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Best-case scenario for climate change is now 1.6°C of warming

New Scientist Feed - Mon, 08/19/2024 - 5:00am
The totemic climate goal of keeping warming below 1.5°C above pre-industrial levels is essentially impossible at this point
Categories: Science

Monday: Hili dialogue

Why Evolution is True Feed - Mon, 08/19/2024 - 4:28am

Meanwhile, in Dobrzyn, Hili is concerned about health and safety:

Hili: You have to remove these roots.
A; Why?
Hili: Because somebody might stumble on them.

Hili: Musisz usunąć te korzenie.
Ja: Dlaczego?
Hili: Bo ktoś może się o nie potknąć.

Categories: Science

Discovery of 'dark' electrons could explain how superconductors work

New Scientist Feed - Mon, 08/19/2024 - 3:00am
Electrons that appear to be undetectable when analysing materials could be responsible for exotic properties, such as high-temperature superconductivity
Categories: Science

Revisiting “integrative oncology”: The battle to integrate quackery with oncology continues

Science-based Medicine Feed - Mon, 08/19/2024 - 12:00am

Nature Reviews Cancer published a propaganda piece disguised as commentary promoting "integrative oncology," or what I like to call "integrating" quackery with oncology.

The post Revisiting “integrative oncology”: The battle to integrate quackery with oncology continues first appeared on Science-Based Medicine.
Categories: Science

Another day, another impala: Day 3 in Manyeleti

Why Evolution is True Feed - Sun, 08/18/2024 - 7:00am

Today’s post covers the drives yesterday afternoon and this morning. Don’t forget to click the photos to enlarge them. And we saw another leopard!

I won’t put up a link or the Latin binomials for animals I’ve done that for already.

At lunch yesterday a vervet monkey (Chlorocebus pygerythrus) somehow found its way into the dining room and made for my plate (I was writing on this site in the adjacent room). But I’d eaten all my lunch, and so it thrust its hand into my water glass and licked off the drops (much like the black cat Toon in Amsterdam).  Vervets are social primates that range widely in East and South Africa, and have been extensively studied by biologists. Here’s a photo of the little guy, who was adorable but skittish:

Another day, another herd of impala, perhaps the most common antelope in the reserve. The males are the ones with horns, but they are very skittish and I’ve had trouble getting a front-on picture of the impressive males. I’ll try again this afternoon.

We’ve not seen many common ostriches in the park—just this one. Like the one near the Cape of Good Hope, it crossed the road, giving rise to an obvious joke:

A couple of elephants yesterday afternoon. It’s amazing to come upon one of these all of a sudden; sometimes I can’t spot them until we’re very close to them, as they often stand still.

A blue wildebeest, one of only two sister species in the genus Connochaetes, the other. being the black wildebeest. Both are mammals formerly known as gnus.  I asked our guide and driver, Dan, why this one let us get to close to him. Dan replied that this wildebeest was an old friend of his.

Wildebeest poop: extraordinarily small (about goat-poop sized, or the size of blueberries) for an animal this large. I’m told that this is because wildebeest have the four classic stomach compartments of many ruminants, and thus digest the short grass they eat very thoroughly, leaving only small, hard remnants of their food.

In contrast, elephants have poor ability to digest grass and foliage, and their droppings are huge, as we discover when we walk to and from our tents (the camp is crawling with elephants night and day). I’m trying to make a photographic collection of animal droppings for your delectation.

Mother and baby elephant:

Surprised by another elephant standing behind a tree:

A giraffe stood nearby as we had our “sundowner” drinks outside the vehicle. Some misguided zoologists have revised the single species Giraffa camelopardalis into four species based on genetic differences alone.  Since no two of them occur in one locality, one can’t use the biological species concept, but my guess is that there’s only one species of giraffe and all the subspecies would interbreed and produce fertile hybrids if they occurred in one locality (see posts here and here).

