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Why Evolution is True Feed - Tue, 12/17/2024 - 6:15am

Send in your photos, folks!

Today we have some arthropod photos from regular Mark Sturtevant, whose IDs and captions are indented. You can enlarge the photos by clicking on them.

Hello again from Eastern Michigan. Here are various insects and spiders that I had photographed in my area from two summers ago. My last post left us at a very productive park near where I work, and this post starts with some things that I’d found during that same outing.

We start with a boldly marked Stink Bug called the Anchor Stink Bug (Stiretrus anchorago).

The field in this park always has numerous Chinese Mantids (Tenodera sinensis). This being early August, they had not yet reached adult-hood so here is a nymph. By early fall I can expect to see many huge adults in the field. It seems guaranteed. I suspect that some years ago, someone had set out many of their oothecae (egg pods), and this thriving population remains the result.

Overlooking the field was a hardwood forest, and I was quite pleased that many interesting kinds of critters were in it. Among these were weird planthoppers from the family Derbidae, which are one of the many good things found under tree leaves. These lack common names, so I gave them my own. First, here is what I call the Flat Derbid (Anotia uhleri) because when fully at rest they spread their wings out flat, making them resemble a small translucent moth. This one was slightly disturbed by my attentions so it had gone into a more alert posture. Although Derbids can jump and fly like other planthoppers, they are rather placid in nature so they are easy to photograph when handled with care. The prominent thingies on the head are its antennae:

The next one is what I call the Red Derbid (Apache degeeri). This is my favorite Derbid, and I found several of these that day. Its antennae are long and squiggly, making it look like it has some kind of weird face. There is a third species that I call the White Derbid. It is nearly the twin of the Red Derbid, but it’s mostly white. These are found under tree leaves that are farther to the south:

The woods were full of orb webs, and most of those belonged to an odd but quite common spider called the Spined Micrathena (Micrathena gracilis). These pea-sized spiders are pretty helpless when displaced outside of their web, but they are quite skillful when in their web and of course they swiftly build their large orb webs at night when they are basically blind:

Among these spiny weirdos I was amazed to find a striking color variant, as shown in the next picture. I had to take this one home for staged pictures! That is one spider that belongs on a heavy metal music album cover!:

The remaining pictures came from other area parks. As I am still feeling spidery after that last one, here is our largest spider, the Fishing Spider (Dolomedes scriptus). The linked picture gives you an idea of their size. Fishing Spiders hunt near and on water, and this one was found along a river bank. This lady had carried her egg sac to the top of a plant, and she is guarding her recently hatched spiderlings in a web nursery. You can see the mass of babies in the background. Fishing Spiders can be irritable at this time, but she was not at all aggressive so I had no trouble taking a wide-angle macro picture. Although the composition does not suggest it, the lens had to pretty much touch the spider since the working distance for wide-angle macro is extremely short:

I have some odds-and-ends remaining, but I will finish with an interesting one.

Next up is an Ailanthus Webworm Moth (Atteva aurea). These small moths have expanded their range northward since they have accepted the invasive Ailanthus or Tree of Heaven as a host plant. If one plays with the lighting, as I have done here, one can get a bit of iridescent blue out of the black markings on the wings:

Next up is a Scaly Bee Fly (Lepidophora lepidocera). Adult Bee Flies feed on nectar, and the larvae are either parasitic or predatory on other insects, depending on the species:

Here are some of our local wasps. First is our native Northern Paper WaspPolistes fuscatus, followed by an Eastern YellowjacketVespula maculifrons. These are of course social wasps:

Next up is a White-banded Potter WaspAncistrocerus albophaleratus. Potter wasps are solitary, and they build a mud-pot nest which they will provision with paralyzed arthropods like caterpillars or spiders, depending on the species:

The above wasps all belong to the family Vespidae, which can be immediately recognized because their front wings are folded lengthwise into a V in cross-section (V is for Vespidae).

