Tropical climates are the most biodiverse on Earth − but it's not only because of how warm and wet they are

Marco Túlio Pacheco Coelho, Postdoctoral research associate, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 

Dave Roberts, Professor Emeritus of Ecology, Montana State University,  

Catherine Graham, Senior Researcher at Swiss Federal Institute for Forest,

 Snow and Landscape Research and Adjunct Associate Professor of Ecology and Evolution, Stony Brook University (The State University of New York)
Thu, September 28, 2023
THE CONVERSATION

Natural selection can get to work in isolated locations. 

Birger Strahl/Unsplash, CC BY

Life exists in every conceivable environment on Earth, from the peaks of towering mountains to the remote stretches of isolated islands, from sunlit surfaces to the darkest depths of the oceans. Yet, this intricate tapestry of existence isn’t spread uniformly.

For centuries, scientists have marveled at the extraordinary variety of species exhibited in tropical regions. The breathtaking biodiversity of the Amazon rainforest, the teeming life in Madagascar’s unique ecosystems, the species-rich cloud forests of Costa Rica – the tropics showcase nature’s opulence.

What makes the tropics so incredibly diverse?

Since the dawn of biodiversity studies, scientists have believed the predominant factor is climate – the long-term patterns of temperature, precipitation and other atmospheric conditions. Thinkers like Alexander von Humboldt set the stage in the early 19th century with their keen observations, highlighting how life-rich regions often shared certain climatic features. Fast-forward to the present, and scientists confidently correlate climate with biodiversity. Simply put, hotter, wetter, resource-rich regions are veritable cradles of life.

The Mediterranean climate is named after where it occurs in Southern Europe, but similar isolated conditions are scattered across the globe in parts of California, central Chile, the Western Cape of South Africa and southwestern Australia. bodrumsurf/iStock via Getty Images Plus

Some climatic conditions spread across vast landscapes, while others appear fragmented, resembling isolated islands amid varying climates. This difference raises an intriguing question: Is an area’s biodiversity solely due to its climate? Or do the size and relative isolation of these climatic pockets influence the richness and abundance of species that thrive within them?
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We are part of an international, interdisciplinary team interested in the puzzle of how the geography of climate and the global patterns of species diversity fit together. Geography of climate is a bigger part of the biodiversity picture than previously assumed, according to our study findings recently published in the journal Nature.

Researchers commonly consider the geographical distribution of species, as displayed on this map highlighting the number of amphibian species across various regions of the world. Marco Túlio Pacheco Coelho

Unraveling the geography of climate

Historically, to study global biodiversity patterns, researchers divided the world into equal area grids and counted the species in each square.

Our study diverged from conventional methods. Instead of focusing solely on specific geographical locations, we centered our attention on the unique climate profiles of regions. Essentially, we weren’t just looking at plots on Earth but every place that shared a particular set of climatic conditions. We then classified these conditions globally and meticulously counted the species – birds, mammals, amphibians and reptiles – that live within the boundaries of each climate.

Mapping species in this climate space, rather than traditional geographical analyses of species diversity, revealed deeper insights into the relationships between biodiversity and climate. Marco Túlio Pacheco Coelho

Central to our investigation was an exploration of the geography of these climates, examining both their size and isolation. Some climates are widespread and common, sprawling over vast areas. Others are more fragmented, emerging as isolated pockets amid different climatic zones, reminiscent of islands in a vast ocean of other diverse climates. Consider tropical climates: They cover vast expanses cumulatively, despite being broken up into smaller, unconnected bits, even on different continents.

Our findings were illuminating. Climate, of course, was an important factor in how many species flourished in a location. But we were intrigued to find that about a third of the variation we found in species diversity across the globe can be attributed solely to the size and degree of isolation of all the instances of a particular climate.

The warm, resource-rich Costa Rican tropical forest bursts with biodiversity − partly because it’s a unique climate island amid a vast ocean of varying conditions. bogdanhoria/iStock via Getty Images Plus

Biodiversity responds not just to the type of climate but its spatial distribution. Beyond the known effects of warmth and moisture, we found that larger and more isolated climates foster greater species diversity. Moreover, these expansive, broken-up climates not only housed a greater number of species but also nurtured a more unique combination of species.

By leveraging but transcending traditional methodologies, our approach unearthed novel insights about the geographical characteristics of climates. We discovered that the larger a climatic zone is, the more fragmented and scattered it tends to be across the landscape.
Isolation spurs diversity

Cooler extra-tropical climates connect more cohesively around the globe. Ciprian Boiciuc/Unsplash, CC BY

Traditionally, scientists have thought of tropical climates as cohesive expanses, standing as barriers between the distinct extra-tropical climates of our planet’s poles. Our analysis confirmed that cooler extra-tropical climates are relatively well connected across much of the planet.

Yet, our findings reveal a different narrative for the tropics: Tropical climates appear more as fragmented islands amid a sea of diverse climates, rather than expansive, interconnected realms. Our revelation underscores that tropical climates, while abundant, are dispersed and disjointed across the Earth’s surface.

Drawing a parallel, consider how mountainous regions harbor isolated valleys where people speak distinct dialects shaped by their seclusion. Nature mirrors this: Species in isolated climatic niches evolve distinctly, creating a diverse and unique tableau of life.

The specter of climate change, however, casts a long shadow over these insights. A world undergoing rapid warming might witness once vast climates fragmenting further. Such shifts could challenge species, compelling them to traverse daunting landscapes to find suitable habitats. If these once expansive climates recede, it could disrupt the entire balance of species interactions.

Understanding the interplay between biodiversity and climate is not merely an intellectual pursuit. It provides direction in helping people protect and appreciate the diverse symphony of life in our evolving world.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts.

It was written by: Marco Túlio Pacheco Coelho, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL); Catherine Graham, Stony Brook University (The State University of New York), and Dave Roberts, Montana State University.

Read more:

Tropical forests can recover surprisingly quickly on deforested lands – and letting them regrow naturally is an effective and low-cost way to slow climate change

Protecting biodiversity – and making it accessible – has paid off for Costa Rica

Catherine Graham receives funding from Swiss National Fund, European Research Council.

