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The existence of gigantic black holes in the very early universe challenges our assumptions of how black holes form and grow. New research suggests that these monsters may have found their origins in the earliest epochs of the Big Bang.

For years astronomers have been troubled by observations of fully grown supermassive black holes before the universe was even a billion years old. This is challenging because as far as we know the only way to make black holes is through the deaths of massive stars. And the only way for them to grow is either through mergers or the accumulation of material. Following these known mechanisms it’s extremely difficult to build the observed black holes, which have masses hundreds of millions of times that of the Sun, so quickly.

And so astronomers have been long attempting to find some other way to explain how these giant black holes arrive on the cosmic scene. In a new paper, a team of researchers point to an seemingly unlikely scenario: the first microseconds of the Big Bang.

In the 1970s Stephen Hawking hypothesized that the tumultuous epochs of the incredibly early universe would cause random fluctuations of matter to spontaneously collapse to form black holes. These primordial black holes might even persist to the present day, and astronomers have even gone so far as to propose that these black holes explain dark matter.

But observations have placed considerable constraints on the populations of primordial black holes. They simply can’t be a major constituent of the universe, otherwise we would have seen evidence for them by now.

But in the new paper the researchers point out that they don’t need to be common to form the seeds of supermassive black holes. They can be incredibly rare, making up less than 1% of all the mass in the universe. But if they are formed in the early universe, then slowly over time they can accrete new material and merge with each other, especially in the first few hundred million years as galaxies are first forming.

This scenario would mean that giant black holes would form not after the appearance of the first stars, but in parallel with them. Then by the time stars and galaxies appear the black holes are already fully grown.

The researchers were able to find a scenario that could explain the observed population of giant black holes in the young universe. However, this is only the first step in the research. The next is to fine-tune these models and incorporate them in more detailed simulations of the evolution of the early universe to see just how plausible this scenario is.

The post The Biggest Black Holes May Start From The Tiniest Seeds appeared first on Universe Today.

Humans (assuming you all experience roughly what I experience, which is a reasonable assumption) have a sense of self. This sense has several components – we feel as if we occupy our physical bodies, that our bodies are distinct entities separate from the rest of the universe, that we own our body parts, and that we have the agency to control our bodies. We can do stuff and affect the world around us. We also have a sense that we exist in time, that there is a continuity to our existence, that we existed yesterday and will likely exist tomorrow.

This may all seem too basic to bother pointing out, but it isn’t. These aspects of a sense of self also do not flow automatically from the fact of our own existence. There are circuits in the brain receiving input from sensory and cognitive information that generate these senses. We know this primarily from studying people in whom one or more of these circuits are disrupted, either temporarily or permanently. This is why people can have an “out of body” experience – disrupt those circuits which make us feel embodied. People can feel as if they do not own or control a body part (such as so-called alien hand syndrome). Or they can feel as if they own and control a body part that doesn’t exist. It’s possible for there to be a disconnect between physical reality and our subjective experience, because the subjective experience of self, of reality, and of time are constructed by our brains based upon sensory and other inputs.

Perhaps, however, there is another way to study the phenomenon of a sense of self. Rather than studying people who are missing one or more aspects of a sense of self, we can try to build up that sense, one component at a time, in robots. This is the subject of a paper by three researchers, a cognitive roboticist, a cognitive psychologist who works with robot-human interactions, and a psychiatrist. They explore how we can study the components of a sense of self in robots, and how we can use robots to do psychological research about human cognition and the self of self.

Obviously we are a long way away from having artificial intelligence (AI) that reproduces human-level general cognition. But by now it’s pretty clear that we do not need this in order to at least simulate aspects of human level cognition and beyond. One great example with reference to robotics is that we do not need human-level general AI to have a robot walk. Instead we can develop algorithms that can respond in real time to sensory information so that robots can maintain themselves upright, traverse terrain, and respond to perturbations. This actually mimics how the human brain works. You don’t have to think too much about walking. There are subcortical pathways that do all the hard-lifting for you – algorithms that utilize sensory input to maintain anti-gravity posture, walk, and react to perturbations. The system is largely subconscious, although you can consciously direct it. Similarly you don’t have to think about breathing. It’s automatic. But you can control your breathing if you want.