The next insect looks like a lovely green-eyed bee, but I soon realized it lacked certain bee characters and so it had to be a wasp. It took a while, but I finally identified it as belonging to the family Crabronidae, and the genus Tachytes – that is all I know. These solitary wasps raise their young in burrows, provisioning them with paralyzed grasshoppers or katydids:

The last insect is rather comical and I don’t understand what it wants. This is a Pixie Robber Fly (Beameromyia sp.). Robber Flies are of course predatory. I occasionally see this species drawn to the porch light at night, as this one was, and for some reason they really want to stand on their head. I managed to coax this one onto a stick for pictures, and while I would tip and turn the stick to get it into frame, it would immediately adjust its stance so that it remained as you see it here. I have no idea why:

Categories: Science

The most encouraging climate solutions and green technologies of 2024

New Scientist Feed - Tue, 12/17/2024 - 6:00am
Renewable energy continued to grow in 2024, and there were other hopeful developments in technologies aiming to reverse the rise in greenhouse gas emissions
Categories: Science

Factory Farming is Better Than Organic Farming

neurologicablog Feed - Tue, 12/17/2024 - 4:58am

Some narratives are simply ubiquitous in our culture (every culture has its universal narratives). Sometimes these narratives emerge out of shared values, like liberty and freedom. Sometimes they emerge out of foundational beliefs (the US still has a puritanical bent). And sometimes they are the product of decades of marketing. Marketing-based narratives deserve incredible scrutiny because they are crafted to alter the commercial decision-making of people in society, not for the benefit of society or the public, but for the benefit of an industry. For example, I have tried to expose the fallacy of the “natural is always good, and chemicals are always bad” narrative. Nature, actually, is quite indifferent to humanity, and everything is made of chemicals.

Another narrative that is based entirely on propaganda meant to favor one industry and demonize its competition is the notion that organic farming is better for health and better for the environment. Actually, there is no evidence of any nutritional or health advantage from consuming organic produce. Further – and most people I talk to find this claim shocking – organic farming is worse for the environment than conventional or even “factory” farming. Stick with me and I will explain why this is the case.

A recent article in the NYT by Michael Grunwald nicely summarizes what I have been saying for years. First let me explain why I think there is such a disconnect between reality and public perception. This gets back to the narrative idea – people tend to view especially complex situations through simplistic narratives that give them a sense of understanding. We all do this because the world is complicated and we have to break it down. There is nothing inherently wrong with this – we use schematic, categories, and diagrams to simplify complex reality and chunk it into digestible bits. But we have to understand this is what we are doing, and how this may distort our understanding of reality. There are also better and worse ways to do this.

One principle I like to use as a guide is the Moneyball approach. This refers to Paul DePodesta who devised a new method of statistical analysis to find undervalued baseball players. Prior to DePodesta talent scouts would find high value players to recruit, players who had impressive classic statistics, like batting average. They would then pay high sums for these star players. DePodesta, however, realized that players without star-quality stats still might be solid players, and for their price could have a disproportionate positive effect on a team’s performance. If, therefore, you have a finite amount of funds to spread out over a team’s players, you might be better off shoring up your players at the low end rather than paying huge sums for star players. Famously this approach worked extremely well (first applied to the Oakland Athletics).

So let’s “Moneyball” farming. We can start with the premise that we have to produce a certain amount of calories in order to feed the world. Even if we consider population control as a long term solution – that’s a really long term solution for any ethically acceptable methods. I will add as a premise that it is not morally or politically feasible to reduce the human population through deliberate starvation. Right now there are 8.2 billion humans on Earth. Estimates are this will rise to about 10 billion before the population starts to come down again through ethical methods like poverty mitigation and better human rights. So for the next hundred years or so we will have to feed 8+ billion people.

