Science

By probing chemical processes observed in the Earth's hot mantle, scientists have started developing a library of basalt-based spectral signatures that not only will help reveal the composition of planets outside of our solar system but could demonstrate evidence of water on those exoplanets.

For a wide variety of emerging quantum technologies, such as secure quantum communications and quantum computing, quantum entanglement is a prerequisite. Scientists have now demonstrated a particularly efficient way in which photons can be entangled with acoustic phonons. The researchers were able to demonstrate that this entanglement is resilient to external noise, the usual pitfall of any quantum technology to date.

Researchers are utilizing artificial intelligence to analyze the behavior of laboratory mice more efficiently and reduce the number of animals in experiments.

A 'deep learning' artificial intelligence model can identify pathology, or signs of disease, in images of animal and human tissue much faster, and often more accurately, than people. The development could dramatically speed up the pace of disease-related research. It also holds potential for improved medical diagnosis, such as detecting cancer from a biopsy image in a matter of minutes, a process that typically takes a human pathologist several hours.

Researchers have implemented polyphenylene-based anion exchange membranes poised to make hydrogen production more efficient and durable. The robust hydrophobic design enables effective ion transport while resisting chemical degradation.

'Cool' white lights -- such as those in modern car headlights -- endanger moths by causing them to fly erratically, new research shows.

Researchers have developed a three-dimensional mathematical model of prostate cancer. The model depicts various processes, including tumour growth, genetic evolution and tumour cell competition.

Researchers have explored how a particular chemical can selectively trap certain molecules in the cavities of its structure -- even though in normal conditions it has no such cavities. This innovative material with now-you-see-them-now-you-don't holes could lead to more efficient methods for separating and capturing chemicals right across industry.

The detection of cancer-associated micro-ribonucleic acids (miRNAs) in urine through a combination of nanowire-based miRNA extraction and machine learning (ML) analysis can fuel the development of early-stage cancer diagnostic tools.

Robots that can sense touch and perceive temperature differences? An unexpected material might just make this a reality. Researchers are developing soft and intelligent sensor materials based on ceramic particles.

I keep thinking that Pamela Paul, who is consistently heterodox by criticizing the “progressive” left, will be given the boot as a regular NYT op-ed columnist. But I’m happy to see that she’s still in there swinging, this time criticizing the progressive (do I need to keep calling it that?) brand of transgender activism in favor of common sense. This is not a “transphobic” point of view, but a liberal and empathic one.

It so happens that Trump campaigned against the extremist, activist form of gender activism, and that helped him win, but aspects of his transgender policy, like cutting off federal funding for people transitioning at any age, are not palatable to many of us. But many of us still refuse to countenance the participation in women’s athletics of men identifying as women, or the placement of  trans women in rape-counseling centers, women’s shelters, or women’s prisons.  Those are the trivially few (but fair) exceptions to otherwise complete legal and moral equality of trans people, and favoring them does not make you transphobic.

Nevertheless, Paul is going to be called transphobic for standing up for reason.  In the article below she points out that her position, which is also mine, is classically liberal:

Democrats have long been on the right side of health care, scientific progress, women’s rights, gay rights and education. This is the party that truly cares about families and aims to address their needs, especially on the more pressing economic issues that have many Americans feeling that their backs are up against a wall. But on transgender issues specifically, one way to make clear that Democrats are listening to their constituencies would be to accept a broader range of perspectives.

Click below to read, or find the article archived here.

 

Paul points out the inordinate effort the Trump campaign put into opposing “progressive” gender issues, and notes that those ads had an effect, even though only a a small proportion of Americans are transgender. That’s because the ads pointed out a strong tilt of Harris’s campaign (and Biden’s administration) towards wokeness, even though I was convinced when Biden was elected in 2020 that he would be more centrist.

Paul:

During the closing weeks of the election, Republican campaigns spent over $65 million on ads ridiculing, among several candidates, Kamala Harris for supporting “taxpayer-funded sex changes for prisoners” and “illegal aliens,” all ending with variations on the tagline: “Kamala Harris is for they/them. President Trump is for you.”

At campaign events Trump attacked the idea of letting transgender girls and women play on female sports teams, and implied that children were having gender surgery in classrooms.