The idea with robots is not that we create a robot that has a full human-level sense of self, but that we start to build in specific components that are the building blocks of a sense of self. For example, robots could have sensors and algorithms that give them feedback that indicates they control their robotic body parts. As with the human brain, a circuit can compare the commands to move a body part with sensors that indicate how the body part actually moved. Similarly, when robots move there can be sensors feeding into algorithms that determine what the effect of that movement was on the outside world (a sense of agency).

This would not be enough to give the robot a subjective experience of self, just as your brainstem would not give you a sense of self without a functioning cortex. But we can start to build the subconscious components of self. We can then do experiments to see how, if at all, these components affect the behavior of the robot. Perhaps this will enable them to control their movements more precisely, or adapt to the environment more quickly and effectively.

I think this is a good pathway for developing robotic AI in any case. Our brains evolved from the bottom up, starting with simple algorithms to control basic functions. It makes sense that we should build robotic intelligence from the bottom up also. Then, as we develop more and more sophisticated AI, we can plug these subconscious algorithms into them.

The big question is – how much will plugging in a bunch of narrow AI / subconscious algorithms into each other contribute to AI sentience and self-awareness? Will (like V-ger or Skynet from science fiction) awareness spontaneously emerge from a complex-enough network of narrow AIs? Is that how vertebrate self-awareness evolved? Arguably, human consciousness is ultimately a bunch of subconscious networks all talking to each other in real time with wakeful consciousness emerging from this process. You can take components away, changing the resulting consciousness, but if you take too many of them away, then wakeful consciousness cannot be maintained.

The other question I have concerns the difference between AI running on a computer and AI in a robot. Does an AI have to be embodied to have human-like self-awareness? Is a Max Headroom type of AI with a completely virtual existence possible? Probably – if they had a virtual body and it was programmed to function like a physical body in the virtual world. But since we are developing robotics anyways, developing robotic AI that mimics human-like embodiment and sense of self makes sense. It evolved for a reason, and we should explore how to leverage that to advance robotics. While we use our understanding of neuroscience to help advance AI and robotics, we can also use AI and robotics to study neuroscience.

As the authors propose, we can use our attempts at building the components of self into robots to see how those components function and what effect they have.

The post Robots and a Sense of Self first appeared on NeuroLogica Blog.

More than 20 million people have joined Bluesky, a social network that gives you fine-grained control over what you see and who you interact with. I think it is the future of social media, says Chris Stokel-Walker

Perhaps the neck manipulation was a bit too aggressive.

The post A New DC Degree. What the World Needs Now. first appeared on Science-Based Medicine.

Four southern giant hornets have been identified in northern Spain, leading to concerns that the species could harm native insects if it becomes widespread

Several populations of Mexican tetra fish that live in darkness have independently evolved to need hardly any sleep, but the reason why is a mystery

This alleged sea serpent terrorized a New England fishing village for two years in the 19th century.

Most mathematicians have been reluctant to start working with artificial intelligence, but a new tool developed by researchers at Meta may change that

The 2024 China International Aviation and Aerospace Exhibition was held in Zhuhai last week – from November 12th to 17th, 2024. Since 1996, and with support from the Chinese aerospace industry, this biennial festival features actual products, trade talks, technological exchanges, and an air show. This year’s big highlight was China’s newly announced reusable space cargo shuttle, the Haolong (Chinese for “dragon”). According to chief designer Fang Yuanpeng, the spacecraft has entered the engineering phase and will be ready for space in the near future.