If our goal is to feed humanity while minimizing any negative effect on the environment, then we have to consider what all the negative effects are of farming. As Grunwald points out – they are huge. Right now we are using about 38% of the land on Earth for farming. We are already using just about all of the arable land – arable land is actually a continuum, so it is more accurate to say we are using the most arable land. Any expansion of farmland will therefore expand into less and less arable land, at greater and greater cost and lower efficiency. Converting a natural ecosystem, whether a prairie, forest, meadow, or whatever, into farmland is what has, by far, the greatest negative effect on the ecosystem. This is what causes habitat loss,  isolates populations, reduces biodiversity, and uses up water. The difference between different kinds of farming is tiny compared to the difference between farming and natural ecosystems.

This all means that the most important factor, by far, in determining the net effect of calorie production for humans on the environment is the amount of land dedicated to all the various kinds of farming. Organic farming simply uses more land than conventional farming, 20-40% more land on average. This fact overwhelms any other alleged advantage of organic farming. I say alleged because organic farms can and many do use pesticides – they just use natural pesticides, which are often less effective requiring more applications. Sometimes they also rely on tilling, which releases carbon from the soil.

But even if we compare maximally productive farming to the most science-based regenerative farming techniques, designed to minimize pesticide use and optimize soil health – maximally efficient farming wins the Moneyball game. It’s no contest. Also, the advantage of efficient factory farming will only get greater as agricultural science and technology improves. GMOs, for example, have the potential for massive improvements in crop efficiency, leaving organic farming progressively in the dust.

But all this does not fit the cultural narrative. We have been fed this constant image of the gentle farm, using regenerative practices, protecting the soil, with local mom and pop farmers producing food for local consumption. It’s a nice romantic image, and I have no problem with having some small local farms growing heirloom produce for local consumption. But this should be viewed as a niche luxury – not the primary source of our calories. Eating locally grown food from such farms is, in a way, a selfish act of privilege. It is condemning the environment so you can feel good about yourself. Again, it’s fine in moderation. But we need to get 95% of our calories from factory farms that are brutally efficient. This also does not mean that factory farms should not endeavor to be environmentally friendly, as long as it does not come at the cost of efficiency.

At this point many people will point out that we can improve farming efficiency by eliminating meat. It is true that overproducing meat for calories is hugely inefficient. But so is underproducing meat. What the evidence shows is that maximal efficiency comes from using each parcel of land for it’s optimal use. Grazing land for animals in many cases is the optimal use. Cattle, for example, can convert a lot of non-edible calories into edible calories. And finishing lots can also use low grade feed not fit for humans to pack on high-grade calories for humans. Yes – many industrialized nations consume too much meat. Part of optimizing efficiency is also optimizing the ratio of which kinds of calories we consume. But zero meat is not maximally efficient. Also – half our fertilizer comes from manure, and we can’t just eliminate the source of half our fertilizer without creating a disaster.

It’s a complicated system. We no longer, however, have the luxury of just letting everyone do what they want to do and what they think is in their best interest. Optimally there would be some voluntary coordination for the world’s agricultural system to maximize efficiency and minimize land use. This can come through science-based standards, and funding to help poorer countries have access to more modern farming techniques, rather than just converting more land for inefficient farming.

But first we have to dispense with the comforting but ultimately fictional narrative that the old gentle methods of farming are the best. We need science-based maximal efficiency.

 

The post Factory Farming is Better Than Organic Farming first appeared on NeuroLogica Blog.

Categories: Skeptic

UK plans to favour AI firms over creators with a new copyright regime

New Scientist Feed - Tue, 12/17/2024 - 3:38am
One of the biggest uncertainties in the ongoing AI revolution is whether these systems can legally be trained on copyrighted data. Now, the UK says it plans to clarify the matter with a change to the law
Categories: Science

Reality

Science-based Medicine Feed - Tue, 12/17/2024 - 2:12am

Reality. Doesn't care what you think.

The post Reality first appeared on Science-Based Medicine.
Categories: Science

Earliest known sabre-toothed predator hunted 270 million years ago

New Scientist Feed - Tue, 12/17/2024 - 2:00am
The fossilised remains of an ancient carnivore provide intriguing hints about how early relatives of mammals began regulating their own body temperature
Categories: Science

Skeptoid #967: Cryonics: A Chilling Prospect

Skeptoid Feed - Tue, 12/17/2024 - 2:00am

Cryonics promises an opportunity for you to be frozen and revived at some distant point in the future — though with plenty of controversy.

