#and if hawking radiation is to be believed even the black holes will evaporate into nothingness

[geekyanglophile]

Dude heard that lobsters are “biologically immortal” because they have a little bit of telomerase going for them and thought that meant death is unnatural lol. You realize many animals have shorter lifespans than humans? In fact, for many species the norm is to live only as long as it takes to reproduce.

And really the argument about whether telomerase would ever be an effective “anti-death” solution is completely irrelevant to the original post (and even if we could be immortal… imagine how quickly we would completely overrun the planet… I mean we already are). The anti-aging argument isn’t really about whether ppl are dying or not… we are literally all dying… every last one of us. Anti-aging products are about beauty standards (which is why they are primarily marketed towards women). These products aren’t actually about stopping aging (you’ll notice none of them contain telomerase). Their only purpose is to cover up, reverse, or minimize the physical signs of aging. And by all means, if those features make you sad or uncomfortable, then use whatever products work for you. But people (and women specifically) should not be expected to use these products to cater to beauty standards. Using these products will not improve your lifespan or overall health (other than sunscreen but I don’t consider that an “anti-aging” product).

scrunching my face real hard rn

[mysticstronomy]

HOW COULD WE DETECT ATOM SIZED BLACK HOLES??

Blog#277

Wednesday, March 8th, 2023

Welcome back,

One of the most intriguing predictions of Einstein's general theory of relativity is the existence of black holes: astronomical objects with gravitational fields so strong that not even light can escape them.

When a sufficiently massive star runs out of fuel, it explodes and the remaining core collapses, leading to the formation of a stellar black hole (ranging from 3 to 100 solar masses).

Supermassive black holes also exist in the center of most galaxies. These are the largest type of black hole, containing between one hundred thousand and ten billion times more mass than our sun.

So far, astronomers have captured images of two supermassive black holes: one in the center of the galaxy M87, and the most recent in our Milky Way (Sagittarius A*).

But it's believed that another kind of black hole exists—the primordial or primitive black hole (PBHs). These have a different origin to other black holes, having formed in the early universe through the gravitational collapse of extremely dense regions.

Theoretically, these primordial black holes can possess any mass, and may range in size from a subatomic particle to several hundred kilometers.

For instance, a PBH with a mass equivalent to Mount Everest could have the size of an atom.

These tiny black holes lose mass at a faster rate than their massive counterparts, emitting so-called Hawking radiation, until they finally evaporate.

Up to now, astronomers have not been able to observe PBHs.

This is a subject of ongoing research since it is assumed that these ultra-compact objects might be part of the long-searched-for dark matter of the universe.

An alternative scenario for detecting atom-sized primordial black holes is proposed in a recent publication.

In this research, the characteristic signal of the interaction between one of these tiny black holes and one of the densest objects in the universe (a neutron star) is studied.

Before embarking on this new astrophysical model, let us now comment on the main characteristics of these fascinating stars.

As previously mentioned, when a massive star runs out of fuel, it explodes and its core collapses, resulting in a stellar black hole.

It ought to be stressed this is not the case in every scenario: for example, if the collapsing core is less massive than about three solar masses, a neutron star is formed.

These are very small and extremely dense objects. For instance, consider a star with 1.5 solar masses compressed into a sphere of only 20 kilometers in diameter (the size of Manhattan island).

The density of a neutron star is extremely high: a tablespoon of star material would weigh millions of tons!

The youngest neutron stars belong to a subclass called pulsars which spin at extremely high velocities (even faster than a kitchen blender). These pulsars emit radiation in the form of narrow beams that periodically reach the Earth.

Over time, these objects cool down and lose their rotational speed, being difficult to detect (only the most energetic pulsars have been observed).

Originally published on phys.org

COMING UP!!

(Saturday, March 11th, 2023)

"WHAT IF THE UNIVERSE STARTED WITH A DARK BIG BANG"??

[phroyd]

Stephen Hawking, the brightest star in the firmament of science, whose insights shaped modern cosmology and inspired global audiences in the millions, has died aged 76.

His family released a statement in the early hours of Wednesday morning confirming his death at his home in Cambridge.

Hawking’s children, Lucy, Robert and Tim, said in a statement: “We are deeply saddened that our beloved father passed away today. He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humour inspired people across the world.

“He once said: ‘It would not be much of a universe if it wasn’t home to the people you love.’ We will miss him for ever.”

For fellow scientists and loved ones, it was Hawking’s intuition and wicked sense of humour that marked him out as much as the fierce intellect that, coupled with his illness, came to symbolise the unbounded possibilities of the human mind.

Hawking was driven to Wagner, but not the bottle, when he was diagnosed with motor neurone disease in 1963 at the age of 21. Doctors expected him to live for only two more years. But Hawking had a form of the disease that progressed more slowly than usual. He survived for more than half a century.