And two sundown photos of the giraffe:

We left this morning heading for a pride of lions that had been spotted, but when Dan got out of the vehicle to look for them in a ravine, he accidentally spooked them. But we had some serendipity: he saw a leopard sleeping in a tree above him, (the guy can find stuff, I tell you). We maneuvered around the other trucks, which didn’t seem to disturb the cat, until we were right below it.

It looked comfortable as hell, with its legs hanging down as it snoozed away. Two leopard spottings in two days: that’s fantastic.

On the way out, the ever-vigilant Dan, who was driving, nevertheless spotted some leopard tracks in the sand. He circled one of them for me:

A female greater kudu (Tragelaphus strepsiceros) either urinating or defecating. They’re relatively uncommon, so I may not get another picture. I’ve put a Wikipedia picture of the male below mine:

A photo of a greater kudu male from Wikipedia. Its spiral horns are striking:

This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. Attribution: © Hans Hillewaert

This is more of less what “the bush” looks like around here, though this patch has a bit more trees than usual. It’s dry as it’s winter, and the rains come in summer; but this year summer was extraordinarily dry and the animals therefore stressed for food.

A panoramic shot of the bush. Click to enlarge:

h/t: Rosemary for IDs and information

 

Categories: Science

Galaxies in Dense Environments Get Larger

Universe Today Feed - Sun, 08/18/2024 - 5:10am

Galaxies are some of the largest clearly defined structures in space. There are trillions of them, and many are clustered around each other. But how does that clustering affect them? That’s been a question for a while, and older papers have yielded contradictory results. Now, a new paper analyzing millions of galaxies from researchers at the University of Washington, Yale, and several other institutions shows a clear pattern that had been debated before – galaxies surrounded by other galaxies tend to be larger.

The path to that conclusion was a long one. Several other surveys showed that galaxies in “dense environments” were both larger and smaller. However, these studies were only conducted using a relatively limited dataset of hundreds or thousands of galaxies. So, the researchers in the new paper, led by Aritra Ghosh, a postdoc at UW, thought, “Why not get more data?”

So they did, using the Subaru telescope’s Hyper Suprime-Cam Subaru Strategic Program. This survey captured high-quality data on millions of galaxies for the first time, so the researchers were able to select 3 million galaxies with the best datasets from the cream of the crop.

Massive datasets on galaxies are becoming more common – Fraser discusses another survey of millions of galaxies.

They then drew “circles” of about 30 million light-years around each of the three million galaxies and assessed how densely packed their local neighborhood was. Statistically, the correlation was obvious – galaxies in more dense spatial neighborhoods were larger than their more isolated cousins. 

Saying the researchers drew circles around 30 million galaxies isn’t accurate, though – they used one of the myriad new machine-learning tools popping up in the astronomical community. This one, called the Galaxy Morphology Posterior Estimation Network, or GaMPEN, was the focal point of Dr. Ghosh’s PhD thesis at Yale. It specializes in estimating galaxy size and accounting for uncertainties in the measurement.

With the tool’s results, the question became, what does this mean? The idea that galaxies are larger in dense areas doesn’t fit well with astronomers’ current conception of how galaxies form. So, it’s time for a new theory to fit the data Subaru has collected, and the paper has analyzed.

Fraser discusses globular clusters, one of the dense states galaxies can find themselves in.

Several theories put forward in a press release could explain the observations. One is that densely clustered galaxies are simply larger from the start. Another is that perhaps they are more effective at merging with closely proximate galaxies to create larger supergalaxies than the two originals.

A third, more intriguing possibility is that dark matter might be involved. But since scientists still don’t understand what dark matter actually is, this is akin to waving a magic wand to explain data that otherwise doesn’t fit the cosmological model.

Regardless of the reason, the study is an excellent example of how large datasets and AI-enabled tools will change astronomy shortly. In some cases, it will confirm existing theories, and in some cases, like the relationship between galaxy density and size, it will call for a new theoretical framework. Either way, it’s exciting to be around for all these new discoveries, whether AI-powered or not.

