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Columbia study finds new way to extract energy from black holes
A new study explains how a chaotic region just outside a black hole's event horizon might provide a virtually endless supply of energy.
- In 1969, the physicist Roger Penrose first proposed a way in which it might be possible to extract energy from a black hole.
- A new study builds upon similar ideas to describe how chaotic magnetic activity in the ergosphere of a black hole may produce vast amounts of energy, which could potentially be harvested.
- The findings suggest that, in the very distant future, it may be possible for a civilization to survive by harnessing the energy of a black hole rather than a star.
Like the Sun, the stars scattered throughout our Milky Way and beyond produce unfathomable amounts of energy. But so, too, do the objects we can't see: black holes.
For decades, scientists have wondered whether it's possible to extract energy from black holes, which are the mysterious regions of spacetime that form when stars collapse into themselves. Siphoning energy from these areas of ultra-condensed matter could provide a virtually endless power supply for deep-space civilizations, if physically and practically possible.
While undoubtedly the stuff of science fiction, the idea is far from new.
In 1969, the physicist and Nobel Laureate Roger Penrose proposed it might be possible to extract energy from a rotating black hole. He thought this could occur in a black hole's ergosphere.
The ergosphere is a region just outside a black hole's event horizon, the boundary of a black hole beyond which nothing, not even light, can escape. But light and matter just outside the event horizon, in the ergosphere, would also be affected by the immense gravity of the black hole. Objects in this zone would spin in the same direction as the black hole at incredibly fast speeds, similar to objects floating around the center of a whirlpool.
The Penrose process states, in simple terms, that an object could enter the ergosphere and break into two pieces. One piece would head toward the event horizon, swallowed by the black hole. But if the other piece managed to escape the ergosphere, it could emerge with more energy than it entered with.
The movie "Interstellar" provides an example of the Penrose process. Facing a fuel shortage on a deep-space mission, the crew makes a last-ditch effort to return home by entering the ergosphere of a blackhole, ditching part of their spacecraft, and "slingshotting" away from the black hole with vast amounts of energy.
In a recent study published in the American Physical Society's Physical Review D, physicists Luca Comisso and Felipe A. Asenjo used similar ideas to describe another way energy could be extracted from a black hole. The idea centers on the magnetic fields of black holes.
"Black holes are commonly surrounded by a hot 'soup' of plasma particles that carry a magnetic field," Comisso, a research scientist at Columbia University and lead study author, told Columbia News.
In the ergosphere of a rotating black hole, magnetic field lines are constantly breaking and reconnecting at fast speeds. The researchers theorized that when these lines reconnect, plasma particles shoot out in two different directions. One flow of particles shoots off against the direction of the spinning black hole, eventually getting "swallowed" by the black hole. But the other flow shoots in the same direction as the spin, potentially gaining enough velocity to escape the black hole's gravitational pull.
The researchers proposed that this occurs because the breaking and reconnecting of magnetic field lines can generate negative-energy particles. If the negative-energy particles get "swallowed" by the black hole, the positive particles would theoretically be exponentially accelerated.
"Our theory shows that when magnetic field lines disconnect and reconnect, in just the right way, they can accelerate plasma particles to negative energies and large amounts of black hole energy can be extracted," Comisso said. "It is like a person could lose weight by eating candy with negative calories."
Event Horizon Telescope Collaboration
While there might not be immediate applications for the theory, it could help scientists better understand and observe black holes. On an abstract level, the findings may expand the limits of what scientists imagine is possible in deep space.
"Thousands or millions of years from now, humanity might be able to survive around a black hole without harnessing energy from stars," Comisso said. "It is essentially a technological problem. If we look at the physics, there is nothing that prevents it."
- Did a lab-made black hole just prove Hawking radiation? - Big Think ›
- Study: spinning black holes power jets with magnetic reconnection ... ›
- Scientists detect radio echoes of a black hole feeding on a star - Big ... ›
The father of all giant sea bugs was recently discovered off the coast of Java.
