Science

Invasive mink, which are native to North America, have been eradicated from most of East Anglia in England after a trial used the scent of the animals' anal glands to lure them into traps

On October 19th, 2017, astronomers with the Pan-STARRS survey detected an interstellar object (ISO) passing through our Solar System for the first time. The object, known as 1I/2017 U1 Oumuamua, stimulated significant scientific debate and is still controversial today. One thing that all could agree on was that the detection of this object indicated that ISOs regularly enter our Solar System. What’s more, subsequent research has revealed that, on occasion, some of these objects come to Earth as meteorites and impact the surface.

This raises a very important question: if ISOs have been coming to Earth for billions of years, could it be that they brought the ingredients for life with them? In a recent paper, a team of researchers considered the implications of ISOs being responsible for panspermia – the theory that the seeds of life exist throughout the Universe and are distributed by asteroids, comets, and other celestial objects. According to their results, ISOs can potentially seed hundreds of thousands (or possibly billions) of Earth-like planets throughout the Milky Way.

The team was led by David Cao, a senior student at Thomas Jefferson High School for Science and Technology (TJSST). He was joined by Peter Plavchan, an associate professor of physics and astronomy at George Mason University (GMU) and the Director of the Mason Observatories, and Michael Summers, a professor of astrophysics and planetary science at GMU. Their paper, “The Implications of ‘Oumuamua on Panspermia,” recently appeared online and is being reviewed for publication by the American Astronomical Society (AAS).

Artist’s impression of the ISO 1I/2017 U1 ‘Oumuamua, detected on October 19th, 2017, by the Pan-STARRS survey. Credit: ESO/M. Kornmesser

To briefly summarize, panspermia is the theory that life was introduced to Earth by objects from the interstellar medium (ISM). According to this theory, this life took the form of extremophile bacteria capable of surviving the harsh conditions of space. Through this process, life is distributed throughout the cosmos as objects pass through the ISM until they reach and impact potentially habitable planets. This makes panspermia substantially different from competing theories of how life on Earth began (aka. abiogenesis), the most widely accepted of which is the RNA World Hypothesis.

This hypothesis states that RNA preceded DNA and proteins in evolution, eventually leading to the first life on Earth (i.e., which arose indigenously). But as Cao told Universe Today via email, panspermia is difficult to assess:

“Panspermia is difficult to assess because it requires so many different factors that need to be incorporated, many of which are unconstrained and unknown. For instance, we must consider the physics behind panspermia (how many objects collided with Earth prior to the earliest fossilized evidence for life?), biological factors (can extremophiles endure supernova gamma radiation?), and so on.

“In addition to each of these factors are questions we do not have answers to yet, or we cannot model effectively, for example, the number of extremophiles that actually reach the Earth even if a life-bearing object collided with Earth, and the probability that life can actually start from the foreign extremophiles. The collection of these factors, along with many more, such as the changing star formation rate and the recent detection of several rogue free-floating planets, makes panspermia difficult to assess, and therefore, our understanding of the plausibility of panspermia is constantly changing.”

The detection of ‘Oumuamua in 2017 constituted a major turning point for astronomy, as it was the first time an ISO was observed. The fact that it was detected at all indicated that such objects were statistically significant in the Universe and that ISOs likely passed through the Solar System regularly (some of which are likely to be here still). Two years later, a second ISO was detected entering the Solar System (2I/Borisov), except there was no mystery about its nature this time. As it neared our Sun, 2I/Borisov formed a tail, indicating it was a comet.

A Hubble image of comet 2I/Borisov speeding through our Solar System. Credit: NASA/ESA/D. Jewitt (UCLA)

Subsequent research has shown that some of these objects become meteorites that impact on Earth’s surface, and a few have even been identified. This includes CNEOS 2014-01-08, a meteor that crashed into the Pacific Ocean in 2014 (and was the subject of study by the Galileo Project). As Cao explained, the detection of these interstellar visitors also has implications for panspermia and the ongoing debate about the origins of life on Earth:

“‘Oumuamua serves as a novel data point for panspermia models, as we can use its physical properties, particularly its mass, size (spherical radius), and implied ISM number density, to model the number density and mass density of objects in the interstellar medium. These models allow us to estimate the flux density and mass flux of objects in the interstellar medium and, with these models, we can approximate the total number of objects that impacted Earth over 0.8 billion years (which is the hypothesized period of time between Earth’s formation and the earliest evidence for life).

“Knowing the total number of collision events on Earth over that 0.8 billion-year period is vital for panspermia, as a greater number of collision events with interstellar objects over that period would imply a higher probability for panspermia. In short, the physical properties of the interstellar ‘Oumuamua allow for the creation of mathematical models that determine the plausibility of panspermia.”

In addition to the mathematical models that consider the physics behind panspermia – i.e., number density, mass density, total impact events, etc. – Cao and his colleagues applied a biological model that describes the minimum object size needed to shield extremophiles from astrophysical events (supernovae, gamma-ray bursts, large asteroid impacts, passing-by stars, etc.). As addressed in a previous article, recent research has shown that cosmic rays erode all but the largest ISOs before they reach another system.