Learn More:
UW – Galaxies in dense environments tend to be larger, settling one cosmic question and raising others
Ghosh et al. – Denser Environments Cultivate Larger Galaxies: A Comprehensive Study beyond the Local Universe with 3 Million Hyper Suprime-Cam Galaxies
UT – This Distant Galaxy Cluster is Totally Relaxed, Unharassed for a Billion Years|
UT – A Collision Between Gigantic Galaxy Clusters. Too Big, Too Early

Lead Image:
Image of Abell 2218, a dense galactic cluster approximately 2 billion light-years from Earth.
Credit – NASA/ESA/Johan Richard

The post Galaxies in Dense Environments Get Larger appeared first on Universe Today.

Categories: Science

Specialized Materials Could Passively Control the Internal Temperature of Space Habitats

Universe Today Feed - Sun, 08/18/2024 - 3:56am

Areas of space have wildly different temperatures depending on whether they are directly in sunlight or not. For example, temperatures on the Moon can range from 121 °C during the lunar “day” (which lasts for two weeks), then drop down to -133 °C at night, encompassing a 250 °C swing. Stabilizing the temperature inside a habitat in those environments would require heating and cooling on a scale never before conducted on Earth. But what if there was a way to ease the burden of those temperature swings? Phase change materials (PCMs) might be the answer, according to a new paper from researchers at the Universidad Politecnica de Madrid. 

PCMs have been known for some time and are currently used in several industries, including batteries, solar power plants, heat pumps, and even spacecraft. Perhaps most interestingly, they’ve been used to cool and heat the interiors of buildings on Earth.

They do so by absorbing heat during the hot parts of a period (whether a day or season) and emitting that heat in the cooler parts of a later period. They act like a giant thermal “sink,” making it take longer to heat or cool and providing insulation to anything it surrounds.

Two-bit DaVinci explains how PCMs work on terrestrial houses.
Credit – Two-bit DaVinci YouTube Channel

Another way to think of this is through the concept of thermal inertia. When an object, like a building, is in the Sun, it is directly impacted by the Sun’s rays, causing it to heat up. Alternatively, if it is no longer in the Sun but still contains a lot of thermal energy, it will start radiating some of that heat away. In vacuums, radiative energy is transmitted through infrared light like space.

PCMs have such large thermal inertia because they either absorb or emit lots of energy as they change between phases, such as between solid and liquid or liquid and gas. For example, the paper describes using n-octadecane as one of the PCMs being considered. It switches state around 28 °C, slightly above room temperature. Which makes it perfect for holding a room at right about that temperature.

Changing the temperature of something built with PCMs is much more complicated, and that challenge can make it easier to regulate the temperature inside a space habitat. The researchers modeled what would happen if a space habitat were built with PCMs inside the walls, and they found a significant decrease in the heating and cooling required to keep the habitat within the temperature range of being comfortable for humans.

Thermal control is one of the aspects of a self-sustaining space habitat, as Fraser discusses with Dr. Annika Rollock.

Other factors were included in the calculation, such as the reflectivity of the outer surface of the wall and the part of the solar cycle the Sun was experiencing. However, the authors found that given optimal conditions; designers could completely passively heat and cool a space habitat using only PCMs.

That is a pretty impressive feat, though the optimal conditions are improbable to ever happen in practice. Still, any energy savings the materials might provide will be welcome on a habitat that will likely be energy-starved when it starts. However, many different ideas exist for how those habitats should be built, including using regolith on the Moon. It is unclear how feasible it would be to include PCMs in cave walls or other structures involving local materials. The sheer amount of PCMs necessary to thermally control a massive human habitat might also be prohibitively expensive to launch at current prices.

However, materials keep improving, and there are obvious advantages to using these materials in this context. While they might not be integrated into some of the early habitats humanity builds in space, they will undoubtedly be used in future ones, and this paper is one step towards that.