Categories: Critical Thinking, Skeptic

The best and weirdest photos of robots from 2024

New Scientist Feed - Tue, 12/17/2024 - 1:00am
A long-envisioned futuristic world of humanoid robots doing all the work has yet to arrive, but these startling images reveal some of the surprising ways that advanced robotics is becoming more ubiquitous in people's lives
Categories: Science

Is social media fuelling a rise in eating disorders?

New Scientist Feed - Mon, 12/16/2024 - 11:00pm
Eating disorders have increased - and many are pointing the finger at sites like Instagram and TikTok
Categories: Science

Towards quantitative point-of-care testing with novel bioluminescent immunosensor

Matter and energy from Science Daily Feed - Mon, 12/16/2024 - 6:46pm
A novel nanobody-based immunosensor, designed to function stably in undiluted biological fluids and harsh conditions, has been developed. Their innovative design leverages BRET -- bioluminescence resonance energy transfer -- and exhibits great potential for point-of-care testing, therapeutic drug monitoring, and environmental applications using paper-based devices.
Categories: Science

A New Study Suggests How we Could Find Advanced Civilizations that Ran Out of Fusion Fuel

Universe Today Feed - Mon, 12/16/2024 - 5:14pm

When it comes to our modern society and the many crises we face, there is little doubt that fusion power is the way of the future. The technology not only offers abundant power that could solve the energy crisis, it does so in a clean and sustainable way. At least as long as our supplies of deuterium (H2) and helium-3 hold up. In a recent study, a team of researchers considered how evidence of deuterium-deuterium (DD) fusion could be used as a potential technosignature in the Search for Extraterrestrial Intelligence (SETI).

The study was conducted by David C. Catling and Joshua Krissansen-Totton of the Department of Earth & Space Sciences and the Virtual Planetary Laboratory (VPL) at the University of Washington (respectively) and Tyler D. Robinson of the VPL and the Lunar & Planetary Laboratory (LPL) at the University of Arizona. In their paper, which is set to appear in the Astrophysical Journal, the team considered how long-lived extraterrestrial civilizations may deplete their supplies of deuterium – something that would be detectable by space telescopes.

At the heart of SETI lies the foregone conclusion that advanced civilizations have existed in our galaxy long before humanity. Another conclusion extends from this: if humanity can conceive of something (and the physics are sound), a more advanced civilization is likely to have already built it. In fact, it has been suggested by many SETI researchers and scientists that advanced civilizations will adopt fusion power to meet their growing energy needs as they continue to grow and ascend the Kardashev Scale.

The spherical tokamak MAST at the Culham Centre for Fusion Energy (UK). Photo: CCFE

This is understandable, considering how other forms of energy (fossil fuels, solar, wind, nuclear, hydroelectric, etc.) are either finite or inefficient. Space-based solar power is a viable option since it can provide a steady supply of energy that is not subject to intermittency or weather patterns. Nevertheless, nuclear fusion is considered a major contender for future energy needs because of its efficiency and energy density. It is estimated that one gram of hydrogen fuel could generate as much as 90,000 kilowatt-hours of energy – the equivalent of 11 metric tons (12 U.S. tons) of coal.

In addition, deuterium has a natural abundance in Earth’s oceans of about one atom of deuterium in every 6,420 atoms of hydrogen. This deuterium interacts with water molecules and will replace one or both hydrogen atoms to create “semi-heavy water” (HOD or DOH) and sometimes “heavy water” (D2O). This works out to 4.85×1013 or 48.5 billion metric tons (5.346×1013 U.S. tons) of deuterium. As they argue in their paper, extracting deuterium from an ocean would decrease its ratio of deuterium-to-hydrogen (D/H), which would be detectable in atmospheric water vapor. Meanwhile, the helium produced in the nuclear reactions would escape to space.

