投稿時間:2023-11-27 01:04:11 RSSフィード2023-11-27 01:00分まとめ(4件)

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IT	気になる、記になる…	【セール】macOS向けシステムモニタアプリ｢iStat Menus 6.0｣が75％オフに	https://taisy0.com/2023/11/27/179964.html	bjango,istatmenus,macos	2023-11-26 15:53:34
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海外TECH	Engadget	Amazon Cyber Monday deals drop the price of the 2nd-gen Apple Pencil to an all-time low of $80	https://www.engadget.com/amazon-cyber-monday-deals-drop-the-price-of-the-2nd-gen-apple-pencil-to-an-all-time-low-of-80-154236215.html?src=rss	Whether you re an artist or an avid notetaker an Apple Pencil can transform the way you work on your iPad Normally they don t come cheap ーbut in a Cyber Monday deal on Amazon Apple s second generation Apple Pencil is down to its lowest price yet at You ll be saving nearly on the stylus that s made just for the iPad Without a discount it costs around The second generation Apple Pencil brought a number of improvements over the previous version including double tap controls and magnetic attachment to the iPad for easy storage and wireless charging You can t do any better than an Apple Pencil if you re looking for a stylus to work with your iPad It was crafted with Apple s tablet in mind and as such it s one of the best iPad accessories available The second gen Apple Pencil offers low latency so there s no lag as you re writing or drawing on the touchscreen and Apple says it achieves pixel perfect precision It also has pressure and tilt sensitivity for more natural control over things like stroke width opacity and shading You can double tap the pencil to easily switch between tools The second generation Apple Pencil doesn t work with every model of iPad though and you ll want to double check compatibility before picking one up It s compatible with the iPad Pro inch third generation and later all generations of iPad Pro inch iPad Air fourth and fifth gen and the iPad mini sixth gen The Apple Pencil can magnetically attach to the side of these iPads to charge wirelessly while it s not in use For those who have an iPad Pro it also supports Apple Pencil hover which lets you preview tools or colors before committing to them Apple also still offers the first generation Apple Pencil which is compatible with older iPad models and it s on sale for Cyber Monday too It s down to from its usual price of and works with iPad Pro inch first and second generation iPad Pro inch iPad Pro inch the third generation iPad Air fifth generation iPad mini and iPad sixth gen and later Apple s more budget friendly Apple Pencil with USB C charging is discounted right now as well dropping to from That model works with the same iPad models as the second generation Apple Pencil plus the th generation iPad Your Cyber Monday Shopping Guide See all of Yahoo s Cyber Monday coverage here Follow Engadget for Cyber Monday tech deals Learn about Cyber Monday trends on In The Know Hear from Autoblog s experts on the best Cyber Monday deals for your car garage and home and find Cyber Monday sales to shop on AOL handpicked just for you This article originally appeared on Engadget at	2023-11-26 15:42:36
海外TECH	Engadget	Black hole behavior suggests Dr. Who's 'bigger on the inside' Tardis trick is theoretically possible	https://www.engadget.com/hitting-the-books-white-holes-carlo-rovelli-riverhead-153058062.html?src=rss	Do black holes like dying old soldiers simply fade away Do they pop like hyperdimensional balloons Maybe they do or maybe they pass through a cosmic rubicon effectively reversing their natures and becoming inverse anomalies that cannot be entered through their event horizons but which continuously expel energy and matter back into the universe nbsp In his latest book White Holes physicist and philosopher Carlo Rovelli focuses his attention and considerable expertise on the mysterious space phenomena diving past the event horizon to explore their theoretical inner workings and and posit what might be at the bottom of those infinitesimally tiny infinitely fascinating gravitational points In this week s Hitting the Books excerpt Rovelli discusses a scientific schism splitting the astrophysics community as to where all of the information ーwhich from our current understanding of the rules of our universe cannot be destroyed ーgoes once it is trapped within an inescapable black hole nbsp nbsp nbsp Riverhead BooksExcerpted from by White Holes by Carlo Rovelli Published by Riverhead Books Copyright by Carlo Rovelli All rights reserved In Stephen Hawking made an unexpected theoretical discovery black holes must emit heat This too is a quantum tunnel effect but a simpler one than the bounce of a Planck star photons trapped inside the horizon escape thanks to the pass that quantum physics provides to everything They tunnel beneath the horizon nbsp So black holes emit heat like a stove and Hawking computed their temperature Radiated heat carries away energy As it loses energy the black hole gradually loses mass mass is energy becoming ever lighter and smaller Its horizon shrinks