Hawking once estimated he worked only 1,000 hours during his three undergraduate years at Oxford. In his finals, he came borderline between a first- and second-class degree. Convinced that he was seen as a difficult student, he told his viva examiners that if they gave him a first he would move to Cambridge to pursue his PhD. Award a second and he threatened to stay. They opted for a first.

Those who live in the shadow of death are often those who live most. For Hawking, the early diagnosis of his terminal disease, and witnessing the death from leukaemia of a boy he knew in hospital, ignited a fresh sense of purpose. “Although there was a cloud hanging over my future, I found, to my surprise, that I was enjoying life in the present more than before. I began to make progress with my research,” he once said. Embarking on his career in earnest, he declared: “My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”

He began to use crutches in the 1960s, but long fought the use of a wheelchair. When he finally relented, he became notorious for his wild driving along the streets of Cambridge, not to mention the intentional running over of students’ toes and the occasional spin on the dance floor at college parties.

Hawking’s first major breakthrough came in 1970, when he and Roger Penroseapplied the mathematics of black holes to the universe and showed that a singularity, a region of infinite curvature in spacetime, lay in our distant past: the point from which came the big bang.

Penrose found he was able to talk with Hawking even as the latter’s speech failed. Hawking, he said, had an absolute determination not to let anything get in his way. “He thought he didn’t have long to live, and he really wanted to get as much as he could done at that time.”

In 1974 Hawking drew on quantum theory to declare that black holes should emit heat and eventually pop out of existence. For normal-sized black holes, the process is extremely slow, but miniature black holes would release heat at a spectacular rate, eventually exploding with the energy of a million one-megaton hydrogen bombs.

His proposal that black holes radiate heat stirred up one of the most passionate debates in modern cosmology. Hawking argued that if a black hole could evaporate, all the information that fell inside over its lifetime would be lost forever. It contradicted one of the most basic laws of quantum mechanics, and plenty of physicists disagreed. Hawking came round to believing the more common, if no less baffling, explanation that information is stored at a black hole’s event horizon, and encoded back into radiation as the black hole radiates.

Marika Taylor, a former student of Hawking’s and now professor of theoretical physics at Southampton University, remembers how Hawking announced his U-turn on the information paradox to his students. He was discussing their work with them in the pub when Taylor noticed he was turning his speech synthesiser up to the max. “I’m coming out!” he bellowed. The whole pub turned around and looked at the group before Hawking turned the volume down and clarified the statement: “I’m coming out and admitting that maybe information loss doesn’t occur.” He had, Taylor said, “a wicked sense of humour.”

Hawking’s run of radical discoveries led to his election in 1974 to the Royal Society at the young age of 32. Five years later, he became the Lucasian professor of mathematics at Cambridge, arguably Britain’s most distinguished chair, and a post formerly held by Isaac Newton, Charles Babbage and Paul Dirac, one of the founding fathers of quantum mechanics.

Hawking’s seminal contributions continued through the 1980s. The theory of cosmic inflation holds that the fledgling universe went through a period of terrific expansion. In 1982, Hawking was among the first to show how quantum fluctuations – tiny variations in the distribution of matter – might give rise through inflation to the spread of galaxies in the universe. In these tiny ripples lay the seeds of stars, planets and life as we know it.

But it was A Brief History of Time that rocketed Hawking to stardom. Published for the first time in 1988, the title made the Guinness Book of Records after it stayed on the Sunday Times bestsellers list for an unprecedented 237 weeks. It sold 10m copies and was translated into 40 different languages. Nevertheless, wags called it the greatest unread book in history.

Continue Reading ... 

Phroyd

[scifigeneration]

Stephen Hawking: Martin Rees looks back on colleague's spectacular success against all odds

by Martin Rees, University of Cambridge

Lwp Kommunikáció/Flickr, CC BY-SA

Soon after I enrolled as a graduate student at Cambridge University in 1964, I encountered a fellow student, two years ahead of me in his studies, who was unsteady on his feet and spoke with great difficulty. This was Stephen Hawking. He had recently been diagnosed with a degenerative disease, and it was thought that he might not survive long enough even to finish his PhD. But he lived to the age of 76, passing away on March 14, 2018.

It really was astonishing. Astronomers are used to large numbers. But few numbers could be as large as the odds I’d have given against witnessing this lifetime of achievement back then. Even mere survival would have been a medical marvel, but of course he didn’t just survive. He became one of the most famous scientists in the world – acclaimed as a world-leading researcher in mathematical physics, for his best-selling books and for his astonishing triumph over adversity.