These additional considerations ultimately affect the number of objects that will impact Earth (that were not sterilized by astrophysical sources) and the plausibility of panspermia. “In order to derive the minimum object size, we applied various models, for instance, the sphere packing method to give a rough estimate of an ejecta’s distance to the nearest supernova progenitor (using Orion A, a dense star cluster, as our model), the gamma radiation that reaches that ejecta, and the attenuation coefficient (how much radiation the ejecta absorbs) based on the most probable chemical composition of ejecta (water ice),” said Cao.

Artist’s Concept of ‘Oumuamua. Credit: William Hartmann

Based on their combined physical and biological models, the team derived estimates for the number of ejecta that struck Earth before life emerged. According to the oldest fossilized evidence found in western Australia (from rocks dating to the Archaean Eon), the earliest life forms emerged ca. 3.5 billion years ago. Said Cao:

“We conclude that the maximum probability that panspermia sparked life on Earth is on the order of magnitude of 10-5, or 0.001%. Although this probability appears low, under the most optimistic conditions, potentially 4×109 total habitable zone exoplanets exist in our Galaxy, which could indicate a total of 104 habitable worlds harboring life.

“Additionally, we restricted our analysis to the first 0.8 billion years of Earth’s history prior to the earliest fossilized evidence for life, but because life can be seeded at any point in a planet’s lifetime, and planets have significantly longer habitable lifespans (up to 5-10 billion years), we boosted our estimate for the total number of habitable worlds harboring life in our Galaxy by one order of magnitude.”

From this, Cao and his colleagues obtained a final result of about 105 habitable planets that could harbor life in our galaxy. However, these estimates are based on the most optimistic projections regarding planetary habitability. In other words, it assumes that all Earth-sized rocky planets orbiting within habitable zones are capable of supporting life, meaning they have thick atmospheres, magnetic fields, liquid water on their surfaces, and all life-bearing ejecta that survive entering our atmosphere are capable of depositing microbes on the surface.

As Cao summarized, their results do not prove panspermia or settle the debate on the origins of life here on Earth. Nevertheless, they provide valuable insight and constraints on the possibility that life came here via objects like ‘Oumuamua. No matter what, these findings are likely to have significant implications for astrobiology, which is becoming an increasingly diverse field:

“We incorporate physics, biology, and chemistry into studying panspermia as the origin of life, and it is rare to have such a diverse range of topics in one research area. I think that astrobiology is trending toward becoming more interdisciplinary, which I believe is a positive trend because it would allow experts of all backgrounds to advance astrobiology. Our research may contribute to this trend. In terms of our findings on panspermia, the probability that panspermia sparked life on Earth is unlikely, but the number of habitable zone planets harboring life in our Galaxy is substantially larger.

“Future astrobiology studies may use these findings to build on our research on panspermia. However, we do not incorporate or even know all factors that may affect the plausibility of panspermia. I believe our findings open up new lines of inquiry for future panspermia studies to build off of by updating our models or incorporating additional factors. One potential area of study if we do find evidence for life on other worlds in the future, whether in our Solar System or via biosignatures in exoplanet atmospheres, is to consider experimental and observational tests to distinguish between life that arrived by the panspermia mechanism or life that evolved and arose independently.”

Further Reading: arXiv

The post Since Interstellar Objects Crashed Into Earth in the Past, Could They Have Brought Life? appeared first on Universe Today.

The idea that we have libertarian free will, in the real sense of “being able to make any one of several decisions at a given time”, has made a comeback in the pages of The New York Review of Books, a magazine that never quite recovered from the death of editor Robert B. Silvers in 2017. It was once the magazine to read for thoughtful analyses of books, but it’s gone downhill.  I had a subscription on and off, but quit a while back.

But I digress. In the latest issue, the respected author and historian of science James Gleick reviews a recent book on free will, Free Agents: How Evolution Gave us Free Will by Kevin Mitchell.  I haven’t read the book, so all I can do is reprise what Gleick says about the book, which is that Mitchell’s case for libertarian free will is convincing, and that determinism—or “naturalism” as I prefer to call it, since I take into account the inherent unpredictability of quantum mechanics—is not all there is to our actions and behaviors. Mitchell, says Gleick, maintains that natural selection has instilled humans with the ability to weigh alternatives and make decisions, not only apparent decisions but real ones, decision that involve us weighing alternatives, thinking about the future, and then making make one of several possible decisions even at the moment you decide. In other words, determinism doesn’t rule all of our behaviors and decisions. Apparently, this is libertarian free will: facing a restaurant menu, with everything else in the universe the same (a classic scenario), you could have ordered something other than what you did.

The problem is that Gleick never defines “free will” in this way; he only implies that Mitchell accepts libertarian free will, and then tries to show how evolution gives it to us.

But I’m getting ahead of myself: click on the screenshot below to read:

here

Gleick argues that life without libertarian free will is pointless. I maintain that this is incorrect—that the point of our life is the gratification we get from our actions, and we don’t need libertarian free will for that. All we need is a sense of satisfaction. You don’t even really need that if you define “point” post facto as “doing what you felt you had to do.”  But, say compatibilists like Dennett—and compatibilists are all physical determinists—we need to have some conception of free will, even if what we do is determined, for society would fall apart without it. And Gleick agrees:

Legal institutions, theories of government, and economic systems are built on the assumption that humans make choices and strive to influence the choices of others. Without some kind of free will, politics has no point. Nor does sports. Or anything, really.