- A new species of isopod with a resemblance to a certain Sith lord was just discovered.
- It is the first known giant isopod from the Indian Ocean.
- The finding extends the list of giant isopods even further.
Humanity knows surprisingly little about the ocean depths. An often-repeated bit of evidence for this is the fact that humanity has done a better job mapping the surface of Mars than the bottom of the sea. The creatures we find lurking in the watery abyss often surprise even the most dedicated researchers with their unique features and bizarre behavior.
A recent expedition off the coast of Java discovered a new isopod species remarkable for its size and resemblance to Darth Vader.
The ocean depths are home to many creatures that some consider to be unnatural.
According to LiveScience, the Bathynomus genus is sometimes referred to as "Darth Vader of the Seas" because the crustaceans are shaped like the character's menacing helmet. Deemed Bathynomus raksasa ("raksasa" meaning "giant" in Indonesian), this cockroach-like creature can grow to over 30 cm (12 inches). It is one of several known species of giant ocean-going isopod. Like the other members of its order, it has compound eyes, seven body segments, two pairs of antennae, and four sets of jaws.
The incredible size of this species is likely a result of deep-sea gigantism. This is the tendency for creatures that inhabit deeper parts of the ocean to be much larger than closely related species that live in shallower waters. B. raksasa appears to make its home between 950 and 1,260 meters (3,117 and 4,134 ft) below sea level.
Perhaps fittingly for a creature so creepy looking, that is the lower sections of what is commonly called The Twilight Zone, named for the lack of light available at such depths.
It isn't the only giant isopod, far from it. Other species of ocean-going isopod can get up to 50 cm long (20 inches) and also look like they came out of a nightmare. These are the unusual ones, though. Most of the time, isopods stay at much more reasonable sizes.
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During an expedition, there are some animals which you find unexpectedly, while there are others that you hope to find. One of the animal that we hoped to find was a deep sea cockroach affectionately known as Darth Vader Isopod. The staff on our expedition team could not contain their excitement when they finally saw one, holding it triumphantly in the air! #SJADES2018
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What benefit does this find have for science? And is it as evil as it looks?
The discovery of a new species is always a cause for celebration in zoology. That this is the discovery of an animal that inhabits the deeps of the sea, one of the least explored areas humans can get to, is the icing on the cake.
Helen Wong of the National University of Singapore, who co-authored the species' description, explained the importance of the discovery:
"The identification of this new species is an indication of just how little we know about the oceans. There is certainly more for us to explore in terms of biodiversity in the deep sea of our region."
The animal's visual similarity to Darth Vader is a result of its compound eyes and the curious shape of its head. However, given the location of its discovery, the bottom of the remote seas, it may be associated with all manner of horrifically evil Elder Things and Great Old Ones.
New study analyzes gravitational waves to confirm the late Stephen Hawking's black hole area theorem.
- A new paper confirms Stephen Hawking's black hole area theorem.
- The researchers used gravitational wave data to prove the theorem.
- The data came from Caltech and MIT's Advanced Laser Interferometer Gravitational-Wave Observatory.
The late Stephen Hawking's black hole area theorem is correct, a new study shows. Scientists used gravitational waves to prove the famous British physicist's idea, which may lead to uncovering more underlying laws of the universe.
The theorem, elaborated by Hawking in 1971, uses Einstein's theory of general relativity as a springboard to conclude that it is not possible for the surface area of a black hole to become smaller over time. The theorem parallels the second law of thermodynamics that says the entropy (disorder) of a closed system can't decrease over time. Since the entropy of a black hole is proportional to its surface area, both must continue to increase.
As a black hole gobbles up more matter, its mass and surface area grow. But as it grows, it also spins faster, which decreases its surface area. Hawking's theorem maintains that the increase in surface area that comes from the added mass would always be larger than the decrease in surface area because of the added spin.
