of the Solar System. HST, however, is in Low Earth Orbit (LEO), and suffers very slight amounts of drag from the faint outer reaches of the atmosphere. Over time it will gradually lose speed, drifting downwards until it enters the atmosphere proper and crashes to Earth. Because of its size, it will not burn up completely, and large chunks will smash into the surface.

Because it cannot be predicted where exactly it will re-enter, mission planners always intended to capture it with the Space Shuttle and return it to Earth before this happened. Its final resting place was supposed to be in display in a museum, but unfortunately the shuttle program was cancelled. The current plan is to send up an uncrewed rocket which will dock with the telescope (a special attachment was installed on the final servicing mission for this purpose), and deorbit it in a controlled way to ensure that its pieces land safely in the ocean.

You can find the original paper at https://arxiv.org/abs/2410.01187

The post Hubble and Webb are the Dream Team. Don't Break Them Up appeared first on Universe Today.

On November 26th, 2018, NASA’s Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) mission landed on Mars. This was a major milestone in Mars exploration since it was the first time a research station had been deployed to the surface to probe the planet’s interior. One of the most important instruments InSight would use to do this was the Heat Flow and Physical Properties Package (HP3) developed by the German Aerospace Center (DLR). Also known as the Martian Mole, this instrument measured the heat flow from deep inside the planet for four years.

The HP3 was designed to dig up to five meters (~16.5 ft) into the surface to sense heat deeper in Mars’ interior. Unfortunately, the Mole struggled to burrow itself and eventually got just beneath the surface, which was a surprise to scientists. Nevertheless, the Mole gathered considerable data on the daily and seasonal fluctuations below the surface. Analysis of this data by a team from the German Aerospace Center (DLR) has yielded new insight into why Martian soil is so “crusty.” According to their findings, temperatures in the top 40 cm (~16 inches) of the Martian surface lead to the formation of salt films that harden the soil.

The analysis was conducted by a team from the Microgravity User Support Center (MUSC) of the DLR Space Operations and Astronaut Training Institution in Cologne, which is responsible for overseeing the HP3 experiment. The heat data it obtained from the interior could be integral to understanding Mars’s geological evolution and addressing theories about its core region. At present, scientists suspect that geological activity on Mars largely ceased by the late Hesperian period (ca. 3 billion years ago), though there is evidence that lava still flows there today.

The “Mars Mole,” Heat Flow and Physical Properties Package (HP³). Credit: DLR

This was likely caused by Mars’ interior cooling faster due to its lower mass and lower pressure. Scientists theorize that this caused Mars’ outer core to solidify while its inner core became liquid—though this remains an open question. By comparing the subsurface temperatures obtained by InSight to surface temperatures, the DLR team could measure the rate of heat transport in the crust (thermal diffusivity) and thermal conductivity. From this, the density of the Martian soil could be estimated for the first time.

The team determined that the density of the uppermost 30 cm (~12 inches) of soil is comparable to basaltic sand – something that was not anticipated based on orbiter data. This material is common on Earth and is created by weathering volcanic rock rich in iron and magnesium. Beneath this layer, the soil density is comparable to consolidated sand and coarser basalt fragments. Tilman Spohn, the principal investigator of the HP3 experiment at the DLR Institute of Planetary Research, explained in a DLR press release:

“To get an idea of the mechanical properties of the soil, I like to compare it to floral foam, widely used in floristry for flower arrangements. It is a lightweight, highly porous material in which holes are created when plant stems are pressed into it... Over the course of seven Martian days, we measured thermal conductivity and temperature fluctuations at short intervals.

“Additionally, we continuously measured the highest and lowest daily temperatures over the second Martian year. The average temperature over the depth of the 40-centimetre-long thermal probe was minus 56 degrees Celsius (217.5 Kelvin). These records, documenting the temperature curve over daily cycles and seasonal variations, were the first of their kind on Mars.”

NASA’s In­Sight space­craft land­ed in the Ely­si­um Plani­tia re­gion on Mars on 26 Novem­ber 2018. Credit: Credit: NASA-JPL/USGS/MOLA/DLR

Because the encrusted Martian soil (aka. “duricrust”) extends to a depth of 20 cm (~8 inches), the Mole managed to penetrate just a little more than 40 cm (~16 inches) – well short of its 5 m (~16.5 ft) objective. Nevertheless, the data obtained at this depth has provided valuable insight into heat transport on Mars. Accordingly, the team found that ground temperatures fluctuated by only 5 to 7 °C (9 to 12.5 °F) during a Martian day, a tiny fraction of the fluctuations observed on the surface—110 to 130 °C (230 to 266 °F).

Seasonally, they noted temperature fluctuation of 13 °C (~23.5 °F) while remaining below the freezing point of water on Mars in the layers near the surface. This demonstrates that the Martian soil is an excellent insulator, significantly reducing the large temperature differences at shallow depths. This influences various physical properties in Martian soil, including elasticity, thermal conductivity, heat capacity, the movement of material within, and the speed at which seismic waves can pass through them.

“Temperature also has a strong influence on chemical reactions occurring in the soil, on the exchange with gas molecules in the atmosphere, and therefore also on potential biological processes regarding possible microbial life on Mars,” said Spohn. “These insights into the properties and strength of the Martian soil are also of particular interest for future human exploration of Mars.”

What was particularly interesting, though, is how the temperature fluctuations enable the formation of salty brines for ten hours a day (when there is sufficient moisture in the atmosphere) in winter and spring. Therefore, the solidification of this brine is the most likely explanation for the duricrust layer beneath the surface. This information could prove very useful as future missions explore Mars and attempt to probe beneath the surface to learn more about the Red Planet’s history.

Further Reading: DLR

The post Scientists Have Figured out why Martian Soil is so Crusty appeared first on Universe Today.

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