The Haolong shuttle is being developed by the Chengdu Aircraft Design and Research Institute, which has developed several Chinese fighter jets in the past. It has a large wingspan, measuring eight meters (26.25 ft) in width and about 10 meters (33 ft) long, with a high lift-to-drag ratio. From the image provided (above), the design is clearly inspired by the now-retired Space Shuttle and features the same type of payload bay with two bay doors. While the cargo shuttle has a comparable wingspan (8.7 m; 29 ft), it is significantly shorter than the Space Shuttle, which measured 56.1 m (184 ft) in length.

This makes the Haolong (in terms of size) more akin to the X-37B and China’s Shenlong spaceplane. Like these spaceplanes, the Haolong spacecraft will be autonomous and feature cutting-edge aviation technologies. The design was one of several concepts issued in response to a solicitation by the China Manned Space Agency (CMSA) for low-cost and commercial cargo spacecraft. These will provide logistical support for China’s Tiangong space station as it undergoes expansion in the coming years.

Artist’s impression of China’s reusable Shenlong spaceplane. Credit: China Aerospace Studies Institute

According to the state-owned news agency Xinhua, the winners of the solicitation were announced on October 29th. This included the CMSA’s Haolong shuttle and the Qingzhou spacecraft, an integrated cargo capsule submitted by the Innovation Academy for Microsatellites of the Chinese Academy of Sciences (IAMCAS). According to Lin Xiqiang, the deputy director of the CMSA, both companies won contracts for the flight verification phase of their proposals. According to Fang, the space shuttle Haolong will launch into orbit via a commercial carrier rocket, make atmospheric reentry, and land horizontally on a runway.

Once it reaches orbit, it will unfold its solar panels and open its docking shield. The shuttle’s rear will dock with Tiangong, where taikonauts can access the cargo bay and transfer the payload to the space station. According to Fang, “the Hoalong can receive maintenance similar to an aircraft after landing, so it can conduct another mission.” The spacecraft has already completed the design phase and is moving into engineering development. Fang indicated that this phase is well underway and will be followed by the cargo mission phase. “I believe that the public will see it soon,” he said.

Meanwhile, the Qingzhou cargo spacecraft has a cargo volume of up to 27 cubic meters, which is expected to provide logistics flexibility and significantly reduce transportation costs. According to Xinhua, Qingzhou also has an intelligent transportation system capable of supporting crewed and uncrewed in-orbit experiments. The cargo spacecraft is scheduled to be launched by the Lijian-2, a reusable rocket currently under development by CAS Space. This rocket is one of several reusable medium-lift launch vehicles China plans to debut in the coming years.

Lin also noted that “this strategic move will not only slash cargo transportation costs for the space station but also pave the way for new opportunities in the growth of the country’s commercial space industry.” According to market research, China’s commercial space industry is expected to reach a market value of 2.34 trillion yuan ($323.35 billion) by the end of 2024.

Further Reading: Global Times

The post China’s Proposed Cargo Shuttle, the Haolong, Has Entered Development appeared first on Universe Today.

In recent years, astronomers have developed techniques to measure the metal content of stars with extreme accuracy. With that capability, astronomers have examined sibling stars to see how their metallicity differs. Some of these co-natal stars have pronounced differences in their metallicity.

New research shows that stars engulfing rocky planets are responsible.

Co-natal stars are born in the same giant molecular cloud (GMC), though they’re not necessarily in binary relationships with each other. These stars are expected to have very similar metallicities, even though no GMC is totally homogenous and small differences are common in the stars that form together. But when the differences are pronounced, there must be some other explanation.

New research titled “Metal pollution in Sun-like stars from destruction of ultra-short-period planets” suggests that rocky planets are the source of these discrepancies. The authors are Christopher E. O’Connor and Dong Lai from Northwestern University and Cornell University, respectively. The research is on the pre-print server arxiv.org and has been submitted to the AAS journals.

“Detailed studies of chemical composition among co-natal stellar pairs—stars with a common origin—reveal unexpectedly large differential abundances among refractory elements,” the authors write. The authors refer to this as pollution after a similar thing that happens in white dwarfs. The source of this pollution is rocky planets, which are rich in metals.

