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Extremely cold atoms that perpetually move in repeating patterns could be a promising building block for quantum computers

A few months ago, I wrote about how antivaxxers misrepresent vaccine safety studies to portray vaccines as dangerous, using a large study of outcomes in adults as an example.. They're doing it again, but this time it's a large study of COVID-19 vaccines in children.

The post How antivaxxers weaponize vaccine safety studies to falsely portray vaccines as dangerous, part 2: The children first appeared on Science-Based Medicine.

In his classic book On the Structure of Scientific Revolutions, the philosopher Thomas Kuhn posited that, for a new scientific framework to take root, there has to be evidence that doesn’t sit well within the existing framework. For over a century now, Einstein’s theory of relativity and gravity has been the existing framework. However, cracks are starting to show, and a new paper from researchers at Case Western Reserve University added another one recently when they failed to find decreasing rotational energy in galaxies even millions of light years away from the galaxy’s center.

Galaxies are known to rotate – even our solar system travels in a circle around the center of the Milky Way galaxy at around 200 km per second, though we can’t perceive any motion on human time scales. According to Newtonian dynamics, this rotational speed should slow down the farther away a star is from the center of a galaxy. However, observations didn’t support this, showing that the speed kept up no matter how far away the star is.

That led scientists to create another force impacting the speed of rotation of the farthest-out stars. Today, we commonly call it dark matter. However, scientists have also spent decades trying to puzzle out what exactly dark matter is made of and have yet to come up with a coherent theory.

Anton dives into a weird quirk of galaxy rotation.
Credit – Anton Petrov YouTube Channel

But in some cases, even the existence of dark matter as we know it doesn’t match the observational data. Dr. Tobias Mistele, a post-doc at Case, found that the rotational speed of galaxies doesn’t drop off, no matter how far out they are and no matter how long they’ve been doing so. This data flies in the face of a traditional understanding of dark matter, where its gravitational influence is felt by a “halo” surrounding the dark matter itself. Even these dark matter halos have an effective area. Dr. Mistele and his co-authors found evidence of maintained rotational speed that should be well outside the sphere of influence of any dark matter halo existing in these galaxies.

To collect this data, the authors used a favorite tool of cosmologists – gravitational lensing. They collected data on galaxies that were far away and had their light amplified by a galaxy cluster or similarly massive object that was nearer. When collecting the data, Dr. Mistele analyzed the speed of rotation of the stars in a galaxy and plotted it against the distance of those stars from the galaxy’s center. This is known as a “Tully-Fisher” relation in cosmology.

The result was an almost perfectly straight line – the rotational speed of stars in a galaxy did not seem to diminish with distance from the galaxy’s center, as both traditional Newtonian dynamics and relativity via dark matter predicted it would. So, what alternative explanations are there?

Why do galaxy rotation curves matter? Nora explains.
Credit – Nora’s Guide to the Galaxy YouTube Channel

Paper co-author Stacy McGaugh points out in a press release that one theory in physics accurately predicted the data his team had collected—the modified Newtonian Dynamics (or MOND) theory. Designed explicitly to account for things like galaxy rotations, MOND was developed in 1983 and remains controversial to this day. It struggles with things like the gravitational lensing with which the paper’s data was collected. 

That disconnect points to the need for a deeper understanding of gravity – what Kuhn called a “crisis,” which many cosmologists already believe is afflicting the discipline. While there is no current consensus on what might resolve that crisis, the evidence is mounting for the need for resolution. If we’re truly going to understand our place in the universe, we will eventually need to figure out a solution – it just might take a while.

Learn More:
CWRU – New, groundbreaking research shows that rotation curves of galaxies stay flat indefinitely, corroborating predictions of modified gravity theory as an alternative to dark matter
Mistele et al. – Indefinitely Flat Circular Velocities and the Baryonic Tully-Fisher Relation from Weak Lensing
UT – Will Wide Binaries Be the End of MOND?
UT – New Measurements of Galaxy Rotation Lean Towards Modified Gravity as an Explanation for Dark Matter
UT – The Earliest Galaxies Rotated Slowly, Revving up Over Billions of Years

Lead Image:
Illustration of the galaxy rotation curve used in the research.
Credit – Mistele et al.

The post Rotation Curves of Galaxies Stay Flat Indefinitely appeared first on Universe Today.

In the years before the JWST’s launch, astronomers’ efforts to understand the early Universe were stymied by a stubborn obstacle: the light from the early Universe was red-shifted to an extreme degree. The JWST was built with extreme redshifts in mind, and one of its goals was to study Galaxy Assembly.

Once the JWST activated its segmented, beryllium eye, the Universe’s most ancient, red-shifted light became visible.

The light emitted by the first galaxies is not only faint but has been stretched by billions of years of cosmic expansion. The galaxies that emitted that light are called high-redshift galaxies, where redshift is indicated by the letter z. Since its shifted into the red, only infrared telescopes can see it. Telescopes like the Hubble and the Spitzer can see some redshifted light. But the JWST has far more power than its predecessors, allowing it to effectively see further back in time.

“Using advanced instruments such as JWST allows us to study more distant galaxies with greater detail than ever before.”

Yicheng Guo, Department of Physics and Astronomy, University of Missouri

Observations have shown that galaxies grow large through mergers and collisions and that up to 60% of all galaxies are spirals. But how did the process play out? When did the first spirals emerge? An answer to that question trickles down and affects other outstanding questions about galaxies.

Spiral arms host active star formation, where successive generations of stars create heavier elements. Those elements allow rocky planets to form and are also a requirement for life. So, an understanding of when spiral galaxies formed helps astronomers understand the parameters of star formation, rocky planet formation, and even, potentially, the appearance of life.

“Knowing when spiral galaxies formed in the universe has been a popular question in astronomy because it helps us understand the evolution and history of the cosmos.”

Vicki Kuhn, Department of Physics and Astronomy, University of Missouri

One of the JWST’s observing efforts is CEERS, the Cosmic Evolution Early Release Science Survey. In CEERS, the JWST was the first telescope to capture images of the Universe’s early galaxies. CEERS found the most distant active supermassive black hole and galaxies that existed in the distant past when the Universe was only about 500 to 700 million years old.

Image of CEERS scientists looking at the Epoch 1 NIRCam color mosaic in TACC’s visualization lab at UT Austin. Credit: R. Larson

New research published in The Astrophysical Journal Letters examined galaxies from CEERS to determine how many of these ancient galaxies were spirals. The title is “JWST Reveals a Surprisingly High Fraction of Galaxies Being Spiral-like at 0.5 ≤ z ≤ 4.” The first author is Vicki Kuhn, a graduate student in the University of Missouri’s Department of Physics and Astronomy.

“Scientists formerly believed most spiral galaxies developed around 6 to 7 billion years after the universe formed,” said Yicheng Guo, an associate professor in Mizzou’s (University of Missouri) Department of Physics and Astronomy and co-author of the study. “However, our study shows spiral galaxies were already prevalent as early as 2 billion years afterward. This means galaxy formation happened more rapidly than we previously thought.”