“Can you imagine you’re a parent and your son leaves the house,” he said at a rally in Wisconsin, “and you say, ‘Jimmy, I love you so much, go have a good day in school,’ and your son comes back with a brutal operation?”

Why did Trump and his allies devote so much attention and resources to something that seemingly affects a small number of people compared with top voter concerns like immigration, the economy, crime, abortion and democracy? Maybe because it worked. According to Harris’s leading super PAC, viewers shifted 2.7 percentage points toward Trump after watching one of these ads.

If that was true in general, then this issue alone would be sufficient to have swung the election towards Trump. But those who opposed Trump, including both Paul and me, have the concerns that I noted above, including as well some schools hiding children’s changed gender identities from their parents, as well the dangers of “gender-affirming care”:

Trump’s charge that children are undergoing gender transition surgeries in school is obviously absurd. But his words may have struck a chord with those who disagree with school districts that have teachers and administrators hide from parents that their children have adopted new gender identities. As The Times reported last year, one mother of a 15-year-old only accidentally discovered her child’s public school had been covering up the fact that for six months, her child had been going by a new name and using the boys’ bathroom.

In recent years, the concepts of gender identity and the possibility of being born in the wrong body have been introduced as early as elementary school. But a Washington Post poll found that 77 percent of Americans do not want teachers discussing these ideas in kindergarten through third grade and more than half oppose trans identity being talked about even in middle school.

The Democratic Party’s platform includes a pledge to defend gender-affirming care for minors. For people who are not well versed in the issue, this may sound like therapy to make children feel comfortable in their bodies; what it usually means in practice is allowing children to adopt a new name and pronouns, and in many cases, enabling them to change their bodies to resemble that of the opposite sex. This process can include puberty-blocking drugs, cross-sex hormones and, in some cases, surgery. More than 14,000 American children had gender-related medical interventions between 2019 and 2023.

While much of Europe has been pulling back from the gender-affirmation model, evidence has emerged that in the United States, proponents of this approach have let politics color science.

Trust in Democrats has also been hurt by their refusal to publicize data that might hurt the progressive form of gender activism, and that is offensive not just to the public, but also to scientists:

To cite two recent examples, one prominent advocate of gender-affirming care suppressed her own government-funded research because she feared it might be “weaponized” against her agenda, The Times reported. Meanwhile, Rachel Levine, the assistant secretary of health and human services chosen by President Biden, worked to get a transgender organization to remove age limits from its proposed guidelines for surgeries, including mastectomies and hysterectomies for minors, because she said they would give fuel to political foes, according to recently released court documents. After this disclosure, the Biden administration released a statement saying it opposed such surgeries for minors.

Yet the Department of Health and Human Services continues to say that gender-affirming care is “crucial” for young people and “has been shown to increase positive outcomes for transgender and nonbinary children and adolescents” — even though the most comprehensive overview of research, which assessed all major American and global studies on the subject, found scant evidence of this. Even so, all the leading American medical associations continue to back gender-affirming care.

I have written about this before,(so has Paul) and it’s simply wrong to remove age limits for surgeries (I favor 18 or 21), much less to suppress research showing that gender-affirming care isn’t all it’s cracked up to be, and doesn’t have the uniformly positive results that many advocates claim. Suppressing results that hurt your political platform, of course, is harmful because it injects ideology into science, but, more important, this impedes proper treatment of gender-dysphoric children.

In the end, people of good will are not “transphobic” in the sense of being bigoted against trans people. But there are limits—limits based on fairness and danger to women—in saying that transwomen should always be treated the same as biological women, and the same goes for transmen being treated as men. But those are exceptions, and I utterly reject people saying that those views are transphobic. As Paul says at the end:

Democrats should fight these tendencies and ensure that everyone, regardless of gender identity or sexual orientation, is respected and protected under existing law. Rather than double down on beliefs and policies that are out of step with the best medical evidence, Democrats and everyone else who support transgender rights should embrace a common-sense approach from their government, their schools, their mental health care workers and their doctors. Vulnerable people are depending on it.

May she have a long run at the NYT!

When it comes to telescopes, bigger really is better. A larger telescope brings with it the ability to see fainter objects and also to be able to see more detail. Typically we have relied upon larger and larger single aperture telescopes in our attempts to distinguish exoplanets around other stars. Space telescopes have also been employed but all that may be about to change. A new paper suggests that multiple telescopes working together as interferometers are what’s needed. 

