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Methane concentrations in Earth's atmosphere increased at record speed over the past five years. At least two-thirds of annual methane emissions now come from human activities, including fossil fuel use, agriculture, and landfills and other waste.

A research team developed a microbial strain that efficiently produces aromatic polyester using systems metabolic engineering.

Researchers have introduced a novel method for converting the greenhouse gas carbon dioxide (CO2) into ethanol, a sustainable fuel. This significant advancement could pave the way for more environmentally friendly and economically viable alternatives to fossil fuels.

Bioactive glasses, a filling material which can bond to tissue and improve the strength of bones and teeth, has been combined with gallium to create a potential treatment for bone cancer. Tests in labs have found that bioactive glasses doped with the metal have a 99 percent success rate of eliminating cancerous cells and can even regenerate diseased bones.

Researchers report on a new defect passivation strategy for improved power conversion efficiency and stability of perovskite solar cells.

A study has developed an innovative method that overcomes the limitations of traditional additive manufacturing (3D printing), significantly simplifying and accelerating the production of geometrically complex cellular ceramics. This groundbreaking approach has the potential to revolutionize the design and processing of multifarious ceramic materials, opening up new possibilities for new applications in energy, electronics, and biomedicine, including robotics, solar cells, sensors, battery electrodes, and bactericidal devices.

When cars, planes, ships or computers are built from a material that functions as both a battery and a load-bearing structure, the weight and energy consumption are radically reduced. A research group is now presenting an advance in so-called massless energy storage -- a structural battery that could halve the weight of a laptop, make the mobile phone as thin as a credit card or increase the driving range of an electric car by up to 70 percent on a single charge.

From migrating sauropods and semi-aquatic predators to doting parents, palaeontologists are finally uncovering the mysteries of the lifestyles of dinosaurs

As I’ve said many times, while over 100 American colleges and Universities have adopted a version of the University of Chicago’s policy of free speech, only a handful have adopted our complementary policy of institutional neutrality (“The Kalven Report”). That policy mandates that our University, its departments, and other “official” units, are forbidden from making statements espousing a specific ideology or taking moral or political stand—except when making such a statement directly supports the university’s mission of teaching, learning, and research. Institutional neutrality—which in our school also involves investment decisions—is designed to buttress freedom of expression: nobody feels that they would be punished if they went against some “official” political statement.

As I wrote in an earlier post announcing that Columbia University also has professed this policy (I’ll believe it when I see it there):

The only universities that have adopted Kalven-esque principles, besides us, number two: The University of North Carolina at Chapel Hill, and Vanderbilt University. (Vanderbilt’s Chancellor, Daniel Diermeier, is a free-speech advocate who was Provost here before he moved south.)  Some professors at Northwestern University have urged adoption of institutional neutrality, but so far little seems to have happened.

(See Diermeier’s WSJ critique of Harvard’s lame attempt at institutional neutrality.)

So, including Chicago, we had four schools adopting a policy that should be universal.  But if you count Simon Fraser University near Vancouver, B.C. as “American” (well, it’s North American), now we have five.  Read the announcement from Simon Fraser’s President by clicking on the screenshot below.

A transcript (I’ve bolded the important stuff except for the title and subtitle, but some of the bolded stuff is troubling, at least to me):

Message from the President: the Role of Universities in Troubled Times

September 09, 2024

As president of SFU, I am often asked by students, faculty and staff to take a stance on partisan political matters and current events. These requests have increased greatly in the past year, during which this topic has been at the forefront of discussion on university campuses around the world. I want to share some thoughts on why I have come to the view that it is important for university administration not to take public positions on such matters.

Universities are comprised of thousands of students, faculty and staff who all hold unique opinions and views, informed by their scholarly work and lived experiences. I believe that universities need to be a place where people can freely engage in academic inquiry, share ideas, learn from each other, disagree constructively and peacefully protest. And I believe that my role as university president is to help facilitate an environment where people can have robust conversations, including on controversial topics.