. . . If the denial of free will has been an error, it has not been a harmless one. Its message is grim and etiolating. It drains purpose and dignity from our sense of ourselves and, for that matter, of our fellow living creatures. It releases us from responsibility and treats us as passive objects, like billiard balls or falling leaves.

One senses from these statements that the choices we make are not merely apparent choices, conditioned by the laws of physics, but real ones: choices that we didn’t have to make. In other words, we have libertarian, I-could-have-done-otherwise free will.

That construal of free will is buttressed by Gleick’s characterization of Mitchell’s argument as showing that we have purpose, and that purpose (again, not explicitly defined), is the proof that we have libertarian free will:

Agency distinguishes even bacteria from the otherwise lifeless universe. Living things are “imbued with purpose and able to act on their own terms,” Mitchell says. He makes a powerful case that the history of life, in all its complex grandeur, cannot be appreciated until we understand the evolution of agency—and then, in creatures of sufficient complexity, the evolution of conscious free will.

And this purpose is apparently an emergent property from natural selection, not only not predictable from physics, but somehow incompatible with physical law, which, are, says Gleick, are only descriptions of the universe and not really “laws” that the substance of our bodies and brains must obey:

This is why so many modern physicists continue to embrace philosophical determinism. But their theories are deterministic because they’ve written them that way. We say that the laws govern the universe, but that is a metaphor; it is better to say that the laws describe what is known. In a way the mistake begins with the word “laws.” The laws aren’t instructions for nature to follow. Saying that the world is “controlled” by physics—that everything is “dictated” by mathematics—is putting the cart before the horse. Nature comes first. The laws are a model, a simplified description of a complex reality. No matter how successful, they necessarily remain incomplete and provisional.

The incompleteness apparently creates the gap where you can find libertarian free will.

And the paragraphs below, describing the results of natural selection, seem to constitute the heart of the book’s thesis:

Biological entities develop across time, and as they do, they store and exchange information. “That extension through time generates a new kind of causation that is not seen in most physical processes,” Mitchell says, “one based on a record of history in which information about past events continues to play a causal role in the present.” Within even a single-celled organism, proteins in the cell wall respond chemically to changing conditions outside and thus act as sensors. Inside, proteins are activated and deactivated by biochemical reactions, and the organism effectively reconfigures its own metabolic pathways in order to survive. Those pathways can act as logic gates in a computer: if the conditions are X, then do A.

“They’re not thinking about it, of course,” Mitchell says, “but that is the effect, and it’s built right into the design of the molecule.” As organisms grow more complex, so do these logical pathways. They create feedback mechanisms, positive and negative. They make molecular clocks, responding to and then mimicking the solar cycle. Increasingly, they embody knowledge of the world in which they live.

The tiniest microorganisms also developed means of propulsion by changing their shape or deploying cilia and flagella, tiny vibrating hairs. The ability to move, combined with the ability to sense surroundings, created new possibilities—seeking food, escaping danger—continually amplified by natural selection. We begin to see organisms extracting information from their environment, acting on it in the present, and reproducing it for the future. “Information thus has causal power in the system,” Mitchell says, “and gives the agent causal power in the world.”

We can begin to talk about purpose. First of all, organisms struggle to maintain themselves. They strive to persist and then to reproduce. Natural selection ensures it. “The universe doesn’t have purpose, but life does,” Mitchell says.

My response to this is basically “so what?” Natural selection is simply the differential reproduction of gene forms, which, when encased in an organism, can leave more copies when they give that organism the ability to survive and reproduce.  Organisms thus evolve to act as if they have purpose. But that “purpose” is simply anthropormorphizing the results of the mindless process of natural selection.  So, when we decide to go hunting for food, or get pleasure from being with a mate, we can say that those embody our “purpose”. But there’s nothing in all this that implies that, at a given moment, we can make any number of decisions independent of physics.

But, Gleick implies, there is a way we can do this: by leveraging the “random fluctiations” in our brains:

It’s still just chemistry and electricity, but the state of the brain at one instant does not lead inexorably to the next. Mitchell emphasizes the inherent noisiness of the system: more or less random fluctuations that occur in an assemblage of “wet, jiggly, incomprehensibly tiny components that jitter about constantly.” He believes that the noise is not just inevitable; it’s useful. It has adaptive value for organisms that live, after all, in an environment subject to change and surprise. “The challenges facing organisms vary from moment to moment,” he notes, “and the nervous system has to cope with that volatility: that is precisely what it is specialized to do.” But merely adding randomness to a deterministic machine still doesn’t produce anything we would call free will.

That’s correct, though what Mitchell or Gleick mean as “random fluctuations in the brain” is undefined. Robert Sapolsky argues, in his recent book Determined: A Science of Life Without Free Will, that there are no “random” fluctuations in the brain: neurons interact with each other according to the principles of physics.  To have true free libertarian will, those neurons would have to fire in different ways under exactly the same conditions in the brain. Sapolsky spends a lot of time convincingly showing that this cannot be the case. Ergo, no brain fluctuations.