Will Farr, one of the co-authors of the study that was published in Physical Review Letters, said their finding demonstrates that "black hole areas are something fundamental and important." His colleague Maximiliano Isi agreed in an interview with Live Science: "Black holes have an entropy, and it's proportional to their area. It's not just a funny coincidence, it's a deep fact about the world that they reveal."
What are gravitational waves?
Gravitational waves are "ripples" in spacetime, predicted by Albert Einstein in 1916, that are created by very violent processes happening in space. Einstein showed that very massive, accelerating space objects like neutron stars or black holes that orbit each other could cause disturbances in spacetime. Like the ripples produced by tossing a rock into a lake, they would bring about "waves" of spacetime that would spread in all directions.
As LIGO shared, "These cosmic ripples would travel at the speed of light, carrying with them information about their origins, as well as clues to the nature of gravity itself."
The gravitational waves discovered by LIGO's 3,000-kilometer-long laser beam, which can detect the smallest distortions in spacetime, were generated 1.3 billion years ago by two giant black holes that were quickly spiraling toward each other.
What Stephen Hawking would have discovered if he lived longer | NASA's Michelle Thaller | Big Think www.youtube.com
Confirming Hawking's black hole area theorem
The researchers separated the signal into two parts, depending on whether it was from before or after the black holes merged. This allowed them to figure out the mass and spin of the original black holes as well as the mass and spin of the merged black hole. With this information, they calculated the surface areas of the black holes before and after the merger.
"As they spin around each other faster and faster, the gravitational waves increase in amplitude more and more until they eventually plunge into each other — making this big burst of waves," Isi elaborated. "What you're left with is a new black hole that's in this excited state, which you can then study by analyzing how it's vibrating. It's like if you ping a bell, the specific pitches and durations it rings with will tell you the structure of that bell, and also what it's made out of."
The surface area of the resulting black holes was larger than the combined area of the original black holes. This conformed to Hawking's area law.
As a form of civil disobedience, hacking can help make the world a better place.
- Hackers' motivations range from altruistic to nihilistic.
- Altruistic hackers expose injustices, while nihilistic ones make society more dangerous.
- The line between ethical and unethical hacking is not always clear.
The following is an excerpt from Coding Democracy by Maureen Webb. Reprinted with Permission from The MIT PRESS. Copyright 2020.
As people begin to hack more concertedly at the structures of the status quo, the reactions of those who benefit from things as they are will become more fierce and more punitive, at least until the "hackers" succeed in shifting the relevant power relationships. We know this from the history of social movements. At the dawning of the digital age, farmers who hack tractors will be ruthlessly punished.
Somewhere on the continuum of altruism and transgression is the kind of hacking that might lead the world toward more accountable government and informed citizenries.
Of course, it must be acknowledged that hackers are engaged in a whole range of acts, from the altruistic to the plainly nihilistic and dangerous. On the altruistic side of the continuum, they are creating free software (GNU/Linux and other software under GPL licenses), Creative Commons (Creative Commons licensing), and Open Access (designing digital interfaces to make public records and publicly funded research accessible). They are hacking surveillance and monopoly power (creating privacy tools, alternative services, cooperative platforms, and a new decentralized internet) and electoral politics and decision making (Cinque Stelle, En Comú, Ethelo, Liquid Democracy, and PartidoX). They have engaged in stunts to expose the technical flaws in voting, communications, and security systems widely used by, or imposed on, the public (by playing chess with Germany's election voting machines, hacking the German Bildschirmtext system, and stealing ministers' biometric identifiers). They have punished shady contractors like HackingTeam, HBGary, and Stratfor, spilling their corporate dealings and personal information across the internet. They have exposed the corruption of oligarchs, politicians, and hegemons (through the Panama Papers, WikiLeaks, and Xnet).