In their research letter, the authors examined 873 galaxies from CEERS with redshift 0.5 ≤ z ≤ 4 and stellar mass ≤ 1010 solar masses. They found that 216 of them had spiral structures. “This fraction is surprisingly high and implies that the formation of spiral arms, as well as disks, was earlier in the Universe,” the authors write in their paper.

This figure from the research shows some of the galaxies in the sample. Redshift increases from left to right, and the rows from top to bottom show the range of galaxies classified as spiral to nonspiral. “Spiral structure is easier to see at the lower redshift ranges and becomes less pronounced at higher redshifts.” the authors write. The top three rows show galaxies identified as spirals with strong confidence, the middle three rows show galaxies identified as spirals with less confidence, and the bottom row shows non-spirals. Image Credit: Kuhn et al. 2024

“Knowing when spiral galaxies formed in the universe has been a popular question in astronomy because it helps us understand the evolution and history of the cosmos,” said lead author Kuhn. “Many theoretical ideas exist about how spiral arms are formed, but the formation mechanisms can vary amongst different types of spiral galaxies. This new information helps us better match the physical properties of galaxies with theories — creating a more comprehensive cosmic timeline.”

Spiral galaxies started as disks of gas. These results, when combined with other studies of high-redshift galaxies, paint a picture of the history of galaxy evolution in the early Universe. Dynamically hot gaseous disks appear around z = 4 to 5. These disks settled down to become dynamically cold gaseous disks around z = 3 to 4. Since stars form when gas cools and clumps together, large numbers of dynamically cold stellar disks appeared at z = 3 to 4, as indicated by their spiral arms.

This research also illuminates the relationships between spiral arms and other galaxy substructures. Gas-rich disks at high redshifts are very turbulent, and gravitational instabilities form giant clumps of star formation. Later, hot stars disperse young galaxies’ velocities, allowing them to settle down and become less turbulent. These bulges of star formation can also merge, helping to further stabilize the disks. The conclusion is that gravitational instabilities primarily lead to spiral arms, with clumps playing a secondary role since they co-exist with spirals at high redshifts.

The authors point out some caveats in their work. Galaxies that are merging can appear as spirals. The long tails prevalent during mergers can look like spiral arms, so their numbers could be off a little. But on the other hand, spirals can also look like mergers, adding to the uncertainty. “This situation is more severe for galaxies at z > 2, as the merger fraction is believed to be higher then,” the authors write.

But these facts likely don’t affect the conclusion much. “The observed spiral fraction decreases with increasing redshift, from ~43% at z = 1 to ~4% at z = 3,” the researchers conclude. So, while spirals are rarer the further we look back in time, they’re still more plentiful earlier than thought.

“Using advanced instruments such as JWST allows us to study more distant galaxies with greater detail than ever before,” Guo said. “A galaxy’s spiral arms are a fundamental feature used by astronomers to categorize galaxies and understand how they form over time. Even though we still have many questions about the universe’s past, analyzing this data helps us uncover additional clues and deepens our understanding of the physics that shaped the nature of our universe.”

The post Almost a Third of Early Galaxies Were Already Spirals appeared first on Universe Today.

Many years ago, there was a viral YouTube video called “History of the entire world, i guess,” which has been an endless source of internet memes since its release. One of the most prominent is also scientifically accurate—when describing why animals couldn’t start living on land, the video’s creator, Bill Wurtz, intones, “The Sun is a deadly laser.” 

Early in planetary development, the X-ray and ultraviolet radiation level of a planet’s host stars could sterilize the entire planet’s surface, even if it is in the so-called “habitable zone.” To narrow down the search for potentially habitable planets, the team at the Chandra X-ray Observatory and XMM-Newton telescopes took a look at stars that had planets in their habitable zone and analyzed them for whether the star’s radiation itself might preclude life as we know it from developing there.

Over ten observational days on Chandra and 26 on XMM-Newton, scientists observed 57 stars close enough to Earth to have their exoplanets explored by the next generation of exoplanet-hunting telescopes, such as the Habitable Worlds Observatory. While not all of them had known exoplanets, at least some did. 

YouTube Video detailing the research.
Credit – Chandra X-ray Observatory YouTube Channel

However, those exoplanets were typically much larger than Earth, even if they were in the habitable zone. It is much easier to detect giant planets orbiting close to their stars using modern date exoplanet detection techniques like transiting and astrometry. A press release from Chandra notes how many more rocky exoplanets the size of Earth are likely hiding around these stars, but our limited detection methods are not yet capable of finding them.

That isn’t to say we can’t learn much about their host stars, though, and that is where the data from the paper presented to the 244 meeting of the American Astronomical Society in Madison, Wisconsin, comes in. Watching the X-ray emissions of these local stars allowed the team to narrow down what stars to look at for potentially habitable exoplanets, thereby allowing the future powerful planet hunters to focus their observational time on candidates that are more likely to produce results.

Fraser details the path towards detecting 100 million exoplanets over the next thirty years.

Some of the stars in the study were indeed promising, with X-ray exposure similar to, or even less than, that of Earth when life began forming here billions of years ago. The data measured several aspects of the star’s output, including their brightness, how much energy those X-rays pack, and how powerful the star’s flares are. All of those could significantly impact the ability of life to form on any orbiting planets.

Fifty-seven stars is a relatively small sample size. Still, the proof of concept for how Chandra and XMM-Newton can be used to scout potential systems for habitability can be scaled up before any long-term observing mission for the new planet finders—no doubt they will be shortly as HWF and other missions get closer to fruition.

However, Chandra itself is facing budgetary challenges, causing many in the media to speculate that it might soon go “dark.” XMM-Newton itself is almost a quarter century old at this point, and a new joint X-ray mission, XRISM, is facing its own technical challenges, with a stuck door limiting it from observing in some of its potential wavelengths.

With luck, X-ray astronomy will continue to evolve over the next few decades. Part of that mission might be leading the scouting team for one of the most important astronomical searches humanity is currently undergoing.

Learn More:
Chandra Press Room – Coming in Hot: NASA’s Chandra Checks Habitability of Exoplanets
UT – Chandra’s X-ray Vision Combined With JWST Reveals Even More Details About the Universe
UT – A Collection of New Images Reveal X-Rays Across the Universe
UT – Chandra and JWST Join Forces in a Stunning Series of Images

Lead Image:
Illustration of hot exoplanet.
Credit – NASA/CXC/M.Weiss

The post Which Stars are Lethal to their Planets? appeared first on Universe Today.

Not content with shapes in two or three dimensions, mathematicians like to explore objects in any number of spatial dimensions. Now they have discovered shapes of constant width in any dimension, which roll like a wheel despite not being round

I’ve been meaning to write about this issue for a while, as I covered the beginning of it (see all posts here).  And the longer I delayed, the more complicated the issue became, until I became unable to remember everything, much less synthesize it.

The story in short: two people made a documentary movie, “The Fall of Minneapolis” (watch it here) maintaining that George Floyd was not murdered by Minneapolis police officer Derek Chauvin, but died of his many ailments (including a big titer of fentanyl in his blood), not from having his neck compressed so that he was asphyxiated. (Nor, the movie maintained, was his neck really compressed: Chauvin was supposedly using procedures taught him by his department).  The movie convinced both John McWhorter and Glenn Loury, as well as me, that Chauvin was not guilty of murder—at least if you use the “reasonable doubt” standards mandated in such a case.

Then a former Washington Post reporter, Radley Balko, wrote a multipart attack on the movie on his webpage arguing that the thesis of “The Fall of Minneapolis” was wrong on several counts, including its claim that Floyd was not asphyxiated.  Balko’s analysis was enough to convince Loury (and, to some extent, McWhorter) that they were wrong—that perhaps Chauvin really did murder Floyd. Having read all this stuff, and intending to post on it, the sheer magnitude of the task defeated me. But I felt remiss in not calling attention to Balko’s attack. And I couldn’t come to my own conclusions, for essential material, like the training procedure for Minneapolis police, was missing.

In January, Coleman Hughes, now an essayist for The Free Press, wrote a piece arguing that Chauvin was not a murderer but a scapegoat for all those who wanted him convicted for supposedly killing a black man.  Hughes and Balko went back and forth about having a debate, and eventually had one, but one that, says Coleman, was stacked because the moderators were on Balko’s side.

Now we have the longest article yet published in the Free Press, a second piece by Coleman Hughes reiterating his claim that Chauvin should not have been found guilty of the murder of Floyd. His claim, as you’ll see below (click on the headline to read) is not that Chauvin was clearly innocent, but that the standards of evidence supposed to be applied by the jury, involving “reasonable doubt,” would have found such doubt in the prosecution’s evidence against Chauvin. Ergo, Chauvin should have been found not guilty.

The article is informative and, to me, convincing—Chauvin seems to have gotten a bad trial, including jurors biased against the prosecution, a prosecution that didn’t properly give the evidence, a defense that didn’t do its job, a judge who didn’t seem to know what was going on, and the venue (and the judge’s instructions) terrifying the jurors that if they didn’t find Chauvin guilty, there would be riots.

Read it; it has all the links that you need, including to Balko’s work and the debate.

Here’s Coleman’s main points in the essay:

The purpose of this essay is to set the record straight on Balko’s claims, which range from useful counterarguments to misleading assertions and outright errors. Our disagreements fall into two basic categories: the first is the question of how exactly Floyd died. And the second pertains to whether or not Chauvin was following his training.

One final, important note before I dive in: Balko’s series generally mischaracterizes my essay as arguing for the definite truth of various propositions—or doing a “just asking questions” routine—when in fact I was arguing for the existence of reasonable doubt.

In a typical debate, each side is trying to prove a claim by summoning more evidence than the other side—“guns are helpful” vs. “guns are harmful,” for instance. The burden assigned to each side is symmetric. If either side summons more evidence than the other, then that side wins.

Criminal trials are deliberately not like this. They are highly asymmetric—and that’s intentional.

It’s not enough for a majority of the evidence to indicate guilt. And it’s not enough if the defendant’s guilt is “highly and substantially more likely to be true than untrue.” That is the “clear and convincing evidence” standard.

Rather, “beyond a reasonable doubt” means that “there is no other reasonable explanation that can come from the evidence presented at trial” other than the defendant having committed the crime in question. Keep that phrase—no other reasonable explanation—at the top of your mind. My Free Press piecewas written from the perspective of reasonable doubt. In the essay, I summed up my thesis like this: “In short, there are two major justifications to reasonably doubt Chauvin’s felony murder charge: whether he caused Floyd’s death and whether he committed a felony.”

There remains significant uncertainty about the death of George Floyd—uncertainty that was not settled at trial. My purpose in this essay, as in my original column, is not to settle that uncertainty for good by putting forward a definitive version of events—that is not the defense’s burden anyway. My purpose is to convey the existence of other reasonable explanations.

With that throat-clearing out of the way, let’s move on to Balko’s substantive arguments.

The arguments turn on what really killed George Floyd (he had several medical conditions and was full of drugs), whether the restraint technique used by Floyd really involved asphyxiation, whether that technique was part of the regular training, verbal or written, by the Minneapolis police, what “homicide” means to a coroner versus a jury, whether the jury was tainted by people who were pro-Floyd to begin with, and what are the criteria for conviction.  And more.

Read it for yourself; I’ll simply give Hughes’s conclusions in brief:

I think there was clearly reasonable doubt on whether Chauvin caused Floyd’s death. There were two rival theories of his death: the positional asphyxia theory (put forth by Dr. Tobin and endorsed by the prosecution), and the adrenaline surge theory (put forth by Dr. Baker and rejected by the prosecution). Both were reasonable theories, but only the former implicated Chauvin. That alone should have introduced reasonable doubt on all three charges.

As for whether Chauvin assaulted Floyd—that is, whether he used unlawful force outside the scope of MPD training—reasonable people can disagree on whether there was reasonable doubt. Balko would emphasize that MPD [Minneapolis Police Department] officers were trained to worry about positional asphyxia, move people to the side-recovery position as soon as possible, and use the hobble.

. . . .What are the odds that Chauvin received a trial in accordance with these instructions? Given the jurors who spoke about their fears for their physical safety, given the juror who was found wearing a “GET YOUR KNEE OFF OUR NECKS” t-shirt before the trial, given that everyone knew the city would burn if he was acquitted yet the trial location wasn’t changed, and given that the jury wasn’t sequestered in one of the most talked-about trials in modern American history—I would submit that the odds are close to zero.

Ultimately, we’ll never know how a jury might have weighed the evidence under even halfway normal conditions. And it is probably too late for any of this to matter for Chauvin himself. What is clear, however, is that there were many reasons to doubt that Chauvin was guilty of the crimes he was charged with, and the American public should not be afraid to say so.

Once again, this is a complicated issue that you should judge for yourself, ideally after having watched the movie, read Balko’s ripostes, and having read at least Hughes’s second essay: the one quoted here.  Chauvin’s conviction for murdering Floyd spawned the “racial reckoning” that has persisted until today, and regardless of whether we need a reckoning or not, the conviction that started it all needs to be carefully examined. More important, the conviction of a man for a “crime” that carries reasonable doubt is a miscarriage of justice that needs to be rectified (Chauvin is serving 22 years in prison, and will be 60 when he’s released). In my view, they need to try Chauvin again, but bringing in all the evidence and with a jury that is not intimidated.

Tribalism can be toxic, yet we need more of it if we are to meet today’s global challenges, argues one anthropologist. His research reveals how to create a “teratribe”

A robot named Musashi with a human-like "skeleton" and "musculature" can perform basic driving tasks – but this isn’t the safest approach to autonomous transport

This new paper in Nature gives a rare picture of human sacrifice among ancient Mayans from the Yucatán peninsula in Mexico.  Paleoanthropologists had found remains before, mostly children, preserved by being tossed in sacred cenotes (wells), but this group of 64 ancient individuals was not only collected, but their DNA was analyzed from the ear bones, giving surprising results about genetic relatedness.

As with the Aztecs, human sacrifice was a fixture of ancient Mayan society, though the people killed (in this case, children) were probably captives rather than residents of the place where the killers lived. Sacrifice could have occurred via either decapitation, extraction of the heart from living individuals, or killing with arrows.

Click below to read the piece, or find the pdf here.  

The figure below shows where the remains were found: in a chultún (an underground cistern) next to an airport runway near the ancient Mayan city of Chichén Itzá (now a World Heritage Site), which flourished between about 600 and 1200 A.D. This map gives the location:

(From the paper) a, Location of the Maya region in the Americas. b, Geographical locations of Chichén Itzá and Tixcacaltuyub in the Yucatan Peninsula. c, Stratigraphy for the chultún and the adjacent cave in which the burial was found (adapted from ref. 4). d, Location of the chultún within the archaeological site of Chichén Itzá and its relation to El Castillo (adapted from ref. 10). Modern roads are marked in light grey; the chultún abuts an airport runway.

They found the bones of 64 individuals, carbon-dated as being from the 7th to the 12 centuries AD. How did they know how many individuals were represented in their sample? Because they recovered 64 left petrous parts, the bit of the skull’s temporal bone that surrounds the inner ear (this bone, sequestered away from the outside of the skull, is often used to extract ancient DNA).  64 left petrous bones means 64 individuals.

First, every one of the individuals was a male between 3 and 6 years old, showing that the Mayans preferred to sacrifice young boys. Why? It’s not clear, but there’s speculation that sacrifices helped local maize crops flourish (the method of sacrifice wasn’t specified in the paper).  However, other sacrificed individuals recovered, as in the famous sacred cenote, have been mixtures of males and females, but also overrepresented with children. The authors don’t speculate why, in this location, only boys were killed.

The ancestry of the sacrificed individuals was compared among each other, as well as to 68 individuals of Mayan descent living the nearby town of Tixcacaltuyub. One surprising finding was that those sacrificed included two pairs of identical (monozygotic) twins (easily seen in DNA, which is identical among two different earbones).  The authors note that twins held a special position in Mayan mythology.  But, as the plot of “pairwise mismatch rates” shows below), 11 pair of individuals were “close relatives”, represented by the hollow diamonds (the twins, with a mismatch rate of zero, are the two pairs of twins.  The authors speculate (see below) that the individuals came from a single big event of mass killing.

The paper doesn’t say how “close” the “close relatives were”, or whether they were contemporaneous, like brothers, but given the age of the individuals, it seems likely that the related pair members came from the same family.

(From paper): e, Genetic pairwise mismatch rate (PMR) for child pairs in the chultún identifies 11 close relative pairs (hollow diamonds), including two pairs of monozygotic twins (highlighted in grey). A low overall PMR for unrelated individuals (black triangles) confirms low genetic diversity in the population; only pairs with PMR < 0.20 are visualized in the plot. See Supplementary Fig. 2 for individual annotations.

The comparison of the DNA of the sacrificed children with that of living people in Tixcacaltuyub, as in the principal-component cluster graph below, showed that the sacrificed individuals )”YCH”, dark purple stars) fell into a cluster of Native Americans, other Mayan individuals, people from Belize, and individuals from the nearby town (“TIX”, light blue stars), and were considerably different from individuals in Africa, Asia, and Oceania, as expected. (This shows diagnostic genetic differences between geographic groups, demonstrating that the idea of “races”—defined as “diagnostically genetically differentiated populations”—is not purely a social construct, but contains biological information.)  However, the ancient sacrificed individuals, which also had a dollop of genes from the Caribbean, didn’t particularly cluster with the present day Mayans living nearby, who had their own admixture of genes from Africa and Europe, perhaps reflecting turnover of populations over time. In the sixteenth century there was a big poulation bottleneck, perhaps due to diseases introduced by Europeans. In fact, this bottleneck reduced the population of what is now Mexico by 90%!)

(From paper): (From paper): a, PCA showing ancient Chichén Itzá (YCH) individuals and present-day Tixcacaltuyub (TIX) in a worldwide PCA plot.

One other bit of information. We are able, looking at contemporary DNA sequences of a population, to judge whether natural selection is acting on genes or groups of genes. If variable genes such as the HLA (“human leukocyte antigen”) genes involved in immune response show coordinated variation (that is, variant “A” of one gene tends to co-occur with variant “B” of another gene in individuals), this gives evidence that selection is acting on groups of genes—in this case genes affecting immunity. The authors identified several HLA variants that look like they were subject to selection, and also tested some by making copies of sequences of some HLA variants and seeing how strongly they bound to proteins derived from Salmonella bacteria (strong binding means that the HLA proteins were reacting and presumably neutralizing the bacterial proteins). The authors suggest that the selection acting to promote the rise in frequency of some HLA variants was due to typhoid or paratyphoid-like infections.

The upshot:  Although the data from HLA genes does indicate that there was selection for immunity in both ancient and historic times, what I find most interesting is that the sacrifice involved children, all male children, and many were close relatives. This, at least, gives us a pretty strong sociological picture of one aspect of ancient Mayan culture. To quote the authors,

In comparing the subadults in the chultún to other ancient and present-day populations in the Maya region, we find evidence of long-term genetic continuity, which also suggests that the sacrificed children and sibling pairs at Chichén Itzá were obtained from nearby ancient Maya communities. Among present-day individuals at TIX, we detect evidence of European and African admixture since the Contact period.

and

Overall, 25% of the children had a close relative within the assemblage, suggesting that the sacrificed children may have been specifically selected for their close biological kinship. Moreover, this may underestimate the true number of relatives present in chultún as only 64 of the estimated 106 individuals in the chultún had a preserved petrous portion of the left temporal bone available for analysis. The further finding that the closely related children in each set seem to have consumed a similar diet and died at a similar age suggests that they have been sacrificed during the same ritual event as a pair or twin sacrifice.

and, finally,

The discovery of two sets of identical twins, as well as other close relatives, in a ritual mass burial of male children suggests that young boys may have been selected for sacrifice because of their biological kinship and the importance of twins in Maya mythology. We show that, at a genome-wide level, the present-day Maya of Tixcacaltuyub exhibit genetic continuity with the ancient Maya who once inhabited Chichén Itzá and we demonstrate through several lines of evidence the involvement of the HLA region in a pathogen-driven selection event(s) probably caused by infectious diseases brought into the Americas by Europeans during the colonial period.

The interest of the Mayans in identical twins reminds me of Josef Mengele in Auschwitz, who also took a particular interest in twins, but in his case he did gruesome experiments on them before killing them.

By combining two approaches to quantum computing into one device, Google has been able to simulate the behaviour of magnets in detail - and found discrepancies with our current understanding of certain magnet systems

Today’s batch of marine-life photos comes from math professor Abigail Thompson at UC Davis. We’ve met her before (in 2018) when she was widely and publicly demonized for simply writing a piece criticizing diversity statements (see this post, which is missing many links). But today we see her photographic skills with pictures of nudibranchs and other marine invertebrates. As she says, “I spend a lot of time up to my knees in cold water.”  Abby’s captions and IDs are indented, and you can click on the photos to enlarge them. And remember that nudibranchs are molluscs.

These are all from the same 1-mile stretch of Northern California coastline during the past year.   The pictures are mostly  taken from above the water, at low tide.  Most are of sea-slugs, beautiful animals with a terrible (common) name (although nudibranch sounds a bit better), with some ID help from inaturalist.   Lots more pictures here or at inaturalist.

Ectopleura marina A hydroid, a (very small) animal that just stays put:

Acanthodoris rhodoceras, nudibranch:

Aeolidia loui, nudibranch:

Polycera atra, nudibranch:

Phidiana hiltoni, nudibranch:

Eurylepta californica, a species of marine flatworm:

Triopha catalinae, nudibranch:

Crassadoma gigantea,  actually, a not-very-big scallop.   The black dots are eyes:

Epactis handi, a fairly rare (and beautiful) anemone:

Doto kya (probably), nudibranch:

Equipment: One photo was with an iPhone through a microscope, but the rest were taken with an Olympus TG-6 or -7, the almost-indestructible tidepoolers favorite, with a sensational macro setting (I did manage to destroy the TG-6, but it took real effort).

Note: Three new photos added by readers’ request:

Coast-in-a-fog; that’s a deer in the middle.   They come down to the water at night (for salt?) so if you’re out very early in the morning you see them there:

View towards Pt. Reyes from the top of a ridge:

 I think those are pelicans on top of the rocks, at sunset:

This is a great scientific question because it challenges how we ask and answer scientific questions. Are animals conscious? This is a question discussed in a recent BBC article that peaked my interest. They eventually get to a question that they should have opened with – how do we specifically define “consciousness”? We can’t answer questions about an alleged phenomenon unless we know what it is. Ideally we would have an operational definition, a list of inclusion and exclusion criteria that need to be met to fit the definition.

So I am going to start with this question – how do we define consciousness? I think there are at least two different contexts here. In medicine we use the term to refer to different states in people. We know, from our own experience, that humans are conscious, and from one point of view we define consciousness as what humans experience. We assume other fully functioning humans are conscious because we are, and there is no reason to think that other beings with brains similar to our own have a fundamentally different phenomenon driving their behavior. In fact part of consciousness is a theory of mind, which is the ability to think about what other beings think and feel.

So when we talk about consciousness in humans the question revolves around the health and functioning of the brain. Someone might be unconscious, or comatose, or vegetative. We label these as “disorders of consciousness”. We might also discuss consciousness in the context of healthy altered states, such as sleeping. Here we do have very specific technical definitions, based upon neurological examination. However, even here our definition is being challenged by new technology, such as functional MRI scanning, which may shows signs of subtle consciousness in someone who does not show signs on exam.

An entirely separate question is whether any non-human entity is or can be conscious. This includes machines (general AI) and animals. The challenge here is that we cannot base any conclusion on extrapolation from ourselves. We cannot experience what another entity is thinking or feeling. We can only observe their behavior. This has led some scientists to take an approach called behaviorism, which only seeks to understand and model behavior, and not to examine or speculate about internal states. In humans behaviorism has largely given way to cognitive psychology, which explicitly deals with internal cognitive states.

So – can we have a cognitive psychology of animals or are we limited to behaviorism? There is one difference with humans – language. Humans can tell you how they feel and what they think, because humans have language. It is controversial whether or not animals can learn sign language and communicate like humans, so let me put that question aside for this essay. Without language we only have behavior. The question therefore is – can we infer from behavior alone the internal cognitive state of a non-human?

There are two types of error we can make here. One is to anthropomorphize, to assume that an animal behavior which superficially seems analogous to a human behavior results from a similar underlying mental state. We tend to project human feelings and experiences onto other agents operating in the world. In fact, we are wired to so do. The other type of error is to dismiss non-human consciousness solely because of the absence of language, or because that consciousness is different than typical human consciousness.

This, in my opinion, leads to an inherent dilemma in asking the question about consciousness. The answer will be yes or no depending on how narrowly or broadly we define consciousness. The question, in a way, becomes meaningless (except at the extremes, rocks are not conscious while humans are the gold standard of consciousness). For everything between rocks and humans, starting with viruses, the best approach might be to consider consciousness as a continuum. Actually, I don’t think viruses are on this continuum, but bacteria might be (with a broad enough definition). By the time you get to multicellular creatures, we are seeing complex behavior that we could anthropomorphize and call consciousness, or broaden the definition enough to include their behavior.

Here is one example from the BBC article – bees have been observed to roll little balls for no apparent useful purpose. Some researchers believe the bees do this because they enjoy it, and therefore it is the equivalent of playing. I have a problem with this conclusion. I think it is a great example of the first type of error – anthropomorphizing. We can’t really know what the bees are experiencing, and there could be many reasons why their primitive behavioral algorithms encoded in their networks would include such behavior. It could easily be an incidental behavior, something the system does while idling. Or perhaps it reduces the probability that the bees will engage in other behavior that might be counterproductive. Or it is a tradeoff, a behavior that emerges when the algorithm is programmed for some other useful behavior. But it’s a real stretch to say the bees are “enjoying” the behavior and therefore they are conscious in a way that is closer to humans than we thought. I don’t buy it. Or at least, I don’t think that conclusion serves any scientific purpose.

Are bees conscious? Sure, if you define consciousness to include whatever bees experience. Does that help explain their behavior? I’m not convinced.

Because consciousness is a continuum, and we are all connected evolutionarily, the closer you get to humans phylogenetically the closer you get to human consciousness. Anyone who has owned a dog I think would have no problem believing that dogs are conscious to a high degree (although not human level). They communicate with us, they can read our behavior and have been shown to have an impressive vocabulary. They appear to have emotional states. They have dog consciousness. Even here, though, it is tempting to anthropomorphize, to go beyond doggie consciousness and assume human-level motivation behind their behavior. Again, it’s what we do.

When you get to primates then I think we have to be especially careful. Now we are so close to humans evolutionarily that we are also getting close to human-like consciousness. But I do think that human evolution does include a unique feature – the evolution of sophisticated language ability, that fundamentally altered the way we think. We have a lot of brain power that chimps, for example, simply don’t have.

Also, evolutionary branches that diverged off the one that ultimately lead to humans evolved different brains with different types of consciousness. Birds have bird-consciousness, which is different than mammalian consciousness. Cephalopods, like octopuses, have cephalopod consciousness, which is different than vertebrate consciousness. We should try to understand them on their own terms, and not dismiss consciousness because it is non-human, nor try to shoehorn their apparent consciousness into human analogues (like play).

It’s very challenging research, and it makes me think the behaviorists have a point. We can model behavior, but it is very tricky to infer internal states from that behavior. But I am open to research that tries to do just that, as long as they can make falsifiable hypothesis. We may never be able to know for sure, but we can at least come up with some useful testable hypothesis and some indirect inference. But again – we have to proceed very carefully.

The post Are Animals Conscious? first appeared on NeuroLogica Blog.

A while back, after New Atheism took hold, I remember somewhat of a backlash, mostly directed at the atheistic books of Dawkins, Harris, Hitchens, and Dennett (they could also, with the possible exception of Dennett’s book be called anti-theistic). The New Atheists, so the plaint went, were angry and wanted to take away people’s toys, i.e., the comforts of faith.

In fact, this criticism mistook passion and argumentation for anger, as rarely did any of the Horsemen lose their temper.  This “anger” trope was so pervasive that there were tons of such articles criticizing New Atheism, many written by atheists who nevertheless saw religion as beneficial as a sort of “social glue”.  These people were called “atheist butters”, because of their arguments that included “I am an atheist, but . . . ” or, as Dennett called them, exponents of “belief in belief.” (Dennett also felt that free will, like religion, was a belief necessary for social cohesion.)

A counterargument for religion, one I have made, is that you can have perfectly well-functioning societies without religion and its detriments (e.g., divisiveness, proselytizing, terrorizing of children, and of course the trope of faith—the idea that one doesn’t need evidence for what one sees as true).  There’s no doubt that Judaism and Christianity are disappearing from the West, as we see from the rise of “nones”—and yet the world is morally and materially better off than a century ago, much less five centuries ago.  Here’s a new tweet from Pinker documenting it (and read his two big books on the subject):

Believers, especially Christians, respond to this progress by saying, “Well, Western values were taken from and built on Christianity, so even atheists have benefited from religion.”  But Western values are built on Enlightenment and humanistic values, which come from the rejection of religion. But we don’t have the controlled experiment of seeing what the world would be like had religion not arisen. Still, we do have an experiment, at least in the West, of seeing what countries would be like when they lose religion, and the answer does not support the societal benefits of faith. (I do agree that the lives of some people are improved by their faith. I’m talking about the net societal benefits, or lack thereof, of the institution of religion.)

In the end, religion, as opposed to other ideologies and superstitions, including Marxism and flat-earth-ism, still seems relatively untouchable, as if criticizing it is somehow distasteful. You can’t take away other people’s toys! (Hitchens’s response to that was “it’s okay if you play with your toys, but don’t try to make me play with your toys.”) I’m not sure why it’s considered as “angry” to criticize the tenets of faith (and faith itself); perhaps it’s because, for believers, religion has more far-reaching implications for their lives than does any other ideology.

But I digress. The article below, from Quillette, was written by Kushal Mehra, who was brought up as a Hindu in India. He’s identified as “host of the Cārvāka Podcast”, and has new book, Nastik: Why I Am Not an Atheist.

Mehra is a non-believer, but is still exploring religion. Yet he can’t comport the sacred texts of the Bible and Qur’an with their supposed message of love. Below he also gets in a lick at those Angry Atheists:

I felt a sense of bewilderment, as I struggled to reconcile the image of a benevolent, loving deity with the wrathful God that emerged from the pages of both books. God was constantly exhibiting rage, jealousy, and vengeance. For a while, I became one of those angry young atheists we all sometimes encounter on social media.

As I continued to explore and question, however, I sought out alternative interpretations of these texts, hoping to find a way to reconcile the conflicting images of God they presented. Growing up as a Hindu child, I was raised with a different understanding of the divine. Most schools of Hinduism, with their vast pantheon of gods (devatas) and goddesses (devis), and emphasis on the interconnectedness of all things, presented a more inclusive and tolerant worldview than I encountered in the Bible or the Quran.

So much for Ayaan Hirsi Ali’s claim that the message of Christianity is “love”! It may have morphed into that after going through the liberal theological sausage grinder, but remember that the message of secular humanism is also love, and was from the get-to. No sausage grinder needed!

Here are few more licks at the Angry Atheists from Mehra, who seems to see himself as superior because he’s “questioning and introspective”, something, he says, that comes from “India’s ancient cultural traditional of religious tolerance.” (Well, Modi’s getting rid of that!):

Without getting into all of the interactions I had in these spaces, I will report that I am one of the few people (I know of) who’s been banned from atheist forums for not being sufficiently angry at religion. I’d believed that atheists were my people, but, in fact, our perspectives diverged—as their intolerance toward non-atheists seemed to mirror that of religious puritans.

And here’s his familiar argument of why atheism is bad because it provides no substitute for religion, leaving that famous “god-shaped hole.” As Mehra sees it, that hole was filled by wokeness (bolding is mine):

By focusing on these Indian approaches to expressing religious doubt, I hope to make readers aware of the limitations of the “neo-atheism” movement that emerged over the last two decades, thanks largely to the influence of prominent atheists such as Richard Dawkins, Christopher Hitchens, Sam Harris, and Daniel Dennett. While the movement has become popular, it also has created a vacuum of meaning and purpose in society. And since nature abhors a vacuum, it isn’t surprising that the resulting void has been filled by political and ideological trends that function as ersatz religious movements (such as the fanatical form of social-justice advocacy known as “wokeism”).  

There’s no doubt that if someone gave up a faith that comforted them, and had no community of like-minded believers to fill their need for a social group, they would feel bereft. And it may be true that, for some, part of that lacuna was filled by wokeness. After all, John McWhorter’s book was called Woke Racism: How a New Religion Has Betrayed Black America.

But I’m not going to pin wokeness on atheism. The arguments of New Atheism didn’t include a plan to replace religion with a new system of belief. Rather, they were arguments showing that the tenets of religion, which are foundational beliefs, were not only empirically unsupportable, but generally harmful. They were meant to show that faith—belief without evidence—is not a good way to deal with life, especially when there can potentially be evidence supporting one’s belief. As the late Victor Stenger argued, the absence of evidence is evidence for absence if that evidence should be there.  And for religion, that evidence is simply not there.

And Mehra’s rationale for why religion is a net good:

Religion has long been a source of both solace and strife for humanity. And any discussion of its role in society—including a discussion among non-believers—should be informed by its status as a cornerstone of human culture, art, literature, and morality. Yes, religion has been used to justify wars, persecution, and discrimination, as well as the suppression of scientific progress and critical thinking. But it also promotes altruism and compassion, and gives people a framework for coping with life’s challenges and the inevitability of death. Scientific studies suggest that the religious impulse is deeply encoded in our evolutionary upbringing. It cannot be purged from our collective history simply by browbeating believers in books or YouTube videos, or by mocking them with clever memes or slogans.

First, I’ll reject the idea that “the religious impulse”—I’ll take “religion” to mean, as Dennett did, “social systems whose participants avow belief in a supernatural agent whose approval is to be sought”—is “deeply encoded in our evolutionary upbringing”. To me this means that human DNA contains genes directly promoting belief in supernatural agents.  I know of no such genes. Yes, religion could be a byproduct of other evolved traits, like our tendency to obey authorities or look for agency, but that’s not the same thing.

Beyond that, we again have no evidence that religion is necessary for good and cohesive societies. My argument has but four words: “Northern Europe and Scandinavia”. Also, as religion vanishes from the West, our well being and morality increases.  As Pinker argues, religious belief was simply an impediment to societal well being, and the Enlightenment simply shoved it aside.

I’m not denying that humans benefit from social interaction with others. We are, after all, social animals who evolved in small groups, and I’m pretty sure that this is why people get lonely and even depressed without other people around.  It is also why people do tend to become part of groups, like book clubs, soccer fans, and yes, woke-ism. It is something that escaped Richard Dawkins when he argued with Ayaan Hirsi Ali.

What I argue is two things. First, that religion is not the best form of “social glue”.  It is divisive, harmful to children, something that often demands to be forced upon others through proselytizing, and has many other detrimental effects you can see in the books of the Horsemen. I’d argue that secular humanism, if it’s really acted on by society and informed by data and reason, is the best form of social glue.