In the past, I have made statements related to world events in an attempt to be responsive to issues our community is concerned with. However, I have come to understand that taking a public position on behalf of the university can have a chilling effect on the vigorous discussion and debate of students, faculty and staff. While these statements were intended to provide comfort to and express solidarity with members of the university community, their potential impact on open discussion runs contrary to the university’s purpose. I also recognize that there are many local, global and personal issues affecting community members at any given time, and issuing statements on some topics but not others can further contribute to feelings of exclusion.

If SFU is truly to be a place where people feel comfortable sharing their ideas and participating in meaningful dialogue, the university must be non-sectarian and non-political in principle. In order to facilitate this, I believe that the institution—and senior leadership as representatives of the institution—must refrain from taking public positions on topics unrelated to the business of the university, including partisan matters and world events.

Living by Our Values

Academic freedom, as enshrined in our collective agreements and underscored in What’s Next: The SFU Strategy, creates the conditions for scholars to freely examine, question, teach and learn within their area of study, provided that these actions are based on an honest search for knowledge. To truly live by our core values of academic freedom and critical thinking, we need to hold space for difficult and controversial conversations to take place responsibly and respectfully, as well as defending and protecting the human right to express views within the bounds of the law.

As outlined in What’s Next, we are also committed to embedding the values of equity and belonging in every decision and action. We have a collective responsibility to create a culture of inclusive excellence where all feel welcome, safe, accepted and appreciated. Taken together, academic freedom and inclusive excellence support each other and work together to create a vibrant academic community where everyone feels a sense of belonging.

One of the foundational practices of university life is to be exposed to different points of view, broaden our perspectives and have our beliefs and ideas challenged. This may be uncomfortable, but it is also an important part of being an engaged citizen. As we take on this work, it is important to remember that students, staff and faculty are accountable to SFU’s policies and codes of conduct. If violations of established codes of conduct, university policies or laws occur, we will follow the appropriate processes and procedures to address them.

In a time of increased polarization, we must preserve the vibrancy of our academic community while ensuring that difficult conversations are grounded in care and respect for each other. This is a challenging task, but I believe it is one we can accomplish, together. I want to assure you that senior leaders are committed to doing our part by promoting—not shutting down—healthy dialogue at SFU.

Joy Johnson
Pronouns: she, her, hers
President & Vice-Chancellor
Simon Fraser University

Now the “pronoun statement at the bottom undermines this statement just a tad, but on the whole Dr. Johnson (a researcher in “gender and health”) seems to understand the issues at play. But there is one bit of her message that seriously undermines her statement:

As outlined in What’s Next, we are also committed to embedding the values of equity and belonging in every decision and action. We have a collective responsibility to create a culture of inclusive excellence where all feel welcome, safe, accepted and appreciated.

This statement is indeed a debatable political assertion, because “equity” is not equal opportunity for everyone, which is not only the law but morally correct. Rather, “equity” is a policy of equal outcomes, and is premised on the debatable claim that a lack of equal outcomes must perforce reflect bias against an underrepresented group (e.g., “structural racism” or “structural sexism”). The University of Chicago would never adopt a policy calling for equity, but of course we do have a policy of equality of opportunity.  Our University would never assert that it tries to ensure “equity” because that is a debatable statement about ideology.

Further, ensuring that everyone feels “welcome, safe, accepted, and appreciated” may not be possible if there is true freedom of speech.  For that kind of speech almost invariably assures that, at least at some times, some students claim that they feel “unsafe” and “unwelcome”.  That, for example, was one reason that an art history professor at the private Hamline University in Minnesota was fired for showing images of old Islamic pictures in which Muhammed’s face was unveiled.  Showing those pictures (which some Muslims feel is disrespectful or even blasphemous) made some students feel “unsafe,” and that  “they didn’t belong.”  (The professor sued Hamline and, I think, got an other job.)

Finally, “inclusive excellence,” though it links to an explanation of its meaning, is really a slippery concept.  In many cases where students and groups differ in achievement, the words “inclusive” and “excellence” may not be compatible.

So this statement is a sort-of acceptance of Kalven, but shows some unsettling signs of wokeness. For the time being we’ll see what happens at Simon Fraser. It is a public university, but there’s no First Amendment in Canada.

The link was sent to my reader Mike, who is associated with Simon Fraser. Mike said this in an email:

I wanted to share some good news. My university president today publicly embraced institutional neutrality for the university and its senior leadership.  (See below).