But, as Gleick says above, randomness alone doesn’t give us agency. Still, under Mitchell’s model it’s essential for free will. And this is the big problem, for how does one’s “will” harness that randomness to come up with decisions that are independent of physical processes? Gleick:

Indeed, some degree of randomness is essential to Mitchell’s neural model for agency and decision-making. He lays out a two-stage model: the gathering of options—possible actions for the organism to take—followed by a process of selection. For us, organisms capable of conscious free will, the options arise as patterns of activity in the cerebral cortex, always subject to fluctuations and noise. We may experience this as “ideas just ‘occurring to you.’” Then the brain evaluates these options, with “up-voting” and “down-voting,” by means of “interlocking circuit loops among the cortex, basal ganglia, thalamus, and midbrain.” In that way, selection employs goals and beliefs built from experience, stored in memory, and still more or less malleable.

Ergo we have to have the brain’s “randomness”, which is neither defined nor, at least according to Sapolsky, doesn’t exist. Then one harnesses that randomness to come up with your decisions:

Mitchell proposes what he calls a “more naturalized concept of the self.” We are not just our consciousness; we’re the organism, taken as a whole. We do things for reasons based on our histories, and “those reasons inhere at the level of the whole organism.” Much of the time, perhaps most of the time, our conscious self is not in control. Still, when the occasion requires, we can gather our wits, as the expression goes. We have so many expressions like that—get a grip; pull yourself together; focus your thoughts—metaphors for the indistinct things we see when we look inward. We don’t ask who is gathering whose wits.

Well, we can always confabulate “reasons” for what we do, but, in my view, the whole process of pondering is simply the adaptive machinery of your brain, installed by natural selection, taking in environmental information and spitting out a solution that’s usually “adaptive”.  And because different people’s brains are wired differently (there is, after all, genetic and developmental variation), people tend to have somewhat different neuronal programs, so they behave in somewhat different ways, often predictable. This is what we call our “personalities”: the programs that are identified with different bodies. “Pondering” is not something we do freely; it’s what’s instilled in our brains by natural selection to produce adaptive behavior. We ponder just as a chess-playing computer ponders: working through programs until one produces the best available solution (in the case of a computer, to make a move that best insures you’ll win; in the case of a human, to make a move that gives the most “adaptive” result).

In none of this, however, do I detect anything other than giving the name “free will” to neuronal processes that we get from natural selection, and spitting out decisions and behaviors that could not have been otherwise in a given situation. (That situation, of course, includes the environment, which influences our neurons.) In none of this do I see a way that a numinous “will” or “agency” can affect the physical workings of our neurons. And in none of this can i see a way to do something differently than what you did.

In the end, and of course I haven’t read Mitchell’s book, Gleick doesn’t make a convincing case for libertarian free will. Yes, he can make a case for “compatibilist” free will, depending on how you define that (“actions that comport with our personalities,” “decisions not made under compulsion,” etc.). But as I’ve emphaszied, all compatibilists are at bottom, determinists (again, I’d prefer “naturalists”). Remember, determinism or naturalism doesn’t mean that behaviors need be completely predictable—quantum indeterminacy may act, though we’re not sure it acts on a behavioral level—but quantum indeterminacy does not give us “agency”.  “Compatibilist” free will still maintains that, at any given moment, we cannot affect the behaviors that flow from physics, and we cannot do other that what we did. It’s just that compatibilists think of free will as something other than libertarian free will, and there are as many versions of compatibilism as there are compatibilist philosophers.

I can’t find in this review any basis for libertarian free will—not in natural selection, not in the “random” fluctuations of the brain, not in the fact that different people have different personalities and may act differently in the same general situation. You can talk all you want about randomness and purpose and “winnowing of brain fluctuations,” but until someone shows that there’s something about our “will” that can affect physical processes, I won’t buy libertarian free will. Physicist Sean Carroll doesn’t buy it, either. He’s a compatibilist, but argues this:

There are actually three points I try to hit here. The first is that the laws of physics underlying everyday life are completely understood. There is an enormous amount that we don’t know about how the world works, but we actually do know the basic rules underlying atoms and their interactions — enough to rule out telekinesis, life after death, and so on. The second point is that those laws are dysteleological — they describe a universe without intrinsic meaning or purpose, just one that moves from moment to moment.

The third point — the important one, and the most subtle — is that the absence of meaning “out there in the universe” does not mean that people can’t live meaningful lives.

(See also here.)

We are physical beings made of matter. To me that blows every notion of libertarian free will out of the water. I’ll be curious to see how Mitchell obviates this conclusion.

 

h/t: Barry

The latest report from the American Academy of Pediatrics is filled with misinformation and missing key articles that support the well-researched conclusion that there is no legitimate evidence of negative health effects of glyphosate.

The post A good journal breaks bad: AAP spreads misinformation about glyphosate first appeared on Science-Based Medicine.

Today is the Lord’s Day, but also John’s Day, for we have another dollop of themed bird photos from Dr. Avise.. His notes and IDs are indented, and you can enlarge his photos by clicking on them.  I’ll add here that I’m scheduled to go to South Africa in August to visit friends in Capetown and to see the animals at Kruger National Park. I have to see the big “game” before I croak!