When telescopes were invented they were single aperture instruments. A new technique emerged in the late 1800’s to combine optics from multiple instruments. This achieved higher resolution than would ordinarily be achieved by the instruments operating on their own. The concept involves analysis of the interference pattern when the incoming light from all the individual optical elements is combined. This is used very successfully in radio astronomy for example at the aptly named Very Large Array. It is not just radio waves that are used, infra-red and even visible light interferometers have been developed saving significant costs and producing results that would otherwise not be achievable from a single instrument.

Image of radio telescopes at the Karl G. Jansky Very Large Array, located in Socorro, New Mexico. (Credit: National Radio Astronomy Observatory)

One area of astronomical research is the study of exoplanets. Observing alien worlds orbiting distant stars presents a number of challenges but the two key difficulties are that they lie at great distances and orbit bright stars. The planets are usually small and faint making them almost (but not quite) impossible to study directly due to the brightness and proximity to their star. Some understanding of their nature can be gleaned from using the transit method of study. This involves studying starlight as it passes through any atmosphere present to reveal its composition. 

Direct imaging and study is a little more challenging and requires high resolution and sometimes a way of blocking light from the nearby star. To achieve direct observations requires angular resolution of a few milliarcseconds or even less (the full Moon covers 1,860,000 milliarcseconds!) This depends largely on the planets size and distance from Earth and from its host star. To give some idea of context, to resolve a planet like Earth orbiting the Sun from a distance of just 10 light years requires an angular resolution of 0.1 milliarcseconds. The James Webb Space Telescope has a resolution of 70 milliarcseconds so even that will struggle. 

This artist’s impression depicts the exomoon candidate Kepler-1625b-i, the planet it is orbiting and the star in the centre of the star system. Kepler-1625b-i is the first exomoon candidate and, if confirmed, the first moon to be found outside the Solar System. Like many exoplanets, Kepler-1625b-i was discovered using the transit method. Exomoons are difficult to find because they are smaller than their companion planets, so their transit signal is weak, and their position in the system changes with each transit because of their orbit. This requires extensive modelling and data analysis.

A paper recently authored by Amit Kumar Jha from the University of Arizona and a team of astronomers explores this very possibility. They look at using interferometry techniques to achieve the required resolutions, at using advanced imaging techniques like the Quantum Binary Spatial Mode Demultiplexing to analyse the point spread function (familiar to amateur astronomical imagers) and at using quantum based detectors.

The study draws upon radio interferometric techniques with promising results. They showed that a multi-aperture interferometry approach utilising quantum based detectors are more effective than single aperture instruments. They will provide a super-resolution imaging solution that has to date not been used in exoplanetary research. Not only will it hugely increase resolution, it’s also a very cost effective way to observe exoplanets and indeed other objects across the cosmos. 

Source : Multi-aperture telescopes at the quantum limit of super-resolution imaging : Detecting subRayleigh object near a star

The post Interferometry Will Be the Key to Resolving Exoplanets appeared first on Universe Today.

The Proba-3 mission consists of two spacecraft that will fly in close formation to study the sun, with the shadow of one creating an artificial solar eclipse from the perspective of the other

Pluto may have been downgraded from full-planet status, but that doesn’t mean it doesn’t hold a special place in scientist’s hearts. There are practical and sentimental reasons for that – Pluto has tantalizing mysteries to unlock that New Horizons, the most recent spacecraft to visit the system, only added to. To research those mysteries, a multidisciplinary team from dozens of universities and research institutes has proposed Persephone – a mission to the Pluto system that could last 50 years.

New Horizons rocketed past the Pluto system in 2015, which is now technically considered part of the Kuiper Belt. The mission collected data on the dwarf planet and its unique moon, Charon. Scientists have now had time to analyze the data from that mission, and it left them wanting more—in particular, data about some of the surface features that they observed.

Persephone has four main scientific questions it is designed to answer, according to a paper published back in 2021:

1) “How has the population of the Kuiper Belt evolved?”
2) “What are the particle and magnetic field environments of the Kuiper Belt?”
3) “How have the surfaces of both Pluto and Charon changed?”
4) “What are the internal structures of Pluto and Charon?”

