Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have identified a potentially much more efficient way to achieve nuclear fusion, the process that powers the Sun. Their calculations suggest that changing the order in which plasma is heated and compressed could dramatically reduce the energy needed to reach ignition, a crucial milestone in the pursuit of practical fusion power.

For more than seven decades, scientists have relied on an equation called the Lawson criterion to determine whether plasma can remain sufficiently hot and dense for long enough to sustain fusion reactions without additional external heating. Developed in the 1950s, this equation establishes the conditions required for ignition, but it does not explain the most efficient way to achieve them.

Now, PPPL physicists Luis Delgado-Aparicio, Masayuki Ono, and Jonathan Menard have updated that decades-old framework. By incorporating four additional factors that influence the behavior of fusion plasma, they have developed a more comprehensive model for determining how fusion systems should heat and maintain their fuel.

To understand the significance of the discovery, it helps to know what plasma is. Often called the fourth state of matter, plasma is a gas so hot that its particles become electrically charged. When plasma reaches ignition, the energy released by fusion reactions produces enough heat to sustain the process without further external heating. Achieving this condition efficiently is one of the central challenges facing fusion energy researchers...

Attachment is the term psychologists use for the most significant relationships that hold people's lives together. But what makes an attachment relationship different from all others? According to the pioneering American–Canadian developmental psychologist Mary Ainsworth, it must meet the following six conditions.

The relationship must persist over time, and it must have been formed with a particular subject who cannot be replaced. The relationship must be emotionally significant, involve the desire to remain close to them and cause distress at involuntary separation. Finally, when threatened, the person must seek security and comfort in their relationship with that subject.

The first five conditions describe any lasting affectionate bond, such as a close friendship. Only the sixth turns it into an attachment bond specifically. Simply liking someone, feeling close to them or spending hours together isn't enough to create an attachment relationship.

Interestingly, though, nothing in these six conditions specifies a human on the other side.

This was already noticed long before the emergence of AI chatbots with the power to converse. Deities, pets and objects (ranging from children's blankets and stuffed animals to cherished household items and even phones and computers) have all been found to supply security and comfort when someone is feeling distressed.

Today, AI companion apps are commonly sold on the promise of lasting and close relationships. Many of their users describe feeling real grief when an app is updated or withdrawn. But do such experiences meet the narrow definition of attachment?

The honest answer is: We don't really know yet.

What the evidence suggests
Research on human–AI relationships has so far recorded users' feelings about chatbots, their frequency of use and their reactions to chatbot withdrawal. It hasn't tested these relationships comprehensively against the six conditions described above...

When you’re stressed, you lose some control. Stress hormones flood your bloodstream. Your heart rate and blood pressure go up. You breathe faster. These changes happen without thought. They’re run by what’s known as your sympathetic nervous system. And they kick in whether you’re facing true danger or just a big exam. But scientists are learning how to guide our nervous systems out of that fight-or-flight mode and into relaxation.

Some calming techniques come naturally. Maybe you’ve already used slow, deep breaths to recenter yourself. Now, though, there’s mounting data to support a range of zanier approaches. Ever tried humming, or tapping on your skin? What about dunking your face in cold water?

Explainer: How our body deals with stress

“Consciously, you can’t tell your heart to slow down,” explains Patricio Millar Vernetti. He’s a neurologist at NYU Langone Health in New York City. “But by doing these interventions, you have a little bit more control.”

On social media, these practices are often described as ways to “regulate” your nervous system. But it’s really about balancing two branches of your nervous system. That “sympathetic” branch is in charge of stress responses. It gets you ready for action, pumping blood to your brain and muscles. Its counterpart — the parasympathetic nervous system — calms things down.

Getting that parasympathetic nervous system to kick in can help calm us back to a resting state. It lowers stress hormone levels. It slows the heart and lowers blood pressure.

Being able to control this back-and-forth may yield big health benefits. Over time, an over-active stress response can contribute to a range of problems. These include high blood pressure, strain on the heart, inflammation and other issues.

These systems normally work without our giving them thought. But research is finding ways to turn on the parasympathetic nervous system when we feel it’s needed...

Long before modern astronomy, humans looked to the stars and were absolutely astounded by what they saw. Even by the most ancient reckoning, the night sky offered enough to inspire awe and wonder, make us feel insignificant, fire our imaginations, and foster hope and a sense of connection. Yet, for as long as humans have surveyed the heavens, they have seen no indication that life as we know it exists elsewhere - what has come to be known as the "Great Silence."

For many, the disparity between the assumed prevalence of life in the Universe and the lack of evidence for it raises a troubling incongruity often erroneously referred to as "Fermi's Paradox" (in truth, it was neither Fermi's nor a Paradox). It seems like a valid question when you consider the facts. Given the age, size, and density of the known Universe, shouldn't we have found unambiguous evidence of extraterrestrial life (and intelligence) by now?

Sixty years after the first Search for Extraterrestrial Intelligence (SETI) experiment (Project Ozma), scientists are still asking the question: "Are we alone in the Universe?" In addition to listening to the cosmos for radio signals and other signs of technological activity ("technosignatures"), efforts have been mounted to send messages to space for the purpose of making contact with an extraterrestrial intelligence (ETI).

This practice has come to be known as Messaging Extraterrestrial Intelligence (METI) to distinguish it from its more "passive" SETI cousin. Previously, we chronicled the history of SETI by examining some of its greatest milestones. Today, we will begin looking at the brief(-ish) history of METI and how it came to be...

The largest artificial intelligence (AI) firms increasingly understand that they are hostages of one another. If one firm pushes ahead recklessly, others may feel compelled to follow. If one deploys a dangerous model without adequate safeguards, others may see it as a green light to do the same.

The debate over AI has centered on what governments should do to regulate this frontier technology. That remains essential. But a more immediate question is emerging: Can the companies building these powerful systems take action independently before they lose credibility and suffer legal consequences?

That question no longer looks theoretical and is being recognized as an urgent challenge. We've already seen AI firms lose control of their models — for example, in Australia, a rogue AI hacked a government healthcare website. If we are not careful, it's only a matter of time before one of these incidents causes large-scale, real-world harm, like shutting down an electricity grid or municipal water system, or a mass misdiagnosis in a health system. If this trend continues, the entire industry could become tarnished.

But there is a blueprint for self-regulation in a risky business: the nuclear industry, which has built up layers of oversight, controls and self-scrutiny over decades.

Frontier AI may require something similar: private regulation among competitors that do not trust one another but have a mutual interest in preventing outcomes that could damage them all. This does not appeal to the better angels of human nature — it's self-preservation for the industry itself.

There is a historical precedent for this kind of arrangement. The nuclear sector did not become safe because every actor suddenly became benevolent. It became safer through a layered system of peer scrutiny, technical standards, information-sharing and external oversight. International organizations such as the International Atomic Energy Agency (IAEA), which was established in 1957, emerged to coordinate monitoring and verification, while national regulators and industry bodies gradually built professional norms around catastrophic risk.

The result was not perfect safety, as the Chernobyl disaster in 1986 clearly attests. But nuclear governance architecture is designed around the recognition that in high-risk technological systems, one actor's failure can become everyone's problem. This was seen following Chernobyl: global nuclear safety increased significantly after the disaster, with upgrades to reactor designs, improved training and international monitoring networks...

Is there a link between Earth's geomagnetic reversals and extinctions? Nobody has proven it, despite their efforts. But the idea just won't go away.

The Earth's magnetic poles haven't remained consistent over the planet's 4.5 billion year history. It's experienced multitudes of pole flips, or geomagnetic reversals, where its north and south poles swap positions.

Scientists rely on paleomagnetism to detect them. Paleomagnetism detects the orientiation of Earth's poles across geological time in lava and sediments. The orientation of magnetic minerals in lava and ancient sediments record the locations of the poles at the time they solidified or accumulated.

Scientists think reversals are triggered by changes in the heat that flows across Earth's core-mantle boundary, but finding a pattern in geomagnetic reversals is a daunting task. They seem to occur about once every 450,000 years; evidence shows 183 of them in the last 83 million years. The last one was about 780,000 years ago, so by that measure, we're overdue for the next one But the 450,000-year average is kind of a mathetmatical abstraction. There's no indication of a periodic cycle.

Determining when a reversal happened can be difficult, and determining how long the reversal took to complete is likewise challenging. Predicting one is next to impossible.

Lava and sediments present a tangled history that needs to be painstakingly untangled. Deciphering the history of these reversals is made more difficult because sometimes there are long periods of stability punctuated by shorter periods of rapid multiple reversals. To add to that, individual reversals are chaotic events.

"The Permian witnessed profound geomagnetic, environmental, and biotic upheavals, yet high-resolution paleomagnetic constraints across critical transitions remain sparse," the authors write. In this work, the authors present a magnetostratigraphic record from what's called the Fengshan section in South China that covers 3.75 million years. The record spans what's called the Guadalupian-Lopingian transition (end-Guadalupian extinction), which occurred from 262.5-258.75 Mya...

Antimatter is not known for being easy to get ahold of. That’s part of why these particles remain so cryptic. But recently, a team of physicists at Northwestern University managed to trap a single antimatter particle for months. Cooling it to temperatures near absolute zero, they could control its quantum states with great precision without even touching it. The experiment, published in Physical Review Letters, represents a breakthrough in our understanding of one of the great mysteries of physics.

In theory, antimatter should be everywhere. Mathematics predicts that every particle of matter has an equivalent antiparticle, a fact that scientists have verified experimentally. The universe should therefore contain similar amounts of both, but almost everything we observe is made up of ordinary matter, and we still don’t know why.

It is possible to produce antimatter particles in laboratories, but studying them is still incredibly difficult. When an antiparticle comes into contact with ordinary matter, the two annihilate each other and release energy. To prevent research facilities from exploding, scientists use vacuum chambers and electromagnetic fields that suspend the antiparticles in isolation. But this only partially solves the problem. Studying these particles, especially experimenting with their behavior on a quantum scale, remains challenging.

For this experiment, researchers at Northwestern trapped a positron, the antimatter counterpart of electrons. The team, led by Gerald Gabrielse, developed a device known as a single-positron quantum cyclotron, which used electric and magnetic fields to hold the positron in a vacuum at a temperature close to absolute zero. This means the antimatter particle was at its lowest energy state, allowing the researchers to induce controlled changes in its quantum behavior. Unlike other methods in particle physics, this approach didn’t destroy the particle. The researchers were therefore able to keep the single antiparticle trapped for months, allowing them to repeat measurements.

So what can taming antimatter particles actually teach us? Scientists know that matter and antimatter have very similar properties. For example, an electron and a positron have exactly the same mass, although their electric charges are opposite. However, questions still remain about exactly how similar these two forms of matter are and whether there are small differences that have gone unnoticed in experiments conducted to date...

‘He has a seriously creepy vibe. I’m not going anywhere with him.’, ‘This seems like phishing. I wouldn’t click that link.’, ‘Something about this deal feels off. Walk away.’ When people say such things, they are not typically drawing conclusions from a chain of reasoning. The person who avoids getting in the stranger’s car is not thinking: ‘He displayed these three behavioural cues and, therefore, he poses a risk.’ The email isn’t flagged by going through an explicit checklist. The deal doesn’t announce its flaws through a formal audit. In each case, something is simply presented as having a certain character: the man as creepy, the email as fraudulent, the deal as suspect. And yet, acting on these intuitions seems not merely excusable but entirely reasonable. If the man really does strike you as creepy, staying out of his car was probably the smart call – even if you can’t say why.

Despite this, ‘vibes’ and ‘intuitions’ are often dismissed both in daily life and in academic enquiry as irrational or merely heuristic devices. And while we cannot always trust such reactions, they are central, indeed indispensable, to our ability to rationally navigate the world. Philosophers, however, have done surprisingly little to illuminate the rational credentials of these ordinary kinds of intuitions. Instead, they have focused the bulk of their attention on a much more rarefied kind of intuition called rational intuition, which is taken to function primarily in the a priori disciplines of philosophy, logic and mathematics.

My objective is to explain why our everyday intuitive reactions can have such rational force. The key is to see that intuition works in much the same way as perception, in that both can directly present something to us as actual. Once we understand what gives perception this feature, we can see why intuitions might involve exercising the same basic kind of cognitive capacity...

Researchers at Delft University of Technology (the Netherlands) have succeeded in controlling the magnetism in the nucleus of a single atom with radio waves. This came as a surprise: until now, physicists believed that this nuclear spin could not be manipulated directly. The discovery could open up new possibilities for storing and reading quantum information. The research is published in the journal Nature Communications.

In metals such as iron and nickel, every atom is slightly magnetic. But inside the atom, different magnetic "compass needles," known in quantum mechanics as spins, are also at work. "By far the strongest magnetism comes from the electrons," says lead researcher Sander Otte. "But in some atoms, the nucleus also carries a spin. That spin is much weaker, but it is also much better shielded from the outside world."

Otte's group studies spins using a converted scanning tunneling microscope. This enables electrical signals to be directed with extreme precision at a single atom. In the past, the researchers mainly focused on the electron spin, which is the easiest to read out. The nuclear spin appeared only indirectly, through the so-called hyperfine interaction. This causes the spins of the nucleus and the electron to become slightly entangled.

Control against expectations
In their latest experiment, main author Hester Vennema and her colleagues sent two different signals to an atom simultaneously: one targeting the electron and one targeting the nucleus. This allowed them to study the influence of each signal independently. To their surprise, they found that they could flip the nuclear spin even when the two spins were largely disentangled.

That result came unexpectedly. "According to our simple understanding, this should not really happen," says Otte. "The nuclear spin should not be sensitive at all to the electrical signals from a scanning tunneling microscope." ...

The theory that comets delivered the molecular building blocks for life on Earth is a long-standing one, since comets are known to carry many of these molecules. However, a new study challenges this idea.

The researchers, led by the University of Cambridge, found the cometary delivery of these building blocks would be—at best—a 'one-off fluke,' and not the steady rain of prebiotic molecules that had been theorized.

Using computer modeling, the researchers determined that comets travel too fast and at too sharp an angle to Earth's atmosphere for the fragile organic molecules to survive: they would almost certainly vaporize on impact with the surface. However, the researchers also found that another planet in our system—Mars—could be a slightly more promising candidate for cometary delivery of prebiotic molecules, although this is still highly unlikely. The results are published in the journal Scientific Reports.

"Historically, scientists thought that comets were important for the origin of life on Earth, because they carried carbon- and nitrogen-bearing molecules, so these giant space snowballs were almost like a 'get out of jail free card' that brought all the molecules a planet would need to seed life," said lead author Dr. Richard Anslow from Cambridge's Institute of Astronomy. "It's kind of a romantic idea, but our results suggest it's highly unlikely."

Testing the planet-hopping comet theory
In 2023, Anslow and several of his co-authors on the current paper theorized that in systems where planets orbit closely together, comets might slow down by 'bouncing' from one planet to the next, delivering organic molecules as they went.

Building on the earlier study, Anslow and his colleagues investigated whether such a scenario might be possible in our own solar system. "We're learning more and more all the time about how our solar system and the Earth formed, and pulling this together with lots of different advances in modeling, which allowed us to investigate this idea that has been around for close to a century," he said.

However, the new study shows just how rare that scenario is. The researchers used recent advances in comet impact simulations, comet-atmosphere interactions and dynamic modeling of the origin and evolution of comets to conduct their study. Taken together, the researchers found that while the successful delivery of prebiotic molecules cannot be ruled out completely, it would be extremely unlikely...

Many of the world's leading happiness researchers say they consciously spend more time with loved ones after seeing the evidence, according to a new paper. "Happiness emerges from a symphony of factors, but if I had to pinpoint one secret to happiness, relationships with other people might be it," says Lara Aknin, a professor of social psychology at Simon Fraser University.

Earlier this year, Aknin took part in a Zoom call with 12 other international leaders in well-being science. On the agenda? What their collective 600 years of happiness research and their own lived experiences reveal about living a good life and the future of the field they helped to create. Their reflections were captured in a recent paper published in the Journal of Happiness Studies.

"Having relationships is one of the most reliable predictors of happiness that has emerged from a robust body of evidence spanning the social sciences," says Aknin, who coauthored the paper with Harvard University's Säde Stenlund and Kelsey O'Connor, a senior researcher at Luxembourg's National Institute of Statistics and Economic Studies.

"We know that having just one person you can count on is extremely consequential. Having more relationships and more communities that you feel a part of compounds that sense of well-being."

Researchers also talked about well-being as a journey, says Aknin. Generally happy people aren't constantly happy, nor is happiness reserved only for people with ideal lives, perfect circumstances or a natural sense of optimism. Instead, it can be developed through conscious choices, self-awareness and adaptation, even when life gets hard, she says.

Some of the leading models on happiness suggest that roughly 10% of one's happiness is attributable to one's life circumstances—things that are big and relatively difficult to change, like where you live, your age, your employment status or your relationship status. But as much as 40% of one's happiness is related to "volitional activities" or how you choose to spend your time...

As NASA and its partners prepare for longer human missions beyond Earth, University of Florida researchers are investigating a challenge that could affect astronauts' ability to grow fresh food in space: plant disease.

The university's MVP-Plant-02 investigation, launched to the International Space Station on Oct. 13, will examine how plants respond to a fungal plant pathogen in microgravity. The research will help scientists determine whether the space environment changes a plant's defenses against disease and could make infections more severe.

Led by UF/IFAS researchers Andrew C. Schuerger, Ph.D., Robert Ferl, Ph.D., and Anna-Lisa Paul, Ph.D., the investigation brings together expertise in plant pathology and plant physiology from across UF's Institute of Food and Agricultural Sciences. The science team members are combining decades of experience studying how phytopathogens develop on vegetable crops and how plants grow and respond to the space environment.

"As humanity begins to establish bases on the moon and Mars, crews will benefit from the production of fresh fruits and vegetables in habitats called bioregenerative life support systems," Schuerger said. "Wherever plants and humans go, plant pathogens are soon to follow."

Bioregenerative life support systems use plants and other biological processes to help provide food and regenerate essential resources, including oxygen and water. Such systems could reduce astronauts' dependence on supplies transported from Earth, but they will need to remain productive and healthy over extended missions.

Understanding how plant diseases develop in space is an important step toward making those systems reliable...

You may have heard that sharks are older than trees. And yes, sharks are truly ancient, with an evolutionary lineage dating back hundreds of millions of years.

But are they really older than trees? Experts told Live Science that the answer depends on what we classify as a shark.

"It's all in the fine print," John Maisey, the curator-in-charge emeritus of fossil fish at the American Museum of Natural History in New York, told Live Science. "The takeaway is that the shark lineage within the fishes generally does go back further than trees. But it really depends on how you define what we mean by shark."

The modern sharks we see today first emerged around 195 million years ago, during the Jurassic period. Fossils of ancient sharks from this time can be traced to living lineages, namely Hexanchiformes, an order of sharks identified by their six or seven gills and single dorsal fin.

This means that modern sharks, at least, are not older than trees. Experts generally agree that trees first evolved in the Middle Devonian epoch, around 380 million to 390 million years ago. "I think it's not very controversial, when we had the first trees," Cindy Looy, a paleobotanist at the University of California, Berkeley, told Live Science.

For instance, the first true tree in the evolutionary record is considered to be Archaeopteris, an extinct genus discovered in a 385 million-year-old fossil forest near Cairo, New York. Looking at these fossils, Archaeopteris has many characteristics of trees we have today, including a tall, woody trunk; leaves; and a deep root system. Other early trees — such as Eospermatopteris found in ancient forests near Gilboa, New York, and Calamophyton in southwest England  — also appeared in the fossil record 390 million and 393 million years ago, respectively.

But when we look at the extinct relatives of modern sharks, "that's where it gets a bit wobbly," Maisey said. There are fossils from the sister groups of modern sharks that can be traced back through the Permian period and into the Devonian period (around 359 million to 420 million years ago). The most abundant group are hybodonts, an extinct group of spiny fish that have a unique calcification pattern in their cartilage that is similar to that of modern sharks.

"It’s called tessellated calcified cartilage, and that's a very important hallmark of most of the shark-like fishes and their ancestors," said Maisey, who has studied a spiny fish fossil called Doliodus problematicus from the early Devonian. If this definition is used, these sharks first appeared around 400 million years ago, before trees emerged.

Sharks' rough skin can be traced even further back, with the dermal denticles — the tooth-like scales that roughen a shark's skin — first appearing in the fossil record around 450 million years ago.

These transition fossils, where fish were evolving into sharks and gaining shark-like traits, introduce a gray area in the definition of sharks. "When you get back into the ancient past, when you're not dealing with things that we have living examples to compare with anymore, then it becomes a bit more tricky [to figure out what they are]," Maisey said...

You finally started an online conversation with a stranger you find attractive, yet you don't really know what to say. They seem happy to talk, but you struggle to find the correct responses. You worry that their patience is growing thin. You pray for some guidance. Luckily, the solution could be just a few clicks away.

After all, you have the power of AI at your fingertips. Why not use it to come up with something fun and interesting to say?

Yet many of us might hesitate in this scenario. Researchers have already warned of "cognitive debt"—students can use AI to write excellent assignments, but then fail miserably in final exams because they remember nothing. No one would want to show up to a date unable to recall anything they had copied and pasted into an online conversation.

Flirting online, like many other emotionally loaded tasks such as writing an apology, a eulogy or a message of congratulations, reflects how you feel about the person. The philosopher Talbot Brewer wrote that a person's efforts to make sense of their emotions through articulating them can reveal what they value.

For example, suppose someone thought she didn't especially care about her work. But then she found herself feeling pride when she was promoted. Her emotion may reveal to her that she does in fact care about workplace success.

How your emotions reveal yourself to you
In our recent research, we contend that using AI to flirt—or for any other task where personal connection is valuable—risks bypassing those moments where emotions can reveal important self-knowledge.

Perhaps in flirting online, a person may not read what their date says carefully. Instead, they might quickly copy the text into ChatGPT and then equally quickly paste the response back into the chat.

Alternatively, perhaps an AI wingman is already integrated into the dating app, allowing people to simply click and send the suggested text. They don't pay attention to what the date says, maybe overlooking potential deal-breakers, things that might be odd or small stylistic details that would otherwise give them some pause.

By outsourcing this emotional task to ChatGPT, it's possible for a person to deprive themselves of the opportunity to really let the moments affect them. They could miss the chance to properly consider whether they would be happy to make compromises for their date. They may not even know whether they are genuinely excited about the date.

Instead of slowly articulating their feelings and, in so doing, working out what they value in a relationship, they are authorizing AI to say whatever might impress their date.

There's also the issue of privacy—the flirty exchanges could find their way into training data. And is the AI wingman even trustworthy? It could misrepresent the person using it—and the other party might feel they'd suffered a deception. Even before AI, researchers have questioned whether lying on dating platforms invalidates consent.

At the end of the day, it just feels a bit disrespectful. The output of AI has little to do with how someone feels about their date, but draws more from the training data. This data has nothing to do with the person or their date.

But maybe some people are less careless. Plenty of daters would make sure to scrutinize the AI output before sending it.

Yet humans have a tendency to overly trust AI. Another study found that when people regularly let AI produce their first draft, they tend to accept the output uncritically. The study also found that people can easily adopt the biases of large language models (LLMs), even if they know those biases exist...

We all know that black holes can collide. It has happened since black holes began to form, early in cosmic time. The result is always a clash that gives off gravitational waves and a giant bang. Since black holes have such strong gravity, it's almost impossible to imagine a way that any force could break one apart. Yet, that's the task that a group of scientists in Europe set for themselves.

In a study of possible mechanisms for black hole fragmentation, Francesco Sannino of the University of Naples Federico II in Italy and the Quantum Field Theory Center at the University of Southern Denmark, along with Giacomo Cacciapaglia (Laboratoire de Physique Théorique et Hautes Énergies) and Manuel Del Piano and Vania Vellucci, both from the Quantum Field Theory Center, conducted a series of calculations showing that under the right conditions, a black hole could split up into two black holes. It's an unusual possibility, to say the least, but the team has calculated what needs to happen if such an event were to occur.

The two pieces would have to stay apart, according to Sannino. "The two resulting black holes must also be able to separate rather than immediately fall back together. When we include this requirement, the window largely closes again, except possibly for black holes rotating close to their maximum possible rate," he said. If such a split-up could happen, the event horizon of the black hole would form a trouser-like shape as the split-up proceeded. Essentially, it would form two legs of a pair of pants, which is why the team called it a "pair-of-pants topology."

Could This Happen?
That's one possibility for what happens if/when a black hole splits into pieces. No one has seen such an event (yet), so it's still largely theoretical. There's one major impediment, however. That's called entropy, the measure of how many different microscopic ways a physical system can be arranged while still appearing the same from the outside. For example, a rock's shape can remain solid and static until some outside force changes it, such as heating. In the case of an ordinary, non-rotating black hole, breaking it into two pieces would reduce its entropy and make the process thermodynamically unlikely.

However, let's say we have a rotating black hole, spinning very rapidly. According to the team, such a system could break up into two pieces. However, they have to separate quickly, or risk falling back together. So, it turns out it could happen if both black holes have to keep rotating as fast as they possibly can (or close to it). But what would cause the split to occur? The answer lies in the rotation. It alters the relationship between black hole mass, its angular momentum as it spins, and entropy. It's possible that change could lead to the black hole fragmenting. If so, then the next steps are for the black hole "twins" to move apart and retain the momentum and speed of the original...

Lucid dreaming — in which the dreamer is aware that they are dreaming and can sometimes influence the dream's trajectory — is a skill that can be honed, a new study finds. And the researchers found that doing this is surprisingly easy, after training participants to do exactly that using virtual reality (VR) twice a week for just one month.

The study's results could have practical benefits, said Daniel Morris, a cognitive neuroscientist at Northwestern University who studies dreams and was not involved with the work. "Lucid dreaming can benefit people with nightmares by allowing them to transform their nightmares into positive dreams and feel greater agency in their dreams," Morris told Live Science in an email.

Before this study, published Sept. 28 in the journal Frontiers in Psychology, neuroscientists tried to induce lucid dreaming with various methods. These included meditation exercises and so-called reality checks, in which participants ask themselves while awake whether unusual phenomena they encounter — such as people wearing odd Halloween costumes — are real or if they're dreaming. The idea is that they will ask themselves the same question in their sleep during bizarre dreams.

However, "for most people, our day-to-day lives may not feel 'dream-like,'" Morris said, explaining why reality checks have had mixed results and don't reliably trigger lucid dreaming.

Since dream-like scenarios are rare in waking life, the neuroscientists behind the new study used VR simulations of bizarre situations to complement reality-check exercises...