In recent years, it has been suggested that excess carbon dioxide and radioactive isotopes in an exoplanet’s atmosphere could be used to infer the presence of an industrial civilization. In the same vein, low values of D/H in an exoplanet’s atmosphere (along with helium) could be used to detect a highly advanced and long-lived civilization. As Catling explained in a recent interview with phys.org, this possibility is one he began pondering years ago.

“I didn’t do much with this germ of idea until I was co-organizing an astrobiology meeting last year at Green Bank Observatory in West Virginia,” he said. “Measuring the D/H ratio in water vapor on exoplanets is certainly not a piece of cake. But it’s not a pipe dream either.”

A model JWST transmission spectrum for an Earth-like planet, showing the wavelengths of sunlight that molecules like ozone (O3), water (H2O), carbon dioxide (CO2), and methane (CH4) absorb. Credit: NASA, ESA, Leah Hustak (STScI)

To model what an advanced civilization dependent on DD fusion would look like, Catling and his colleagues considered projections for what Earth will look like by 2100. At this point, the global population is expected to reach 10.4 billion, and fusion power is projected to provide 100 Terawatts (TW). They then multiplied that by a factor of ten (1,000 TW) for a more advanced civilization and found that they would reduce the D/H value of an Earth-like ocean to that of the interstellar medium (ISM) in about 170 million years.

The beauty of this approach is that the low D/H values in an exoplanet’s atmosphere would persist long after a civilization went extinct, migrated off-world, or became even more advanced and “transcended.” In terms of search strategies, the team used the Spectral Mapping Atmospheric Radiative Transfer (SMART) model to identify the specific wavelengths and emission lines for HDO and H2O. These findings will be useful for future surveys involving the James Webb Space Telescope (JWST), NASA’s proposed Habitable Worlds Observatory (HWO), and the Large Interferometer For Exoplanets (LIFE).

“It’s up to the engineers and scientists designing [HWO] and [LIFE] to see if measuring D/H on exoplanets might be an achievable goal. What we can say, so far, is that looking for D/H from LIFE appears to be feasible for exoplanets with plenty of atmospheric water vapor in a region of the spectrum around 8 microns wavelength.”

Further Reading: phys.org, arXiv

The post A New Study Suggests How we Could Find Advanced Civilizations that Ran Out of Fusion Fuel appeared first on Universe Today.

Categories: Science

Microchips capable of detecting and diagnosing diseases

Matter and energy from Science Daily Feed - Mon, 12/16/2024 - 3:47pm
Researchers have developed microchips using field-effect transistors that can detect multiple diseases from a single air sample with high sensitivity. The technology enables rapid testing and could lead to portable diagnostic devices for home and medical use.
Categories: Science

Microchips capable of detecting and diagnosing diseases

Computers and Math from Science Daily Feed - Mon, 12/16/2024 - 3:47pm
Researchers have developed microchips using field-effect transistors that can detect multiple diseases from a single air sample with high sensitivity. The technology enables rapid testing and could lead to portable diagnostic devices for home and medical use.
Categories: Science

Electric vehicle transition could create unwanted air pollution hotspots in China and India

Matter and energy from Science Daily Feed - Mon, 12/16/2024 - 1:52pm
New research has uncovered a potential unintended consequence of the electric vehicle transition in India and China, finding that sulfur dioxide emissions could actually increase over current levels if the countries were to fully onshore their electric vehicle supply chains. The overwhelming majority of those emissions would come from refining and manufacturing nickel and cobalt -- important minerals for today's electric vehicle batteries.
Categories: Science

New paper examines the elusive nature of liquid brines on Mars

Space and time from Science Daily Feed - Mon, 12/16/2024 - 1:51pm
The combination of low temperature, atmospheric pressure and water vapor pressure on Mars means any liquid water found there would likely freeze, boil or evaporate immediately, making its presence unlikely.
Categories: Science