South Africa Birds, Part 3 

This week’s post is Part 3 of a mini-series on birds I photographed in South Africa during an extended seminar trip in 2007.  It shows another dozen or so species from that avian-rich part of the world.  All of today’s birds have the word “Cape” in their common name and were photographed in the Cape Town area.

Cape Batis (Batis capensis) female:

Cape Bulbul (Pycnonotus capensis):

Cape Francolin (Pternistis capensis):

Cape Glossy Starling (Lamprotornis nitens):

Cape Grassbird (Sphenoeacus afer):

Cape Gull (Larus dominicanus) (also known as the Kelp Gull):

Cape Robin-chat (Cossypha caffra):

Cape Sparrow (Passer melanurus):

Cape Sugarbird (Promerops cafer) male:

Cape Sugarbird female:

Cape Teal (Anas capensis):

Cape Turtle Dove (Streptopelia capicola):

Cape Wagtail (Motacilla capensis):

Cape Weaver (Ploceus capensis) male:

Titan’s methane seas have ephemeral “magic islands” that have baffled scientists for years. They may be made of odd, porous clumps of snow

Titan’s methane seas have ephemeral “magic islands” that have baffled scientists for years. They may be made of odd, porous clumps of snow

Everybody knows that the explosive deaths of supermassive stars (called supernovae) lead to the creation of black holes or neutron stars, right? At least, that’s the evolutionary path that astronomers suggest happens. And, these compact objects exist throughout the Universe. But, no one’s ever seen the actual birth process of a neutron star or black hole in action before.

That changed when supernova SN 2022jli occurred in the nearby galaxy NGC 157. This catastrophic stardeath event was discovered in May 2022 by amateur astronomer Berto Monard. Its behavior quickly caught the attention of two teams of professional astronomers. Observations from the European Southern Observatory’s Very Large Telescope and New Technology Telescope provided high-quality light-curve measurements as well as other data. Those measurements and radiation showed something unusual, not like a “normal” supernova.

Focusing on the Supernova

Astronomers Ping Chan of the Weizmann Institute of Science in Israel and Thomas Moore of Queen’s University, Belfast, Northern Ireland each led teams who studied the weird behavior of this supernova. Their analysis showed the supernova explosion ended up creating a massive compact object. That was pretty exciting because until now, no one has observed the process happen in (almost) real-time. That makes the light curve a useful window on the creation of either a neutron star or a black hole.

Chan’s team wanted to establish a direct connection between the death of a massive supergiant star and the creation of the object. “In our work, we establish such a direct link,” Chan said and reported the work at the recent American Astronomical Society meeting.

Moore’s team was also intrigued by the light curve of this event. “In SN 2022jli’s data we see a repeating sequence of brightening and fading,” he said. “This is the first time that repeated periodic oscillations, over many cycles, have been detected in a supernova light curve.”

Finding the Missing Link Between Supernovae, Black Holes, and Neutron Stars

Supernovae occur pretty frequently in the Universe. Astronomers study them and chart how their brightness changes over time. After the initial explosion, the light it generates fades out over some time. Usually, it’s a pretty smooth change in the light curve. But, SN 2022jli didn’t fit the “normal” curve, so to speak. Instead of fading out smoothly, the brightness of light from the explosion oscillated in a 12-day-long period. Both teams noticed this oscillation, and Chan’s group also detected the motions of hydrogen gas and gamma-ray bursts in the region.

This is a JWST view of the Crab Nebula. Like other supernovae, a star exploded to create this scene. The result is a rapidly spinning neutron star (a pulsar) at its heart, surrounded by material rushing out from the site of the explosion. SN 2022jli could have either a neutron star or a black hole orbiting with a companion star.

What story does SN 2022jli’s strange light curve tell us about the creation of black holes or neutron stars? Let’s start with the explosion itself. It was a fine example of what astronomers call “Type II supernovae”. Basically, at the end of its life, a supermassive star collapses and then explodes outward. The remaining core collapses further to create one of two types of massive objects. A neutron star is one. It’s what’s left over after the rapidly collapsing core of the star crushes the remaining protons and neutrons of matter into neutrons. It’s essentially a ball of neutrons. Most neutron stars have about the mass of the Sun crushed inside themselves. But, they are small—really small, compared to their progenitor stars. Most are maybe 20 or so kilometers across.

Stellar-mass black holes also come from the deaths of supermassive stars that were at least 20 times the mass of the Sun or more. The core collapses during the event, the same as with a neutron star. But, the mass is so great that the event creates a black hole, crushing all the leftover core material into a pinpoint of dense matter.

Putting Together the Link Between Supernovae and Compact Massive Objects

All the data from the observations helped both teams suggest the following scenario. Like many massive stars, the progenitor of SN 2022jli appears to have had at least one companion star. It probably survived the supernova explosion. The outburst threw out huge amounts of material, and the companion star interacted with it. That caused its atmosphere to “puff up”. The newly created compact object passes through the orbit of the star and sucks hydrogen gas away from the star. That material funnels into an accretion disk around the compact object. Those periodic episodes of matter theft from the star release lots of energy, which gets picked up as regular changes of brightness in the light curve measurements as well as the gamma-ray signals.