Perhaps surprisingly, Hawking was rather laid back as an undergraduate student at Oxford University. Yet his brilliance earned him a first class degree in physics, and he went on to pursue a research career at the University of Cambridge. Within a few years of the onset of his disease, he was wheelchair-bound, and his speech was an indistinct croak that could only be interpreted by those who knew him. In other respects, fortune had favoured him. He married a family friend, Jane Wilde, who provided a supportive home life for him and their three children.

Early work

The 1960s were an exciting period in astronomy and cosmology. This was the decade when evidence began to emerge for black holes and the Big Bang. In Cambridge, Hawking focused on the new mathematical concepts being developed by the mathematical physicist Roger Penrose, then at University College London, which were initiating a renaissance in the study of Einstein’s theory of general relativity.

Using these techniques, Hawking worked out that the universe must have emerged from a “singularity” – a point in which all laws of physics break down. He also realised that the area of a black hole’s event horizon – a point from which nothing can escape – could never decrease. In the subsequent decades, the observational support for these ideas has strengthened – most spectacularly with the 2016 announcement of the detection of gravitational waves from colliding black holes.

Hawking at the University of Cambridge. Lwp Kommunikáció/Flickr, CC BY-SA

Hawking was elected to the Royal Society, Britain’s main scientific academy, at the exceptionally early age of 32. He was by then so frail that most of us suspected that he could scale no further heights. But, for Hawking, this was still just the beginning.

He worked in the same building as I did. I would often push his wheelchair into his office, and he would ask me to open an abstruse book on quantum theory – the science of atoms, not a subject that had hitherto much interested him. He would sit hunched motionless for hours – he couldn’t even to turn the pages without help. I remember wondering what was going through his mind, and if his powers were failing. But within a year, he came up with his best ever idea – encapsulated in an equation that he said he wanted on his memorial stone.

Scientific stardom

The great advances in science generally involve discovering a link between phenomena that seemed hitherto conceptually unconnected. Hawking’s “eureka moment” revealed a profound and unexpected link between gravity and quantum theory: he predicted that black holes would not be completely black, but would radiate energy in a characteristic way.

This radiation is only significant for black holes that are much less massive than stars – and none of these have been found. However, “Hawking radiation” had very deep implications for mathematical physics – indeed one of the main achievements of a theoretical framework for particle physics called string theory has been to corroborate his idea.

Indeed, the string theorist Andrew Strominger from Harvard University (with whom Hawking recently collaborated) said that this paper had caused “more sleepiness nights among theoretical physicists than any paper in history”. The key issue is whether information that is seemingly lost when objects fall into a black hole is in principle recoverable from the radiation when it evaporates. If it is not, this violates a deeply believed principle of general physics. Hawking initially thought such information was lost, but later changed his mind.

Hawking continued to seek new links between the very large (the cosmos) and the very small (atoms and quantum theory) and to gain deeper insights into the very beginning of our universe – addressing questions like “was our big bang the only one?”. He had a remarkable ability to figure things out in his head. But he also worked with students and colleagues who would write formulas on a blackboard – he would stare at it, say whether he agreed and perhaps suggest what should come next.

He was specially influential in his contributions to “cosmic inflation” – a theory that many believe describes the ultra-early phases of our expanding universe. A key issue is to understand the primordial seeds which eventually develop into galaxies. Hawking proposed (as, independently, did the Russian theorist Viatcheslav Mukhanov) that these were “quantum fluctuations” (temporary changes in the amount of energy in a point in space) – somewhat analogous to those involved in “Hawking radiation” from black holes.

He also made further steps towards linking the two great theories of 20th century physics: the quantum theory of the microworld and Einstein’s theory of gravity and space-time.

Declining health and cult status

In 1987, Hawking contracted pneumonia. He had to undergo a tracheotomy, which removed even the limited powers of speech he then possessed. It had been more than ten years since he could write, or even use a keyboard. Without speech, the only way he could communicate was by directing his eye towards one of the letters of the alphabet on a big board in front of him.

But he was saved by technology. He still had the use of one hand; and a computer, controlled by a single lever, allowed him to spell out sentences. These were then declaimed by a speech synthesiser, with the androidal American accent that thereafter became his trademark.

His lectures were, of course, pre-prepared, but conversation remained a struggle. Each word involved several presses of the lever, so even a sentence took several minutes to construct. He learnt to economise with words. His comments were aphoristic or oracular, but often infused with wit. In his later years, he became too weak to control this machine effectively, even via facial muscles or eye movements, and his communication – to his immense frustration – became even slower.

Hawking in zero gravity. NASA

At the time of his tracheotomy operation, he had a rough draft of a book, which he’d hoped would describe his ideas to a wide readership and earn something for his two eldest children, who were then of college age. On his recovery from pneumonia, he resumed work with the help of an editor. When the US edition of A Brief History of Time appeared, the printers made some errors (a picture was upside down), and the publishers tried to recall the stock. To their amazement, all copies had already been sold. This was the first inkling that the book was destined for runaway success, reaching millions of people worldwide.