In the jargon we say that the black hole evaporates nbsp Heat emission is the most characteristic of the irreversible processes the processes that occur in one time direction and cannot be reversed A stove emits heat and warms a cold room Have you ever seen the walls of a cold room emit heat and heat up a warm stove When heat is produced the process is irreversible In fact whenever the process is irreversible heat is produced or something analogous Heat is the mark of irreversibility Heat distinguishes past from future nbsp There is therefore at least one clearly irreversible aspect to the life of a black hole the gradual shrinking of its horizon But careful the shrinking of the horizon does not mean that the interior of the black hole becomes smaller The interior largely remains what it is and the interior volume keeps growing It is only the horizon that shrinks This is a subtle point that confuses many Hawking radiation is a phenomenon that regards mainly the horizon not the deep interior of the hole Therefore a very old black hole turns out to have a peculiar geometry an enormous interior that continues to grow and a minuscule because it has evaporated horizon that encloses it An old black hole is like a glass bottle in the hands of a skillful Murano glassblower who succeeds in making the volume of the bottle increase as its neck becomes narrower nbsp At the moment of the leap from black to white a black hole can therefore have an extremely small horizon and a vast interior A tiny shell containing vast spaces as in a fable In fables we come across small huts that when entered turn out to contain hundreds of vast rooms This seems impossible the stuff of fairy tales But it is not so A vast space enclosed in a small sphere is concretely possible nbsp If this seems bizarre to us it is only because we became habituated to the idea that the geometry of space is simple it is the one we studied at school the geometry of Euclid But it is not so in the real world The geometry of space is distorted by gravity The distortion permits a gigantic volume to be enclosed within a tiny sphere The gravity of a Planck star generates such a huge distortion nbsp An ant that has always lived on a large flat plaza will be amazed when it discovers that through a small hole it has access to a large underground garage Same for us with a black hole What the amazement teaches is that we should not have blind confidence in habitual ideas the world is stranger and more varied than we imagine nbsp The existence of large volumes within small horizons has also generated confusion in the world of science The scientific community has split and is quarreling about the topic In the rest of this section I tell you about this dispute It is more technical than the rest ーskip it if you like ーbut it is a picture of a lively ongoing scientific debate nbsp The disagreement concerns how much information you can cram into an entity with a large volume but a small surface One part of the scientific community is convinced that a black hole with a small horizon can contain only a small amount of information Another disagrees nbsp What does it mean to contain information nbsp More or less this Are there more things in a box containing five large and heavy balls or in a box that contains twenty small marbles The answer depends on what you mean by more things The five balls are bigger and weigh more so the first box contains more matter more substance more energy more stuff In this sense there are more things in the box of balls nbsp But the number of marbles is greater than the number of balls In this sense there are more things more details in the box of marbles If we wanted to send signals by giving a single color to each marble or each ball we could send more signals more colors more information with the marbles because there are more of them More precisely it takes more information to describe the marbles than it does to describe the balls because there are more of them In technical terms the box of balls contains more energy whereas the box of marbles contains more information nbsp An old black hole considerably evaporated has little energy because the energy has been carried away via the Hawking radiation Can it still contain much information after much of its energy is gone Here is the brawl Some of my colleagues convinced themselves that it is not possible to cram a lot of information beneath a small surface That is they became convinced that when most energy has gone and the horizon has become minuscule only little information can remain inside nbsp Another part of the scientific community to which I belong is convinced of the contrary The information in a black holeーeven a greatly evaporated oneーcan still be large Each side is convinced that the other has gone astray nbsp Disagreements of this kind are common in the history of science one may say that they are the salt of the discipline They can last long Scientists split quarrel scream wrangle scuffle jump at each other s throats Then gradually clarity emerges Some end