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How Big Could a Space Habitat Get?

How big could space habitats really get? From O’Neill cylinders to Ringworlds and Topopolises, we explore the true limits of megastructure scale.

Get Nebula using my link for 50% off an annual subscription: https://go.nebula.tv/isaacarthur.
Watch my exclusive video Chronoengineering: https://nebula.tv/videos/isaacarthur–… Join this channel to get access to perks: / @isaacarthursfia 🛒 SFIA Merchandise: https://isaac-arthur-shop.fourthwall… 🌐 Visit our Website: http://www.isaacarthur.net ❤️ Support us on Patreon: / isaacarthur ⭐ Support us on Subscribestar: https://www.subscribestar.com/isaac-a… 👥 Facebook Group: / 1,583,992,725,237,264 📣 Reddit Community: / isaacarthur 🐦 Follow on Twitter / X: / isaac_a_arthur 💬 SFIA Discord Server: / discord Credits: How Big Could a Space Habitat Get? Written, Produced & Narrated by: Isaac Arthur Editor: Tim Liusko Graphics from Fishy Tree, Jarred Eagley, Jeremy Jozwik, J. Dixon, Ken York, Udo Schroeter Music Courtesy of Chris Zabriskie & Stellardrone Select imagery/video supplied by Getty Images Music by Epidemic Sound: http://nebula.tv/epidemic & Stellardrone Chapters 0:00 Intro 2:03 Basics of Habitat Scaling 9:30 Cylinder & Ring Habitats — Linear and Radial Extremes 11:00 Banks Orbitals 12:42 Ringworlds 16:24 Chrono-Engineering 17:24 The Topopolis 21:03 Planet-Wrapping Habitats 22:55 Matrioshka Shellworlds 26:17Alternative & Exotic Designs.

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You can turn off yourself #shorts @lexfridman

“Joscha Bach Bits” features short videos of Joscha Bach’s ideas, opinions, and perspectives on various topics, edited from interviews.

#JoschaBachBits #Philosophy #CognitiveScience #ComputerScience #ArtificialIntelligence #shorts.

This video is edited from the “Lex Fridman” channel:
https://www.youtube.com/c/lexfridman.

Watch the full interview here:
https://www.youtube.com/watch?v=P-2P3MSZrBM

“Joscha Bach Bits” is not an official channel.
One time donations: https://ko-fi.com/joschabachbits.
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Scientists identify key brain mechanism behind ayahuasca’s ability to reduce PTSD symptoms

A study in European Neuropsychopharmacology finds that ayahuasca helps rats learn that a previously dangerous environment is safe. This effect appears to rely on BDNF signaling within the infralimbic cortex, suggesting a potential biological pathway for treating trauma.

Scientists show how to narrow the hunt for merging giant black holes

A new detection framework explains how astronomers can isolate extremely slow gravitational wave signals.

By combining subtle distortions in spacetime with observations of unusually bright galactic centers, the study authors have demonstrated a practical method for identifying likely locations of merging supermassive black holes.

Pulsar timing hints at a nearby dark matter ‘sub-halo’

A group of US astronomers may have uncovered the first evidence for a dark matter sub-halo lurking just beyond our stellar neighborhood. Reporting their findings in Physical Review Letters, a team led by Sukanya Chakrabarti at the University of Alabama in Huntsville suggests that an unseen clump of dark matter could be subtly tugging on nearby pulsars. If confirmed, the result could shed new light on the elusive nature of dark matter and how it is distributed throughout our galaxy.

Despite never having been observed directly, astronomers estimate that dark matter makes up around 85% of the total mass of the universe. According to the best available cosmological models, this invisible material forms vast, diffuse “halos” that completely envelop the flat disks of galaxies like the Milky Way. These halos, in turn, should be populated by numerous smaller structures known as dark matter sub-halos.

If theoretical predictions are correct, such sub-halos should be abundant throughout the galaxy. Yet even with masses potentially exceeding tens of millions of times that of the sun, their limited gravitational influence on visible matter has so far made them extraordinarily difficult to detect.