And he quickly became somewhat of a cult figure, featuring on popular TV shows ranging from the Simpsons to The Big Bang Theory. This was probably because the concept of an imprisoned mind roaming the cosmos plainly grabbed people’s imagination. If he had achieved equal distinction in, say, genetics rather than cosmology, his triumph probably wouldn’t have achieved the same resonance with a worldwide public.

As shown in the feature film The Theory of Everything, which tells the human story behind his struggle, Hawking was far from being the archetype unworldy or nerdish scientist. His personality remained amazingly unwarped by his frustrations and handicaps. He had robust common sense, and was ready to express forceful political opinions.

However, a downside of his iconic status was that that his comments attracted exaggerated attention even on topics where he had no special expertise – for instance, philosophy, or the dangers from aliens or from intelligent machines. And he was sometimes involved in media events where his “script” was written by the promoters of causes about which he may have been ambivalent.

Ultimately, Hawking’s life was shaped by the tragedy that struck him when he was only 22. He himself said that everything that happened since then was a bonus. And what a triumph his life has been. His name will live in the annals of science and millions have had their cosmic horizons widened by his best-selling books. He has also inspired millions by a unique example of achievement against all the odds – a manifestation of amazing willpower and determination.

Martin Rees is Emeritus Professor of Cosmology and Astrophysics at the University of Cambridge.

This article was originally published on The Conversation. 

[orbemnews]

Black hole breakthrough: UK experts observe first ‘backreaction’ in black hole simulation Black holes are areas of spacetime exhibiting gravity so extreme nothing – even light – can escape. Scientists have now significantly expanded awareness about black holes’ bizarre behaviour, following research simulating a phenomenon called “backreaction”. University of Nottingham scientists used their simulation of a black hole, involving a specially-designed water tank, for the study. The team’s laboratory simulation was the first to demonstrate how black holes’ evolution are a direct consequence of their surrounding fields. The researchers used a water tank simulator consisting of a draining vortex. This is almost identical to those formed when a plug is pulled out of a bath tub. This act in fact imitates a black hole as waves encroaching too close to the drain are dragged down the plug hole. READ MORE: NASA anger as astronaut reports ISS ‘anomaly’ to Mission Control Surprisingly simple systems like these have in recent years grown increasingly-popular as methods for testing complex gravitational phenomena. For example, Hawking Radiation has also been observed in an analogue black hole experiment involving quantum optics. Researchers using this plug hole technique have for the first time demonstrated when waves are sent into an analogue black hole, the properties of the black hole itself can alter significantly. The mechanics responsible for this effect in this simulation has a remarkably-simple explanation. “We have demonstrated that analogue black holes, like their gravitational counterparts, are intrinsically backreacting systems. “We showed that waves moving in a draining bathtub push water down the plug hole, modifying significantly the drain speed and consequently changing the effective gravitational pull of the analogue black hole. “What was really striking for us is that the backreaction is large enough that it causes the water height across the entire system to drop so much that you can see it by eye. This was really unexpected. “Our study paves the way to experimentally probing interactions between waves and the spacetimes they move through. “For example, this type of interaction will be crucial for investigating black hole evaporation in the laboratory.” The research’s release has coincidental with a study reporting how colliding galaxies may actually “stave” their black hole inhabitants. The study, also largely-based on simulations, centres on the idea of the galactic gas reservoir and the galactic nuclei. During these head-on galaxy collisions, something very unusual can happen in the galactic nuclei. Dr Yohei Miki, research associate at the University of Tokyo and lead author, said: “At the heart of most galaxies lies a massive black hole, or MBH. “For as long as astronomers have explored galactic collisions, it has been assumed that a collision would always provide fuel for an MBH in the form of matter within the nucleus. “And that this fuel would feed the MBH, significantly increasing its activity, which we would see as ultraviolet and X-ray light amongst other things. “However, we now have good reason to believe that this sequence of events is not inevitable and that in fact, the exact opposite might sometimes be true.” if(typeof utag_data.ads.fb_pixel!=="undefined"&&utag_data.ads.fb_pixel==!0)!function(f,b,e,v,n,t,s)if(f.fbq)return;n=f.fbq=function()n.callMethod?n.callMethod.apply(n,arguments):n.queue.push(arguments);if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';n.queue=[];t=b.createElement(e);t.async=!0;t.src=v;s=b.getElementsByTagName(e)[0];s.parentNode.insertBefore(t,s)(window,document,'script','https://connect.facebook.net/en_US/fbevents.js');fbq('init','568781449942811');fbq('track','PageView') Source link Orbem News #backreaction #Black #Breakthrough #experts #hole #observe #simulation

[followthistrendingworld]

Stephen Hawking, renowned scientist, dies at 76

Stephen Hawking, the brilliant British theoretical physicist who overcame a debilitating disease to publish wildly popular books probing the mysteries of the universe, has died, according to a family spokesman. He was 76.