Fraser discusses what we learned about Pluto from New Horizons

That last one might be the most intriguing, as the answer for Pluto’s internal structure might be that it has a subsurface ocean despite being so far away from the Sun. There is already some evidence for this, as Pluto appears to have an active surface, and an ice sheet called Sputnik Planitia could potentially be caused by a subsurface ocean. We don’t have enough data yet to prove it.

That is what Persephone is designed to provide. Unfortunately, with the unforgiving logic of orbital mechanics and current constraints on propulsion technology, any such mission would take multiple decades, even with a gravity assist from Jupiter. The mission design for Persephone has been operational for almost 31 years, including a 28-year cruise phase and a three-year orbit period around Pluto and Charon. It could then have an extended operational mission to visit other Kuiper belt objects to help constrain the variance in the different kinds of objects in that massive section of space.

That travel time could be helped by the development of a more effective nuclear electric propulsion system, which could shave up to 2 years off it even with a heavier payload than currently planned for Persephone. Such a system has been described but might not be available for the planned 2031 launch date for Persephone on board an SLS rocket.

Fraser discusses the longevity of spacecraft, which will definitely be a consideration for any future missions to Pluto.

Persephone will take a suite of sensors, no matter its propulsion system, which can be “brought to bear on any and every object encountered during the mission,”. According to the flight plan, that would include Jupiter and its moons. These sensors include cameras, spectrometers, radar, magnetometers, and altimeters to meet the mission’s necessary science objectives.

A critical differentiator for the mission is that it is designed to be an orbiter rather than a flyby. According to the authors, much of the data needed to be collected would be infeasible with the short period a flyby would provide with the system. An orbiter would be able to stick around and collect data over the three-year period about both Pluto and Charon, including their active surface dynamics.

This proposal is just one of many mission proposals to the outer planets seeking further funding, and a preliminary estimate of $3bn puts it in the higher range of those missions. But if it is funded in some capacity, it could provide answers to the questions that New Horizons posed, even if it would take several decades to reach them.

Learn More:
Howett et al – Persephone: A Pluto-system Orbiter and Kuiper Belt Explorer
UT – The (Dwarf) Planet Pluto
UT – NASA’s New Horizons Mission Still Threatened
UT – New Horizons is Funded Through the Decade. Enough to Explore Another Kuiper Belt Object

Lead Image:
Graphic of Pluto being visited by Persephone and all the different questions the mission could answer.
Credit – Howett et al.

The post A New Mission To Pluto Could Answer the Questions Raised by New Horizons appeared first on Universe Today.

If you were lucky enough to observe a total eclipse, you are certain to remember the halo of brilliant light around the Moon during totality. It’s known as the corona, and it is the diffuse outer atmosphere of the Sun. Although it is so thin we’d consider it a vacuum on Earth, it has a temperature of millions of degrees, which is why it’s visible during a total eclipse. According to our understanding of black hole dynamics black holes should also have a corona. And like the Sun’s corona, it is usually difficult to observe. Now a study in The Astrophysical Journal has made observations of this elusive region.

For an active black hole, it’s generally thought that there is a donut-shaped torus of gas and dust surrounding the black hole, in which there is an accretion disk of heated material aligned along the rotational plane of the black hole. Streaming from the polar regions of the black hole are jets of ionized gas speeding away at nearly the speed of light. This model would explain the various types of active galactic nuclei (AGNs) we observe, since the orientation of the black hole relative to us changes the appearance of the AGN.

According to the model, the innermost region of the accretion disk should be a superheated region at near vacuum density, which streams into the black hole. It is a corona like the Sun’s, but instead of millions of degrees, it has a temperature of billions of degrees. But because it’s so diffuse, its light is overwhelmed by the light of the accretion disk.

Diagram of the polarization behavior of obscured black holes. Credit: Saade, et al

In this new study, the team used a trick similar to observing the Sun’s corona during a total eclipse. The orientation of a black hole relative to us means that for some black holes the torus of gas and dust obscures our view of the accretion disk region, while for other black holes we can see the disk directly. These are known as obscured and unobscured black holes. The obscured black holes are similar to an eclipsed Sun, since the light of the accretion disk is blocked from view. Unfortunately, so is the black hole’s corona. But the corona is so hot that it emits extremely high-energy X-rays. These X-rays can scatter off material in the torus and reflect into our line of site.