Dave Roberts received a stipend from WSL when he was a Fellow there during his stay in Switzerland when this work was initiated.

 Paleontologists Find Trilobite’s Last Meal in 465-Million-Year-Old Fossilized Stomach

Isaac Schultz

Wed, September 27, 2023 




Here’s something to chew on: a fossilized trilobite from the Ordovician Period, which is so well preserved that a team of paleontologists was able to identify its last meal, now mineralized in the creature’s fossil stomach.

The discovery is the first direct evidence of the trilobite diet, taken straight from the animal’s belly. Using synchrotron microtomography, the team identified fragmented shells in the trilobite that they attributed to a host of marine critters, including ostracods, hyoliths, and bivalves. The team’s research describing the contents was published today in Nature.

The fossil is of Bohemolichas incola, one of more than 20,000 trilobite species that existed during their 270-million-year reign on Earth. The specimen was found over a century ago—perhaps 1908—and has since been kept at the Museum of Buroslav Horák, in Rokycany, a town in the Czech Republic. Petr Kraft, a paleontologist at Charles University in Prague and the study’s lead author, took note of the fossil and the apparent gut contents when he visited the museum as a child. But the technology to peer within the trilobite didn’t exist.

Now it does, and when Kraft’s former PhD student Valéria Vaškaninová and Ahlberg were working on fossil fishes from the region using synchrotron microtomography, they got in touch with Kraft.

“It was clearly an unselective feeder, basically gobbling up whatever it encountered that was small enough to fit in its mouth, or fragile enough to be broken up with ease,” Ahlberg said. “We can’t really be sure whether the food items were alive, or dead, or a mix of the two.”

The researchers believe the trilobite owes its immaculate preservation to being engulfed and buried by an underwater mud flow. That would make the case of the trilobite surprisingly similar to a remarkable fossil of a mammal and a beaked dinosaur entwined with one another, which was described in a paper published in Scientific Reports in July.

In a gnarly twist, the fossil also showed evidence of burrowing by other scavengers; that is, after the trilobite died, it was itself scavenged by other bottom feeders. Those scavengers tried to get at the trilobite’s soft tissue, the team noted, but avoided the animal’s gut. That may be because the trilobite’s digestive tract had some sort of noxious conditions that made it a less-than-appetizing meal for other Ordovician eaters.

The fossil is a remarkable window into life as a trilobite, and a rare example of how well-preserved remains can reveal about the ancient past.

 Gizmodo

DNA remnants found in fossil of 6 million year old turtle

Reuters
Thu, September 28, 2023 

Researchers excavate the 6 million year old fossil remains of a sea turtle of the genus Lepidochelys near La Pina along the Caribbean coast of Panama

(Reuters) - Remnants of DNA have been discovered in fossilized remains dating to 6 million years ago of a sea turtle closely related to today's Kemp's ridley and olive ridley turtles, marking one of the rare times genetic material has been identified in such ancient fossils of a vertebrate, researchers said on Thursday.

The researchers said some bone cells, called osteocytes, were exquisitely preserved in the fossil, which was excavated along Panama's Caribbean coast in 2015. The fossil is partial, with a relatively complete carapace - the turtle's shell - but not the rest of the skeleton. The turtle would have been about a foot (30 cm) long when alive, they said.

In some of the osteocytes, the cell nuclei were preserved and reacted to a chemical solution that allowed the researchers to recognize the presence of remnants of DNA, the molecule that carries genetic information for an organism's development and functioning, said paleontologist Edwin Cadena, lead author of the study published in the Journal of Vertebrate Paleontology.

"I want to point out that we did not extract DNA, we only were able to recognize the presence of DNA traces in the nuclei," added Cadena, of Universidad del Rosario in Bogota and the Smithsonian Tropical Research Institute.


DNA is quite perishable, though in the right conditions it has been preserved in some ancient remains. Researchers last year reported the discovery of DNA from animals, plants and microbes dating to about 2 million years ago from sediment at Greenland's remote northernmost point.

Cadena said the only older vertebrate fossils than the newly described turtle to have been found with similar DNA remnants were of two dinosaurs - Tyrannosaurus, which lived about 66 million years ago, and Brachylophosaurus, which lived about 78 million years ago. Cadena said DNA remnants also have been reported in insects dating to tens of millions of years ago.

The turtle is from the same genus - Lepidochelys - as two of the world's seven living species of sea turtles - the Kemp's ridley, the world's smallest sea turtle, and the olive ridley, Cadena said. Kemp's ridley, with a triangular-shaped head and a slightly hooked beak, is primarily found in the Gulf of Mexico. The olive ridley, which closely resembles the Kemp's ridley, has a larger distribution, primarily found in the tropical regions of the Pacific, Indian and Atlantic oceans.

The fossil represents the oldest-known member of Lepidochelys and helps to shed light on the poorly understood evolutionary history of this genus, the researchers said. They did not identify it by species because the remains were too incomplete, Cadena said.

"Each fossil, each fossil site has specific conditions of preservation that in some cases could have favored preservation of original biomolecular remains such as proteins and DNA," Cadena said.

"Maybe in the future and with more studies of this kind, we could be able at some point to sequence very small pieces of DNA and to infer things about their close relatives or involve that information in a broader molecular evolutionary study," Cadena added.

(Reporting by Will Dunham in Washington; Additional reporting by Elida Moreno; Editing by Rosalba O'Brien)

This 6-million-year-old turtle shell still has some DNA
Laura Baisas
Fri, September 29, 2023

The researchers found preserved bone cells in the carapace, which exhibited structures like the nucleus of a cell, where DNA traces were found.


Sea turtles have been around for at least 110 million years, yet relatively little is known about their evolution. Two of the most common sea turtles on Earth are olive ridley and Kemp’s ridley turtles that belong to a genus called Lepidochelys that could help fill in some of the gaps of sea turtle biology and evolution. A team of paleontologists not only discovered the oldest known fossil of turtle from the Lepidochelys genus, but also found some traces of ancient turtle DNA. The findings are detailed in a study published September 28 in the Journal of Vertebrate Paleontology.

The DNA comes from the remains of a turtle shell first uncovered in 2015 in the Chagres Formation on Panama’s Caribbean coast. It represents the oldest known fossil evidence of Lepidochelys turtles. The turtle lived approximately 6 million years ago, curing the upper Miocene Epoch. At this time, present day Panama’s climate was getting cooler and drier, sea ice was accumulating at Earth’s poles, rainfall was decreasing, sea levels were falling.

“The fossil was not complete, but it had enough features to identify it as a member of the Lepidochelys genus,” study co-author and Universidad del Rosario in Bogotá, Colombia paleontologist Edwin Cadena tells PopSci. Cadena is also a research associate at the Smithsonian Tropical Research Institute in Panama.

The team detected preserved bone cells called osteocytes. These bone cells are the most abundant cells in vertebrates and they have nucleus-like structures. The team used a solution called DAPI to test the osteocytes for genetic material.

“In some of them [the osteocytes], the nuclei were preserved and reacted to DAPI, a solution that allowed us to recognize remains of DNA. This is the first time we have documented DNA remains in a fossilized turtle millions of years old,” says Cadena.

According to the study, fossils like this one from vertebrates preserved in this part of Panama are important for our understanding of the biodiversity that was present when the Isthmus of Panama first emerged roughly 3 million years ago. This narrow strip of land divided the Caribbean Sea and the Pacific Ocean and joined North and South America. It created a land bridge that made it easier for some animals and plants to migrate between the two continents.

This specimen could also have important implications for the emerging field of molecular paleontology. Scientists in this field study ancient and prehistoric biomatter including proteins, carbohydrates, lipids, and DNA that can sometimes be extracted from fossils.

Molecular paleontology aims to determine if scientists can use this type of evidence to determine more about the organisms than their physical shape, which is typically what is preserved in most fossils. Extracting this tiny material from bones was critical in sequencing the Neanderthal genome, which earned Swedish scientist Svante Pääbo the 2022 Nobel prize in physiology or medicine.

“Many generations have grown up with the idea of extracting and bringing back to life extinct organisms,” says Cadena. “However, that is not the real purpose of molecular paleontology. Instead, its goal is to trace, document, and understand how complex biomolecules such as DNA and proteins can be preserved in fossils.”

This new turtle specimen could help other molecular paleontologists better understand how soft tissues can be preserved over time. It could also shift the idea that original biomolecules like proteins or DNA have a specific timeline for preservation in fossils and encourage re-examining older specimens for traces of biomolecules.

A giant moon collision may have given rise to Saturn's iconic rings, study suggests

Tereza Pultarova

SPACE . COM
Thu, September 28, 2023 

A giant moon collision may have given rise to Saturn's iconic rings, study suggests

A collision between two ancient icy moons that may have once orbited Saturn could have given rise to the planet's iconic ring system, a new study reveals.

Saturn is probably the most eye-catching planet in the solar system, but it may also be one of the most mind-boggling. Surrounded by a series of seven concentric rings and orbited by an army of 245 moons, the gas giant, second in size only to Jupiter, has puzzled astronomers for centuries.

A new study may have found an answer to one of Saturn's mysteries — the origin of its rings. The study, based on dozens of computer simulations, used data collected by NASA's Cassini mission that orbited Saturn for 13 years between 2004 and 2017. The probe found the material that makes up the rings, first observed by Galileo Galilei in 1610, consists of icy fragments that are very pristine and unpolluted by dust. Those Cassini findings suggested that the iconic rings of Saturn must be fairly young, only a few million years old, and that for the majority of the solar system's 4.5 billion-year history, the iconic Saturn looked much more bland.

Related: Saturn's moon Enceladus has all the ingredients for life in its icy oceans. But is life there?

The researchers behind the new study, a team consisting of experts from NASA and Durham University in the U.K., speculated that the rings may have formed from a relatively recent collision of two ancient icy moons. They used powerful supercomputers to simulate nearly 200 scenarios of such a collision.

The results revealed that a collision between two moons about as large as Saturn's current moons Dione and Rhea (which have diameters equivalent to one third and a little under a half of Earth's moon diameter respectively), could explain the existence of those rings.

"We tested a hypothesis for the recent formation of Saturn’s rings and have found that an impact of icy moons is able to send enough material near to Saturn to form the rings that we see now," Vincent Eke, Associate Professor in the Department of Physics/Institute for Computational Cosmology at Durham University, said in a statement.

Although the rings are made almost purely from ice, scientists think that Saturn's icy moons have rocky cores. The simulations confirmed that the icy fragments and the rocky bits would scatter in different ways after a collision, allowing the rocks to coalesce into new moons while the ice would get dispersed in orbits closer to Saturn's surface.

Rings can only form around celestial bodies within the Roche limit, a boundary where the gravity of the orbiting material is weaker than the tidal forces of the body it orbits.

The simulations show that many of the hypothetical collisions would inject a lot of ice into lower altitudes while the rocks would clump together in higher orbits.

RELATED STORIES:

— Detecting life on Saturn moon Enceladus would require 100 flybys through its geyser plume, study suggests

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— If we want to find life on Saturn's moon Enceladus, we need to rule out Earthly hitchhikers

"This scenario naturally leads to ice-rich rings because when the progenitor moons smash into one another, the rock in the cores of the colliding bodies is dispersed less widely than the overlying ice," Eke said.

Saturn's ice-covered moons are of great interest to scientists as some of them, such as the tiny Enceladus, might harbor conditions suitable for the emergence of life. There is still a lot that scientists don't know about Saturn and its past, and the results of the study are only a small step toward cracking the planet's mysteries.

The study was published in The Astrophysical Journal on Sept. 27.

How did Saturn get its rings? NASA might have answers

Bill Shannon
Wed, September 27, 2023 



(WTAJ) — Saturn is a visual marvel in our solar system, but how did it get those awe-inspiring rings? A new series of NASA supercomputer simulations might have the answer.

In fact, they believe the rings formed back when dinosaurs roamed the Earth. NASA released a video explaining that the rings potentially evolved from debris created after two icy moons smashed into each other a few hundred million years ago. The debris may have also combined to create some of Saturn’s 145 moons.

How to see the ‘ring of fire’ eclipse this October, total solar eclipse in April ’24

“There’s so much we still don’t know about the Saturn system, including its moons that host environments that might be suitable for life,” said Jacob Kegerreis, a research scientist at NASA’s Ames Research Center in California’s Silicon Valley. “So, it’s exciting to use big simulations like these to explore in detail how they could have evolved.”

NASA’s Cassini mission made scientists question just how young Saturn’s rings and some moons might actually be. This opened up new questions about how everything formed around Saturn.

Saturn’s rings currently live in the Roche limit. It’s the farthest orbit where a planet’s gravity is powerful enough to tear apart large pieces of rock or ice, according to NASA. Beyond this point, these materials could have formed moons.

“When the icy progenitor moons smash into one another, the rock in the cores of the colliding bodies is dispersed less widely than the overlying ice,” said Vincent Eke, an associate professor at Durham University’s Department of Physics and Institute for Computational Cosmology.

Scientists simulated nearly 200 versions of the impact and found several scenarios that would scatter the right amount of ice into Saturn’s Roche limit, creating those iconic rings. This would explain why Saturn’s rings are made of almost entirely ice chunks.

Your Guide To Surviving Your Saturn Return

• 
  
• 
  
• Collette Grimes
  Wed, September 27, 2023

  
  There are fewer astrological events that cause more panic than a Saturn returnwith Mercury retrograde being a close second.
• Known as a years-long period of suck, a Saturn return usually starts around one's 27th birthday, bringing in a wave of chaos and upheaval, as well as offering perspective-altering epiphanies via life-shattering situations. Saturn returns illicit such fear because it breaks you down to build you up. Representing responsibility, discipline and moral obligations, you can think of Saturn as the big daddy of all planets, enforcing structure wherever needed. When the seven ringed-planet returns to the same place it was when you were born, it will force you to learn the life lessons you need in order to move forward and grow. It will give you its hardest battles to test your strength as a spiritual soldier.
• 
  While it's impossible to predict exactly what potential storms your Saturn return will bring your way, building healthy coping mechanisms and bolstering your support system can help you ride its waves. Hypebae sat down with astrologer and tattoo artist
• 
  
• What is a Saturn return?
  
  Saturn return is when Saturn returns to the sign and degree your natal Saturn is at. It is an astrological coming of age that prepares you for future transits that impact your later life. Think of it as the gateway to your truest self. What Saturn does during his return is he takes away things in your life that no longer serve you. He makes you slow down and really take a look at the foundation of your life.
  What does the planet Saturn symbolize?
  
  Saturn is ruled by Capricorn and ultimately Saturn symbolizes time. The other things he brings to the table are contraction, control, discipline, boundaries -- just to name a few. He represents above and below -- bringing to reality concepts that have been working in the shadows for quite some time. During his "return," he brings a lot of this to light in your life.
• 
  When does it usually occur in a person's life?
  
  For most of us, there are three Saturn returns. They happen on average every 29.5 years though you can go through your return anywhere from 27 to 31 for the first one.
  
  Even if you have your Saturn in a late degree, you can still feel the shift in your life as Saturn moves into your natal sign. This does not mean your return starts when Saturn moves signs however. Your Saturn return is specifically when Saturn is conjunct, meaning the same degree, as your natal Saturn. This sometimes can last just a few months, but for others if your natal sign is retrograded, you can feel it for quite some time.
  What signs are most impacted?
  
  If you look at your chart at the circle in the middle, you can see what planets Saturn is connected to. Those lines are called aspects and you can see what planets will be impacted based on what Saturn is aspected to. Any planets Saturn is conjunct with will be impacted as well. A conjunction is usually when planets fall between 0 and 8 degrees of one another. The closer the degree the stronger the conjunction, meaning they operate more as "one planet" or a team rather than individually.
  Can one prepare for a Saturn return? How do you best get through it?
  
  Just roll with Saturns punches. His bark is worse than his bite -- I promise you that. The more you push back the harder it is. Saturn is the planet of contraction and you've gotta breathe through contractions in order to feel expansion. So look at this moment in your life as a doorway or a gateway to this next chapter. Remember -- growing is painful, that's how you know you're getting taller and wiser.
  

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Chinese astronauts light a match on Tiangong space station (video)

DANGER, DANGER, WILL ROBINSION

Andrew Jones
Thu, September 28, 2023



China's Shenzhou 16 astronauts conducted an eye-raising experiment in space involving open flames aboard the Tiangong space station.

Astronauts Gui Haichao and Zhu Yangzhu lit a candle during a live lecture broadcast from China's Tiangong space station on Sept. 21 to demonstrate how flames burn in microgravity. Strikingly, the flames appear nearly spherical, rather than the teardrop-shaped flames we're familiar with back on Earth.

Lit candles on Earth produce flames shaped through buoyancy-driven convection, with hot air rising and cold air descending. That combustion convection current is weak in the microgravity environment of low Earth orbit, however. This means flames diffuse in all directions, resulting in spherical fireballs.

The livestreamed lecture was the fourth so-called "Tiangong classroom" hosted on China's space station. The astronauts interacted with students in five classrooms across China, demonstrating a number of microgravity phenomena. As with previous classrooms, the astronauts demonstrated that many physical processes behave differently than they do on Earth.

However the candle experiment — in which Gui strikes a match to produce an open flame to light the candle — would likely be met by surprise by International Space Station participants, who have strict rules regarding flammable materials and open flames.

RELATED STORIES:

— Fire on the space station! Astronauts preparing ongoing combustion research.

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Strict fire safety measures aboard the ISS are in part a response to a significant fire on the Russian space station Mir in in 1997.

Combustion in microgravity has been the subject of numerous experiments on the ISS, but usually using a specially-designed combustion integrated rack, keeping fire isolated and contained.

Tiangong also has its Combustion Experiment Rack (CER) for serious research in this area.

Watch a 180-year-old star eruption unfold in new time-lapse movie (video)

Samantha Mathewson
Wed, September 27, 2023 

Watch a 180-year-old star eruption unfold in new time-lapse movie (video)

Using over two decades of data from NASA’s Chandra X-ray Observatory, astronomers have crafted a stunning new video of a stellar eruption that took place some 180 years ago.

The time-lapse video uses Chandra observations from 1999, 2003, 2009, 2014 and 2020 — along with data from ESA’s XMM-Newton spacecraft — and retraces the history of the stellar explosion known as Eta Carinae. This famous star system contains two massive stars. One of those stars is about 90 times more massive than the sun, scientists say, while the other is  about 30 times more massive than the sun.

The massive explosion, dubbed the "Great Eruption, came from Eta Carinae. It is believed to be the result of a merger between two stars that originally belonged to a triple star system. The aftermath of the collision was witnessed on Earth in the mid-19th century, and the new video shows how the stellar eruption has since continued to rapidly expand into space at speeds reaching up to 4.5 million miles per hour , according to a statement from NASA.

Related: Eta Carinae's epic supernova explosion comes to life in new visualization

"During this event, Eta Carinae ejected between 10 and 45 times the mass of the sun,” NASA officials said in the statement. "This material became a dense pair of spherical clouds of gas, now called the Homunculus Nebula, on opposite sides of the two stars."

The Homunculus Nebula is the bright blue cloud at the center of the image, fueled by high-energy X-rays produced by the two massive stars, which are too close to be observed individually. They are surrounded by a bright orange ring of X-ray emissions that appear to grow and expand rapidly over time.

"The new movie of Chandra, plus a deep, summed image generated by adding the data together, reveal important hints about Eta Carinae’s volatile history," NASA officials said in the statement. "This includes the rapid expansion of the ring, and a previously-unknown faint shell of X-rays outside it.

The faint X-ray shell is outlined in the image above, showing that it has a similar shape and orientation to the Homunculus nebula, which suggests both structures have a common origin, according to the statement.

Based on the motion of clumps of gas, astronomers believe  the stellar material was blasted away from Eta Carinae sometime between the years 1200 and 1800 — well before the Great Eruption was observed in 1843. As the blast extended into space, it collided with interstellar material in its path. The collision then heated the material, creating the bright X-ray ring observed. However, the blast wave has now traveled beyond the ring, given the X-ray brightness of Eta Carinae has faded with time, scientists said.

Their findings on Eta Carinae’s expansion were published in a 2022 study in the Astrophysical Journal.

"We’ve interpreted this faint X-ray shell as the blast wave from the Great Eruption in the 1840s," Michael Corcoran at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the study, said in a statement from the Chandra X-ray Observatory. "It tells an important part of Eta Carinae’s backstory that we wouldn’t otherwise have known."

Scientists confirm that the first black hole ever imaged is actually spinning

The researchers analyzed 22 years' worth of observations of the galaxy M87.

Mariella Moon
·Contributing Reporter
Thu, September 28, 2023 

Elen11 via Getty Images


The first black hole humanity has ever imaged has also provided us with what researchers are calling "unequivocal evidence" that black holes spin. An international team of scientists headed by Chinese researcher Dr. Cui Yuzhu analyzed 22 years of observational data gathered by more than 20 telescopes around the world. What they found was that the black hole at the center of galaxy M87, which is 6.5 billion times more massive than our sun, exhibits an oscillating jet that swings up and down every 11 years. This phenomenon confirms that the black hole is indeed spinning.

Black holes gobble up huge amounts of gas and dust, which they attract with their massive gravitational pull. A small fraction of those particles that don't fall into the black hole get spewn out and travel close to the speed of light, showing up as narrow beams along the axis. These beams are called "jets." The telescopes' observations show that M87's jet oscillates by 10 degrees in a recurring 11-year cycle, just as predicted by Einstein's General Theory of Relativity.

So, what causes the M87's jet to swing back and forth? The researchers' analysis indicates that the black hole's spin axis doesn't perfectly align with the rotational axis of its accretion disk. This disk-like structure is typically found surrounding a black hole, because it's made of materials that gradually spiral into the void to be consumed. That misalignment between the rotating mass and the matter that swirls around it causes "a significant impact on surrounding spacetime," which affects the movement of nearby objects in what the General Theory of Relativity calls "frame-dragging."

This is a significant discovery that massively improves our understanding of the mysterious region of spacetime — aside from proving Einstein right, of course. Scientists have yet to find out the size of M87's accretion disk and how fast its black hole is spinning, though, and that entails further observation and analysis.

Scientists just proved that 'monster' black hole M87 is spinning — confirming Einstein’s relativity yet again

Ben Turner
Thu, September 28, 2023 

An artist's illustration of the black hole M87* wobbling on its axis.

Astronomers have found the first direct evidence of a black hole spinning, and it's confirmed Einstein's theory of relativity yet again.

The discovery was made by studying powerful jets of energy beamed from the solar system-size black hole at the center of the neighboring Messier 87 galaxy. The black hole, called M87, is the best studied black hole to date and the first to ever be directly imaged in 2019, with its "donut hole" shadow crowned by a fuzzy halo of light.

Astrophysicists have long predicted that black holes spun, but the challenge of imaging the cosmic monstrosities has, until now, made evidence hard to come by. The researchers published their findings Sept. 27 in the journal Nature.

Related: The closest black holes to Earth may be 10 times closer than we thought

"After the success of black hole imaging in this galaxy with the [Event Horizon Telescope (EHT)], whether this black hole is spinning or not has been a central concern among scientists," Kazuhiro Hada, an astronomer at the National Astronomical Observatory of Japan, said in a statement. "Now anticipation has turned into certainty. This monster black hole is indeed spinning."

Black holes have such a powerful gravitational pull that nothing (not even light) can escape their maws, but this doesn't mean they can't be seen. This is because active black holes are surrounded by accretion disks — vast plumes of material stripped from gas clouds and stars, heated to red-hot temperatures by friction as it spirals into the black holes' mouths.



Some of this material is spat out, forming two jets of hot material that, in roughly a tenth of cases, travels at 99.9% the speed of light. How black hole jets acquire the enormous energy needed to do this has been a mystery, but physicists used Einstein's general theory of relativity to suggest the material could get it from the cosmic monsters' magnetic fields, if they were spinning rapidly on their axes.

Black holes likely acquired some of their spin from their early days as stars that, as they suddenly collapsed inward, became like figure skaters pulling in their arms to rotate faster. Over time, this spin probably grew faster due to the effect of infalling matter from stars ripped apart by the black holes, or from catastrophic collisions with other massive objects.

To search for clues of this elusive spin, astronomers turned to the M87 supermassive black hole, an enormous space-time tear that uses its mass (6.5 billion times that of the sun) to anchor an entire galaxy.

By studying M87* using a global network of radio telescopes from 2000 to 2022, the astronomers found that the black hole's jets were ticking back and forth like metronomes marking out an 11-year cycle. This showed that the black hole was precessing or wobbling on its axis as it rotated, just like a spinning top.

"We are thrilled by this significant finding," lead author Cui Yuzhu, an astronomer at Zhejiang Lab in Hangzhou, China, said in the statement. "Since the misalignment between the black hole and the disk is relatively small and the precession period is around 11 years, accumulating high-resolution data tracing M87's structure over two decades and thorough analysis are essential to obtain this achievement."

Beyond confirming Einstein's theory yet again, a number of exciting questions emerge from the discovery of black hole spin. Among them are ones relating to what catastrophic events could have caused the rapid rotation, as well as the possibility of discovering photon spheres — a faint ring of light surrounding the black hole that could give important hints into a theory of quantum gravity.

Scientists get closer to solving mystery of antimatter

Pallab Ghosh - BBC Science correspondent

Wed, September 27, 2023 

Scientists have made a key discovery about antimatter - a mysterious substance which was plentiful when the Universe began.

Antimatter is the opposite of matter, from which stars and planets are made.

Both were created in equal amounts in the Big Bang which formed our Universe. While matter is everywhere, though, its opposite is now fiendishly hard to find.

The latest study has discovered the two respond to gravity in the same way.

For years, physicists have been scrambling to discover their differences and similarities, to explain how the Universe arose.

Discovering that antimatter rose in response to gravity, instead of falling would have blown apart what we know about physics.

They've now confirmed for the first time that atoms of antimatter fall downwards. But far from being a scientific dead end this opens the doors to new experiments and theories. Does it fall at the same speed, for example?

During the Big Bang, matter and antimatter should have combined and cancelled each other, leaving nothing but light. Why they didn't is one of physics' great mysteries and uncovering differences between the two is the key to solving it.

Somehow matter overcame antimatter in those first moments of creation. How it responds to gravity, may hold the key, according to Dr Danielle Hodgkinson, a member of the research team at Cern in Switzerland, the world's largest particle physics laboratory.

"We don't understand how our Universe came to be matter-dominated and so this is what motivates our experiments," she told me.

Engineers adding liquid helium to the system to keep antimatter at minus 270 celcius, near to the lowest possible temperature, absolute zero

Most antimatter exists only fleetingly in the Universe, for fractions of seconds. So to carry out experiments, the Cern team needed to make it in a stable and long-lasting form.

Prof Jeffrey Hangst has spent thirty years building a facility to painstakingly construct thousands of atoms of antimatter from sub-atomic particles, trap them and then drop them.

"Antimatter is just the coolest, most mysterious stuff you can imagine," he told me.

"As far as we understand, you could build a universe just like ours with you and me made of just antimatter," Prof Hangst told me.

"That's just inspiring to address; it's one of the most fundamental open questions about what this stuff is and how it behaves."
What is antimatter?

Let's start with what matter is: Everything in our world is made from it, from tiny particles called atoms.

The simplest atom is hydrogen. It's what the Sun is mostly made from. A hydrogen atom is made up of a positively charged proton in the middle and negatively charged electron orbiting it.

With antimatter, the electric charges are the other way round.

Take antihydrogen, which is the antimatter version of hydrogen, used in the Cern experiments. It has a negatively charged proton (antiproton) in the middle and a positive version of the electron (positron) orbiting it.

These antiprotons are produced by colliding particles together in Cern's accelerators. They arrive at the antimatter lab along pipes at speeds that are close to the speed of light. This is much too fast for them to be controlled by the researchers.

The first step is to slow them down, which the researchers do by sending them around a ring. This draws out their energy, until they are moving at a more manageable pace.

The antiprotons and positrons are then sent into a giant magnet, where they mix to form thousands of atoms of antihydrogen.

The magnet creates a field, which traps the antihydrogen. If it were to touch the side of the container it would instantly be destroyed, because antimatter can't survive contact with our world.

When the field is turned off the antihydrogen atoms are released. Sensors then detect whether they have fallen up or down.

Some theorists have predicted that antimatter might fall up, though most, notably Albert Einstein in his General theory of Relativity more than a hundred years ago, say it should behave just like matter, and fall downwards.

The researchers at Cern have now confirmed, with the greatest degree of certainty yet, that Einstein was right.

But just because antimatter doesn't fall up, it doesn't mean that it falls down at exactly the same rate as matter.

For the next steps in the research, the team are upgrading their experiment to make it more sensitive, to see if there is a slight difference in the rate at which antimatter falls.

If so, it could answer one of the biggest questions of all, how the Universe came into existence.

The results have been published in the journal Nature.

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Mysterious antimatter observed falling down for first time

Daniel Lawler

AFP
Wed, September 27, 2023 

Physicists an CERN used a 25-centimetre-long cylinder, called ALPHA-g, to observe antimatter falling downwards due to gravity (Handout)


For the first time, scientists have observed antimatter particles -- the mysterious twins of the visible matter all around us -- falling downwards due to the effect of gravity, Europe's physics lab CERN announced on Wednesday.

The experiment was hailed as "huge milestone", though most physicists anticipated the result, and it had been predicted by Einstein's 1915 theory of relativity.

It definitively rules out that gravity repels antimatter upwards -- a finding that would have upended our fundamental understanding of the universe.

Around 13.8 billion years ago, the Big Bang is believed to have produced an equal amount of matter -- what everything you can see is made out of -- and antimatter, its equal yet opposite counterpart.

However there is virtually no antimatter in the universe, which prompted one of the greatest mysteries of physics: what happened to all the antimatter?

"Half the universe is missing," said Jeffrey Hangst, a member of CERN's ALPHA collaboration in Geneva which conducted the new experiment.

"In principle, we could build a universe -- everything that we know about -- with only antimatter, and it would work in exactly the same way," he told AFP.

Physicists believe that matter and antimatter did meet and almost entirely destroyed each other after the Big Bang.

Yet matter now makes up nearly five percent of the universe -- the rest is even less understood dark matter and dark energy -- while antimatter vanished.

- Newton's apple flying up? -

One of the key outstanding questions about antimatter was whether gravity caused it to fall in the same way as normal matter.

While most physicists believed that it did, a few had speculated otherwise.

A falling apple famously inspired Isaac Newton's work on gravity -- but if that apple was made of antimatter, would it have shot up into the sky?

And if gravity did in fact repel antimatter, it could have meant that impossibilities such as a perpetual motion machine were possible.

"So why not drop some and see what happens?" Hangst said.

He compared the experiment to Galileo's famous -- though likely apocryphal -- 16th-century demonstration that two balls of different mass dropped from the Leaning Tower of Pisa would fall at the same rate.

But this experiment -- the result of 30 years of work on antimatter at CERN -- was "a little bit more involved" than Galileo's, Hangst said.

One problem was that antimatter barely exists outside of rare, short-lived particles in outer space.

However in 1996, CERN scientists produced the first atoms of antimatter -- antihydrogen.

Another challenge was that, because matter and antimatter have an opposite electrical charge, the moment they meet they destroy each other in a violent flash of energy scientists call annihilation.

- A magnetic trap -

To study gravity's effect on antimatter, the ALPHA team constructed a 25-centimetre-long (10-inch) bottle placed on its end, with magnets at the top and bottom.

Late last year, the scientists placed around 100 very cold antihydrogen atoms into this "magnetic trap" called ALPHA-g.

As they turned down the strength of both magnets, the antihydrogen particles -- which were bouncing around at 100 metres a second -- were able to escape out either end of the bottle.

The scientists then simply counted how much antimatter was annihilated at each end of the bottle.

Around 80 percent of the antihydrogen went out of the bottom, which is a similar rate to how regular bouncing hydrogen atoms would behave if they were in the bottle.

This result, published in the journal Nature, shows that gravity causes antimatter to fall downwards, as predicted by Einstein's 1915 theory of relativity.

In more than a dozen experiments, the CERN scientists varied the strength of the magnets, observing gravity's effect on antimatter at different rates.

While the experiment rules out that gravity makes antihydrogen go upwards, Hangst emphasised it did not prove that antimatter behaves in exactly the same way as normal matter.

"That's our next task," he said.

Marco Gersabeck, a physicist who works at CERN but was not involved in the ALPHA research, said it was "a huge milestone".

But it marks "only the start of an era" of more precise measurements of gravity's effect on antimatter, he told AFP.

Other attempts to better understand antimatter include using CERN's Large Hadron Collider to investigate strange particles called beauty quarks.

And there is an experiment onboard the International Space Station trying to catch antimatter in cosmic rays.

But for now, exactly why the universe is awash with matter but devoid of antimatter "remains a mystery," said physicist Harry Cliff.

Since both should have annihilated each other completely in the early universe, "the fact that we exist suggests there is something we don't understand" going on, he added.

Antimatter isn't immune to gravity, landmark experiment confirms

Peter Weber
Thu, September 28, 2023 

Antihydrogen Laser Physics Apparatus (ALPHA) lab at CERN.


Antimatter — the mysterious substance that's the mirror opposite of matter in most ways — falls downward in gravity like everything else in the universe, a team of physicists reported Wednesday in the journal Nature. In a delicate, groundbreaking experiment conducted at the European Center for Nuclear Research (CERN), the scientists pretty conclusively proved that antiparticles are not governed by antigravity.

The results are a bit of a wet blanket for science fiction. "The bottom line is that there's no free lunch, and we're not going to be able to levitate using antimatter," study coauthor Joel Fajans of the University of California, Berkeley, told The New York Times. But they are kind of a relief for science. The tug of gravity on antimatter conforms with Albert Einstein's general theory of relativity. If the antiparticles had floated upward in the experiment, as some scientists had hypothesized, it would have turned the world of physics on its head.

"Antimatter is just the coolest, most mysterious stuff you can imagine," Jeffrey Hangst, the particle physicist whose 30 years of work trapping antiparticles led to the discovery, told BBC. "As far as we understand, you could build a universe just like ours with you and me made of just antimatter."

For this experiment, Fajans and his colleagues collected and suspended antihydrogen — the antimatter version of hydrogen, with one positively charged electron (positron) orbiting a negatively charged proton (antiproton) — in a magnetic field inside a specially designed tube. When the magnetic force was turned down on the top and bottom of the tube, some of the antiparticles rose but about 80% fell, roughly in line with hydrogen atoms.

The experiment left a bunch of huge questions about antimatter unanswered, however. The big one: Where is it?

When matter and antimatter meet, they annihilate each other in flashes of pure energy. Scientists believe that when the universe was born, the Big Bang created equal quantities of matter and antimatter. And they don't understand why matter won out while antimatter all but disappeared, only fleetingly observed in cosmic ray showers or created by colliding particles in labs like CERN.

One theory to explain what happened posited that all the antimatter was drawn away from the matter by antigravity and formed its own mirror antigravity universe. That hypothesis looks more implausible now.

One of world’s greatest physics mysteries finally decoded

Vishwam Sankaran
Thu, September 28, 2023

One of world’s greatest physics mysteries finally decoded


Physicists have answered the long-standing question of whether antimatter falls up or down under gravity, an advance that could help crack one of the biggest mysteries of why almost everything in the universe is only made of matter.

The new study, published in the journal Nature on Wednesday, found that antimatter falls downwards under gravity – as expected by much of the scientific community,

Antimatter is made of particles possessing the opposite electric charge as ordinary particles.

For instance, the antimatter equivalent of the negatively charged electron is the positron, and the two annihilate each other to produce gamma radiation if they collide.

One of the strangest mysteries of the universe, scientists have observed, is that almost all the visible matter in the universe is made of ordinary matter and not antimatter.

“Right now, we don’t have an explanation about where all the antimatter in the universe is. To find a solution for this conundrum, what we do is test the elements of the physics of antimatter to see if we can find an inconsistency,” study co-author Robert Thompson from the University of Calgary in Canada said.

In the new study, scientists assessed the gravitational characteristics of antihydrogen – the simplest atom in antimatter that mirrors hydrogen.

Matter dropped from any height on Earth accelerates towards the planet’s surface at the constant rate of about 9.8m/s each second – a mathematical constant used in physics calculations, known as acceleration due to gravity g.

Now, with the latest groundbreaking study, physicists say, this value for antihydrogen – accounting for errors in the experiment – “is consistent with a downward gravitational acceleration of 1g” or about“32 feet per second per second”.

Graphic shows antihydrogen atoms falling and annihilating inside a magnetic trap, part of the ALPHA-g experiment at CERN to measure the effect of gravity on antimatter.

 (U.S. National Science Foundation)

The experiment, which has never been done before, is a milestone in physics marking “a leap forward” in the world of antimatter research, they say.

Researchers used the new ALPHA-g apparatus in operation at CERN – Europe’s largest physics laboratory.

In the experiment, physicists created antimatter and trapped the neutral antihydrogen atoms in a magnetic bottle, making the environment as cold as possible.

They then released the antihydrogen within the vertical apparatus to witness and measure its gravitational behaviour under free-fall.

Scientists observed the physical properties of the antihydrogen by making precise measurements, including of its charge and colour spectrum.

The milestone study is the first step in taking precise measurements of the gravitational properties of antimatter to determine whether antimatter falls in the exact same way as matter.

“Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth,” scientists wrote in the study.

Researchers have also ruled out “repulsive ‘antigravity’” in this case – findings that can help better understand the lack of antimatter observed in the universe.

“We know there’s a problem somewhere in quantum mechanics and gravity. We just don’t know what it is. There has been a lot of speculation on what happens if you drop antimatter, though it’s never been tested before now because it’s so hard to produce and gravity is very weak,” Timothy Friesen, another author of the study, said.

The new finding, according to scientists, allows for more precise studies of the magnitude of the acceleration of anti-atoms under the influence of Earth’s gravitational force.

Antimatter Reacts to Gravity in the Same Way as Ordinary Matter, Physicists Find

Isaac Schultz
Wed, September 27, 2023 



In the 95 years we’ve known about antimatter, physicists have not tested how the elusive inverse of ordinary matter is affected by gravity, the force that pulls masses to Earth and seems to affect all things in the classical realm.

Now, a group of physicists have. Members of the Antihydrogen Laser Physics Apparatus (ALPHA) collaboration at CERN directly observed antihydrogen—hydrogen’s antimatter foil—free-falling in a container. The observations confirm the weak equivalence principle set forth by Einstein in his general theory of relativity, which holds that all masses react the same way to gravity, regardless of their composition. The team’s research was published today in Nature.

“In modern physics, inertial mass is encoded in the standard model of particle physics, whereas gravitational mass is dealt with in Einstein’s general theory of relativity,” wrote Anna Soter, a physicist at ETH Zürich, in an accompanying News & Views article. “The assumed equivalence of inertial mass and gravitational mass is incorporated in the weak equivalence principle, which is the cornerstone of general relativity—but no proposal has yet succeeded in unifying the theories.”

Plans to test gravity’s force on antimatter were first made by 2018, as Gizmodo reported at the time, when the ALPHA collaboration built ALPHA-g, a magnetic trap for antihydrogen atoms. The antimatter particles are suspended and then dropped inside the trap, in a 21st-century equivalent to the story of Galileo Galilei dropping objects off the Leaning Tower of Pisa.

The antimatter particles are cooled in order to slow their movement, giving the physicists precious time to observe and measure them. In 2021, the ALPHA collaboration announced that they managed to cool antihydrogen to near-absolute zero. “Slowing down the motion of antiatoms allows us to perform more precise measurements on its properties. In daily life, you can imagine things moving fast are harder to see than things moving slowly,” Makoto Fujiwara, a particle physicist with Canada’s TRIUMF particle accelerator team, told Gizmodo at the time. “The same thing happens in quantum physics…. The more time you have to observe a certain property, the more precise your measurement.”

As the cooled antihydrogen escaped the magnetic trap, the particles entered a vertical vacuum chamber; if the particles came in contact with the sides of the chamber or its ends (i.e., regular matter) they were annihilated. The researchers fiddled with the strength of the magnetic field, but found that when the fields were balanced on either side of the chamber, about 80% of the antimatter particles annihilated towards the bottom of the trap. Which is to say, gravity got them there.

It’s a good thing that gravity influences matter the same way it does the ordinary stuff—if it didn’t, it would mean that physicists were missing something pretty fundamental to the standard model. It’s not yet clear if antimatter was affected by gravity in the exact same way as ordinary matter, but the very fact that it’s affected affirms both Einstein and the standard model.

But mysteries remain. The magnitude of the gravitational acceleration on the antihydrogen was not precisely measured, but set the foundations for such future experiments. That can be done with even colder atoms—and better understand the weak equivalence principle. And beyond—which is to say below—the masses of the smallest particles, there is the quantum realm, which seems to be beyond the influence of gravity, at least as we know it.

Put in perspective, it seems that this confirmation of something long suspected is just a baby step in physicists’ understanding of the forces of nature and particle physics. But the baby steps are the most important ones to take.

More: Antimatter Could Travel Through Our Galaxy With Ease, Physicists Say

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