After SN 2022jli exploded this may be what it looks like. A compact object and its companion star orbit each other. The possible neutron star or black hole steals hydrogen gas from the neighbor star. Courtesy ESO/L. Calçada

Of course, we can’t see light coming from the compact object itself—whether it’s a neutron star or a black hole. But, we do see radiation from the heated material drawn into the accretion disk around the compact object. And, since astronomers were able to track the changes in the light curve due to activity by the massive object, it amounted to watching its formation. “Our research is like solving a puzzle by gathering all possible evidence,” Chen said about the findings. “All these pieces lining up lead to the truth.”

The next step is to figure out exactly what astronomers saw being formed. Was it a neutron star with tremendously strong magnetic fields and gravity, or a black hole with gravity so strong nothing (not even light) could escape it? Determining that requires additional observations and the capabilities of telescopes not yet online, such as the Extremely Large Telescope due to begin operations in a few years.

For More Information

Missing Link Found: Supernovae Give Rise to Black Holes or Neutron Stars
SN 2022jli: A Type 1c Supernova with Periodic Modulation of Its Light Curve and an Unusually Long RiseA 12.4-day Periodicity in a Close Binary System After a Supernova

The post Black Holes and Neutron Stars are Finally Linked to Supernovae appeared first on Universe Today.

Does the size of an exomoon help determine if life could form on an exoplanet it’s orbiting? This is something a February 2022 study published in Nature Communications hopes to address as a team of researchers investigated the potential for large exomoons to form around large exoplanets (Earth-sized and larger) like how our Moon was formed around the Earth. Despite this study being published almost two years ago, its findings still hold strong regarding the search for exomoons, as astronomers have yet to confirm the existence of any exomoons anywhere in the cosmos. But why is it so important to better understand the potential for large exomoons orbiting large exoplanets?

Dr. Miki Nakajima, who is an Assistant Professor of Physics and Astronomy at the University of Rochester and lead author of the study, tells Universe Today, “For Earth, the Moon plays a major role to determine the length of the day of Earth, ocean tides, and Earth’s spin axis tilt. These are extremely important parameters for life on Earth. Thus, understanding whether a planet has a moon or not would help us understand whether an exoplanet is similar to Earth or not.”

For the study, the researchers used a series of computer models to simulate how exomoons could form around an exoplanet based on the giant-impact theory that is the currently accepted model for how our Moon formed around the Earth. The researchers conducted these simulations using a variety of conditions, including rocky and icy exoplanets with the maximum target size being six Earth masses, the size and size ration of the impactor and target, along with a fixed impact velocity and impact angle for the impactor striking the target. In the end, the simulations produced some interesting results pertaining to the formation and evolution of exomoons.

“In my opinion, the most significant result is that our study made a prediction for future exomoon observations,” Dr. Nakajima tells Universe Today. “We predict that relatively small planets (< ~ 1.6 Earth radii) are good candidates to host exomoons. Up until now, most exomoon searches have focused on larger planets. So now we propose that future searches should instead focus on these smaller planets.”

As noted, this study was published almost two years ago, but its findings still hold true in terms of hypothesizing about the existence and potential future discoveries of exomoons, which could help astronomers better understand the conditions necessary for finding life beyond Earth. While the Earth’s Moon is responsible for allowing life to thrive on this planet, smaller moons throughout our solar system have demonstrated that size might not matter in terms of allowing life to potentially thrive on, or beneath, their surfaces. Examples include Jupiter’s icy moon, Europa, and Saturn’s largest moon, Titan, and its smaller icy moon, Enceladus. Given this study focused on exomoons forming around large exoplanets, what can exomoons, regardless of their size, teach us about finding life beyond Earth?

“In my opinion, a planet does not have to have a large moon to host life on its surface,” Dr. Nakajima tells Universe Today. “However, at least for Earth, the Moon plays a crucial role on the life on Earth. So, if we want to find a second Earth, a planet with a large moon would be a great candidate. I hope our study helps us to identify what planets likely host moons.”

In terms of follow-up studies that might have occurred in the two years since this study was published, Dr. Nakajima tells Universe Today that her and her colleagues have written a recent study about how the Earth’s Moon might have formed under a different process, and the paper is currently in peer-review. Additionally, Dr. Nakajima tells Universe Today she is currently participating in a proposal for NASA’s James Webb Space Telescope (JWST) with the goal of identifying exomoons orbiting relatively small exoplanets.

This 2022 study and upcoming JWST proposal both highlight how exomoons have come to the forefront for the search for life beyond Earth, and specifically beyond our solar system. While the existence of even one exomoon has yet to be confirmed, a growing list of exomoon candidates has garnered the attention of astronomers, with these exomoon candidates potentially orbiting both Jupiter- and Earth-sized worlds.

When will astronomers find the first exomoon, and how many exomoons will researchers find in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Big Planets Don’t Necessarily Mean Big Moons appeared first on Universe Today.