Using data from NASA’s Imaging X-ray Polarimetry Explorer (IPXE), the team gathered data on a dozen obscured black holes, including Cygnus X-1 and X-3 in the Milky Way, and LMG X-1 and X-3 in the Large Magellanic Cloud. They were not only able to observe scattered X-rays from the coronas of these black holes, they were also able to detect a pattern among them. Based on the data, the corona surrounds the black hole in a disk similar to the accretion disk, rather than surrounding the black hole in a sphere similar to the Sun’s corona.

Research such as this will help astronomers refine our models of black holes. It will also help us better understand how black holes consume matter and power the AGNs we observe in distant galaxies.

Reference: Saade, M. Lynne, et al. “A Comparison of the X-Ray Polarimetric Properties of Stellar and Supermassive Black Holes.” The Astrophysical Journal 974.1 (2024): 101.

The post Astronomers Map the Shape of a Black Hole's Corona for the First Time appeared first on Universe Today.

Readers give higher ratings to AI-generated poetry than the works of poets such as William Shakespeare, Walt Whitman and Emily Dickinson – perhaps because they often have more straightforward themes and simpler structure

It is surely within the ambit of scientific journals to take stands on issues that affect the fields they cover, but endorsing political candidates is a dangerous matter. In 2020, for example, Nature endorsed Joe Biden for President (a first for them). It did not change the readers’ views of Biden, but it eroded the credibility of both the journal and science in general. This is according to a study by Floyd Zhang published in Nature Human Behavior, and is summarized in a later issue of Nature:

Overall, the study provides little evidence that the endorsement changed participants’ views of the candidates. However, showing the endorsement to people who supported Trump did significantly change their opinion of Nature. When compared with Trump supporters who viewed Nature’s formatting announcement, Trump supporters who viewed the endorsement rated Nature as significantly less well informed when it comes to “providing advice on science-related issues facing the society” (Fig. 1). Those who viewed the endorsement also rated Nature significantly lower as an unbiased source of information on contentious or divisive issues. There was no comparable positive effect for Biden supporters.

Zhang also found that viewing Nature’s political endorsement reduced Trump supporters’ willingness to obtain information about COVID-19 from Nature by 38%, when compared with Trump supporters who saw the formatting announcement. This finding echoes other work on how partisanship influences interest in scientific information5. Furthermore, Trump supporters who viewed the endorsement also rated US scientists, in general, as much less well informed and unbiased than did Trump supporters who viewed the formatting article. There was no comparable positive effect for Biden supporters.

This lesson was apparently lost on Nature‘s American competitor, Science, which (like the new Nature article below it), is calling for scientists to hold Trump to account on things like climate change, pandemics, and so on.  That’s fair enough, but then they politicize the whole thing by demonizing Trump from the outset, doing exactly the thing that will erode confidence in the journal and its pronouncements.

The article was written by Science‘s editor, Holden Thorp. He considers himself “progressive,” and has debated my partner in crime, Luana Maroja, on the role of politics in science (see also this video).  Thorp also devoted a column in his journal to criticizing a paper on which both Luana and I were coauthors, a paper on “In Defense of Merit in Science” by Abbot et al.

Click to read:

Here’s the way it starts, guaranteed to alienate Republicans:

The reelection of Donald Trump for a second, nonconsecutive term as US president—mirroring only Grover Cleveland’s 22nd and 24th presidencies after the Civil War—underscores a reality: Although his success stems partly from a willingness to tap into xenophobia, sexism, racism, transphobia, nationalism, and disregard for truth, his message resonates with a large portion of the American populace who feel alienated from America’s governmental, social, and economic institutions. These include science and higher education. Winning back this disaffected group will require science leaders to foster and promote a more inclusive scientific landscape for all Americans and lay out how science can be successful under Trump.

How willing will readers be to take these lessons to heart if they are Republicans? (Granted, most readers, who are budding scientists, will be Democrats, but then they don’t need these lessons.) Who wants to be implicitly told that they are xenophobes, racists, sexists, and nationalists?