Ultra-short-period (USP) exoplanets orbit their stars very closely and typically complete an orbit in only a few hours. They have similar compositions to Earth and are seldom more than two Earth radii. Their origins are not clear. They could have formed further out and then migrated closer to their star, or they could be the remains of much larger planets that lost their atmosphere due to stellar irradiation.

This artist’s rendering shows a star stripping away a planet’s atmosphere. Image Credits: NASA/GSFC

USP planets are not very common. Only about 0.5% of Sun-like stars have them. They’re very hot, so their surfaces are melted, and they’re tidally locked to their stars.

Though uncommon, they may form in greater numbers and then be consumed by their stars.

“Short-period exoplanets are potentially vulnerable to tidal disruption and engulfment by their host stars,” the authors write. Research shows that between 3 to 30% of co-natal, main-sequence, Sun-like (FGK) stars have engulfed rocky planets between 1 to 10 Earth masses.

There are many ways this can happen. “Many forms of violent dynamical evolution are possible in planetary systems, each potentially able to inject a planet into the star,” O’Connor and Lai write. However, evidence shows that, at most, about 2% of single FGK stars are polluted by all violent mechanisms combined.

Astronomers have proposed three main scenarios where stars can engulf USP planets.

One is called high-eccentricity (high-e) migration. In this scenario, a proto-USP becomes very close to its star and has a high eccentricity. Because of its proximity to the star and its gravitational draw, the planet rapidly loses its eccentricity and adopts a circular orbit.

Another is low-eccentricity (low-e) migration. In this scenario, the USP migrates towards its star more slowly. Low-e migration occurs in compact systems with three or more planets, which helps moderate its eccentricity.

The well-known TRAPPIST-1 system is an example of a compact, multi-planet system. Image Credit: By NASA/JPL-Caltech – Catalo, Public Domain

The third scenario is obliquity-driven migration. In this scenario, a companion planet to the USP excites the USP’s obliquity and captures it in a secular spin-orbit resonance. The USP rapidly migrates towards its star, but the migration ends when the USP escapes the resonance.

The authors developed a model to predict the number of USPs that form and the time it takes for them to become engulfed. Their model can reproduce both the low observed occurrence of USPs around Sun-like stars and their polluted metallicity. Their results favour the low-e migration scenario where USPs are part of compact, multi-planet systems.

“We find that USP engulfment is a natural consequence of the low-e migration scenario. A connection between USPs and engulfed rocky planets in Sun-like stars, therefore, seems plausible,” they write.

Their results show that USPs become engulfed between 0.1 and 1 gigayear after they form. If this engulfment is the main source of pollution in Sun-like stars, the authors say there’s a correlation between pollution and compact, multi-planet systems. “Some 5–10% of polluted stars should have a transiting planet of mass ? 5M? and period ~ 4–12 days,” they explain. They also predict the reverse: there should be an anti-correlation between USP occurrence and pollution.

The authors point out some caveats regarding their results.

The signatures of metallicity pollution can fade over time. The metals can settle into the star, making the signal disappear. Depending on how effective that is, it could mean our understanding of how many stars are polluted is inaccurate. It could mean more than 30% of Sun-like stars are polluted.

When a star eats a planet, it changes the star’s metallicity, which astronomers call pollution. But the signal from the pollution can fade as the metals sink into the star. Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick/M. Zamani

The second caveat is that more violent mechanisms could inject planets into their stars. Planet-planet scattering could drive planets into engulfment, especially rocky Super-Earths. However, the authors explain that “We find only ~ 1% of stars can be polluted through the violent destruction of super-Earths, despite their ubiquity as exoplanets.”

Their final caveat concerns Hot Jupiters (HJs). These gas-giant planets orbit very closely to their stars. Astronomers believe that HJs are destroyed by engulfment during their stars’ main sequence lifetime. HJs also have a similar occurrence rate as USPs around Sun-like stars. It’s a fair question to ask if they contribute to the observed metallicity pollution.