Astronomers routinely explore the universe using different wavelengths of the electromagnetic spectrum from the familiar visible light to radio waves and infra-red to gamma rays. There is a problem with studying the Universe through the electromagnetic spectrum, we can only see light from a time when the Universe was only 380,000 years old. An alternate approach is to use gravitational waves which are thought to have been present in the early Universe and may allow us to probe back even further. 

The concept of gravity waves is really quite simple. Imagine the fabric of space as an enormous sea.  The movement of any object within that lake will cause ripples that permeate through the water. Just as a sea fog will limit the visibility, the ripples can still travel through . Gravity waves are like ripples in space caused by the movement of objects. It was an idea predicted by Einstein in 1916 in his General Theory of Relativity. 

Gravity waves are not just a theory though, they have been detected. The LIGO-Virgo observatory detected gravity waves on 15 September 2015 from the merging of two black holes with 29 and 36 solar masses 1.3 billion light years away. There have since been over 100 detections so gravity waves are most certainly real. 

LIGO Observatory

Using gravity waves, Rishav Roshan and Graham White from University of Southampton believe they can probe the Universe’s earliest moments.  In the early moments of the formation of the Univserse, space was opaque becuase the Universe was full of ionised gas and electromagnetic radiation could not permeate. It is this barrier that Roshan and White believe they can break through.

In their paper, they discuss three major strategies for detecting gravitational waves; pulsar timing arrays, astrometry and interferometry. The techniques are similar and all rely upon gravity waves disturbing the space in between elements of the systemn. In the case of the interferometer, the disturbance of space between the optics of the system reveal gravity waves; in pulsar arrays, the variation in timings of pulses from known pulsar systems gives away their presence and with the astrometric technique, tiny changes in the target object’s angular velocity reveal the presence of the waves. 

Since their discovery, gravitational waves have provided invaluable information about events in the far reaches of the Universe. Now it looks like they can also be used to unlock some of the mysteries not only across space, but across time. To enable us to get a more fuller understanding of the Universe beyond the Standard Model (which was developed in the 1970’s it articulates how matter behaves taking account of the four fundamental forces; strong, weak, electromagnetic and gravitation) it seems gravity waves hold the key.

Source : Using gravitational waves to see the first second of the Universe

The post Gravitational Waves Could Show us the First Minute of the Universe appeared first on Universe Today.

On Earth, it seems to be true that life will find a way; in the deepest ocean, the saltiest ocean or the highest mountain, live seems to find a way to get a foothold. One of the key ingredients for life seems to be the necessity for water. Until now, it was thought that there was a limit to the level of salinity within which life could thrive. A team of biologists have found bacterial life thrives in salty ponds where the water evaporates leaving high levels of salt. This only serves to expand the likely envrionments across the Universe that life could evolve. 

The search for life away from planet Earth has long fascinated humanity. Studies have often focussed on salt water environments since the salt lowers the waters freezing point allowing it to remain liquid over a wider range of temperatures. There are the added benefits with salt that is a fabulous preservative for any life that may have evolved and left signs of its existence. 

The research is part of a larger program of work called Oceans Across Space and Time which is led by Cornell Iniversity and funded by NASAs Astrobiology program. It has the ambitious aim to understand how ocean worlds and life co-evolve to produce detectable signs of life, past or present! They hope to be able to help advance our understanding of teh conditions that make ocean worlds habitable and develop new ways to detect it. 

The team from Standord University paper was published their report showing the analysis of the metabolic activity in thousands of individual cells from brine ponds in California. In these ponds, the salt is harvested by allowing the water to evaporate. It is in these samples that that life has been found to survive. 

Examples of just how life has evolved in such environments can be seen in the South Bay Salt Works which were part of this study. The ponds have an amazing array of colours thanks to microbes that glow green, red, pink and orange. These amazing microbes have adapted to survive the high levels of salinity that would ordinarily have been inhospitable to other forms of life.

The ultimate goal of the study was to find out at what point cell activity such as division, cease to exist. Pure water has an activity level of 1 while salt water level is around 0.98. Prior to this study, it was believed that most activity stoped below 0.9 where salt levels become too high although laboratory studies showed that cell division would cease around 0.63. Following the study, it seems life can be sustained at levels as low as 0.54.

The results have started to change our views of the environments within which life can evolve and even be sustained. Not only does this now increase the likelihood of finding life, it enables us to widen the search for life across high salinity bodies of water and it even helps us to refocus the techniques used to continue the search.

Source : New research on microbes expands the known limits for life on Earth and beyond

The post Microbes Can Survive in Saltier Water than Previously Believed appeared first on Universe Today.

The early universe, according to the Standard Model of Cosmology, ought to be a fairly homogenous place, with little structure or arrangement. In 2021, however, astronomers discovered a large pattern of galaxies forming a giant arc 3.3 billion light years across. Now, a second large-scale pattern has emerged. This time, it’s an enormous circle of galaxies, nicknamed the Big Ring. Together, the Giant Arc and the Big Ring present a challenge to the Standard Model, and may send cosmologists back to the drawing board.