And there’s a statement whose first part is tautological and the second part is debatable:

Make no mistake, the political assaults on science stem largely from those who seek to undermine the truth for political gain, and this dynamic is the major contributor to declining trust in science.

Some of the declining trust in science is also due to scientists’ changing their views, as during the COVID crisis, but much of that was simply due to the acquisition of new information and is not the fault of scientists. We are supposed to change our minds when new data undercuts our previous stands. But that erosion is not due to scientists “undermining the truth for political gain”. There is no mention of Nature’s contribution to declining trust in science by simply endorsing a candidate in 2020.  Other erosion of trust occurs when scientists or journals make statements like “human biological sex is a spectrum,” something that is flatly wrong and contradicts what people already know.

The article above, then, is not only bound to do precisely what it’s decrying—eroding trust in science by politicizing it—but is also disingenuous by neglecting the causes of distrust in science that come from progressive politics, as well as from the infusion of politics in science.

The rest of the article is anodyne, urging scientists to change their minds when they’re wrong, not to engage in falsifying results (duh!), and not to blame “their students and postdocs for problems” (duh again!).  The article ends by taking another swipe at an administration that hasn’t yet begun:

The attacks [on science] are going to keep coming and probably accelerate for the next 4 years. As painful as that will be, it’s up to the scientific community to respond in a way that makes those blows less successful.

The “four years” implies that the Trump administration will be bad for science. That may well be true, but we don’t know yet! Here we have journals playing Chicken Little.

Nature, already stung by its endorsement of Biden in 2020, didn’t endorse anyone in the last election, but might as well have endorsed Biden if you read this article. The piece also contains a survey showing that nearly 40% of  Nature readers in the U.S. would consider moving out of the country if Trump won. I wonder how many actually will move?

At any rate, the new Nature article below also evinces fear of the Trump administration, but does so in a fear-mongering way that I wouldn’t employ were I editor. It also gives anodyne advice. But it’s not as bad as the Science article:

A few excerpts:

When Donald Trump was first elected to the US presidency in 2016, Nature advised scientists to constructively engage with Trump. We said that the incoming president’s contrary approach to evidence, among other things, had no place in modern society. We added that the science community had a responsibility to step up and work with the president and his new administration so that they govern on the basis of research and evidence.

. . .The United States has now re-elected Donald Trump as president. Many researchers have told Nature that they are in despair, seeing the election result as a step backwards for facts, reason, knowledge and civility.

Last week, Nature said that the United States needs a leader who respects evidence. The incoming administration must embody this principle. On behalf of the research community, we will hold it to account if it falls short.

We hope that the incoming administration will govern in the best interests of the United States. That means holding on to the best of what the previous administration did, and not returning to some of the policies of the first Trump presidency.

Is it journalism to cite the “many scientists who are in despair” without mentioning that some scientists (granted, a minority, given our political leanings) are happy?  This is a slanted take.

The article then calls out the Trump administration (properly) for its weakness on recignizing climate change and for threatening to defund the World Health Organization.  But then it becomes anodyne like the Science article above, and ends on a lame note:

The research community must engage with the new administration with courage, tenacity, strength and unity. At the same time, scientists in the United States must know that they are not alone. The research community is a global one. We need to stand together and stand strong for the challenges that are to come. And that will mean continuing to speak facts to power.

“Stand together” clearly means “stand together against the Trump administration,” and I think that’s obvious to any reader with eyes.

Readers here know that I abhor Trump, but even more than that I abhor the ideological erosion of my beloved science. In four years Trump will be gone (hopefully to be replaced by someone who’s not mentally ill), but any damage done to the reputation of science by journals rushing to take sides will last a lot longer.

With the help of a ruby cube and two laser beams, researchers made one ray of light cast a shadow when illuminated by the other

Despite the fact that our universe is old, cold, and well past its prime, it’s not done making new galaxies yet.

Galaxy formation first got started when our universe was only a few hundred million years old. In those dark ages the first stars gathered enough material to trigger nuclear fusion and ignite. Slowly over time those clumps of stars found each other and began to build the first young protogalaxies. 

Over time those protogalaxies accumulated more material and merged together to quickly grow to become the massive galaxies that sprinkle throughout the universe today.