Considered by many to be the world's greatest living scientist, Hawking was also a cosmologist, astronomer, mathematician and author of numerous books including the landmark "A Brief History of Time," which has sold more than 10 million copies.

With fellow physicist Roger Penrose, Hawking merged Einstein's theory of relativity with quantum theory to suggest that space and time would begin with the Big Bang and end in black holes. Hawking also discovered that black holes were not completely black but emit radiation and would likely eventually evaporate and disappear.

Lawrence Krauss, a theoretical physicist and cosmologist, wrote on Twitter, a star just went out in the cosmos. We have lost an amazing human being.

Hawking suffered from ALS (amyotrophic lateral sclerosis), a neurodegenerative disease commonly known as Lou Gehrig's Disease, which is usually fatal within a few years. He was diagnosed in 1963, when he was 21, and doctors initially only gave him a few years to live. The disease left Hawking wheelchair-bound and paralyzed. He was able to move only a few fingers on one hand and was completely dependent on others or on technology for virtually everything bathing, dressing, eating, even speech.

Hawking used a speech synthesizer that allowed him to speak in a computerized voice with an American accent.

He said, I try to lead as normal a life as possible, and not think about my condition, or regret the things it prevents me from doing, which are not that many. I have been lucky that my condition has progressed more slowly than is often the case. But it shows that one need not lose hope.

Cosmologist Stephen Hawking on October 10, 1979 in Princeton, New Jersey. Hawking was married twice. He and his first wife, Jane Wilde, wed when he was still a grad student and remained together for 30 years before divorcing in 1995. Hawking was later married for 11 years to Elaine Mason, one of his former nurses.

Hawking was born in Oxford, England, on what turned out to be an auspicious date: January 8, 1942, the 300th anniversary of the death of astronomer and physicist Galileo Galilei.

In an exclusive interview with CNN in October 2008, Hawking said that if humans can survive the next 200 years and learn to live in space, then our future will be bright. 

Hawking told CNN's Becky Anderson , I believe that the long-term future of the human race must be in space. It will be difficult enough to avoid disaster on planet Earth in the next 100 years, let alone next thousand, or million. The human race shouldn't have all its eggs in one basket, or on one planet. Let's hope we can avoid dropping the basket until we have spread the load.

At Cambridge, he held the position of Lucasian Professor of Mathematics the prestigious post held from 1669 to 1702 by Sir Isaac Newton, widely considered one of the greatest scientists in modern history. Yet Hawking once said if he had the chance to meet Newton or Marilyn Monroe, he would opt for the movie star.

Hawking became a hero to math and science geeks and pop culture figure, guest-starring as himself on "Star Trek: The Next Generation" and "The Simpsons." His life was dramatized in the 2014 movie, "The Theory of Everything."

He had at least 12 honorary degrees and was awarded the CBE in 1982. A CBE, or Commander in the Most Excellent Order of the British Empire, is considered a major honor for a British citizen and is one rank below knighthood. Despite being a British citizen he was awarded the Presidential Medal of Freedom, the US's highest civilian honor, in 2009 by President Barack Obama.

In September 2016 Hawking joined 375 "concerned" scientists in penning an open letter criticizing then-presidential candidate Donald Trump, citing the threat of climate change and blasting his push for the US to leave the Paris Accord. Fellow scientists hailed Hawking for his work and influence in the field.

Neil deGrasse Tyson tweeted, his passing has left an intellectual vacuum in his wake. But it's not empty. Think of it as a kind of vacuum energy permeating the fabric of spacetime that defies measure.

Hawking leaves behind three children and three grandchildren. 

Hawking's children, Lucy, Robert and Tim, said we are deeply saddened that our beloved father passed away today. He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humor inspired people across the world. 

He once said, It would not be much of a universe if it wasn't home to the people you love. We will miss him forever.

[monkeyandelf]

Is the universe a giant hologram?

A German scientist's experiment called GEO600 for the search for gravitational waves, which has been going on for seven years, has led to unexpected results, according to New Scientist.