Learn More:
Kachalov et al – Preliminary Design of a Space Habitat Thermally Controlled Using Phase Change Materials
UT – The Future of Space Colonization – Terraforming or Space Habitats?
UT – Where Could Humans Survive in our Solar System?
UT – Watch a House-Sized Space Habitat (Intentionally) Burst

Lead Image:
Artist’s depiction of a habitat on the Moon.
Credit: ESA/Foster + Partners


The post Specialized Materials Could Passively Control the Internal Temperature of Space Habitats appeared first on Universe Today.

Categories: Science

Sunday: Hili dialogue

Why Evolution is True Feed - Sun, 08/18/2024 - 12:41am

Meanwhile, in Dobrzyn, Hili – like many cats – is bemused:

Hili: It’s difficult to figure all of it out. A: Figure out what? Hili: I told you – all of it.

 

Hili: Trudno się w tym wszystkim zorientować.
Ja: W czym?
Hili: Powiedziałam, że we wszystkim.
Categories: Science

Dr. Scott Atlas: “I Never Read the Full Great Barrington Declaration Website and Everything”.

Science-based Medicine Feed - Sun, 08/18/2024 - 12:07am

Dr. Scott Atlas said the Great Barrington Declaration was aligned with the advice he gave to the President of the United States. He also said he never read it.

The post Dr. Scott Atlas: “I Never Read the Full Great Barrington Declaration Website and Everything”. first appeared on Science-Based Medicine.
Categories: Science

Bones, Bias, and Backlash: Elizabeth Weiss on the Politicization of Anthropology

Skeptic.com feed - Sat, 08/17/2024 - 11:00am
https://traffic.libsyn.com/secure/sciencesalon/mss457_Elizabeth_Weiss_2024_08_17.mp3 Download MP3

Archaeologist Elizabeth Weiss’s new book, On the Warpath, is an autobiographical account of her storied career on the front lines of the culture war in our colleges and universities. Her opposition to the reburial of Native American skeletal remains, her insistence that indigenous knowledge is not science but myth, and her fight against wokeism and political correctness in academia exposed her to numerous controversies and cancel culture campaigns, and a court case.

A photograph of Weiss with a skull — as natural to anthropologists as a doctor being pictured with a stethoscope — led to her university shutting her out of the collection and changing the locks. This became an international news story, as did the American Anthropological Association canceling one of her presentations because she explained that a skeleton’s sex is binary and not gender fluid.

This hard-hitting and often humorous book tells the story of Dr. Weiss’s fight for science against superstition, and her attempts to promote free speech and academic freedom. It also exposes the current rot in today’s universities, through the lens of her battles against day-to-day absurdities. These include an attempt to bar “menstruating personnel” (formerly known as women) from the curation facility, a campaign to ban research on ancient Carthaginian remains because the individuals concerned never consented to photography, and a plan to declare X-rays sacred, so that they can be repatriated to Native Americans (who may actually be Mexicans), prior to being burned or buried.

Elizabeth Weiss is a controversial and world-renowned anthropology professor, specializing in the analysis of human skeletal remains. For much of her career she was based at San Jose State University, where she curated one of the largest collections of skeletal remains in the US. She is the author of numerous books and articles, and she played an essential role in bringing the Smithsonian’s traveling exhibition “What Does it Mean to be Human?” to the San Francisco Bay Area. She’s been featured in the New York Times, Science and USA Today, and has been interviewed on Fox News and Newsmax. She currently lives in New York City, where she holds a visiting fellowship with Heterodox Academy.