Modifiable Risk Factors Suggest Potential for Improving Cancer Prevention

Approximately 4 of 10 cancer cases in 2022 may have been averted by avoiding exposure to key preventable risk factors, according to findings from a global analysis study published in Nature Medicine.1

Of 18.7 million cancer cases recorded in 2022, approximately 7.1 million (37.8%) were linked to modifiable risk factors. Cancer cases due to modifiable risk factors were reported in 29.7% of women with cancer compared with 45.4% of men. The highest cancer burden for female populations was observed in sub-Saharan Africa, where 38.2% of cases were linked to modifiable risk factors; male populations experienced the highest burden in East Asia, where 57.2% of cases were associated with such risk factors.

Across the world, new cancer cases in women were typically linked to infections (11.5%), smoking (6.3%), and high body mass index (BMI; 3.4%). Among men, the most common risk factors associated with cancer cases included smoking (23.1%), infections (9.1%), and alcohol consumption (4.6%).

Hair-thin silica fiber microphone detects ultrasound from 40 kHz to 1.6 MHz

Researchers have fabricated a hair-thin microphone made entirely of silica fiber that can detect a large range of ultrasound frequencies beyond the reach of the human ear. Able to withstand temperatures up to 1,000°C, the device could eventually be used inside high-voltage transformers to detect early signs of failure before power outages occur.

“Conventional electronic sensors often fail under thermal stress or suffer from severe signal interference,” said Xiaobei Zhang, a member of the research team from Shanghai University. “Our all-fiber microphone can survive in hazardous environments and is completely immune to electromagnetic interference while remaining sensitive enough to hear the subtle early warning signals of equipment failure.”

In an article published in Optics Express, the researchers describe their new microphone, which is sensitive to frequencies from 40 kHz to 1.6 MHz. Unlike traditional microphones that rely on bulky housing, the new microphone is entirely integrated within a fiber just 125 microns in diameter.

Light-based Ising computer runs at room temperature and stays stable for hours

A team of researchers at Queen’s University has developed a powerful new kind of computing machine that uses light to take on complex problems such as protein folding (for drug discovery) and number partitioning (for cryptography). Built from off-the-shelf components, it also operates at room temperature and remains remarkably stable while performing billions of operations per second. The research was published in Nature.

The breakthrough shows that it is possible to build a practical and scalable machine that can tackle extremely difficult problems.

The project, led by Bhavin Shastri, Canada Research Chair in Neuromorphic Photonic Computing and professor in the Department of Physics, Engineering Physics, and Astronomy, with a team of his graduate students including Nayem Al Kayed and Hugh Morison, uses commercially available lasers, fiber optics, and modulators—the same technology that powers today’s internet infrastructure. The team partnered with McGill University researcher David Plant and his graduate student Charles St-Arnault.

Supermassive black hole at heart of the Milky Way is approaching the cosmic speed limit

“Discovering that Sgr A is rotating at its maximum speed has far-reaching implications for our understanding of black hole formation and the astrophysical processes associated with these fascinating cosmic objects,” Xavier Calmet, a theoretical physicist at the University of Sussex who was not involved in the research, told Live Science in an email.

Related: Black holes: Everything you need to know

A black hole’s spin is different from those of other cosmic objects. Whereas planets, stars and asteroids are solid bodies with physical surfaces, black holes are actually regions of space-time bounded by an outer nonphysical surface called the event horizon, beyond which no light can escape.

Novel electronic structures and magnetic properties in twisted two-dimensional graphene/Janus 2H–VSeTe heterostructures

In the experiments, the stacking of other layers can be stacked layer by layer by using the method of direct growth, such as chemical bath deposition [17] and chemical vapor deposition [18]. To date, many vertical stacking structures based on graphene have been explored, such as graphene/Janus 2H-VSeTe [19], graphene/Janus 2H-VSeX (X = S, Te) [20], graphene/WTe2, etc. Scientists have done a lot of research on heterostructures, from the aspects of spin-orbital coupling [21], strains, applied electric field and Lattice mismatch, etc.

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