This illustration shows a Jupiter-mass exoplanet getting perilously close to its star. If they become engulfed, they may produce a different signature on the star than a rocky planet does. Image Credit: C. Carreau / ESA.

The authors say it’s possible that high-eccentricity migration can drive HJs into stellar engulfment. However, they also point out that there’s good reason to doubt that. “Again, an engulfed HJ may not produce a similar chemical signature to a rocky planet: the masses and bulk metallicities of HJs vary
widely,” they write. All of the hydrogen and helium in HJs could also dilute the extra metals. Additionally, tidal disruption of HJs may not lead directly to engulfment. It’s possible that mass transfer could reduce the HJ down to a super-Earth remnant made of the original core and a residual atmosphere.

According to O’Connor and Lai, more study is needed before we can understand how HJs might contribute to stellar pollution.

Their results also show that a main sequence star can only form one USP during its main sequence, so only one can be engulfed. In a compact system, only the innermost planet can suffer enough tidal decay to become a USP.

In their conclusion, the authors write that stars hosting USPs should have ages and kinematics similar to Milky Way field stars and should rarely show signs of previous planet engulfment. They also conclude that polluted FGK stars should host compact multi-planet systems.

The post Up to a Third of Stars Ate Some of their Planets appeared first on Universe Today.

Researchers have introduced a technique for compressing a large language model's reams of data, which could increase privacy, save energy and lower costs. The new algorithm works by trimming redundancies and reducing the precision of an LLM's layers of information. This type of leaner LLM could be stored and accessed locally on a device like a phone or laptop and could provide performance nearly as accurate and nuanced as an uncompressed version.

Researchers have introduced a technique for compressing a large language model's reams of data, which could increase privacy, save energy and lower costs. The new algorithm works by trimming redundancies and reducing the precision of an LLM's layers of information. This type of leaner LLM could be stored and accessed locally on a device like a phone or laptop and could provide performance nearly as accurate and nuanced as an uncompressed version.

Using zero liquid discharge to increase water recovery from desalination is an emerging method to combat water scarcity, but is expensive, energy-intensive and comes with environmental risks. Researchers have optimized zero liquid discharge technologies for cost, energy consumption and land use.

A supercomputer simulation of iron and carbon atoms in Earth’s inner core may explain how a molten ball at the centre of our planet froze solid

The weird thermodynamics found in time crystals could be harnessed to store energy in a quantum battery-like device

Changes to the structure of DNA within fat cells may be why it is often so hard to keep weight off after you have lost it

Surfaces play a key role in numerous chemical reactions, including catalysis and corrosion. Understanding the atomic structure of the surface of a functional material is essential for both engineers and chemists. Researchers used atomic-resolution secondary electron (SE) imaging to capture the atomic structure of the very top layer of materials to better understand the differences from its lower layers.

Researchers have used machine learning and supercomputer simulations to investigate how tiny gold nanoparticles bind to blood proteins. The studies discovered that favorable nanoparticle-protein interactions can be predicted from machine learning models that are trained from atom-scale molecular dynamics simulations. The new methodology opens ways to simulate efficacy of gold nanoparticles as targeted drug delivery systems in precision nanomedicine.

Researchers have used machine learning and supercomputer simulations to investigate how tiny gold nanoparticles bind to blood proteins. The studies discovered that favorable nanoparticle-protein interactions can be predicted from machine learning models that are trained from atom-scale molecular dynamics simulations. The new methodology opens ways to simulate efficacy of gold nanoparticles as targeted drug delivery systems in precision nanomedicine.

Alongside carbon dioxide, methane is a key driver of global warming. To detect and monitor the climate pollutants in the atmosphere precisely, scientists have developed an advanced laser technology. A high-power ytterbium thin-disk laser drives an optical parametric oscillator (OPO) to generate high-power, stable pulses in the short-wave infrared (SWIR) spectral range. This allows researchers to detect and analyze a wide variety of atmospheric compounds. This novel method can play a crucial role in tracking greenhouse gas cycles and the effects of climate change.