Shermer and Weiss discuss:

  • How she became interested in archaeology and when her field became politicized
  • Whatever happened to Kennewick Man, and who was he anyway?
  • When studying bones, why sex is binary
  • How wokeness has ruined anthropology and archaeology
  • The anthropology wars of the 1990s and the archaeology wars of the 2020s
  • Why science is never complete and so burying fossils after a preliminary scientific analysis is inappropriate
  • Why the fossil remains of most Native American sites have tenuous or no connection whatsoever to modern tribal peoples living nearby
  • The peopling of the Americas and what the consensus is on how long ago migrations began
  • Alternative archaeology and how scientists handle anomalous findings (e.g., 130,000-year old Mammoth fossils in San Diego that suggest they may have been butchered by humans)
  • Why archaeologists who support cultural relativism and respect for other people’s origin stories do not apply that same attitude toward, say, Christian creationists or Mormon creation stories
  • How she has been discriminated against as a woman researcher by some Native American groups (and why her otherwise liberal or progressive colleagues don’t defend her here)
  • Her lawsuit against San Jose State University for defaming her as a “racist” and blocking her from further scientific study of the fossil collection she has curated for 17 years
  • What’s behind cancel culture and identity politics
  • The future of archaeology on its present trajectory toward the politicization of science.

If you enjoy the podcast, please show your support by making a $5 or $10 monthly donation.

Categories: Critical Thinking, Skeptic

Another day in Manyeleti: stinking elephant corpses with vultures and hyenas, a leopard sighting, and many other beasts

Why Evolution is True Feed - Sat, 08/17/2024 - 7:00am

NOTE: Click the pictures to enlarge them.

Here are the latest results from our twice-daily game drives at Manyeleti Game Reserve. I’ll put up photos of food, our facilities, and other such stuff later, but for me the important stuff is the animals and their behavior. This post covers the second game drive yesterday and the first one this morning.

Yesterday afternoon we came upon a breeding herd of African bush elephants (I won’t give links or species names henceforth for animals I’ve named previously). The one on the right is a female (angular head), there are two infants of indeterminate sex, and it’s unclear what sex the elephant on the left is.

Rosemary says that the elephant below is probably a male, but can’t be sure because it’s facing us and is also fairly young (ca. 10-12 years). But it is apparently both giving us an alert pose and sniffing the air to see what our vehicle is (elephants have poor eyesight):

This is definitely a female, as shown by the sharp angle of the forehead (adult males have rounder foreheads).

I asked Martim about this bird, and he said this:

I would say this is a Greater Blue-eared Starling, Lamprotornis chalybeus. Although the photo suggests a black belly (rather than blue), I guess this is an effect of the light angle.

A blue wildebeest (Connochaetes taurinus), formerly known as the brindled gnu, is a large antelope that’s common across southern Africa:

Another “lion wedding party,” as our guide Dan calls it. Same pair as yesterday (they can copulate up to 50 times a day over several days), and in the same spot. And, like yesterday, copulation took less than a minute and the mail roared halfway through (is that a lion orgasm?). He then swiped at and roared at a nearby juvenile male (“leave my wife alone!”), lit a cigarette, and then both lions rested:

Afterglow:

The female, perhaps pregnant by now:

A trio of giraffes (Giraffa sp.; they’ve named seven but I don’t believe that number). Several zebras were following them around; apparently other herbivores use giraffes, whose height allows them to see far away, as lookouts to give an alert to nearby predators.

Watch out for antelopes! A sign quickly photographed at high speed. You can see my reflection in the mirror.

Hippos (Hippopotamus amphibius)  in a nearby “dam” (a big water pond). I think this is the closest we’ll get to them. There is only one species and usually you just get to see their eyes and nose. They are, I believe the closest terrestrial animal to whales. They are born and nurse underwater, and can swim before they can walk.

In the last half hour of our evening game drive, we stop, have drinks, and chat. On the house: wine, beer, soda, or gin and tonics (coffee, tea or cocoa in the morning). In the foreground is Dan, our knowledgeable and amiable driver (I’m glad I’ll have him the whole time). This ritual is known as a “sundowner”:

And. . . sundown by the lake, watching the hippos submerge and pop up again:

Last night I skipped dinner as I’ve been eating too much, and retired to my heated bed to read (The Razor’s Edge by Somerset Maugham). As I read, the lions made their “here I am calls”, which sound to me like a combination of snoring and growling. You can hear it below. They do this, apparently, to let other males in their group know where they are. Here’s a video that Rosemary found:

Reading while hearing the lions call nearby was as close to paradise as I can envision.