Staying sharp: Study explores how brain changes may affect financial skills

Matter and energy from Science Daily Feed - Mon, 12/16/2024 - 1:51pm
A new article sheds light on how age-related changes may affect the way we handle finances -- and how we can stay sharp as we age.
Categories: Science

We Might Finally Know How Galaxies Grow So Large

Universe Today Feed - Mon, 12/16/2024 - 12:54pm

Astronomers have spent decades trying to understand how galaxies grow so large. One piece of the puzzle is spheroids, also known as galactic bulges. Spiral galaxies and elliptical galaxies have different morphologies, but they both have spheroids. This is where most of their stars are and, in fact, where most stars in the Universe reside. Since most stars reside in spheroids, understanding them is critical to understanding how galaxies grow and evolve.

New research focused on spheroids has brought them closer than ever to understanding how galaxies become so massive.

Elliptical galaxies have no flat disk component. They’re smooth and featureless and contain comparatively little gas and dust compared to spirals. Without gas and dust, new stars seldom form, so ellipticals are populated with older stars.

Astronomers don’t know how these ancient, bulging galaxies formed and evolved. However, a new research letter in Nature may finally have the answer. It’s titled “In situ spheroid formation in distant submillimetre-bright galaxies.” The lead author is Qing-Hua Tan from the Purple Mountain Observatory, Chinese Academy of Sciences, China. Dr. Annagrazia Puglisi from the University of Southampton co-authored the research.

“Our findings take us closer to solving a long-standing mystery in astronomy that will redefine our understanding of how galaxies were created in the early universe.”

Dr. Annagrazia Puglisi, University of Southampton

The international team of researchers used the Atacama Large Millimetre/sub-millimetre Array (ALMA) to examine highly luminous starburst galaxies in the distant Universe. Sub-millimetre means it observes electromagnetic energy between far-infrared and microwave. Astronomers have suspected for a long time that these galaxies are connected to spheroids, but observing them is challenging.

“Infrared/submillimetre-bright galaxies at high redshifts have long been suspected to be related to spheroid formation,” the authors write. “Proving this connection has been hampered so far by heavy dust obscuration when focusing on their stellar emission or by methodologies and limited signal-to-noise ratios when looking at submillimetre wavelengths.”

This image shows two of the Atacama Large Millimeter/submillimeter Array (ALMA) 12-metre antennas. ALMA has 66 antennas that work together as an interferometer. (Credit : Iztok Bonina/ESO)

The researchers used ALMA to analyze more than 100 of these ancient galaxies with a new technique that measures their distribution of light. These brightness profiles show that the majority of the galaxies have tri-axial shapes rather than flat disks, indicating that something in their history made them misshapen.

Two important concepts underpin the team’s results: The Sersic index and the Spergel index.

The Sersic index is a fundamental concept in describing the brightness profiles of galaxies. It characterizes the radial distribution of light coming from galaxies and basically describes how light is concentrated in a galaxy.

The Spergel index is less commonly used. It’s based on the distribution of dark matter in galaxies. Rather than light, it helps astronomers understand how matter is concentrated. Together, both indices help astronomers characterize the complex structure of galaxies.

These indices, along with the new ALMA observations, led to new insights into how spheroids formed through mergers and the resulting influx of cold, star-forming gas.

It all starts with a galaxy collision or merger, which sends large flows of cold gas into the galactic centre.

This is a JWST image (not from this research) of an ancient galaxy merger from 13 billion years ago. The galaxy, named Gz9p3, has a double nucleus indicating that the merger is ongoing. While astronomers know that mergers are a critical part of galaxy growth and evolution, the role spheroids play has been difficult to discern. Image Credit: NASA/Boyett et al

“Two disk galaxies smashing together caused gas—the fuel from which stars are formed—to sink towards their centre, generating trillions of new stars,” said co-author Puglisi. “These cosmic collisions happened some eight to 12 billion years ago when the universe was in a much more active phase of its evolution.”

“This is the first real evidence that spheroids form directly through intense episodes of star formation located in the cores of distant galaxies,” Puglisi said. “These galaxies form quickly—gas is sucked inwards to feed black holes and triggers bursts of stars, which are created at rates ten to 100 times faster than our Milky Way.”

The researchers compared their observations to hydro-simulations of galaxy mergers. The results show that the spheroids can maintain their shape for up to approximately 50 million years after the merger. “This is compatible with the inferred timescales for the submillimeter-bright bursts based on observations,” the authors write. After this intense period of star formation in the spheroid, the gas is used up, and things die down. No more energy is injected into the system, and the residual gas flattens out into a disk.

This figure from the research shows how the spheroids lose their shape after the intense period of star formation following a merger. (a) shows maps (2×2 kpc) of the central gas in three different
mergers, showing the flattest projection for these systems observed at 12 Myr from coalescence; that is, these systems are 3D spheroidal structures, not face-on disks. (b) shows the star-formation rate peaking and then dimishining over time. (c) shows C/A, which quantifies the relative system thickness encompassing all galactic components, including disks, bars, and bulges. It’s a ratio between C, the shortest axis, and A, the longest axis in a triaxial ellipsoid. Image Credit: Tan et al. 2024.

These types of galaxies were more plentiful in the early Universe than they are now. The researchers’ results show that these galaxies used up their fuel quickly, forming the spheroids that are now populated by old stars.

This isn’t the first time that astronomers have investigated the potential link between spheroids and distant submillimeter-bright galaxies. Previous research that found evidence for tri-axiality also found heavy ellipticity and other evidence showing that submillimeter-bright galaxies are disks with bars in the submillimeter. However, this new research relied on observations with a higher signal-to-noise ratio than previous research.

“Astrophysicists have sought to understand this process for decades,” Puglisi said. “Our findings take us closer to solving a long-standing mystery in astronomy that will redefine our understanding of how galaxies were created in the early universe.”

“This will give us a more complete picture of early galaxy formation and deepen our understanding of how the universe has evolved since the beginning of time.”

The post We Might Finally Know How Galaxies Grow So Large appeared first on Universe Today.

Categories: Science

Plastic chemicals linked to hundreds of thousands of deaths worldwide

New Scientist Feed - Mon, 12/16/2024 - 12:00pm
A review of chemical exposures across 38 countries finds common plastic products are linked to millions of cases of heart disease and thousands of strokes
Categories: Science

Building Concrete on Mars From Local Materials

Universe Today Feed - Mon, 12/16/2024 - 11:36am

Imagine you’ve just gotten to Mars as part of the first contingent of settlers. Your first challenge: build a long-term habitat using local materials. Those might include water from the polar caps mixed with specific surface soils. They might even require some very personal contributions—your blood, sweat, and tears. Using such in situ materials is the challenge a team of Iranian engineers studied in a research project looking at local materials on Mars.

In situ resource utilization has always been part of Mars mission and colonization scenarios. It’s expensive to bring along habitat construction materials with you, and space will be limited onboard the ship. Once you settle on Mars, you can use your ship as a habitat until you build your new colony. But, what are you going to create new homes from?

Cement or concrete come to mind, made from whatever’s available on or just below the surface. The authors of the study, Omid Karimzade Soureshjani, Ali Massumi, and Gholmreza Nouri, focused on Martian cement. They assembled data sets about soil composition from Mars landers and orbiters and came up with a collection of concrete types that future colonists could use. Next, they applied structural engineering principles and suggested some options for onsite construction using what are called spider/radar diagrams and charts. These allow building planners to apply data for different concepts of Mars architecture.

A graph showing steps in the study of possible building materials on Mars. Courtesy: Soureshjani, et al. Click to enlarge. Building That Mars City

The authors, like most of us, foresee permanent settlements in the next decades. They write, “The goal would be to establish a self-sustaining city (self-sufficient megabase) on the surface of Mars, accommodating at least a million people. However, constructing safe, stable, and sufficient buildings that can withstand the harsh Martian environment for such a population will be challenging. Due to the high costs associated with importing buildings, materials, and structural elements from Earth, it is necessary to construct all buildings on-site using local resources.”

Let’s look at the usability and cost-effectiveness of Martian soil (regolith). Chemically, it’s rich in the right amounts of elements to make different types of concrete. Of course, not all the regoliths are equally useful, so they propose surface scans to find the best surface materials mixes. Presumably, those scans will help future inhabitants find the best collections. Access to those raw materials from around the planet should make them cost-effective, eventually.

Challenges to Mars Construction

Of course, there are other factors besides material availability at work in such a construction project. Here on Earth, we have centuries of experience building in this gravity well, with familiar materials. We know how to build things under this atmospheric pressure, and we don’t have to contend with the harsh conditions of a planet constantly bombarded by ultraviolet radiation. Mars presents the challenge of creating buildings that have to withstand that radiation, the lower atmospheric pressure, and water scarcity. That lower pressure and gravity on Mars could seriously affect the durability of a given concrete made from Martian materials.

In addition to planetary geology and surface conditions, it takes energy to collect, process, and create the building materials needed for long-term habitation. You need a simple, cost-effective energy source—particularly in the beginning. It’s not likely that nuclear power plants will be first on the list to build. Those require a tremendous number of resources. Perhaps later they can be built, but not in the first wave. Solar energy is going to be the “go-to” resource in the beginning. In addition, to make cement, you need water. And, water is a notably scarce resource on much of Mars, except at the poles. They could provide some water from the ice caps, but you’ll likely want to figure out a way to make good cement with the least amount of water.

Using Organic Binders for Mars Home Building Blocks

Interestingly, the authors mention something called “blood concrete”, or its modern version: AstroCrete. It’s a concept based on ancient Roman practices of using organic additives to construction materials (think: animal blood, urine, etc.). Now, they aren’t suggesting that future Martians must “bleed for their art” but our bodies do make plasma rather easily. It could be a useful resource.

A substance called “human serum albumin” (HAS) is under study as a binder to mix with “AstroCrete” materials, along with sweat, tears, and urine. All those will be available in relative abundance in future Mars settlements. The AstroCrete made from Martian soils and human “contributions” is a strong building material you can rely on for strength (and you hope it won’t smell too bad). Essentially, AstroCrete is waterless cement.

Visible light images of the 3D-printed HSA-ERB based on Martian Global Simulant. (a) after fabrication, (b) during compression testing, and (c) after compression testing. Courtesy: Robertsad, et al. Exploring the Possibilities

The authors studied 11 types of cement, including geopolymer and magnesium silica mixtures, all of which require specific materials. They point out that sulfur concrete is probably going to be the most promising avenue for structures on Mars. Others will take more study and implementation to understand their usability in Martian conditions. In the long term, searching out and understanding the materials available on the Red Planet will help future colonists build the necessary habitats and cities. Finally, the authors point out that additional study of both materials and the Martian environment using data from current and future missions is necessary. Their paper is well worth reading in more detail.

For More Information

Martian Buildings: Feasible Cement/concrete for Onsite Sustainable Construction from the Structural Point of View
Martian Concrete Could be Tough Stuff
Blood, Sweat, and Tears: Extraterrestrial Regolith Biocomposites with in vivo Binders

The post Building Concrete on Mars From Local Materials appeared first on Universe Today.

Categories: Science

Exploring excited state dynamics: Advancements in fluorescence and material design

Matter and energy from Science Daily Feed - Mon, 12/16/2024 - 10:03am
Excited state dynamics are essential for understanding fluorescence properties in molecules, impacting their application in technologies. Recent research explores how molecular structure and geometry influence light emission in aggregation-induced emission molecules. The study reveals that changes in molecular shape affect emission behavior in both solution and solid states. These insights are crucial for advancing applications like organic light-emitting diodes and bioimaging, enabling innovations in material design and energy interactions.
Categories: Science

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