“The Big Ring and Giant Arc are the same distance from us, near the constellation of Boötes the Herdsman, meaning they existed at the same cosmic time when the universe was only half of its present age. They are also in the same region of sky, at only 12 degrees apart when observing the night sky,” says Alexia Lopez, a PhD student at the University of Central Lancashire who discovered both structures alongside supervisor Roger Clowes and collaborator Gerard Williger.

“Identifying two extraordinary ultra-large structures in such close configuration raises the possibility that together they form an even more extraordinary cosmological system.”

The Big Ring and the Giant Arc are made up of galaxies that are so dim and so faint they wouldn’t normally be visible. However, distant quasars (bright point sources caused by active black holes at the hearts of galaxies) shine light through the dim galaxies, where matter absorbs some of the light.

In particular, Lopez and her colleagues were looking for evidence of dim galaxies blocking a Magnesium ion called Mg-II. They found it in data from the Sloan Digital Sky Survey, giving them both the position and distance of the otherwise invisible galaxies.

This enabled Lopez to map the galaxies in three dimensions, and doing so revealed the Giant Arc and Big Ring 9.2 billion years away.

The Big Ring, spanning 1.3 billion lightyears in diameter. Credit: University of Central Lancashire.

At that point in the universe’s history, according to the Standard Model, any structure that exists shouldn’t be larger than 1.2 billion light years across. Yet both the Arc and the Ring far exceed that, and they don’t seem to be coincidental:

“We did some statistics and found that the Big Ring has a significance of 5.2 Sigma. This is exceeding that 5-Sigma golden threshold,” says Lopez, referring to the usual level of significance scientists require of themselves to confirm a discovery.

One possible explanation for large structures like these is called Baryonic Acoustic Oscillation (BAO). In the earliest moments of the universe, sound and pressure waves, shaped by gravitational interactions, could form ‘bubbles’ of matter across large scales.

BAO is allowed by the Standard Model of Cosmology. However, it tends to create spherical structures, whereas the Big Ring is two-dimensional.

So a different explanation is necessary.

At a press conference at the American Astronomical Society annual meeting on January 10, 2024, Lopez alluded to two possible alternative explanations.

The first is that the structures might be evidence for cosmic strings: one-dimensional topological defects proposed in the 1970s as part of string theory. Cosmic strings could, theoretically, have been created in the early universe and would have left their mark on the structure of matter.

The Big Ring and the Giant Arc might also be explained by an entirely different model of cosmology, such as the Conformal Cyclic Cosmology (CCC) model proposed by physicist Roger Penrose.

In this model, the universe goes through endless cycles of big bang after big bang. In CCC, there is no need for the universe to collapse back together in a Big Crunch, but rather it expands indefinitely, and all matter decays, until, mathematically, the difference between the empty expanded universe and a Big Bang singularity is just a question of scale – and when there is no matter (as at the end of the universe and at the beginning), scale is irrelevant. An expanded empty universe can become the next singularity, restarting the cycle.

Importantly, CCC would leave behind evidence of the previous cycle (what Penrose calls an Aeon) in the new Aeon. In other words, it could create structures the size of the Big Ring and the Giant Arc.

These are captivating theories. However, so far, no alternative model of the universe, not even CCC, has been able to supplant the Standard Model of Cosmology for its sheer explanatory power to describe what we observe in the universe around us. But the Standard Model does have a growing number of cracks and gaps, hinting that it might one day be improved or supplanted.

The Giant Arc and the Big Ring together represent one such crack, a place where what we know about the physics of the universe fails to explain what we observe.

It is, at the least, a reason to keep looking.

Learn More:

“A Big Cosmological Mystery,” University of Central Lancashire.

Watch the Press Conference. AAS 243, Janurary 10 2024.

The post Two Giant Structures Have Been Found Billions of Light-Years Away appeared first on Universe Today.

A new study presents an innovative graphene-based neurotechnology with the potential for a transformative impact in neuroscience and medical applications.

To combat viruses, bacteria and other pathogens, synthetic biology offers new technological approaches whose performance is being validated in experiments. Researchers applied data integration and artificial intelligence (AI) to develop a machine learning approach that can predict the efficacy of CRISPR technologies more accurately than before.

New research finds that smartphone usage can increase and even become unhealthy for those who have obsessive-compulsive disorder.

Tidal range schemes can protect estuaries and coastal areas from the effects of sea level rise, according to researchers who say that tidal range schemes are vital to protect habitats, housing and businesses from a rising sea level estimated to be over one metre within 80 years. High tides can be limited to existing levels simply by closing sluices and turbines and existing low tide levels can be maintained by pumping. Development of estuarine barrages has been hampered by misconceptions about their operation and fears of disturbance of the ecologically sensitive intertidal areas.

Clothes and other textiles are among the materials that we are the worst at recycling. But this may change. Researchers have developed a new technology that can separate out fibers in mixed fabrics.

Research is helping shed light on the important interaction between users and remote drivers that oversee the operation of automated vehicles.

Research is helping shed light on the important interaction between users and remote drivers that oversee the operation of automated vehicles.

Researchers have developed a sensor array design technology inspired by the human auditory system. By mimicking the human ear's ability to distinguish sounds through tonotopy, this innovative sensor array approach could optimize the application of sensor arrays in fields such as robotics, aviation, healthcare, and industrial machinery.