But galaxies are more than clumps of stars and gas. They are also deep wells of dark matter, which is the invisible substance that makes up the most of the mass of every object in the universe. To make a galaxy you really start with an accumulation of dark matter. That forms the gravitational bedrock for normal matter to gather onto and start forming stars.

The accumulation of dark matter really only happened in the very early universe, and long ago shut off. But those concentrations of dark matter remain today. Evidence from simulations and observations tells us that normal matter is still finding those pockets and triggering fresh rounds of star formation. That means while the seeds of galaxies were only laid down once, new accumulations of matter are still lighting up in the present day cosmos.

It is true that we are well past the peak of star formation and the heyday of galaxy assembly. That epoch came and went over 10 billion years ago. And far into the future our universe will expand so much that this process will slow down and eventually stop. But the universe isn’t done yet. For now, we can still enjoy a universe full of galaxies and knowing that new ones are still coming on the scene.

The post Yes, Virginia, The Universe is Still Making Galaxies appeared first on Universe Today.

Send in your good photos, please, as every day the tank gets lower.

But today we have a text-plus-photo essay by Athayde Tonhasca Júnior on one of his favorite subjects: plant pollination. Athayde’s comments are indented, and you can enlarge the photos by clicking on them.

Fair is foul, and foul is fair: hover through the fog and filthy air (The Weird Sisters)

Most angiosperms (flowering plants) need an agent to move pollen from one flower to another. This service could be provided by the wind, water, bats, birds, or, for the overwhelming majority of cases, insects. But a plant must advertise itself to attract visitors to its flowers. Visual traits such as colour, shape and size are effective lures, but for short distances only because most pollinating insects see as well as Mr Magoo: their visual acuity ranges from centimetres to a few metres, at best. A red flower must have a diameter of at least 26 cm to be recognised by a honey bee (Apis mellifera) 1 m away (Chittka & Raine, 2006). Insects’ vision is mediocre during daytime and goes down to irrelevant at night, except for a few specialised nocturnal species. Other sensory signals such as temperature, texture and even electrical fields are involved in flower recognition. But to attract insects from afar, plants rely on scent.

The majority of flowering plants produce volatile organic compounds (VOCs), a group of organic chemicals (that is, they all contain carbon) that quickly evaporate and disperse in the air. VOCs can act as herbivore deterrents, but a huge variety of them attract pollinators. These volatiles, released by petals or other plant tissues, persist long enough to reach insects and guide them to the flowers, but not for too long so that they don’t accumulate in the air and overwhelm insects’ sensorial capacity. Most of the attractant VOCs are ‘flowery’ scents such as benzyl acetone, which is one of the most abundant aromatic lures in flowers. You are likely to have smelled it from raspberries, cocoa butter, soaps and perfumes.

Ladies making potpourri, a source of benzyl acetone © Edwin Austin Abbey (1852-1911), Wikimedia Commons:

Pollinators are experts in detecting particular compounds from odour blends. And crucially for the pollination angle, they learn to associate specific fragrances with food, so they return repeatedly to its flowery source.

Tracking VOCs seems like a convenient and efficient way to get to pollen and nectar, but there are complexities involved. Scents released by a flower do not travel in a straight line the way light and sounds do. Air turbulence disperses, dilutes and mixes compounds, so that an odour plume is not a well-defined strand of airborne chemicals. And yet, pollinators manage to sort out the chaotic environs and make a run for the smell’s origin. Watch fruit flies navigating confidently through a turbulent atmosphere.

Top: a section of an odour plume, where the shaded area is the projection of an average conical plume. Crosswind transport and odour concentration decrease rapidly outside the cone. Bottom: a two-dimensional section of two blending plumes © Celani et al., 2014:

We don’t have a complete understanding of the ways pollinators track scents to find flowers, but we do know that the presence of certain compounds, their ratios in volatile blends, and the magnitude of the olfactory signal are important. The processes involved are complex, specific, and vulnerable to disturbances. Such as those created by a diesel-guzzling SUV driven to the farmers’ market for the purchase of locally grown organic carrots.