up being right others end up being wrong nbsp At the end of the nineteenth century for instance the world of physics was divided into two fierce factions One of these followed Mach in thinking that atoms were just convenient mathematical fictions the other followed Boltzmann in believing that atoms exist for real The arguments were ferocious Ernst Mach was a towering figure but it was Boltzmann who turned out to be right Today we even see atoms through a microscope nbsp I think that my colleagues who are convinced that a small horizon can contain only a small amount of information have made a serious mistake even if at first sight their arguments seem convincing Let s look at these The first argument is that it is possible to compute how many elementary components how many molecules for example form an object starting from the relation between its energy and its temperature We know the energy of a black hole it is its mass and its temperature computed by Hawking so we can do the math The result indicates that the smaller the horizon the fewer its elementary components nbsp The second argument is that there are explicit calculations that allow us to count these elementary components directly using both of the most studied theories of quantum gravityーstring theory and loop theory The two archrival theories completed this computation within months of each other in For both the number of elementary components becomes small when the horizon is small These seem like strong arguments On the basis of these arguments many physicists have accepted a dogma they call it so themselves the number of elementary components contained in a small surface is necessarily small Within a small horizon there can only be little information If the evidence for this dogma is so strong where does the error lie nbsp It lies in the fact that both arguments refer only to the components of the black hole that can be detected from the outside as long as the black hole remains what it is And these are only the components residing on the horizon Both arguments in other words ignore that there can be components in the large interior volume These arguments are formulated from the perspective of someone who remains far from the black hole does not see the inside and assumes that the black hole will remain as it is forever If the black hole stays this way foreverーrememberーthose who are far from it will see only what is outside or what is right on the horizon It is as if for them the interior does not exist For them nbsp But the interior does exist And not only for those like us who dare to enter but also for those who simply have the patience to wait for the black horizon to become white allowing what was trapped inside to come out In other words to imagine that the calculations of the number of components of a black hole given by string theory or loop theory are complete is to have failed to take on board Finkelstein s article The description of a black hole from the outside is incomplete nbsp The loop quantum gravity calculation is revealing the number of components is precisely computed by counting the number of quanta of space on the horizon But the string theory calculation on close inspection does the same it assumes that the black hole is stationary and is based on what is seen from afar It neglects by hypothesis what is inside and what will be seen from afar after the hole has finished evaporating ーwhen it is no longer stationary nbsp I think that certain of my colleagues err out of impatience they want everything resolved before the end of evaporation where quantum gravity becomes inevitable and because they forget to take into account what is beyond that which can be immediately seen ーtwo mistakes we all frequently make in life nbsp Adherents to the dogma find themselves with a problem They call it the black hole information paradox They are convinced that inside an evaporated black hole there is no longer any information Now everything that falls into a black hole carries information So a large amount of information can enter the hole Information cannot vanish Where does it go nbsp To solve the paradox the devotees of the dogma imagine that information escapes the hole in mysterious and baroque ways perhaps in the folds of the Hawking radiation like Ulysses and his companions escaping from the cave of the cyclops by hiding beneath sheep Or they speculate that the interior of a black hole is connected to the outside by hypothetical invisible canals Basically they are clutching at strawsーlooking like all dogmatists in difficulty for abstruse ways of saving the dogma nbsp But the information that enters the horizon does not escape by some arcane magical means It simply comes out after the horizon has been transformed from a black horizon into a white horizon In his final years Stephen Hawking used to remark that there is no need to be afraid of the black holes of life sooner or later there will be a way out of them There is ーvia the child white hole This article originally appeared on Engadget at	2023-11-26 15:30:58