**********

Another day, another two drives. This covers one we had this m0rning. We started off by passing one of a gazillion termite mounds. Aardvarks use these as places to dig their dens and burrows:

Then onto one of the Two Big Events of the Day. We were clued into it by nearby trees full of vultures:

Martim identified this vulture:

White-backed vulture Gyps africanus (from your photo, the diagnostic trait separating it from the less common Cape Vulture, G. coprotheres, is its black eye)

All the trees were full of vultures! Why? Because there was a dead elephant nearby, pungently rotting away but still recognizable as an African elephant. The corpse was apparently about a week old.

It may have died of old age, but Rosemary says that elephants may die from infectious diseases like “tuberculosis, haemorrhagic septicaemia, trypanosomiasis, pyroplasmosis, foot and mouth disease, pox, bacillary necrosis, salmonellosis, streptococcosis, babesiosis, helminthiasis and ectoparasitism”, as well as rabies and tetanus.

The rotting, stinking corpse was covered with vultures who were picking at it, as well as ripping off bits made available by several hyenas who were also gorging away at this pachyderm buffet.

Note that the elephant still has its tusks, which should be removed before poachers get them.

Note the hyena to the right:

Three hyenas to the left are devouring the corpse; one has its tongue hanging out. The smell, when the wind shifted, was digusting, but I’m sure the birds and hyenas find it delectable and tantalizing:

Spotted hyenas (Crocuta crocuta) come in just two sexes, like all mammals, despite the female having a penis-like organ containing the urethra and vagina. Note: female are NOT a “new” biological sex.

Spotted hyenas are social, live in clans, and are both hunters and scavengers. And they are strong! Wikipedia notes this:

The spotted hyena also has its carnassials situated behind its bone-crushing premolars, the position of which allows it to crush bone with its premolars without blunting the carnassials. Combined with large jaw muscles and a special vaulting to protect the skull against large forces, these characteristics give the spotted hyena a powerful bite which can exert a pressure of 80 kgf/cm2 (1140 lbf/in²), which is 40% more force than a leopard can generate. The jaws of the spotted hyena outmatch those of the brown bear in bone-crushing ability,and free ranging hyenas have been observed to crack open the long bones of giraffes measuring 7 cm in diameter.

According to Martim, the bird below is a “Juvenile Saddle-billed Stork, Ephippiorhynchus senegalensis.” He added, “I hope you get to see the adults!”  Check the link above for the fantastic adult:

Our big spot of the day was a leopard (Panthera pardus), quickly surrounded by game vehicles as the drivers communicated with each other where it was. (I worry about this.) It is a rare sighting, and now I’ve seen four of the Big Five (all but the African buffalo).

But I’m not really ticking off a list, as I’d gladly see even the common animals over and over again. Their behavior is always changing and raises many behavioral and evolutionary questions (e.g. can anything take down a huge and alert giraffe? Answer: yes).

What a gorgeous cat! I was lucky to get a photo as they’re wary, skittish, rare, and there were vehicles nearly surrounding it, which clearly spooked it.  But visitors also help conserve the parks, so there’s an upside, too.

Finally, a good sighting of a Burchell’s zebra (a subspecies of the Plains Zebra). They live in small groups, described by Wikipedia as “harem” or “bachelor” groups, with the former containing one male and a passel of females, and the latter comprising two to eight stallions looking for love.

And now it’s time for lunch and then another game drive. There’s no doubt that we’ll see something interesting. More when I have enough for another post.