The engine invented by Rudolf Diesel (1858-1913) is the most fuel-efficient internal combustion engine because it converts more heat to mechanical work than any of its alternatives. It is also reliable and sturdy, so it was quickly adopted by industry, agriculture and transport to become the main source of power that keeps the world going. The diesel engine largely did away with coal and revolutionised the world’s economy by generating power efficiently and inexpensively. But its allure suffered a serious blow in the 2010s, when the first studies about its collateral effects came to light.

The combustion (burning) of diesel fuel results in a complex mixture of water, gases and aerosols. Study after study have shown that some of these by-products such as particulate matter (soot), nitric oxide (NO), carbon monoxide (CO) and oxides of nitrogen (NOx), are serious health hazards. They cause all sorts of ailments, from lung inflammation to exacerbation of emphysema and asthma. The World Health Organisation considers diesel exhausts carcinogenic agents as dangerous as asbestos. As if this evil cocktail wasn’t bad enough, it also promotes the formation of other harmful compounds such as ozone (O3). In the upper atmosphere, this gas is essential for life on Earth because it blocks most of the ultraviolet radiation from the sun. At ground level, ozone is a pollutant resulting from chemical reactions between NOx and VOCs in the presence of sunlight. These ground level VOCs have nothing to do with plants; rather, they come from solvents, biomass burning, industrial processes and, most importantly, incomplete fuel combustion.

Formation of ground level ozone © DANMUSISI, Wikimedia Commons:

Ozone is bad for us and bad for insects. It degrades plant-emitted VOCs and changes the ratios of compounds in a scent blend. As a result, pollinators detect VOCs at shorter distances, become confused, or worse: they may no longer recognise flowers’ chemical signals (Farré-Armengol et al., 2015). In a laboratory setting, adding ozone at concentrations commonly found in rural areas to the scent produced by the jasmine tobacco (Nicotiana alata) disrupted the attraction of one of its main flower visitors, the tobacco hawkmoth (Manduca sexta) (Cook et al., 2020).

Effect of ozone pollution © Langford et al., 2023:

The pale evening primrose (Oenothera pallida) grows in sandy and rocky habitats in the arid regions of northern Mexico and western USA. Its flowers release a scent loaded with monoterpenes, a class of chemicals found in various herbs, spices, conifers and fruits. Monoterpenes attract several visitors including the tobacco hawkmoth and the white-lined sphinx (Hyles lineata), which are two of the plant’s main pollinators. These moths have a keen sense of smell and can track pale evening primrose flowers from several kilometres away. But this plant-moth interaction can be severely disrupted by the nitrate radical NO3, a gas resulting from the reaction of ozone with NO2, the latter spewed by wildfires, power plants and diesel engines. Monoterpenes break down quickly in the presence of NO3, drastically reducing the reach of olfactory cues that moths rely on to locate flowers. In wind tunnel experiments, nocturnal levels of NO3 typically found in urban settings caused a 70% drop in number of flower visitations, resulting in a 28% reduction in fruit set (Chan et al., 2024). Sunlight degrades NO3, so this chemical is primarily a nighttime pollutant – bad news for moths and other nocturnal pollinators.

A white-lined sphinx visiting a pale evening primrose flower © Ron Wolf, US National Science Foundation:

Image of hawkmoth (Hyles lineata) pollinating Oenothera flower. Researchers at the University of Washington found that nitrate radicals (NO3) in the air degrade the scent chemicals released by a common wildflower, drastically reducing the scent-based cues that nighttime pollinators rely on to locate the flower.

With the industrial revolution, urban spaces became choked with foul air. People in charge slowly woke up to the problem, and today many countries drastically reduced atmospheric pollution thanks to ever improving filtration technologies and strict regulations. Despite these advances, diesel exhaust and other emissions remain major environmental problems, particularly in countries undergoing rapid economic growth such as China and India.

Global emissions of NOx, particulate matter with a diameter of 10 μm or less (PM10), ammonia (NH3) and global exposure to tropospheric O3. Tg: teragrams, ppb: parts per billion © Duque & Steffan-Dewenter, 2024:

The progressive deterioration of worldwide air quality is a serious threat to human health and certainly doesn’t bode well for plant reproduction, although the magnitude of this effect can only be guessed at. We already knew that clean air is vital for our eyes and lungs: more and more evidence tell us that it is also important to pollination services.

Haze over London caused by air pollution. Bad for us and for pollinators © shirokazan, Wikimedia Commons: