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05 March 2024

Research Scientists Reveal How the First Cells Could Have Formed on Earth

Roughly 4 billion years ago, Earth was developing conditions suitable for life. Origin-of-life scientists often wonder if the type of chemistry found on the early Earth was similar to what life requires today.

They know that spherical collections of fats, called protocells, were the precursor to cells during this emergence of life. But how did simple protocells first arise and diversify to eventually lead to life on Earth?

Now, Scripps Research scientists have discovered one plausible pathway for how protocells may have first formed and chemically progressed to allow for a diversity of functions.

The findings, published online on February 29, 2024, in the journal Chem, suggest that a chemical process called phosphorylation (where phosphate groups are added to the molecule) may have occurred earlier than previously expected. This would lead to more structurally complex, double chained protocells capable of harboring chemical reactions and dividing with a diverse range of functionalities. By revealing how protocells formed, scientists can better understand how early evolution could have taken place.

“At some point, we all wonder where we came from. We’ve now discovered a plausible way that phosphates could have been incorporated into cell-like structures earlier than previously thought, which lays the building blocks for life,” says Ramanarayanan Krishnamurthy, PhD, co-corresponding senior author and professor in the Department of Chemistry at Scripps Research. “This finding helps us better understand the chemical environments of early Earth so we can uncover the origins of life and how life can evolve on early Earth.”

Krishnamurthy and his team study how chemical processes occurred to cause the simple chemicals and formations that were present before the emergence of life in prebiotic Earth. Krishnamurthy is also a co-leader of a NASA initiative investigating how life emerged from these early environments.

In this study, Krishnamurthy and his team collaborated with the lab of soft matter biophysicist Ashok Deniz, PhD, co-corresponding senior author and professor in the Department of Integrative Structural and Computational Biology at Scripps Research. They sought to examine if phosphates may have been involved during the formation of protocells. Phosphates are present in nearly every chemical reaction in the body, so Krishnamurthy suspected they may have been present earlier than previously believed.

Scientists thought protocells formed from fatty acids, but it was unclear how protocells transitioned from a single chain to a double chain of phosphates, which is what allows them to be more stable and harbor chemical reactions.

The scientists wanted to mimic plausible prebiotic conditions—the environments that existed prior to the emergence of life. They first identified three likely mixtures of chemicals that could potentially create vesicles, spherical structures of lipids similar to protocells. The chemicals used included fatty acids and glycerol (a common byproduct of soap production that may have existed during early Earth). Next, they observed the reactions of these mixtures and added additional chemicals to create new mixtures. These solutions were cooled and heated on repeat overnight with some shaking to promote chemical reactions.

They then used fluorescent dyes to inspect the mixtures and judge if vesicle formation had taken place. In certain cases, the researchers also varied the pH and the ratios of the components to better understand how these factors impacted vesicle formation. They also looked at the effect of metal ions and temperature on the stability of the vesicles.

“The vesicles were able to transition from a fatty acid environment to a phospholipid environment during our experiments, suggesting a similar chemical environment could have existed 4 billion years ago,” says first author Sunil Pulletikurti, postdoctoral researcher in Krishnamurthy’s lab.

It turns out that fatty acids and glycerol may have undergone phosphorylation to create that more stable, double chain structure. In particular, glycerol derived fatty acid esters may have led to vesicles with different tolerances to metal ions, temperatures, and pH—a critical step in diversifying evolution.

“We’ve discovered one plausible pathway for how phospholipids could have emerged during this chemical evolutionary process,” says Deniz. “It’s exciting to uncover how early chemistries may have transitioned to allow for life on Earth. Our findings also hint at a wealth of intriguing physics that may have played key functional roles along the way to modern cells.”

Next, the scientists plan to examine why some of the vesicles fused while others divided to better understand the dynamic processes of protocells.

29 January 2024

NASA's Webb Depicts Staggering Structure in 19 Nearby Spiral Galaxies

 

The research community’s collective analysis will ultimately inform theorists’ simulations and advance our understanding of star formation and the evolution of spiral galaxies.

Summary

A new treasure trove of Webb images has arrived! Near- and mid-infrared images show off every facet of these face-on spiral galaxies.

Humanity has spent centuries mapping Earth’s features – and we frequently repeat the process by using more advanced instruments. When we combine the data, we get a more complete understanding of our planet.

Now, look outward into space. Astronomers have observed nearby, face-on spiral galaxies for decades. Both space- and ground-based telescopes have contributed to a cache of data in wavelengths from radio to ultraviolet light. Astronomers have long planned to use NASA’s James Webb Space Telescope to obtain the highest resolution near- and mid-infrared images ever taken of these galaxies, and today they are publicly available.

It also spotlights stars that haven’t yet fully formed – they are still encased in the gas and dust that feed their growth, like bright red seeds at the tips of dusty peaks.

Everyone can explore Webb’s newest set of exquisite images, which show stars, gas, and dust on small scales beyond our own galaxy. Teams of researchers are studying these images to uncover the origins of these intricate structures. The research community’s collective analysis will ultimately inform theorists’ simulations and advance our understanding of star formation and the evolution of spiral galaxies.

It’s oh-so-easy to be absolutely mesmerized by these spiral galaxies. Follow their clearly defined arms, which are brimming with stars, to their centers, where there may be old star clusters and – sometimes – active supermassive black holes. Only NASA’s James Webb Space Telescope can deliver highly detailed scenes of nearby galaxies in a combination of near- and mid-infrared light – and a set of these images was publicly released today.

These Webb images are part of a large, long-standing project, the Physics at High Angular resolution in Nearby Galaxies (PHANGS) program, which is supported by more than 150 astronomers worldwide. Before Webb took these images, PHANGS was already brimming with data from NASA’s Hubble Space Telescope, the Very Large Telescope’s Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array, including observations in ultraviolet, visible, and radio light. Webb’s near- and mid-infrared contributions have provided several new puzzle pieces.

“Webb’s new images are extraordinary,” said Janice Lee, a project scientist for strategic initiatives at the Space Telescope Science Institute in Baltimore. “They’re mind-blowing even for researchers who have studied these same galaxies for decades. Bubbles and filaments are resolved down to the smallest scales ever observed and tell a story about the star formation cycle.”

Excitement rapidly spread throughout the team as the Webb images flooded in. “I feel like our team lives in a constant state of being overwhelmed – in a positive way – by the amount of detail in these images,” added Thomas Williams, a postdoctoral researcher at the University of Oxford in the United Kingdom.

Follow the Spiral Arms

Webb’s NIRCam (Near-Infrared Camera) captured millions of stars in these images, which sparkle in blue tones. Some stars are spread throughout the spiral arms, but others are clumped tightly together in star clusters. 

The telescope’s MIRI (Mid-Infrared Instrument) data highlights glowing dust, showing us where it exists around and between stars. It also spotlights stars that haven’t yet fully formed – they are still encased in the gas and dust that feed their growth, like bright red seeds at the tips of dusty peaks. “These are where we can find the newest, most massive stars in the galaxies,” said Erik Rosolowsky, a professor of physics at the University of Alberta in Edmonton, Canada.

Something else that amazed astronomers? Webb’s images show large, spherical shells in the gas and dust. “These holes may have been created by one or more stars that exploded, carving out giant holes in the interstellar material,” explained Adam Leroy, a professor of astronomy at the Ohio State University in Columbus.

Now, trace the spiral arms to find extended regions of gas that appear red and orange. “These structures tend to follow the same pattern in certain parts of the galaxies,” Rosolowsky added. “We think of these like waves, and their spacing tells us a lot about how a galaxy distributes its gas and dust.” Study of these structures will provide key insights about how galaxies build, maintain, and shut off star formation.

Dive Into the Interior

Evidence shows that galaxies grow from inside out – star formation begins at galaxies’ cores and spreads along their arms, spiraling away from the center. The farther a star is from the galaxy’s core, the more likely it is to be younger. In contrast, the areas near the cores that look lit by a blue spotlight are populations of older stars.

What about galaxy cores that are awash in pink-and-red diffraction spikes? “That’s a clear sign that there may be an active supermassive black hole,” said Eva Schinnerer, a staff scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany. “Or, the star clusters toward the center are so bright that they have saturated that area of the image.”

Research Galore

There are many avenues of research that scientists can begin to pursue with the combined PHANGS data, but the unprecedented number of stars Webb resolved are a great place to begin. “Stars can live for billions or trillions of years,” Leroy said. “By precisely cataloging all types of stars, we can build a more reliable, holistic view of their life cycles.”

In addition to immediately releasing these images, the PHANGS team has also released the largest catalog to date of roughly 100,000 star clusters. “The amount of analysis that can be done with these images is vastly larger than anything our team could possibly handle,” Rosolowsky emphasized. “We’re excited to support the community so all researchers can contribute.”

13 January 2024

Newly discovered cosmic megastructure challenges theories of the universe

 

Scientists at the University of Central Lancashire have discovered a gigantic, ring-shaped structure in space.

It is 1.3bn light-years in diameter and appears to be roughly 15 times the size of the Moon in the night sky as seen from Earth.

Named the Big Ring by the astronomers, it is made up of galaxies and galaxy clusters.

They say that it is so big it challenges our understanding of the universe.

"This is the seventh large structure discovered in the universe that contradicts the idea that the cosmos is smooth on the largest scales. If these structures are real, then it's definitely food for thought for cosmologists and the accepted thinking on how the universe has evolved over time," he said.

It cannot be seen with the naked eye. It is really distant and identifying all the galaxies that make up the bigger structure has taken a lot of time and computing power.

Such large structures should not exist according to one of the guiding principles of astronomy, called the cosmological principle. This states that all matter is spread smoothly across the Universe.

Although stars, planets and galaxies are huge clumps of matter in our eyes, in the context of the size of the universe they are insignificant - and the theory is that much bigger patches of matter should not form.

The Big Ring is by no means the first likely violation of the cosmological principle and so suggests that there is another, yet to be discovered, factor at play.

According to Dr Robert Massey, deputy director of the Royal Astronomical Society, the evidence for a rethink of what has been a central plank of astronomy is growing.

"This is the seventh large structure discovered in the universe that contradicts the idea that the cosmos is smooth on the largest scales. If these structures are real, then it's definitely food for thought for cosmologists and the accepted thinking on how the universe has evolved over time," he said.

The Big Ring was identified by Alexia Lopez, a PhD student at the University of Central Lancashire (UCLan), who also discovered the Giant Arc - a structure spanning 3.3bn light-years of space.

Asked how it felt to have made the discoveries, she said: "It's really surreal. I do have to pinch myself, because I made these discoveries accidentally, they were serendipitous discoveries. But it is a big thing and I can't believe that I'm talking about it, I don't believe that it's me

"Neither of these two ultra-large structures is easy to explain in our current understanding of the universe," she said.

"And their ultra-large sizes, distinctive shapes, and cosmological proximity must surely be telling us something important - but what exactly?"

Both the Big Ring and the Giant Arc appear relatively close together, near the constellation of Bootes the Herdsman.

Professor Don Pollacco, of the department of physics at the University of Warwick, said the likelihood of this occurring is vanishingly small so the two objects might be related and form an even larger structure.

"So the question is how do you make such large structures?

"It's incredibly hard to conceive of any mechanism that could produce these structures so instead the authors speculate that we are seeing a relic from the early universe where waves of high and low density material are 'frozen' in to extragalactic medium."

There are also similarly large structures discovered by other cosmologists - such as the Sloan Great Wall, which is around 1.5 billion light-years in length, and the South Pole Wall, which stretches 1.4 billion light-years across.

But the biggest single entity scientists have identified is a supercluster of galaxies called the Hercules-Corona Borealis Great Wall, which is about 10 billion light-years wide.

While the Big Ring appears as an almost perfect ring on the sky, analysis by Ms Lopez suggests it has more of a coil shape - like a corkscrew - with its face aligned with Earth.

"The Big Ring and the Giant Arc, both individually and together, gives us a big cosmological mystery as we work to understand the universe and its development."

The findings have been presented at the 243rd meeting of the American Astronomical Society (AAS) in New Orleans.

17 December 2023

NASA Study Finds Life-Sparking Energy Source and Molecule at Enceladus

Discovery at Enceladus - 1 - Eyes on the Solar System - NASA/JPL

A study zooms in on data that NASA’s Cassini gathered at Saturn’s icy moon and finds evidence of a key ingredient for life and a supercharged source of energy to fuel it.

Scientists have known that the giant plume of ice grains and water vapor spewing from Saturn’s moon Enceladus is rich with organic compounds, some of which are important for life as we know it. Now, scientists analyzing data from NASA’s Cassini mission are taking the evidence for habitability a step further: They’ve found strong confirmation of hydrogen cyanide, a molecule that is key to the origin of life.

The researchers also uncovered evidence that the ocean, which is hiding below the moon’s icy outer shell and supplies the plume, holds a powerful source of chemical energy. Unidentified until now, the energy source is in the form of several organic compounds, some of which, on Earth, serve as fuel for organisms.

“Our work provides further evidence that Enceladus is host to some of the most important molecules for both creating the building blocks of life and for sustaining that life through metabolic reactions.”

The findings, published Thursday, Dec. 14, in Nature Astronomy, indicate there may be much more chemical energy inside this tiny moon than previously thought. The more energy available, the more likely that life might proliferate and be sustained.

“Our work provides further evidence that Enceladus is host to some of the most important molecules for both creating the building blocks of life and for sustaining that life through metabolic reactions,” said lead author Jonah Peter, a doctoral student at Harvard University who performed much of the research while working at NASA’s Jet Propulsion Laboratory in Southern California. “Not only does Enceladus seem to meet the basic requirements for habitability, we now have an idea about how complex biomolecules could form there, and what sort of chemical pathways might be involved.”

Versatile and Energetic

“The discovery of hydrogen cyanide was particularly exciting, because it’s the starting point for most theories on the origin of life,” Peter said. Life as we know it requires building blocks, such as amino acids, and hydrogen cyanide is one of the most important and versatile molecules needed to form amino acids. Because its molecules can be stacked together in many different ways, the study authors refer to hydrogen cyanide as the Swiss army knife of amino acid precursors.

“The more we tried to poke holes in our results by testing alternative models,” Peter added, “the stronger the evidence became. Eventually, it became clear that there is no way to match the plume composition without including hydrogen cyanide.”

In 2017, scientists found evidence at Enceladus of chemistry that could help sustain life, if present, in its ocean. The combination of carbon dioxide, methane, and hydrogen in the plume was suggestive of methanogenesis, a metabolic process that produces methane. Methanogenesis is widespread on Earth, and may have been critical to the origin of life on our planet.

 The new work uncovers evidence for additional energy chemical sources far more powerful and diverse than the making of methane: The authors found an array of organic compounds that were oxidized, indicating to scientists that there are many chemical pathways to potentially sustain life in Enceladus’ subsurface ocean. That’s because oxidation helps drive the release of chemical energy.

“If methanogenesis is like a small watch battery, in terms of energy, then our results suggest the ocean of Enceladus might offer something more akin to a car battery, capable of providing a large amount of energy to any life that might be present,” said JPL’s Kevin Hand, co-author of the study and principal investigator of the effort that led to the new results.

Math Is the Way

Unlike earlier research that used lab experiments and geochemical modeling to replicate the conditions Cassini found at Enceladus, the authors of the new work relied on detailed statistical analyses. They examined data collected by Cassini’s ion and neutral mass spectrometer, which studied the gas, ions, and ice grains around Saturn.

By quantifying the amount of information contained in the data, the authors were able to tease out subtle differences in how well different chemical compounds explain the Cassini signal.

“There are many potential puzzle pieces that can be fit together when trying to match the observed data,” Peter said. “We used math and statistical modeling to figure out which combination of puzzle pieces best matches the plume composition and makes the most of the data, without overinterpreting the limited dataset.”

Scientists are still a long way from answering whether life could originate on Enceladus. But as Peter noted, the new work lays out chemical pathways for life that could be tested in the lab.

Meanwhile, Cassini is the mission that keeps giving – long after it revealed that Enceladus is an active moon. In 2017, the mission ended by deliberately plunging the spacecraft into Saturn’s atmosphere. “Our study demonstrates that while Cassini’s mission has ended, its observations continue to provide us with new insights about Saturn and its moons – including the enigmatic Enceladus,” said Tom Nordheim, a JPL planetary scientist who’s a co-author of the study and was a member of the Cassini team.

11 December 2023

Life might have been possible just seconds after the Big Bang



Life has found a home on Earth for around 4 billion years. That's a significant fraction of the universe's 13.77-billion-year history. Presumably, if life arose here, it could have appeared anywhere. And for sufficiently broad definitions of life, it might even be possible for life to have appeared mere seconds after the Big Bang.

To explore the origins of life, first we have to define it. There are over 200 published definitions of the term, which shows just how difficult this concept is to grapple with. For example, are viruses alive? They replicate but need a host to do so. What about prions, the pathogenic protein structures? Debates continue to swirl over the line between life and nonlife. But for our purposes, we can use an extremely broad, but very useful definition: Life is everything that's subject to evolution.

This definition is handy because we'll be exploring the origins of life itself, which, by definition, will blur the boundaries between life and nonlife. At one point, deep in the past, Earth was not alive. Then it was. This means that there was a transition period that will naturally stretch the limits of any definition you can muster. Plus, as we dig deeper into the past and explore other potential options for life, we want to keep our definition broad, especially as we explore the more extreme and exotic corners of the universe.

With this definition in hand, life on Earth arose at least 3.7 billion years ago. By then, microscopic organisms had already become sophisticated enough to leave behind traces of their activities that persist to the present day. Those organisms were a lot like modern ones: They used DNA to store information, RNA to transcribe that information into proteins, and the proteins to interact with the environment and make copies of the DNA. This three-way combo allows those batches of chemicals to experience evolution.

But those microbes didn't just fall out of the sky; they evolved from something. And if life is anything that evolves, then there had to be a simpler version of life appearing even earlier in Earth's past. Some theories speculate that the first self-replicating molecules, and hence the simplest possible form of life on Earth, could have arisen as soon as the oceans cooled, well over 4 billion years ago.

And Earth may not have been alone — Mars and Venus had similar conditions at that time, so if life happened here, it may have happened there, too.

The first life among the stars 

But the sun was not the first star to ignite into fusion; it is a product of a long line of previous generations of stars. Life as we know it requires a few key elements: hydrogen, oxygen, carbon, nitrogen and phosphorus. With the exception of hydrogen, which appeared in the first few minutes after the Big Bang, all of these elements are created in the hearts of stars during their life cycles. So, as long as you have at least one or two generations of stars living and dying, and thereby spreading their elements out into the wider galaxy, you can have Earth-like life appearing in the universe.

This pushes the clock back on the possible first appearance of life to well over 13 billion years ago. This era in the history of the universe is known as the cosmic dawn, when the first stars formed. Astronomers aren't exactly sure when this transformative epoch took place, but it was somewhere within a few hundred million years after the Big Bang. As soon as those stars appeared, they could have started creating the necessary elements for life.

So, life as we know it — built on chains of carbon, using oxygen to transport energy, and submersed in a bath of liquid water — may be much, much older than Earth. Even other hypothesized forms of life based on exotic biochemistries require a similar mixture of elements. For example, some alien life may use silicon instead of carbon as a basic building block or use methane instead of water as a solvent. No matter what, those elements have to come from somewhere, and that somewhere is in the cores of stars. Without stars, you can't have chemical-based life.

The first life in the universe 

But perhaps it's possible to have life without chemistry. It's hard to imagine what these creatures might be like. But if we take our broad definition — that life is anything subject to evolution — then we don't need chemicals to make it happen. Sure, chemistry is a convenient way to store information, extract energy and interact with the environment, but there are other hypothetical pathways.

For example, 95% of the energy contents of the universe are unknown to physics, literally sitting outside the known elements. Scientists aren't sure what these mysterious components of the universe, known as dark matter and dark energy, are made of. 

Perhaps there are additional forces of nature that work only on dark matter and dark energy. Maybe there are multiple "species" of dark matter — an entire "dark matter periodic table." Who knows what interactions and what dark chemistry play out in the vast expanses between the stars? Hypothetical "dark life" may have appeared in the extremely early universe, well before the emergence of the first stars, powered and mediated by forces we do not yet understand.

The possibilities can get even weirder. Some physicists have hypothesized that in the earliest moments of the Big Bang, the forces of nature were so extreme and so exotic that they could have supported the growth of complex structures. For example, these structures could have been cosmic strings, which are folds in space-time, anchored by magnetic monopoles. With sufficient complexity, these structures could have stored information. There would have been plenty of energy to go around, and those structures could have self-replicated, enabling evolution. 

Any creatures existing in those conditions would have lived and died in the blink of an eye, their entire history lasting less than a second — but to them, it would have been a lifetime.

02 December 2023

Essential life molecules may originate near new stars and planets

New research postulates that basic amino acids could have “formed alongside stars or planets within interstellar ices.

Scientists have long been in the quest to uncover the source from which Earth obtained its essential ingredients of life. 

Since the detection of organic molecules in a Murchison meteorite that landed in Australia in 1969, they have been captivated by the prospect that the fundamental components of life may have originated in outer space.

The question remains: Where and when did these crucial molecules come into existence before finding their way to Earth preserved within meteorites?

Now, new research postulates that fundamental amino acids, such as carbamic acid, could have "formed alongside stars or planets within interstellar ices."

Amino acids play a vital role in life as they are the fundamental building blocks of proteins, carrying out diverse functions within living organisms.

Model of interstellar ice reveals key details

Multiple theories propose scenarios explaining how Earth acquired the building blocks of life. 

One predominant theory suggesting the origin of life centers on the concept of a "primordial soup." It basically refers to a mixture of organic molecules that may have evolved in Earth's early oceans as a result of the reaction of simple chemicals.

An alternate theory posits that meteorites could have delivered amino acids to the Earth's surface during its forming years. 

As per the official release, these celestial bodies, or space rocks, could have accumulated the molecules from dust or interstellar ice, which consist of water and other gases frozen into solid form due to the extremely cold temperatures of outer space. 

However, the mystery lies in the fact that since meteorites originated from distant regions in the universe, scientists are perplexed about the precise location of the formation of these molecules. The question remains: Where and when did these crucial molecules come into existence before finding their way to Earth preserved within meteorites?

The researchers from the University of Hawaii went on to obtain a better grasp of the situation, concentrating on the chemical processes that may have occurred in interstellar ices that were once present in the vicinity of newly forming stars and planets.

They created a model including interstellar ice containing ammonia and carbon dioxide to study this. These ices were then progressively heated after being put on a silver substrate.

The team employed Fourier transform infrared spectroscopy to understand the interstellar ice better. 

The formation of amino acids

The findings revealed that carbamic acid began to form at -348 degrees Fahrenheit, while ammonium carbamate initiated its formation at -389 degrees Fahrenheit.

"These low temperatures demonstrate that these molecules — which can turn into more complex amino acids — could have formed during the earliest, coldest stages of star formation," revealed the press release. 

"In addition, the researchers found that at warmer temperatures, similar to those produced by a newly formed star, two carbamic acid molecules could link together, making a stable gas," the release added. 

The team put forward a hypothesis suggesting that these molecules might have become part of the basic constituents of the solar system. After its formation, comets or meteorites, acting as cosmic deliverers, could have transported these molecules to early Earth.

The results could serve as valuable insights for training sophisticated telescopes such as the James Webb Space Telescope to explore distant, star-forming regions of the universe in search of prebiotic molecules.

20 November 2023

Many physicists assume we must live in a multiverse – but their basic maths may be wrong

 

One of the most startling scientific discoveries of recent decades is that physics appears to be fine-tuned for life. This means that for life to be possible, certain numbers in physics had to fall within a certain, very narrow range.

One of the examples of fine-tuning which has most baffled physicists is the strength of dark energy, the force that powers the accelerating expansion of the universe. If that force had been just a little stronger, matter couldn’t clump together. No two particles would have ever combined, meaning no stars, planets, or any kind of structural complexity, and therefore no life.

This is not how we expected science to turn out. It’s a bit like in the 16th century when we first started to get evidence that we weren’t in the centre of the universe. Many found it hard to accept that the picture of reality they’d got used to no longer explained the data.

I believe we’re in the same situation now with fine-tuning. We may one day be surprised that we ignored for so long what was lying in plain sight – that the universe favours the existence of life.

If that force had been significantly weaker, it would not have counteracted gravity. This means the universe would have collapsed back on itself within the first split-second – again meaning no stars or planets or life. To allow for the possibility of life, the strength of dark energy had to be, like Goldilocks’s porridge, “just right”.

This is just one example, and there are many others.

The most popular explanation for the fine-tuning of physics is that we live in one universe among a multiverse. If enough people buy lottery tickets, it becomes probable that somebody is going to have the right numbers to win. Likewise, if there are enough universes, with different numbers in their physics, it becomes likely that some universe is going to have the right numbers for life.

For a long time, this seemed to me the most plausible explanation of fine-tuning. However, experts in the mathematics of probability have identified the inference from fine-tuning to a multiverse as an instance of fallacious reasoning – something I explore in my new book, Why? The Purpose of the Universe. Specifically, the charge is that multiverse theorists commit what’s called the inverse gambler’s fallacy.

Suppose Betty is the only person playing in her local bingo hall one night, and in an incredible run of luck, all of her numbers come up in the first minute. Betty thinks to herself: “Wow, there must be lots of people playing bingo in other bingo halls tonight!” Her reasoning is: if there are lots of people playing throughout the country, then it’s not so improbable that somebody would get all their numbers called out in the first minute.

But this is an instance of the inverse gambler’s fallacy. No matter how many people are or are not playing in other bingo halls throughout the land, probability theory says it is no more likely that Betty herself would have such a run of luck.

It’s like playing dice. If we get several sixes in a row, we wrongly assume that we are less likely to get sixes in the next few throws. And if we don’t get any sixes for a while, we wrongly assume that there must have been loads of sixes in the past. But in reality, each throw has an exact and equal probability of one in six of getting a specific number.

Multiverse theorists commit the same fallacy. They think: “Wow, how improbable that our universe has the right numbers for life; there must be many other universes out there with the wrong numbers!” But this is just like Betty thinking she can explain her run of luck in terms of other people playing bingo. When this particular universe was created, as in a die throw, it still had a specific, low chance of getting the right numbers.

Either it’s an incredible fluke that our universe happened to have the right numbers. Or the numbers are as they are because nature is somehow driven or directed to develop complexity and life by some invisible, inbuilt principle.

At this point, multiverse theorists bring in the “anthropic principle” – that because we exist, we could not have observed a universe incompatible with life. But that doesn’t mean such other universes don’t exist.

Suppose there is a deranged sniper hiding in the back of the bingo hall, waiting to shoot Betty the moment a number comes up that’s not on her bingo card. Now the situation is analogous to real world fine-tuning: Betty could not have observed anything other than the right numbers to win, just as we couldn’t have observed a universe with the wrong numbers for life.

Even so, Betty would be wrong to infer that many people are playing bingo. Likewise, multiverse theorists are wrong to infer from fine-tuning to many universes.

What about the multiverse?

Isn’t there scientific evidence for a multiverse though? Yes and no. In my book, I explore the connections between the inverse gambler’s fallacy and the scientific case for the multiverse, something which surprisingly hasn’t been done before.

The scientific theory of inflation – the idea that the early universe blew up hugely in size – supports the multiverse. If inflation can happen once, it is likely to be happening in different areas of space – creating universes in their own right. While this may give us tentative evidence for some kind of multiverse, there is no evidence that the different universes have different numbers in their local physics.

There is a deeper reason why the multiverse explanation fails. Probabilistic reasoning is governed by a principle known as the requirement of total evidence, which obliges us to work with the most specific evidence we have available.

In terms of fine-tuning, the most specific evidence that people who believe in the multiverse have is not merely that a universe is fine-tuned, but that this universe is fine-tuned. If we hold that the constants of our universe were shaped by probabilistic processes – as multiverse explanations suggest – then it is incredibly unlikely that this specific universe, as opposed to some other among millions, would be fine-tuned. Once we correctly formulate the evidence, the theory fails to account for it.

The conventional scientific wisdom is that these numbers have remained fixed from the Big Bang onwards. If this is correct, then we face a choice. Either it’s an incredible fluke that our universe happened to have the right numbers. Or the numbers are as they are because nature is somehow driven or directed to develop complexity and life by some invisible, inbuilt principle. In my opinion, the first option is too improbable to take seriously. My book presents a theory of the second option – cosmic purpose – and discusses its implications for human meaning and purpose.

This is not how we expected science to turn out. It’s a bit like in the 16th century when we first started to get evidence that we weren’t in the centre of the universe. Many found it hard to accept that the picture of reality they’d got used to no longer explained the data.

I believe we’re in the same situation now with fine-tuning. We may one day be surprised that we ignored for so long what was lying in plain sight – that the universe favours the existence of life.

Ancient 'Large-Scale Structure' Discovered In Deep Space: Bio-cosmos

The "Cosmic Vine" is a massive structure in the cosmic web that links 20 galaxies in the early universe.

The universe is more connected than you might think: In recent years, scientists have used new tools and techniques to map the “cosmic web,” which is made up of intertwined strands of gas structures known as filaments that link galaxies. Now, a team of researchers have identified a new “large-scale structure” in the universe that they call the “Cosmic Vine.”

The researchers hail from numerous universities and institutions across Denmark, Chile, the U.K., and the Netherlands. They published a preprint of their work to the arXiv server on November 8. According to the study, the Cosmic Vine was spotted after poring over data collected by the James Webb Space Telescope (JWST), humanity’s most powerful tool for peering into the far reaches of space and time. 

According to the researchers, it is a massive “vine-like structure” that encompasses 20 galaxies and stretches for over 13 million light years. It’s also very ancient: The researchers pegged it at redshift 3.44, meaning it’s situated in the early universe. Redshift refers to the way light stretches as it travels longer distances through time, with higher redshifts indicating an object is older. A redshift of 3.44 would mean light from the Cosmic Vine has been traveling for between 11 and 12 billion years before reaching JWST. The universe is roughly 13 billion years old. 

The discovery is notable because it can teach us more about how galaxies form. Indeed, recent work on the cosmic web has revealed that filament structures are crucial for delivering the materials galaxies need to grow—a previously-discovered filament was referred to as a “pipeline” for fueling this type of growth by researchers. The researchers who identified the Cosmic Vine wrote that galaxy clusters are the “most massive gravitationally-bound structures in the universe” and that studying their progenitors “in the early Universe is fundamental for our understanding of galaxy formation and evolution.” So, characterizing the dynamics of the Cosmic Vine and the galaxies embedded within it could teach us a lot. 

However, the Cosmic Vine raises more questions than it answers. The researchers note that our snapshot of the Vine indicates it’s still in its growing phase, and yet it contains two massive galaxies that are quiescent, meaning they’ve stopped forming stars. These quiescent galaxies are not in the core of the developing cluster, which some theories have held is a requirement for star formation to be halted. “This discrepancy potentially poses a challenge to the models of massive cluster galaxy formation,” the authors wrote. “Future studies comparing a large sample with dedicated cluster simulations are required to solve the problem.”

“What is the culprit quenching their star-formations at so early cosmic time?” the authors ask. Observed features of the galaxies indicate that the culprit could be a starburst triggered by merging galaxies—this is when star formation occurs at a rapid rate that quickly depletes available resources. Another explanation may be due to feedback from a supermassive black hole embedded in one of the galaxies, known as an Active Galactic Nucleus, or AGN. 

Until more work is done, though, we simply don’t know the answer. As our knowledge grows, so do the universe’s many mysteries.

16 November 2023

NASA's James Webb telescope confirms planet formation theory: Evolutionary transubstantiation

"... the Creator waters His incipient sentience via cosmic life processes, and He seeds the universe with the raw materials needed to beget Life."
 

Scientists using NASA’s James Webb Space Telescope just made a breakthrough discovery in revealing how planets are made. By observing water vapor in protoplanetary disks, Webb confirmed a physical process involving the drifting of ice-coated solids from the outer regions of the disk into the rocky-planet zone.

Theories have long proposed that icy pebbles forming in the cold, outer regions of protoplanetary disks — the same area where comets originate in our solar system — should be the fundamental seeds of planet formation. The main requirement of these theories is that pebbles should drift inward toward the star due to friction in the gaseous disk, delivering both solids and water to planets.

A fundamental prediction of this theory is that as icy pebbles enter into the warmer region within the “snowline” — where ice transitions to vapor — they should release large amounts of cold-water vapor. This is exactly what Webb observed.

“Webb finally revealed the connection between water vapor in the inner disk and the drift of icy pebbles from the outer disk,” said principal investigator Andrea Banzatti of Texas State University, San Marcos, Texas. “This finding opens up exciting prospects for studying rocky planet formation with Webb!

“In the past, we had this very static picture of planet formation, almost like there were these isolated zones that planets formed out of,” explained team member Colette Salyk of Vassar College in Poughkeepsie, New York. “Now we actually have evidence that these zones can interact with each other. It’s also something that is proposed to have happened in our solar system.”

Planet-forming Disks


Artist’s Concept: This artist’s concept compares two types of typical, planet-forming disks around newborn, Sun-like stars. On the left is a compact disk, and on the right is an extended disk with gaps. Scientists using Webb recently studied four protoplanetary disks—two compact and two extended. The researchers designed their observations to test whether compact planet-forming disks have more water in their inner regions than extended planet-forming disks with gaps. This would happen if ice-covered pebbles in the compact disks drift more efficiently into the close-in regions nearer to the star and deliver large amounts of solids and water to the just-forming, rocky, inner planets. Current research proposes that large planets may cause rings of increased pressure, where pebbles tend to collect. As the pebbles drift, any time they encounter an increase in pressure, they tend to collect there. These pressure traps don’t necessarily shut down pebble drift, but they do impede it. This is what appears to be happening in the large disks with rings and gaps. This also could have been a role of Jupiter in our solar system — inhibiting pebbles and water delivery to our small, inner, and relatively water-poor rocky planets. [NASA, ESA, CSA, Joseph Olmsted (STScI)]

Harnessing the Power of Webb

The researchers used Webb’s MIRI (the Mid-Infrared Instrument) to study four disks — two compact and two extended — around Sun-like stars. All four of these stars are estimated to be between 2 and 3 million years old, just newborns in cosmic time.

The two compact disks are expected to experience efficient pebble drift, delivering pebbles to well within a distance equivalent to Neptune’s orbit. In contrast, the extended disks are expected to have their pebbles retained in multiple rings as far out as six times the orbit of Neptune.

The Webb observations were designed to determine whether compact disks have a higher water abundance in their inner, rocky planet region, as expected if pebble drift is more efficient and is delivering lots of solid mass and water to inner planets. The team chose to use MIRI’s MRS (the Medium-Resolution Spectrometer) because it is sensitive to water vapor in disks.

The results confirmed expectations by revealing excess cool water in the compact disks, compared with the large disks.

Water Abundance

As the pebbles drift, any time they encounter a pressure bump — an increase in pressure — they tend to collect there. These pressure traps don’t necessarily shut down pebble drift, but they do impede it. This is what appears to be happening in the large disks with rings and gaps.

Current research proposes that large planets may cause rings of increased pressure, where pebbles tend to collect. This also could have been a role of Jupiter in our solar system — inhibiting pebbles and water delivery to our small, inner, and relatively water-poor rocky planets.

Solving the Riddle

When the data first came in, the results were puzzling to the research team. “For two months, we were stuck on these preliminary results that were telling us that the compact disks had colder water, and the large disks had hotter water overall,” remembered Banzatti. “This made no sense, because we had selected a sample of stars with very similar temperatures.”

Only when Banzatti overlaid the data from the compact disks onto the data from the large disks did the answer clearly emerge: the compact disks have extra cool water just inside the snowline, at about ten times closer than the orbit of Neptune.

“Now we finally see unambiguously that it is the colder water that has an excess,” said Banzatti. “This is unprecedented and entirely due to Webb’s higher resolving power!”

Icy Pebble Drift

This graphic is an interpretation of data from Webb’s MIRI, the Mid-Infrared Instrument, which is sensitive to water vapor in disks. It shows the difference between pebble drift and water content in a compact disk versus an extended disk with rings and gaps. In the compact disk on the left, as the ice-covered pebbles drift inward toward the warmer region closer to the star, they are unimpeded. As they cross the snow line, their ice turns to vapor and provides a large amount of water to enrich the just-forming, rocky, inner planets. On the right is an extended disk with rings and gaps. As the ice-covered pebbles begin their journey inward, many become stopped by the gaps and trapped in the rings. Fewer icy pebbles are able to make it across the snow line to deliver water to the inner region of the disk. [(NASA, ESA, CSA, Joseph Olmsted (STScI)

The team’s results appear in the Nov. 8 edition of the Astrophysical Journal Letters.

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30 October 2023

From Big Bang to Big Picture: A Comprehensive New View of All Objects in the Universe

 

The most comprehensive view of the history of the universe ever created has been produced by researchers at The Australian National University (ANU). The study also offers new ideas about how our universe may have started.

Lead author Honorary Associate Professor Charley Lineweaver from ANU said he set out wanting to understand where all the objects in the universe came from.

"When the universe began 13.8 billion years ago in a hot big bang, there were no objects like protons, atoms, people, planets, stars or galaxies. Now the universe is full of such objects," he said.

This plot suggests the universe may have started as an instanton, which has a specific size and mass, rather than a singularity, which is a hypothetical point of infinite density and temperature."

"The relatively simple answer to where they came from is that, as the universe cooled, all of these objects condensed out of a hot background."

To show this process in the simplest possible way, the researchers made two plots. The first shows temperature and density of the universe as it expanded and cooled. The second plots the mass and size of all objects in the universe.

The result is the most comprehensive chart ever created of all the objects in the universe. The study is published in the latest issue of the American Journal of Physics.

Co-author and former ANU research student Vihan Patel said the project raised some important questions.

"Parts of this plot are 'forbidden'—where objects cannot be denser than black holes, or are so small, quantum mechanics blurs the very nature of what it really means to be a singular object." Patel said.

The researchers say the boundaries of the plots and what lies beyond them are also a major mystery.

"At the smaller end, the place where quantum mechanics and general relativity meet is the smallest possible object—an instanton. This plot suggests the universe may have started as an instanton, which has a specific size and mass, rather than a singularity, which is a hypothetical point of infinite density and temperature," Patel said.

"On the larger end, the plot suggests that if there were nothing—a complete vacuum—beyond the observable universe, our universe would be a large, low density black hole. This is a little scary, but we have good reason to believe that's not the case."

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Bonus video 1:

Full video here.

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Bonus video 2:

16 October 2023

Nature’s missing evolutionary law identified


Darwin applied the theory of evolution to life on earth, but not to other massively complex systems like planets, stars, atoms and minerals. Now, an interdisciplinary group of researchers has identified a missing aspect of that theory that applies to essentially everything.

Their paper, “On the roles of function and selection in evolving systems,” published Oct. 16 in the Proceedings of the National Academy of Sciences, describes “a missing law of nature” that recognizes for the first time an important norm within the natural world’s workings.  The new law states that complex natural systems evolve to states of greater patterning, diversity and complexity.

“If increasing functionality of evolving physical and chemical systems is driven by a natural law, we might expect life to be a common outcome of planetary evolution.”

“This was a true collaboration between scientists and philosophers to address one of the most profound mysteries of the cosmos: why do complex systems, including life, evolve toward greater functional information over time?" said co-author Jonathan Lunine, the David C. Duncan Professor in the Physical Sciences and chair of astronomy in the College of Arts and Sciences.

The multi-disciplinary team included three philosophers of science, two astrobiologists, a data scientist, a mineralogist and a theoretical physicist, from the Carnegie Institution for Science, the California Institute of Technology and the University of Colorado, as well as Cornell. Carnegie scientist Michael L. Wong is first author; an astrobiologist, he and Lunine are working on a forthcoming second edition of Lunine’s textbook “Astrobiology: A Multidisciplinary Approach.”

The new work presents a modern addition to “macroscopic” laws of nature, which describe and explain phenomena experienced daily in the natural world. It postulates a “Law of Increasing Functional Information,” which states that a system will evolve “if many different configurations of the system undergo selection for one or more functions.”

This new law applies to systems that are formed from many different components, such as atoms, molecules or cells, that can be arranged and rearranged repeatedly, and are subject to natural processes that cause countless different arrangements to be formed — but in which only a small fraction of these configurations survive in a process called “selection for function.”   

Regardless of whether the system is living or nonliving, when a novel configuration works well and function improves, evolution occurs, say the researchers.

In the case of biology, Darwin equated function primarily with survival — the ability to live long enough to produce fertile offspring. The new study expands that perspective, noting that at least three kinds of function occur in nature. 

The most basic function is stability – stable arrangements of atoms or molecules are selected to continue.  Also chosen to persist are dynamic systems with ongoing supplies of energy. 

The third and most interesting function according to the researchers is “novelty” — the tendency of evolving systems to explore new configurations that sometimes lead to startling new behaviors or characteristics, like photosynthesis. 

The same sort of evolution happens in the mineral kingdom. The earliest minerals represent particularly stable arrangements of atoms. Those primordial minerals provided foundations for the next generations of minerals, which participated in life’s origins. The evolution of life and minerals are intertwined, as life uses minerals for shells, teeth, and bones.

In the case of stars, the paper notes that just two major elements – hydrogen and helium – formed the first stars shortly after the big bang. Those earliest stars used hydrogen and helium to make about 20 heavier chemical elements. And the next generation of stars built on that diversity to produce almost 100 more elements.

The research has implications for the search for life in the cosmos, said Lunine, a member of the Carl Sagan Institute. “If increasing functionality of evolving physical and chemical systems is driven by a natural law, we might expect life to be a common outcome of planetary evolution.”

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More here:

A paper published in the Proceedings of the National Academy of Sciences describes "a missing law of nature," recognizing for the first time an important norm within the natural world's workings.

In essence, the new law states that complex natural systems evolve to states of greater patterning, diversity, and complexity. In other words, evolution is not limited to life on Earth, it also occurs in other massively complex systems, from planets and stars to atoms, minerals, and more.

It was authored by a nine-member team— scientists from the Carnegie Institution for Science, the California Institute of Technology (Caltech) and Cornell University, and philosophers from the University of Colorado.

"Macroscopic" laws of nature describe and explain phenomena experienced daily in the natural world. Natural laws related to forces and motion, gravity, electromagnetism, and energy, for example, were described more than 150 years ago.

In the case of stars, the paper notes that just two major elements—hydrogen and helium—formed the first stars shortly after the big bang. Those earliest stars used hydrogen and helium to make about 20 heavier chemical elements. And the next generation of stars built on that diversity to produce almost 100 more elements.

"Charles Darwin eloquently articulated the way plants and animals evolve by natural selection, with many variations and traits of individuals and many different configurations," says co-author Robert M. Hazen of Carnegie Science, a leader of the research.

"We contend that Darwinian theory is just a very special, very important case within a far larger natural phenomenon. The notion that selection for function drives evolution applies equally to stars, atoms, minerals, and many other conceptually equivalent situations where many configurations are subjected to selective pressure."

The co-authors themselves represent a unique multi-disciplinary configuration: three philosophers of science, two astrobiologists, a data scientist, a mineralogist, and a theoretical physicist.

Dr. Wong said, "In this new paper, we consider evolution in the broadest sense—change over time—which subsumes Darwinian evolution based upon the particulars of 'descent with modification.'"

"The universe generates novel combinations of atoms, molecules, cells, etc. Those combinations that are stable and can go on to engender even more novelty will continue to evolve. This is what makes life the most striking example of evolution, but evolution is everywhere."

Among many implications, the paper offers:
  1. Understanding into how differing systems possess varying degrees to which they can continue to evolve. "Potential complexity" or "future complexity" have been proposed as metrics of how much more complex an evolving system might become.
  2. Insights into how the rate of evolution of some systems can be influenced artificially. The notion of functional information suggests that the rate of evolution in a system might be increased in at least three ways: (1) by increasing the number and/or diversity of interacting agents, (2) by increasing the number of different configurations of the system; and/or (3) by enhancing the selective pressure on the system (for example, in chemical systems by more frequent cycles of heating/cooling or wetting/drying).
  3. A deeper understanding of generative forces behind the creation and existence of complex phenomena in the universe, and the role of information in describing them.
  4. An understanding of life in the context of other complex evolving systems. Life shares certain conceptual equivalencies with other complex evolving systems, but the authors point to a future research direction, asking if there is something distinct about how life processes information on functionality (see also https://royalsocietypublishing.org/doi/10.1098/rsif.2022.0810).
  5. Aiding the search for life elsewhere: if there is a demarcation between life and non-life that has to do with selection for function, can we identify the "rules of life" that allow us to discriminate that biotic dividing line in astrobiological investigations? (See also "Did Life Exist on Mars? Other Planets? With AI's Help, We May Know Soon").
  6. At a time when evolving AI systems are an increasing concern, a predictive law of information that characterizes how both natural and symbolic systems evolve is especially welcome.
Laws of nature—motion, gravity, electromagnetism, thermodynamics—etc. codify the general behavior of various macroscopic natural systems across space and time.

The "law of increasing functional information" complements the 2nd law of thermodynamics, which states that the entropy (disorder) of an isolated system increases over time (and heat always flows from hotter to colder objects).

09 October 2023

AfD is now a ‘major all-German party’

Alternative für Deutschland comes second in Hesse and third in Bavaria as support spreads from east of country

Kate Connolly in Berlin / Mon 9 Oct 2023 10.38 EDT

The anti-immigration Alternative für Deutschland has declared itself a “major all-German party” after winning its biggest ever vote share in a western German state.

The AfD, once seen as a party most relevant to post-communist eastern states, won 18.4% of the vote on Sunday in the powerhouse state of Hesse, around Frankfurt, and came second only to the Christian Democratic Union (CDU). In Bavaria it came third, behind the rightwing populist Freie Wähler (Free Voters) party.

Alice Weidel, the co-leader of the AfD, said the gains were a breakthrough moment, showing that “AfD is no longer an eastern phenomenon, but has become a major all-German party. So we have arrived.”

The three parties that make up the coalition government of the chancellor, Olaf Scholz – his Social Democrats, the Greens and the pro-business FDP – received a drubbing in the two elections, with the FDP failing to get into parliament in Bavaria.

Political analysts and politicians themselves were quick to blame the actions of the central government for the poor showing, with dissatisfaction expressed over everything from its building heating reforms to the cost of living crisis and post-pandemic labour shortages.

The political future of Nancy Faeser, the interior minister who ran as the main candidate for the SPD in Hesse, was in doubt after the party’s dismal performance there, even as Scholz said he would stand behind her.

Around a quarter of all German voters live in Hesse and Bavaria.

In Bavaria, the Greens lost 3.2% of their previous vote share, the SPD 1.3% and the FDP 2.1%. In Hesse, the results were even worse, with the SPD losing 4.7%, the Greens 5%, and the FDP 2.5%.