Out of Africa,
PCC(E)

Categories: Science

The Skeptics Guide #997 - Aug 17 2024

Skeptics Guide to the Universe Feed - Sat, 08/17/2024 - 5:00am
Election Scams; News Items: Childhood Vaccines, Alien Solar Panels, Stuck in the ISS, Framing and Global Warming, Promoting Homeopathy; Who's That Noisy; Science or Fiction
Categories: Skeptic

Webb Relieves the Hubble Tension

Universe Today Feed - Sat, 08/17/2024 - 4:27am

Sometimes, when scientists measure things differently, they get different results. Whenever that happens with something as crucial to humanity’s long-term future as the universe’s expansion rate, it can draw much attention. Scientists have thought for decades that there has been such a difference, known as the Hubble Tension, in measurements of the speed at which the universe is expanding. However, a new paper by researchers at the University of Chicago and the Carnegie Institution for Science using data from the James Webb Space Telescope (JWST) suggests that there wasn’t any difference at all.

To understand this more, let’s first look at the Hubble tension. Edwin Hubble, the namesake of the Hubble Space Telescope, JWST’s predecessor, first found the universe was expanding when he looked at the speed at which galaxies travel. He found galaxies that were farther away from us were traveling faster than those nearest to us, and the best answer that we have as to why is that the universe itself is expanding.

It does not do so on a scale that we would notice in our daily lives, but on the scale of the space between galaxies, it is definitely noticeable, and in a number of ways. Historically, there have been two different ways to measure this Hubble Constant, as the rate of expansion is known. One involved studying the Cosmic Microwave Background (CMB), and one involved looking at the speed of galaxies, as Hubble did.

Fraser discusses JWST’s impact on the Hubble Tension before the newest paper was released

Data on the CMB have been consistent and precise for a long time. Studies have shown that it points to an expansion rate of 67.5 kilometers per second per megaparsec. To put that into perspective, the universe adds a little under an hour of highway drive time every second but does so on the scale of 3.2 million light years. Again, that expansion is not noticeable on our own scale, but on the immense scales of the universe, it is very noticeable.

However, calculations of that expansion value differ for the second method of measuring galaxies. Traditionally, the value is higher by about 9% and is estimated at 74 kilometers per second per megaparsec. That measurement is typically done using data from two different kinds of stars in those far and near galaxies – Cepheid variables and “Tip of the Red Giant Branch.” 

Dr. Wendy Freedman, one of the paper’s authors, is an expert in using Cepheid variables to measure the distance of things, so getting a chance to use JWST’s even more precise instrumentation was likely an excellent moment for her and her team. But they didn’t stop there. They added data from another type of star, whose use in calculating distance to an object has recently become more popular. Carbon stars are known for their consistent brightness and wavelengths in near-infrared – exactly the wavelengths JWST was designed to study. Using those known properties, the researchers could calculate redshift and other variables, allowing them to use this new technique to validate their version of the Hubble Constant.

Measuring distance is hard in astronomical terms, as Fraser discusses in this video.

The number they found was much closer to that calculated by the CMB method – 70 kilometers per second per megaparsec, a difference of only 3.5%. That’s within the bounds of estimations for most astronomical calculations, so the authors suggest there might not be a Tension between the two measurements. 

That claim will undoubtedly spark some controversy in the astronomical community, as there are some theories with plenty of proponents to explain the difference in measurements. But, as instruments like JWST provide more and more detailed data and researchers are better able to constrain some of the astronomically large values, one day, we might prove that this existential crisis that has been sitting at the center of cosmology for decades might never have been a thing at all.

Learn More:
University of Chicago – New Webb Telescope data suggests our model of the universe may hold up after all
Freedman et al. – Status Report on the Chicago-Carnegie Hubble Program (CCHP): Three Independent Astrophysical Determinations of the Hubble Constant Using the James Webb Space Telescope
UT – Astronomers Rule Out One Explanation for the Hubble Tension
UT – If Our Part of the Universe is Less Dense, Would That Explain the Hubble Tension?

Lead Image:
Scientists used new data taken by the James Webb Space Telescope to make a new reading of the rate at which the universe is expanding over time, by measuring light from 10 galaxies including the one known as NGC 3972, above.
Credit – Yuval Harpaz, data via JWST

The post Webb Relieves the Hubble Tension appeared first on Universe Today.