Using a special device - an interferometer - physicists were going to scientifically confirm one of the conclusions of Einstein's theory of relativity. According to this theory, in the Universe there are so-called gravitational waves - perturbations of the gravitational field, “ripples” of the fabric of space-time. Propagating at the speed of light, gravitational waves presumably generate uneven mass movements of large astronomical objects: the formation or collision of black holes, a supernova explosion, etc. Science explains the unobservability of gravitational waves by the fact that gravitational effects are weaker than electromagnetic ones. Scientists who started their experiment back in 2002, intended to detect these gravitational waves, which could later become a source of valuable information about the so-called dark matter, which our Universe basically consists of. Until now, the GEO600 has not been able to detect gravitational waves, but, apparently, scientists using the device managed to make the largest discovery in the field of physics over the past half century. For many months, experts could not explain the nature of the strange noises that interfere with the operation of the interferometer, until suddenly an explanation was offered by a physicist from the Fermilab science laboratory. According to Craig Hogan’s assumption, the GEO600 faced the fundamental boundary of the space-time continuum — the point at which space-time ceases to be a continuous continuum described by Einstein and breaks up into “grains”, as if a photograph enlarged by a few turns into a cluster of individual points . “The GEO600 seems to have stumbled upon microscopic quantum vibrations of space-time,” suggested Hogan. If this information does not seem sensational enough to you, we’ll listen further: “If the GEO600 stumbles on what I suppose, it means that we live in a giant space hologram.” The very idea that we live in a hologram may seem absurd and absurd, but it is only a logical continuation of our understanding of the nature of black holes, based on a completely provable theoretical basis. Oddly enough, a “hologram theory” would essentially help physicists finally explain how the universe works at a fundamental level. The holograms we are used to (like, for example, on credit cards) are applied to a two-dimensional surface, which begins to seem three-dimensional when a light beam hits it at a certain angle. In the 1990s, Nobel Prize winner in physics Gerard Huft of Utrecht University (Netherlands) and Leonard Susskind of Stanford University (USA) suggested that a similar principle could be applied to the Universe as a whole. Our daily existence in itself can be a holographic projection of physical processes that occur in two-dimensional space. It is very difficult to believe in the “holographic principle” of the structure of the Universe: it is difficult to imagine that you wake up, brush your teeth, read newspapers or watch TV just because somewhere on the borders of the Universe several giant space objects collided. Nobody knows what “life in a hologram” will mean to us, but theoretical physicists have many reasons to believe that certain aspects of the holographic principles of the functioning of the Universe are reality. The findings of scientists are based on a fundamental study of the properties of black holes, which was carried out by the famous theoretical physicist Stephen Hawking together with Roger Penrose. In the mid-1970s, the scientist studied the fundamental laws that govern the universe and showed that Einstein's theory of relativity implies such a space-time that begins in the Big Bang and ends in black holes. These results indicate the need to combine the study of the theory of relativity with quantum theory. One of the consequences of such a union is the assertion that black holes are not really “black”: in fact, they emit radiation, which leads to their gradual evaporation and complete disappearance. Thus, a paradox called the “black hole information paradox” arises: the formed black hole loses mass, radiating energy. When a black hole disappears, all the information absorbed by it is lost. However, according to the laws of quantum physics, information cannot be completely lost. Hawking’s counterargument: the intensity of the gravitational fields of black holes is still inexplicably consistent with the laws of quantum physics. Hawking’s colleague, physicist Bekenstein, put forward an important hypothesis that helps resolve this paradox. He hypothesized that a black hole has entropy proportional to the surface area of ​​its conditional radius. This is a kind of theoretical area that masks a black hole and marks the point of non-return of matter or light. Theoretical physicists have proved that microscopic quantum oscillations of the conditional radius of a black hole can encode information inside a black hole, so that there is no loss of information inside a black hole when it evaporates and disappears. Thus, it can be assumed that three-dimensional information about the starting material can be completely encoded into the two-dimensional radius of the black hole formed after its death, approximately how a three-dimensional image of an object is encoded using a two-dimensional hologram. Zuskind and Huft went even further, applying this theory to the structure of the Universe, based on the fact that the cosmos also has a conditional radius - a boundary plane, beyond which light has not yet managed to penetrate over the 13.7 billion years of the existence of the Universe. Moreover, Juan Maldacena, a theoretical physicist at Princeton University, was able to prove that the same physical laws will act in a hypothetical five-dimensional Universe as in four-dimensional space. According to Hogan's theory, the holographic principle of the existence of the Universe radically changes the usual picture of space-time. Theoretical physicists have long believed that quantum effects can cause space-time to randomly pulsate on an insignificant scale. With this level of pulsation, the fabric of the space-time continuum becomes “grainy” and, as if made of the smallest particles, similar to pixels, is only hundreds of billions billion times smaller than the proton. This measure of length is known as the "Planck length" and is a figure of 10-35 m. At present, fundamental physical laws are verified empirically up to distances of 10-17, and the Planck length was considered unattainable until Hogan realized that the holographic principle changes everything. If the space-time continuum is a granular hologram, then the Universe can be represented as a sphere, the outer surface of which is covered with minute surfaces 10-35 m long, each of which carries a piece of information. The holographic principle states that the amount of information covering the outer part of the sphere-Universe must coincide with the number of bits of information contained within the three-dimensional Universe. Since the volume of the spherical Universe is much larger than its entire outer surface, the question arises, how is it possible to observe this principle? Hogan suggested that the bits of information that make up the "interior" of the universe should be larger than the Planck length. “In other words, the holographic universe is like a fuzzy picture,” says Hogan. For those who are looking for the smallest particles of space-time, this is good news. “In contrast to general expectations, the microscopic quantum structure is quite accessible for study,” said Hogan. While particles whose sizes are equal to the Planck length cannot be detected, the holographic projection of these “grains” is approximately 10-16 m. When the scientist made all these conclusions, he wondered whether it was possible to experimentally determine this holographic blurring of space. time. And then the GEO600 came to the rescue. Instruments like the GEO600, capable of detecting gravitational waves, work according to the following principle: if a gravitational wave passes through it, it will stretch the space in one direction and compress it in the other. To measure the wave, scientists direct the laser beam through a special mirror called the "beam splitter." It divides the laser beam into two beams that pass through the 600-meter perpendicular rods and come back. The rays that returned back are again united into one and create an interference picture of light and dark areas where light waves either disappear or reinforce each other. Any change in the position of these sections indicates that the relative length of the rods has changed. Experimentally, it is possible to detect changes in length less than the diameter of the proton. If the GEO600 really detected holographic noise from quantum oscillations of space-time, it will become a double-edged sword for researchers: on the one hand, noise will become an obstacle to their attempts to “catch” gravitational waves. On the other hand, this may mean that the researchers were able to make a much more fundamental discovery than originally thought. However, there is a certain irony of fate: a device designed to catch the waves resulting from the interaction of the largest astronomical objects, found something as microscopic as the "grains" of space-time. The longer scientists can not solve the mystery of holographic noise, the more acute the question arises of conducting further research in this direction. One of the possibilities for research may be the construction of the so-called atomic interferometer, the principle of operation of which is similar to GEO600, but instead of the laser beam, a low-temperature atomic flux will be used. What will the detection of holographic noise mean for humanity? Hogan is sure that humanity is one step away from discovering the quantum of time. “This is the smallest possible time interval: the Planck length divided by the speed of light,” says the scientist. However, most of all the possible discovery will help researchers trying to combine quantum mechanics and Einstein's gravitational theory. The most popular in the scientific world is string theory, which, scientists believe, will help describe everything that happens in the universe at a fundamental level. Hogan agrees that if holographic principles are proved, then no approach to the study of quantum gravity will henceforth be considered outside the context of holographic principles. On the contrary, this will be the impetus for the proofs of string theory and matrix theory. “Perhaps in our hands the first evidence of how space-time follows from quantum theory,” the scientist said. Read the full article