We don’t have a real policy yet, we don’t know how far down the administrative structure this neutrality will extend, and I don’t know whether this or a different message was sent to our students at the same time. But I hope clarifying those things will be a next step. It’s a huge improvement over the past 5 years in which the president created a new vice-president-level DEI infrastructure and pursued other initiatives that have chilled free expression by choosing sides on controversial topics including Hamas terrorism. So although there is work to do this is good news and a good day for my university. The people most responsible for this positive development are the faculty leaders of our Heterodox Academy Campus Community at SFU. Our group has politely, publicly, and insistently urged our colleagues and administrators to back off from adopting public positions on policy or cultural issues on behalf of everyone at the university, and we have extolled the virtues of academic freedom of expression. We think that public campaign has borne its first fruit. I hope its effects will continue to be felt (a real policy, extended to students, and extended down to the level of department chairs).

Mike’s statement about the President setting up a DEI infrastructure is further unsettling. I hope this is good news for Simon Fraser, but, as a cynic, I found the President’s statement worrisome. The first sign that Dr. Johnson means what she says it that she has to dismantle or cut way back on the DEI business. For DEI itself, or at least the ideology behind its most common implementations, is itself ideologically debatable. Remember, the “E” stands for “equity.”

https://traffic.libsyn.com/secure/sciencesalon/mss467_Matthew_Stewart_2024_09_10.mp3 Download MP3

Matthew Stewart is an independent philosopher and historian who has written extensively about the philosophical origins of the American republic, the history of philosophy, management theory, and the culture of inequality. His work has appeared in The Atlantic, the Washington Post, the Wall Street Journal, and Harvard Business Review, among other publications. In recent years he has lived in Boston, New York, and Los Angeles, and is currently based in London. He is the author of Nature’s God: The Heretical Origins of the American Republic and An Emancipation of the Mind: Radical Philosophy, the War over Slavery, and the Refounding of America.

Shermer and Stewart discuss:

• What does the phrase “The Law of Nature and Nature’s God” mean?
• What is heretical about the origins of the American Republic?
• Religion of the founders: John Adams, Thomas Jefferson, Alexander Hamilton, Benjamin Franklin, George Washington, John Jay, James Madison, Thomas Paine
• Ethan Allen and Thomas Young
• The Enlightenment influence on the Founding Fathers
• John Locke, Thomas Hobbes, Rene Descartes, Baruch Spinoza
• Ancient Greek influences on the Founding Fathers
• Epicurus’s Dangerous Idea
• Lucretius’s “swerving” atoms
• Theism, Deism, Pantheism, Atheism
• Reason and empiricism
• Self-evident truths
• Morality and the origin of right and wrong
• Happiness and its pursuit
• The religion of freedom
• Enslaving other humans: what were these people thinking and feeling?
• Should they have known better?
• Racists or creatures of their time in which nearly everyone held such views?
• Monogenism vs. polygenism
• Abolitionism
• John Brown
• Frederick Douglass
• Theodore Parker
• Abraham Lincoln
• Civil War cause: slavery or states’ rights?
• Religious supporters of abolition: Quakers, William Wilberforce
• How did American slavery lead to civil war?
• Why did the war result in emancipation?

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

Five satellites due to launch this week could be brighter than most stars, and astronomers fear the growth of such constellations could have a catastrophic impact

By now we have all seen the impressive robot videos, such as the ones from Boston Dynamics, in which robots show incredible flexibility and agility. These are amazing, but I understand they are a bit like trick-shot videos – we are being shown the ones that worked, which may not represent a typical outcome. Current robot technology, however, is a bit like steam-punk – we are making the most out of an old technology, but that technology is inherently limiting.

The tech I am talking about is motor-driven actuators. An actuator is a device that converts energy into mechanical force, such a torque or displacement. This is a technology that is about 200 years old. While they get the job done, they have a couple of significant limitations. One is that they use a lot of energy, much of which is wasted as heat. This is important as we try to make battery-driven robots that are not tethered to a power cord. Dog-like and humanoid robots typically last 60-90 minutes on one charge. Current designs are also relatively hard, so that limits their interaction with the environment. They also depend heavily on sensors to read their environment.