Second, I claim that people usually don’t seek an explicit “meaning and purpose” for their lives. Rather, they seek what they find fulfilling and like to do: having families, reading books, having a fulfilling job, and so on.  Then, post facto, you confect these into your “meaning and purpose”. If you’ve been brought up as an evangelical Christian or fundamentalism Muslim, then that becomes your “meaning and purpose. ” If you’ve been brought up without religion, but in a big family that makes you family-oriented, then having your own family becomes part of your “meaning and purpose.”  If you love to read and learn, then reading and learning become part of your “meaning and purpose.” Or, if you’re like me, you could answer the question of “what’s the purpose and meaning of your life?”, with “I don’t have one that I’m aware of.”

I’ve written two posts on this topic that you can see here and here. In the second link, 373 comments were addressed to this topic:

If a friend asked you these questions, how would you answer them?

1.) What do you consider the purpose of your life?

2.) What do you see as the meaning of your life?

I won’t go through all the comments, but, as I recall, few if any of the answers involved religion.

I don’t feel at all angry as I write this. The question of the value of religion is an intellectual question, but one with huge societal implications, and I find it absorbing. It’s foolish to dismiss atheism, New or Old, because its proponents are angry, and even more foolish to dismiss it because it doesn’t come with alternatives to religion. Atheism is simply the belief that there’s no evidence for supernatural beings that we must worship and brown-nose. Once we give up unevidenced beliefs, then we can figure out whether (or how) we need to fill that “God-shaped hole.” My own view is that, under secular humanism, the hole is self-filling.

A quote from Ricky Gervais:

When conference organizers told me not to make my talk "political", they were really saying there were certain people and ideas I wasn't allowed to criticize. I didn't get it at the time. I get it now.

The post I’ve Been Silenced, Censored, and Cancelled. The Reason Why Matters. first appeared on Science-Based Medicine.

What a wonderful arguably simple solution. Here’s the problem, we travel to Mars but how do we feed ourselves? Sure we can take a load of food with us but for the return trip that’s a lot. If we plan to colonise the red planet we need even more. We have to grow or somehow create food while we are there. The solution is an already wonderfully simple ‘biosphere’ style system; a fish tank! New research suggests fish could be raised in an aquatic system and nutrient rich water can fertilise and grow plants in the regolith! A recent simulation showed vegetables could be grown in regolith fertilised by the fish tank water!

In the next few decades we may well see human beings colonise Mars. The red planet is 54.6 million km away which, even on board a rocket, takes about 7 months to get there! Future colonists could simply have supply ships drop all they need but that becomes ridiculously expensive to sustain and frankly, isn’t sustainable. The lucky people that colonise Mars will just have to find some way to grow what they need. 

If you have watched ‘The Martian’ movie with Matt Damon you will know how unforgiving the Martian environment is. Ok the film was a little out on scientific accuracy in places but it certainly showed how inhospitable it really is there. Matt managed to cultivate a decent crop of potatoes in Martian regolith fertilised in human faeces.This may not be quite so practical in real life and there may be alternative, less smelly – and dangerous – alternatives. 

NASA astronaut, Dr. Mark Watney played by Matt Damon, as he’s stranded on the Red Planet in ‘The Martian’. (Credit: 20th Century Fox)

Taking the assumption that colonists will have to grow fresh produce locally, a team of researchers decided to explore how feasible this might be. On first glance, it may seem not too great an idea after all, the atmosphere is toxic with 95% carbon dioxide (compared to just 0.04% on Earth). There is a similar length of day on Mars but being able to grow crops will require longer periods of lighting. It is possible at least water may be collected from the ice which forms on and in the Martian rocks.  The rocks most certainly have water stored away but organic compounds that we know of. 

The team wanted to see how fish could help and whether the water from the system could be used to impart nutrients into the Martian regolith. To test the idea, they setup an aquaponic system with fish in tanks to generate the nutrient rich liquid.

The results were very promising. They found that aquaponic systems not only facilitate growing plants within the system itself but the nutrient rich water performed as an excellent fertiliser. This took the organically deficient regolith and turned it into something akin to useable soil. The fish used in the study were tilapia (Oreochromis niloticus) and using them, the team managed to grow potatoes, tomatoes, beans, carrots and much more. To enable all this to happen, the fish received sufficient light and other environmental stimulus. The plants were grown and indeed thrived in a tent that simulated Mars in every way possible. 

It’s an interesting aside that the study not only benefits future space travellers but those inhabitants of more environmentally hostile places on Earth. 

Source : Fish and chips on Mars: our research shows how colonists could produce their own food

The post Fish Could Turn Regolith into Fertile Soil on Mars appeared first on Universe Today.

One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.

As addressed in previous articles, the results of Webb‘s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.

The research team was led by W. Niel Brandt, the Eberly Family Chair Professor of Astronomy and Astrophysics at Penn State’s Eberly College of Science. Their research is described in two papers presented at the 244th meeting of the American Astronomical Society (AAS224), which took place from June 9th to June 13th in Madison, Wisconsin. Their first paper, “Mapping the Growth of Supermassive Black Holes as a Function of Galaxy Stellar Mass and Redshift,” appeared on March 29th in The Astrophysical Journal, while the second is pending publication. Fan Zou, an Eberly College graduate student, was the lead author of both papers.

Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

As they note in their papers, SMBHs grow through two main channels: by accreting cold gas from their host galaxy or merging with the SMBHs of other galaxies. When it comes to accretion, previous research has shown that a black hole’s accretion rate (BHAR) is strongly linked to its galaxy’s stellar mass and the redshift of its general stellar population. “Supermassive black holes in galaxy centers have millions-to-billions of times the mass of the Sun,” explained Zhou in a recent NASA press release. How do they become such monsters? This is a question that astronomers have been studying for decades, but it has been difficult to track all the ways black holes can grow reliably.”

For their research, the team relied on forefront X-ray sky survey data obtained by NASA’s Chandra X-ray Observatory, the ESA’s X-ray Multi-Mirror Mission-Newton (XMM-Newton), and the Max Planck Institute for Extraterrestrial Physics’ eROSITA telescope. They measured the accretion-driven growth in a sample of 8000 active galactic nuclei (AGNs) located in 1.3 million galaxies. This was combined with IllustrisTNG, a suite of state-of-the-art cosmological simulations that model galaxy formation, evolution, and mergers from Cosmic Dawn to the present. This combined approach has provided the best modeling to date of SMBH growth over the past 12 billion years. Said Brandt:

“During the process of consuming gas from their hosting galaxies, black holes radiate strong X-rays, and this is the key to tracking their growth by accretion. We measured the accretion-driven growth using X-ray sky survey data accumulated over more than 20 years from three of the most powerful X-ray facilities ever launched into space.

“In our hybrid approach, we combine the observed growth by accretion with the simulated growth through mergers to reproduce the growth history of supermassive black holes. With this new approach, we believe we have produced the most realistic picture of the growth of supermassive black holes up to the present day.”

This still image shows the timeline running from the Big Bang on the right towards the present on the left. In the middle is the Reionization Period where the initial bubbles caused the cosmic dawn. Credit: NASA SVS

Their results indicate that SMBHs of all masses grew much more rapidly when the Universe was younger and that accretion was the main driver of black hole growth in most cases. They also noted that mergers made notable secondary contributions, especially the largest SMBHs during the past 5 billion years. This suggests that new SMBHs kept emerging during the early Universe, but the formation process was all but settled by ca. 7 billion years ago. As Zou concluded:

“With our approach, we can track how central black holes in the local universe most likely grew over cosmic time. As an example, we considered the growth of the supermassive black hole in the center of our Milky Way Galaxy, which has a mass of 4 million solar masses. Our results indicate that our Galaxy’s black hole most likely grew relatively late in cosmic time.”

In addition to Zou and Brandt, the international team comprised researchers from the Institute for Gravitation and the Cosmos and the Departments of Physics, Statistics, and Astronomy and Astrophysics at Penn State. Other team members included researchers from the University of Michigan, the Nanjing University in China, the University of Science and Technology of China, the Max Planck Institute for Extraterrestrial Physics, and the University of Groningen in the Netherlands.

Further Reading: Chandra X-ray Observatory, The Astrophysical Journal

The post New Simulation Explains how Supermassive Black Holes Grew so Quickly appeared first on Universe Today.

Tomorrow is Father’s Day (I count myself among dads since I’ve helped raise many ducklings), and in honor of the day, Bill Maher did a bit on Real Time about the decline of parenting. Here, despite his own dearth of offspring, he argues that dads today are “doing it wrong.” By that he means that child-raising has gone awry: parents seem to be overindulging their children in ways that don’t prepare them for the real world. One pet peeve is the new method of “gentle parenting” (e.g., do unto your children as you would want done unto you).

Here are four facts he gives (I’ve looked up the references):

From Robert Leahy in Psychology Today: “The average high school kid today has the same level of anxiety as the average psychiatric patient in the early 1950’s.”

This one creeps me out:

From the New York Post: “About one in five college graduates brought their parents with them to a job interview”.

That one is used to explain why employers aren’t hiring recent college grads.

From the National Institutes of Health:  “An estimated 49.5% of adolescents have a mental health disorder at some point in their lives.” This is the lifetime prevalence for children between 13 and 18.

And finally, from the NYT: “PTSD has surged among college students”.  From the article we see that it’s more than doubled between 2017 and 2022, and I presume the criteria used to assess the condition in the two years are the same:

Post-traumatic stress disorder diagnoses among college students more than doubled between 2017 and 2022, climbing most sharply as the coronavirus pandemic shut down campuses and upended young adults’ lives, according to new research published on Thursday.

The prevalence of PTSD rose to 7.5 percent from 3.4 percent during that period, according to the findings. Researchers analyzed responses from more than 390,000 participants in the Healthy Minds Study, an annual web-based survey.

Maher is a bit curmudgeonly here, especially for a non-parent, as he calls for more discipline and the setting of boundaries for children. He doesn’t want dads who were emotionally distant and beat their kids with a belt (that’s my own experience), but does want a “trad dad” who sets rules, givin as the reason “because I said so.” (Note, though, that back in the Fifties I had a leash like the kid who shows up at 7:45. That was because I was unruly in public places. But the fact that I was leashed like a dog still makes me squirm.)

Finally, Maher touts the misogynistic Andrew Tate as the totally inappropriate role model that young boys are seeking these days. I’ve never heard of Tate, but perhaps some readers have.

This isn’t as funny as the usual bits, and has a flavor of “get off my lawn,” but he might be right.  See below the video.

Remember this book? (Click on icon to go to the Amazon site.) I thought it was good, and offers an explanation for the fragility of young people today. It sold very well.

Now Jon Haidt, writing by himself, has a new one, and it’s sold like gangbusters, rising to the top of the NYT bestseller list. It’s about precisely what Maher’s talking about above, so before you dismiss Maher’s lucubrations, perhaps you should read the book.  I haven’t yet, but I bet it’s a bestseller because parents or would-be parents are buying it. And that probably means it contains stuff that rings true. If you’ve read it, weigh in below.

 

Quickie with Evan: Mysterious Signal; News Items: Ultraprocessed Food, Artemis Update, Interstellar Clouds, Prebiotic Soda, Noninvasive Deep Brain Stimulation; Who's That Noisy; Your Questions and E-mails: Baader-Meinhof Phenomenon; Science or Fiction

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Robert Powell, a founding Board member of the Scientific Coalition for UAP Studies, has studied the UFO subject for 17 years. His work is encapsulated in UFOs: A Scientist Explains What We Know (And Don’t Know) which provides a scientific rationale for the reality of non-terrestrial craft that are intelligently controlled.

Powell begins his book by familiarizing the reader with the history of UFOs and he identifies the more enigmatic and interesting UFO sightings. He examines the characteristics of these sightings that argue against a prosaic explanation: extreme acceleration, electromagnetic interference, bending light, no obvious propulsion mechanisms, and a lack of interaction with the atmosphere. Powell discusses the recent events that have caused our government to change the term from UFO to UAP. Included is information never before released indicating the government possesses not just two videos but five videos from 2015 of UFOs operating in the vicinity of the USS Roosevelt nuclear aircraft carrier.

Powell also discuss the extraterrestrial hypothesis considering the thousands of exoplanets that have been discovered in the last twenty years. Powell challenges the reader to consider all the implications that must be considered if intelligent life discovers us first. He looks at how we as individuals and as a society react to UFOs. He documents actions taken by our military that include instances when we have fired on UFOs.

Powell argues that it is time for a change in the study of UFOs. The phenomenon has been with us for 75 years and we have learned very little as the decades have passed. The author makes the case for what needs to be done going forward. The solution he proposes will require a paradigm shift in our thinking and his book provides the information needed to understand that paradigm shift.

Robert Powell is a founding Board member of the Scientific Coalition for UAP Studies (SCU). He was the Director of Research at MUFON from 2007–2017 and created MUFON’s Science Review Board in 2012. Robert is one of two authors of the detailed radar/witness report on the “Stephenville Lights” as well as the SCU report “UAP: 2013 Aguadilla, Puerto Rico”. He is also the primary author on the recently published paper, “A Forensic Analysis of Navy Carrier Strike Group Eleven’s Encounter with an Anomalous Aerial Vehicle” and a secondary author of a paper published in the journal Entropy entitled, “Estimating Flight Characteristics of Anomalous Unidentified Aerial Vehicles.” Robert is a member of the Society for Scientific Exploration, the UFODATA project, and the National Space Society.

Shermer and Powell discuss:

• Separating two questions: Are they out there? Have they come here?
• SETI science vs. UFO/UAP science
• The odds of alien life somewhere in the cosmos
• Will aliens look anything like us? Convergent vs. contingent evolution
• What alien intelligence might be like: biological, digital, or otherwise?
• Bayesian reasoning about UFOs and UAPs
• The quality of evidence in evaluating UFO claims
• The U.S. military UAP videos and what they represent
• The Disclosure Project from the U.S. government about UFOs and UAPs
• An answer to Fermi’s Paradox: where is everyone?
• Projects Sign, Blue Book, Cyclops, Grudge
• AATIP (Advanced Aerospace Threat Identification Program)
• Oumuamua and Avi Loeb’s claim that it was a technosignature
• Technosignatures here and there
• Biosignatures here and there
• Directionality and teleology in evolution of life
• Interstellar travel
• Dyson spheres, rings, and swarms
• Why aliens matter.

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