Categories: Science

Saturday: Hili dialogue

Why Evolution is True Feed - Sat, 08/17/2024 - 2:22am

Meanwhile, in Dobrzyn, Hili and Szaron are preparing for a debate:

Szaron: What are you doing? Hili: I’m seeking the right position for further discussion.

Szaron: Co ty robisz?
Hili: Szukam właściwej pozycji do dalszej rozmowy.
Categories: Science

Project Helianthus – a Solar Sail Driven Geomagnetic Storm Tracker

Universe Today Feed - Fri, 08/16/2024 - 3:53pm

Solar storms captured the imagination of much of the American public earlier this year when auroras were visible well south of their typical northern areas. As the Sun ramps into another solar cycle, those storms will become more and more common, and the dangers they present to Earth’s infrastructure will continue to increase. Currently, most of our early warning systems only give us a few minutes warning about a potentially destructive impending geomagnetic storm event. So a team of researchers from Sapienza University in Rome and the Italian Space Agency proposed a plan to sail a series of detectors to a point out in space where they could give us an early warning. And they want those detectors to stay on station without rockets.

The mission, known as Helianthus, the official name for a sunflower, was initially described at the 6th International Symposium on Space Sailing in June 2023. In a presentation, the Italian scientists explained the mission objective as providing different alarm levels for geomagnetic storms. But more importantly, the mission design would give humanity 100 minutes of warning for fast-moving solar storms, and a large solar sail would entirely control the mission.

Current warning times for solar storms are only a few minutes at best, as the detectors watching for them are located in Low Earth Orbit. To provide much earlier warning times, Helianthus would place a series of specially designed detectors at a point known as sub-L1 in the Sun/Earth system. While it’s unclear what exactly “sub-L1” means in this context, a typical Sun/Earth Lagrange point is about 1.5 million km toward the Sun—about four times as far away as the Moon is from Earth.

Fraser has a soft spot for solar sails, as he describes here.

Getting there using a solar sail is the hardest part of the Helianthus mission. Most solar sails use photons to push themselves outward in the solar system since the source of those photons is the Sun, which is, by definition, the inner part of the solar system. So, getting to a point closer to the Sun than the Earth and then staying there seems counterintuitive. 

How they will do so is the subject of one of a series of papers from the research team behind the project. Others describe the instrumentation, such as a lightweight coronograph and an x-ray spectrometer, and even structural components, such as the booms used to deploy the solar sails and the membranes those sails would be made of. 

Some of the most interesting research described in these papers shows how Helianthus would hold station at a sub-L1 point while still having its solar sail fully deployed. Instead of using rockets for station-keeping, the mission plans to use a series of electrochromic or liquid-crystal actuators to make approximately four station-keeping maneuvers a year. 

Solar sails have been a concept of awhile – Fraser explains what they do.

Driving the development of most of these systems and methodologies is an interest from the Italian Space Agency to improve workforce development in these areas. As stated in one of the papers, they intend to achieve “challenging national development” regarding solar-sail propulsion. And the geomagnetic storm tracker isn’t their only use-case – the same researchers also planned out an Earth-Mars transfer orbit that uses the same solar propulsion technology.

For now, it’s unclear whether Helianthus has the financial backing to make it to the finish line for actual deployment. While some prototypes of the lightweight instrumentation have been built, there is still a lot of engineering work to do before any such solar-sail mission sees the light of day. If it is to do so, the Italian Space Agency must show how committed they are to that idea.

Learn More:
Boni et al. – Structural response of Helianthus solar sail during attitude maneuvers
Vupetti et al. – ASI Project Helianthus: Solar-Photon Sailcraft for Geostorm Early Warning
UT – Solar Sails Could Reach Mars in Just 26 Days
UT – NASA’s New Solar Sail Has Launched and Will Soon Deploy

Lead Image:
An illustration of the Light Sail 2 craft with its solar sails deployed.
Image Credit: Josh Spradling / The Planetary Society

The post Project Helianthus – a Solar Sail Driven Geomagnetic Storm Tracker appeared first on Universe Today.

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