By contrast we can think about biological systems. Muscles are much more energy efficient, are soft, can be incredibly precise, are silent, and contain some of their own feedback to augment control. Developing artificial robotic muscles that would perform similar to biological systems is now a goal of robotics research, but it is a very challenging problem to crack. Such a system would also need to contract slowly or quickly, and even produce bursts of speed (if, for example, you want your robot to jump). They would need to be able to produce a lot of power, enough for the robot to move itself and carry out whatever function it has. It would also need to be able to efficiently hold a position for long periods of times.

As a bonus, human muscles, for example, have stretch receptors in them which provide feedback to the control system which not only enhances control but allow for rapid reflexive movements. Biological systems are actually very sophisticated, which is not surprising given that they have had hundreds of millions of years to evolve. Reverse engineering such systems is no easy task.

Researchers, however, have made some preliminary progress. To start they need a material that can contract or stretch (or change its shape is some way) when a voltage is applied to it. That is the fundamental function of a muscle – they contract when activated by nerve stimulation. Muscles will also contract when an external electrical stimulus is applied to them. The musculoskeletal system is essentially a system of contracting muscles, arranged so as to move joints in different directions – the biceps flexes the elbow while the triceps extends the elbow, for example. But also there are often different muscles for the same action but with different positions of maximal mechanical advantage.

Designing such a system won’t be the challenge for engineers – thinking about such forces is bread and butter for engineers. The limiting factor right now is the material science, the artificial muscle itself. The other technological challenge (where we have already made good progress) is developing the various sensors that work together to provide all the necessary feedback. Humans, for example, use multiple sensory modalities at the same time. We use vision, of course, to see our environment and guild our movements. We also have proprioception which allows our brains to sense where our limbs are in three-dimensional space. This is why you can move accurately with your eyes closed (close your eyes and touch your nose – that’s proprioception). The vestibular system tells us how we are oriented with respect to gravity and senses any accelerating forces acting on us (such as spinning around). We also have tactile sensation so we can sense when we are touching something (our feet against the ground, or something in our hands). Our muscles can also sense when they are being stretched, which further helps coordinate movement.

Our brains process all of this information in real time, comparing them to each other to provide a unified sense of how we are oriented and how we are moving. Motion sickness, vertigo, and dizziness result when the various sensory streams do not all sync up, or if the brain is having difficulty processing it all.

Designing a robotic system that can do all this is challenging, but it starts with the artificial muscles. There are a few approaches in development. MIT researchers, for example, developed a fiber made of different materials with different thermal expansion properties. When stimulated the fiber coils, and therefore shortens. Muscles are made of many individual fibers that shorten when activated, so this could serve as the building block of a similar approach. The question is – will dozens or hundreds of these fibers work together to form a muscle?

More recently scientists have developed an electrohydraulic system – essentially bags of oil that contract or stretch when stimulated. Preliminary testing is promising, with a key feature that the system is energy efficient.

A recent Nature review breaks down the various artificial muscle systems by the environmental stimuli to which they respond: “According to different stimuli, artificial muscles can be categorized as thermoresponsive, electrically responsive, magnetically responsive, photoresponsive, chemically responsive, and pressure driven.” There are also multi-stimuli driven systems. They can also be categories by potential application. These include micro-robotic systems, where very tiny actuators are needed. Also there are biomedical applications, such as prosthetics and implantable devices. And of course there are robotic applications, but this is a huge category that includes many different sizes and designs of robots.

Most of this research has been essentially done in the last decade, so it is still very new. Interest and investment is increasing, however, as the potential of “microactuators” and “soft robotics” is better understood. This could potentially be a transformative technology, with lots of applications beyond just building more efficient and agile robots.

The post Artificial Robotic Muscles first appeared on NeuroLogica Blog.

Four private astronauts are riding a SpaceX Crew Dragon capsule further from Earth than any human since 1972, where they will attempt the first ever civilian spacewalk

Using images captured by the European Space Agency’s Mars Express spacecraft, researchers have created a cloud atlas of Mars, to better understand the climate of the Red Planet

Lots of companies sell pheromone products claiming to calm down your dog or cat, but there's a very big problem with that basic claim.