[crypticphysicist]

Okay so this won’t be super detailed because this is something I just started looking into in my free time, but it has to do with the need for black holes to continue to “consume” other matter to keep up its rotational energy and mass.  Otherwise, it will be very, very gradually worn down by a concept called Hawking Radiation: as matter and antimatter particles pop into existence at the quantum level and annihilate each other, there will be times where one of those particles may escape the black hole while the other doesn’t.  Because that particle is leaving the black hole, it loses energy (and mass, due to the correlation of the two).  Over incomprehensible periods of time, the black holes will evaporate in this manner.  The radiation temperature is also higher the smaller the black hole is, so the dissolving process accelerates over time as the black hole reaches its death.

However, black holes will “live” for very long periods of time despite this, outlasting every other massive structure in the universe as stars and galaxies die out permanently as the materials needed to create them become too spread out to group together as they need to.  Tbh, it’s one of the most terrifying things; how even black holes will eventually die as entropy forces the universe to become more and more uniform over time, destroying the visual marvels we may observe today.  Once the last black hole evaporates, it’s a race to the end of stable matter in the universe (as long as protons decay as we believe we do).

Black holes evaporating are hardly the scariest or most anxiety-inducing thing on that timescale, imo.

Hello I would like to request a fear and I would also like to give you one. Black holes can evaporate.

*puts hair dryer on High Heat n points it into space* die bitches

[sciencespies]

Ask Ethan: Can Black Holes And Dark Matter Interact?

https://sciencespies.com/news/ask-ethan-can-black-holes-and-dark-matter-interact/

Ask Ethan: Can Black Holes And Dark Matter Interact?

An illustration of an active black hole, one that accretes matter and accelerates a portion of it outwards in two perpendicular jets. The normal matter undergoing an acceleration like this describes how quasars work extremely well. The matter that falls into a black hole, of any variety, will be responsible for additional growth in both mass and event horizon size for the black hole, whether it’s normal matter or dark matter.