In contrast, the AfD made a gain of 5.3% in Hesse, while in Bavaria it gained 4.4%, bringing it to 14.6%.

Manfred Güllner, the head of the Forsa polling institute, attributed the far right’s success to “the huge alienation between the governing parties in Berlin and the many normal working people”. The ruling administration ignored their concerns at their peril, he added.

In Bavaria, in particular, concerns over immigration played a considerable role in the way people voted, with 83% choosing parties promising a change in immigration and asylum policy. In polling, 21% of people in Bavaria said migration was the most important issue in deciding how they voted; and this was the case for 18% in Hesse.

Markus Söder, the head of the Christian Social Union, which has ruled in Bavaria for decades and secured the most votes, with 37% – albeit the party’s historically worst result – said voters had sent an “alarm signal” to Berlin. “The topic of migration is a purely federal issue, not a regional policy issue,” he said. He added the only way to halt the growth of the AfD was to “change Germany’s migration policy”.

More below:

The Alternative for Germany long seemed to be little more than a regional rump party, the voice of disgruntled voters in the former communist east but a political earthquake changed all that on Sunday night.

"Centrist politicians expressed dismay. Parts of the AfD have been designated extremist by German domestic intelligence and one of its leaders is to stand trial for using banned Nazi slogans. A former AfD MP was arrested last year over her role in an alleged plot by radicals to overthrow the national government.

"Yet none of that seems to be deterring voters, who are abandoning traditional parties in droves to put their crosses next to the AfD."

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"Exit polls on Sunday showed that 38 per cent of voters who chose the AfD did so out of conviction, not protest. In Bavaria the proportion was higher — 47 per cent. Voters from all other parties had defected to the AfD, Weidel said, proving “we have established ourselves in all sections of the electorate”.

Full article here.

Happy coincidence: October 9 is White Independence Day.

30 September 2023

Cosmic Web Lights Up In The Darkness Of Space

Keck Cosmic Web Imager Offers Best Glimpse Yet of the Filamentous Network That Connects Galaxies

Maunakea, HawaiÊ»i – Like rivers feeding oceans, streams of gas nourish galaxies throughout the cosmos. But these streams, which make up a part of the cosmic web, are very faint and hard to see. While astronomers have known about the cosmic web for decades, and even glimpsed the glow of its filaments around bright cosmic objects called quasars, they have not directly imaged the extended structure in the darkest portions of space—until now.

New results from the Keck Cosmic Web Imager, or KCWI, which was designed by Caltech’s Edward C. Stone Professor of Physics Christopher Martin and his team, are the first to show direct light emitted by the largest and most hidden portion of the cosmic web: the crisscrossing wispy filaments that stretch across the darkest corners of space between galaxies. The KCWI instrument is based at the W. M. Keck Observatory atop Maunakea in HawaiÊ»i.

“We chose the name Keck Cosmic Web Imager for our instrument because we were hoping it would directly detect the cosmic web,” says Martin, who is also the director of the Caltech Optical Observatories, which includes Caltech’s portion of Keck Observatory; other Keck Observatory partners are the University of California and NASA. “I’m very happy it worked out.”

Galaxies in our universe condense out of swirling clouds of gas. That gas then further condenses into stars that light up the galaxies, making them visible to telescopes in a range of wavelengths of light. Astronomers think that cold, dark filaments in deep space snake their way to the galaxies, supplying them with gas, which is fuel for making more stars. In 2015, Martin and his colleagues found “smoking-gun evidence,” as Martin describes it, for this so-called cold-flow model of galaxy formation: a long filament funneling gas into a large galaxy. For this work, they used a prototype instrument to KCWI, the Cosmic Web Imager, which was based at Caltech’s Palomar Observatory.

In that case, the filament was being lit up by a nearby quasar, the bright nucleus of a young galaxy. But most of the cosmic web lies in the desolate territory between galaxies and is hard to image.

“Before this latest finding, we saw the filamentary structures under the equivalent of a lamppost,” says Martin. “Now we can see them without a lamp.”

The new findings appear in a paper published in Nature Astronomy on September 28.

Martin has been driven to reveal the cosmic web in its full glory ever since he was a graduate student. This detailed imaging of the web, he says, will provide astronomers with missing information they need to understand the details of how galaxies form and evolve. It can also help astronomers map the distribution of dark matter in our universe (dark matter makes up about 85 percent of all matter in the universe, but scientists still don’t know what it is made of).

“The cosmic web delineates the architecture of our universe,” he says. “It’s where most of the normal, or baryonic, matter in our galaxy resides and directly traces the location of dark matter.”

The Glow of Filaments

The best way to see the cosmic web directly is to pick up signatures of its main component, hydrogen gas, using instruments called spectrometers, which spread light out into a multitude of wavelengths, also known as a spectrum. Hydrogen gas can be identified within these spectra via its strongest emission line, called the Lyman alpha line. Martin and his colleagues designed KCWI to find these faint Lyman alpha signatures across a two-dimensional (2D) image of the cosmos (hence KCWI is known as an imaging spectrometer). The instrument’s first installment covers the “blue” portion of the visible-light spectrum, spanning wavelength ranges from 350 to 560 nanometers. (The second part of the instrument, called the Keck Cosmic Reionization Mapper, or KCRM, which sees the red, or longer-wavelength portion, of the visible spectrum, was recently installed at Keck Observatory).

KCWI’s precise spectrometers can look for the Lyman alpha signatures of the cosmic web across a range of wavelengths. Because of the expansion of the universe, which stretches light to longer wavelengths, gas that is located farther away from Earth has a redder Lyman alpha signature. The 2D images captured by KCWI at each wavelength of light can be stacked together to make a three-dimensional (3D) map of the emission from the cosmic web. For this observation, KCWI observed a region of space between 10 and 12 billion light-years away.

“We are basically creating a 3D map of the cosmic web,” Martin explains. “We take spectra for every point in an image at range of wavelengths, and the wavelengths translate to distance.”

Confusion with the Diffuse Light of Space

One challenge in detecting the cosmic web is that its dim light can be confused with nearby background light that suffuses the skies above Maunakea, including the glow from the atmosphere, zodiacal light from the solar system (generated when sunlight scatters off interplanetary dust), and even our own galaxy’s light.

To solve this problem, Martin came up with a new strategy to subtract this background light from the images of interest.

“We look at two different patches of sky, A and B. The filament structures will be at distinct distances in the two directions in the patches, so you can take the background light from image B and subtract it from A, and vice versa, leaving just the structures. I ran detailed simulations of this in 2019 to convince myself that this method would work,” he says.

The result is that astronomers now have “a whole new way to study the universe,” as Martin says.

“With KCRM, the newly deployed red channel of KCWI, we can see even farther into the past,” says senior instrument scientist Mateusz Matuszewski. “We are very excited about what this new tool will help us learn about the more distant filaments and the era when the first stars and black holes formed.”