Meanwhile, in Dobrzyn, Hili’s identification of these birds is troubling, given the date. Mind you, she is a cat.

Hili: There will be a storm.
A: Why do you think so?
Hili: The swifts are flying low.

Hili: Będzie burza.
Ja: Dlaczego tak sądzisz?
Hili: Jaskółki nisko latają.

The ESA/JAXA BepiColombo spacecraft made another flyby of its eventual target, Mercury. This is one of a series of Mercury flybys, as the spacecraft completes a complex set of maneuvers designed to deliver it to the innermost planet’s orbit. Its cameras captured some fantastic images of Mercury.

BepiColombo will eventually enter orbit around Mercury in November 2026. However, Mercury is a challenge to visit because of its proximity to the Sun and the Sun’s overwhelming gravity. To eventually orbit Mercury, the spacecraft is performing six gravity-assist flybys of the Solar System’s innermost planet. This is the 4,100 kg spacecraft’s fourth flyby.

The images are a bonus. The spacecraft’s monitoring cameras captured them, and those cameras are there to keep an eye on the spacecraft itself. But in this situation, they were able to image Mercury and some prominent craters. As BepiColombo approached and passed by Mercury, different monitoring cameras were able to capture images.

All three of BepiColombo’s monitoring cameras captured images of Mercury during the recent flyby. Many of the dual-spacecraft’s scientific instruments were also active, giving the mission personnel a chance to check their function. Image Credit: ESA/Work performed by ATG under contract to ESA/CC BY-SA 3.0 IGO

The closest approach during the recent flyby was on September 4th. BepiColombo—named after Italian scientist Giuseppe “Bepi” Colombo—came within about 165 km of Mercury’s surface. This was the first time that the spacecraft had a view of the planet’s south pole.

This image highlights Mercury’s rugged surface, featureless except for craters. BepiColombo’s MC2 captured this image from about 177 km altitude. The camera was aimed at the horizon, so the actual surface is a slightly greater distance away. North is to the lower left in this image. Image Credit: ESA/BepiColombo/MTM CC BY-SA 3.0 IGO

Even though Mercury is so close, it’s seldom visited. BepiColombo is only the third spacecraft to visit the small planet after NASA’s Mariner 10 mission in 1974/75 and Messenger mission from 2011 to 2015. Its proximity to the Sun is a complex challenge.

“BepiColombo is only the third space mission to visit Mercury, making it the least-explored planet in the inner Solar System, partly because it is so difficult to get to,” said Jack Wright, ESA Research Fellow, Planetary Scientist, and M-CAM imaging team coordinator.

“It is a world of extremes and contradictions, so I dubbed it the ‘Problem Child of the Solar System’ in the past. The images and science data collected during the flybys offer a tantalizing prelude to BepiColombo’s orbital phase, where it will help to solve Mercury’s outstanding mysteries,” said Wright.

The next flyby is only a few months away, on December 1st, 2024. The final one is on January 8th, 2025.

BepiColombo is actually two orbiters in one. Once it enters Mercury’s orbit, it’ll separate into the ESA’s Mercury Planetary Orbiter (MPO) and the JAXA-built Mercury Magnetospheric Orbiter (MMO) or Mio. The Mercury Transfer Module is the spacecraft that delivers the pair of orbiters.

This simple schematic shows the three separate spacecraft that combine to make the BepiColombo mission. Image Credit: ESA

There’s a lot we don’t know about Mercury, where it originated, and how it evolved so close to its star. The spacecraft will study Mercury physically, its form, interior, structure, geology, composition, and abundant craters. It’ll also study the planet’s exosphere.

Instead of an atmosphere, Mercury has an exosphere, a region consisting of atoms blasted off the planet’s surface by the Sun and by impacts. The exosphere is dynamic and changes according to how the solar wind interacts with the surface. Studying it is an opportunity to study planetary evolution and space weather. Understanding the exosphere is also critical to future missions, especially any potential landers, because it can affect spacecraft operations.

This image shows Mercury’s 213 km Vivaldi Crater. The two booms are the Mercury Planetary Orbiter’s medium gain antenna (top centre) and magnetometer boom (right). Image Credit: ESA/BepiColombo/MTM CC BY-SA 3.0 IGO

BepiColombo will also study Mercury’s magnetosphere and magnetic fields. Mercury’s global magnetic field is extremely weak, only about 1% as strong as Earth’s. This is mysterious since the planet seems to have a large iron core.

Mercury’s magnetosphere is also an object of interest. The powerful solar wind shapes it and prevents it from rising much above the surface. The magnetosphere is also very dynamic and quickly responds to changes in the solar wind, making it a natural laboratory to study the physics of magnetospheres. Its weakness also challenges our understanding of how planetary dynamos function.

BepiColombo was initially scheduled to reach Mercury’s orbit in December 2025. However, a problem firing its thrusters during a maneuver in April 2024 added 11 months to the mission. The revised orbital insertion will be in November 2026.

Once it reaches the rapidly moving Mercury, we’ll start to learn more than ever about this sometimes overlooked planet.

The post BepiColombo’s New Images of Mercury are Cool appeared first on Universe Today.

Scientists have developed a new AI algorithm that can separate brain patterns related to a particular behavior. This work promises to improve brain-computer interfaces and aid with the discovery of new brain patterns.

Ask most people what a galaxy is made up of, and they’ll say it’s made of stars. Our own galaxy, the Milky Way, hosts between about 100 to 300 billion stars, and we can see thousands of them with our unaided eyes. But most of a galaxy’s mass is actually gas, and the extent of the gas has been difficult to measure.

Researchers have found a way to see how far that gas extends into the cosmos.

One of the foundational questions about galaxies concerns their size. If we limit our observations to stars, then our galaxy, for example, is about 26.8 kiloparsecs, or about 87,000 light-years, across. Our neighbour, Andromeda, is about 46.56 kpcs or 152,000 light-years across. But do these measurements really define the sizes?

In new research published in Nature Astronomy, researchers measured the reach of the gas that extends beyond a galaxy’s stellar population. It’s titled “An emission map of the disk–circumgalactic medium transition in starburst IRAS 08339+6517.” The lead author is Nikole Nielsen, a researcher with Swinburne University and ASTRO 3D and an Assistant Professor at the University of Oklahoma.

Galaxies have gaseous haloes that serve as reservoirs of star-forming material called the circumgalactic medium (CGM). The CGM interfaces with the intergalactic medium (IGM), which is yet more gas that exists between galaxies. The CGM is notoriously difficult to observe because it’s so diffuse and extended. But it makes up about 70% of a typical galaxy (ignoring dark matter) and plays an important role. “This diffuse reservoir of gas, the circumgalactic medium, acts as the interface between a galaxy and the cosmic web that connects galaxies,” the authors explain in their paper.

Astronomers rely on bright background objects to try to observe the CGM. Things like distant quasars, pulsars, or other galaxies can light up the gas and allow astronomers to measure its spectra. But that only works when things line up right, and it only produces a beam-like image of the galaxy.

In this new research, a team of astronomers found a different way of observing the CGM. They used the Keck Cosmic Web Imager (KCWI) on the 10-meter Keck telescope in Hawaii to observe the gas around IRAS 08339+6517. Rather than a limited, beam-like look at the gas, they were able to detect the clouds of gas well outside the typical confines of a galaxy, out to 100,000 light-years beyond the limit of the starlight that typically defines a galaxy.

“We present kiloparsec-scale-resolution integral field spectroscopy of emission lines that trace cool ionized gas from the centre of a nearby galaxy to 30 kpcs into its circumgalactic medium,” the authors write. In their paper, they explain that “… we obtain the equivalent of thousands of quasar sightlines around a single galaxy.”

IRAS 08339+6517 is a starburst galaxy about 56 kpcs away. A starburst galaxy is one that is birthing stars at an extraordinarily high rate. Hubble images show that it’s a face-on spiral galaxy, and 90% of its starlight is contained within a radius of about 2.4 kpcs. “Unlike normal spirals, it has quite extreme properties, with a star formation rate (SFR) = 12.1 solar masses yr-1) that is ~ 10 times higher than typical for its mass and stellar populations that are dominated by very young (~ 4 – 6 Myr) stars,” the authors write.

The researchers found that as the CGM extends beyond the galaxy, the physical properties of the hydrogen and oxygen in the gas changed. The change was ubiquitous at a certain distance and indicates that the gas is interacting with different energy sources.

“We found it everywhere we looked, which was really exciting and kind of surprising,” said lead author Nielsen. “We’re now seeing where the galaxy’s influence stops, the transition where it becomes part of more of what’s surrounding the galaxy, and, eventually, where it joins the wider cosmic web and other galaxies. These are all usually fuzzy boundaries.”

“But in this case, we seem to have found a fairly clear boundary in this galaxy between its interstellar medium and its circumgalactic medium,” said Professor Nielsen.

“In the CGM, the gas is being heated by something other than typical conditions inside galaxies; this likely includes heating from the diffuse emissions from the collective galaxies in the Universe, and possibly some contribution is due to shocks,” said Dr Nielsen.

The boundary is where the gas is heated differently inside the galaxy compared to outside the galaxy. Inside the galaxy’s disk, gas is being photoionized by HII (ionized atomic hydrogen) star-forming regions. At further distances, the gas is being ionized by shocks or the extragalactic UV background.

“It’s this interesting change that is important and provides some answers to the question of where a galaxy ends,” she says.

This figure from the research shows the spatial distribution of ionized gas in the CGM at kiloparsec scales. Emission from [Oiii] ?5007 in the CGM of IRAS08 extends to at least 30 kpc from the galaxy center. The blue rectangle represents the field-of-view of the KCWI pointing covering the galaxy disk (emission map not shown). HI contours indicate levels of constant HI column density from the Very Large Array, where a filament extends from IRAS08 towards a smaller companion galaxy 60 kpc away. Image Credit: Nielsen et al. 2024.

These results make a contribution to one of the most interesting issues in astronomy: How do galaxies evolve?

Gas flows into galaxies and becomes fuel for more star formation. At the same time, gas flows out from a galaxy as part of stellar feedback. There are three broad types of galaxies: starburst galaxies with extreme amounts of star formation, quenched galaxies with very little star formation, and galaxies in between. The gas in the CGM and the IGM play roles in a galaxy’s gas budget.

IRAS08 has a remarkably strong outflow of gas, but its metallicity profile is flat and shallow. Astronomers typically assume that galaxies with these metallicities and high SFRs are acquiring significant amounts of gas. Other scientific observations of IRAS08 indicate “a rapid inflow of gas to the center of the disk that is fueling the very strong starburst and subsequently strong outflows,” the authors explain.

Gas flows into galaxies along spiralling filaments. This image of a galaxy shows a stream of inflowing gas, as rendered in a supercomputer. Image Credit: MPIA (G. Stinson / A.V. Maccio)

However, IRAS 08 is a complex object that’s also interacting with a nearby galaxy. “VLA observations of the HI gas around IRAS08 identified a filament extending out to ~ 40 kpcs from the galaxy and containing 70% of the neutral gas in the system,” the authors write. This filament interacts with a neighbouring galaxy about 60 kpcs away, which is only one-tenth the mass of IRAS-08.

The authors say that this interaction with its neighbour could enhance star formation, but there’s no evidence that it’s affecting IRAS-08’s morphology. This doesn’t appear to be the first stage of an eventual merger.

Finding the boundary between the CGM and the IGM could be a critical step in understanding how gas cycles in and out of galaxies and how gas may interact with neighbours without a merger.

“The circumgalactic medium plays a huge role in that cycling of that gas,” says Dr Nielsen. “So, being able to understand what the CGM looks like around galaxies of different types – ones that are star-forming, those that are no longer star-forming, and those that are transitioning between the two –we can observe differences in this gas, which might drive the differences within the galaxies themselves, and changes in this reservoir may actually be driving the changes in the galaxy itself.”

Nature has few discrete boundaries. Everything interacts with other things, including massive galaxies. The interactions hold the key to understanding.

These results could open up a whole new window into how galaxies, gas, and stars interact and how galaxies evolve.

The post The True Size of Galaxies is Much Larger Than We Thought appeared first on Universe Today.

Every living organism uses tiny quantities of metals to carry out biological functions, including breathing, transcribing DNA, turning food into energy, or any number of essential life processes.