More notoriously, they have coordinated distributed denial of service (DDoS) attacks to retaliate against corporate and government conduct (such as the Anonymous DDoS that protested PayPal's boycott of WikiLeaks; the ingenious use of the Internet of Things to DDoS Amazon; and the shutdown of US and Canadian government IT systems). They have hacked into databases (Manning and Snowden), leaked state secrets (Manning, Snowden, and WikiLeaks), and, in doing so, betrayed their own governments (Manning betrayed US war secrets, and Snowden betrayed US security secrets). They have interfered with elections (such as the hack and leak of the Democratic National Committee in the middle of the 2016 US election) and sown disinformation (the Russian hacking of US social media). They have interfered with property rights in order to assert user ownership, self-determination, and free software's four freedoms (farmers have hacked DRM code to repair their tractors, and Geohot unlocked the iPhone and hacked the Samsung phone to allow users administrator-level access to their devices) and to assert open access to publicly funded research. They have created black markets to evade state justice systems (such as Silk Road on the dark web) and cryptocurrencies that could undermine state-regulated monetary systems. They have meddled in geopolitics as free agents (Anonymous and the Arab Spring, and Julian Assange and his conduct with the Trump campaign). They have mucked around in and could potentially impair or shut down critical infrastructure. (The notorious "WANK worm" attack on NASA is an early, notorious, example, but hackers could potentially target banking systems, stock exchanges, electrical grids, telecommunications systems, air traffic control, chemical plants, nuclear plants, and even military "doomsday machines.")
It is impossible to calculate where these acts nudge us as a species. Some uses of hacking — such as the malicious, nihilistic hacking that harms critical infrastructure and threatens lives, and the hacking in cyberwarfare that injures the critical interests of other countries and undermines their democratic processes — are abhorrent and cannot be defended. The unfolding digital era looks very grim when one considers the threat this kind of hacking poses to peace and democracy combined with the dystopian direction states and corporations are going with digital tech.
But somewhere on the continuum of altruism and transgression is the kind of hacking that might lead the world toward more accountable government and informed citizenries, less corrupt and unfair economic systems, wiser public uses of digital tech, more self-determination for the ordinary user, fairer commercial contracts, better conditions for innovation and creativity, more decentralized and robust infrastructure systems, and an abolition of doomsday machines. In short, some hacking might move us toward a digital world in which there are more rather than fewer democratic, humanist outcomes.
It is not clear where the line between "good" and "bad" hacking should be drawn or how to regulate it wisely in every instance. Citizens should inform themselves and begin to consider this line-drawing seriously, however, since we will be grappling intensely with it for the next century or more. My personal view is that digital tech should not be used for everything. I think we should go back to simpler ways of running electrical grids and elections, for example. Systems are more resilient when they are not wholly digital and when they are smaller, more local, and modular. Consumers should have analogue options for things like fridges and cars, and design priorities for household goods should be durability and clean energy use, not interconnectedness.
In setting legal standards, prohibiting something and enforcing the prohibition are two different things. Sometimes a desired social norm can be struck by prohibiting a thing and not enforcing it strenuously. And the law can also recognize the constructive role that civil disobedience plays in the evolution of social norms, through prosecutorial discretion and judicial discretion in sentencing.
Wau Holland told the young hackers at the Paradiso that the Chaos Computer Club was "not just a bunch of techno freaks: we've been thinking about the social consequences of technology from the very beginning." Societies themselves, however, are generally just beginning to grapple with the social consequences of digital technology and with how to characterize the various acts performed by hackers, morally and legally. Each act raises a set of complex questions. Societies' responses will be part of the dialectic that determines where we end up. Should these various hacker acts be treated as incidents of public service, free speech, free association, legitimate protest, civil disobedience, and harmless pranksterism? Or should they be treated as trespass, tortious interference, intellectual property infringement, theft, fraud, conspiracy, extortion, espionage, terrorism, and treason? I invite you to think about this as you consider how hacking has been treated by societies to date.