Mark A. Garlick

Black holes are some of the most extreme objects in the Universe: the only locations where there’s so much energy in a tiny volume of space that an event horizon gets created. When they form, atoms, nuclei, and even fundamental particles themselves are crushed down to an arbitrarily small volume — to a singularity — in our three-dimensional space. At the same time, everything that falls past the event horizon is forever doomed, simply adding to the black hole’s gravitational pull. What does that mean for dark matter? Patreon supporter kilobug asks:

How does dark matter interact with black holes? Does it get sucked into the singularity like normal matter, contributing to the mass of the black hole? If so, when the black hole evaporates through Hawking radiation, what happens to [it]?

To answer this, we have to start at the beginning: with what a black hole actually is.

The very first launch from NASA’s Cape Kennedy space center was of the Apollo 4 rocket. Although it accelerated no faster than a sportscar, the key to its success was that the acceleration was sustained for so long, enabling payloads to escape Earth’s atmosphere and enter orbit. Eventually, multi-stage rockets would enable humans to escape the gravitational pull of the Earth entirely. The Saturn V rockets later took humanity to the Moon.

NASA

Here on Earth, if you want to send something into space, you need to overcome the Earth’s gravitational pull. The way we normally think about this is in terms of balancing two forms of energy: the gravitational potential energy provided by the Earth itself at its surface, compared with the kinetic energy you’d have to add to your payload to escape from Earth’s gravitational pull.

If you balance these energies, you can derive your escape velocity: how fast you’d have to make an object go for it to eventually achieve an arbitrarily large distance away from the Earth. Even though the Earth has an atmosphere, providing resistance to that motion and requiring us to impart even more energy to a payload than the escape velocity would imply, escape velocity is still a useful physical concept for us to consider.

If the Earth had no atmosphere, then firing a cannonball at a particular speed would be enough to determine whether it fell back to Earth (A, B), remained in a stable orbit around Earth (C, D), or escaped from Earth’s gravitational pull (E). For all objects that aren’t black holes, all five of these trajectories are possible. For objects that are black holes, trajectories like C, D, and E are impossible inside the event horizon.

Wikimedia Commons user Brian Brondel

For our planet, that calculated speed — or escape velocity — is somewhere around 25,000 mph (or 11.2 km/s), which the rockets we’ve developed on Earth can actually achieve. Multi-stage rockets have been launching spacecraft beyond the reach of Earth’s gravity since the 1960s, and out of even the Sun’s gravitational reach since the 1970s. But this is still only possible because of how far away we are from the surface of the Sun at the location of Earth’s orbit.

If we were instead on the surface of the Sun, the speed we’d need to achieve to escape the Sun’s gravitational pull — escape velocity — would be much greater: about 55 times as great, or 617.5 km/s. When our Sun dies, it will contract down to a white dwarf, of about 50% the Sun’s current mass but only the physical size of Earth. In this case, its escape velocity will be about 4.570 km/s, or about 1.5% the speed of light.

Sirius A and B, a normal (Sun-like) star and a white dwarf star. There are stars that get their energy from gravitational contraction, but they are the white dwarfs, which are millions of times fainter than the stars we’re more familiar with. It wasn’t until we understood nuclear fusion that we began to comprehend how stars shine.

NASA, ESA and G. Bacon (STScI)

There’s a valuable lesson in comparing the Sun, as it is today, to the Sun’s far-future fate as a white dwarf. As more and more mass gets concentrated into a small region of space, the speed required to escape this object rises. If you allowed that mass density to rise, either by compressing it into a smaller volume or adding more mass to the same volume, your escape velocity would get closer and closer to the speed of light.

That’s the key limit. Once your escape velocity at the object’s surface reaches or exceeds the speed of light, it isn’t just that light can’t get out, it’s mandatory (in General Relativity) that everything within that object inevitably collapses down to and/or falls into the central singularity. The reason is simple: the fabric of space itself falls towards the central regions faster than the speed of light. Your speed limit is less than the speed at which the space beneath your feet moves, and hence, there’s no escape.

Both inside and outside the event horizon, space flows like either a moving walkway or a waterfall, depending on how you want to visualize it. At the event horizon, even if you ran (or swam) at the speed of light, there would be no overcoming the flow of spacetime, which drags you into the singularity at the center. Outside the event horizon, though, other forces (like electromagnetism) can frequently overcome the pull of gravity, causing even infalling matter to escape.

Andrew Hamilton / JILA / University of Colorado

So if you’re at any point away from a central singularity and you’re trying to hold a more distant object up against gravitational collapse, you can’t do it; collapse is inevitable. And the most common way to crest past this limit in the first place is simple: just begin with a star more massive than about 20-40 times the mass of our Sun.

Like all true stars, it lives its life by burning through the nuclear fuel in its core region. When that fuel gets used up, the center implodes under its own gravity, creating a catastrophic supernova explosion. The outer layers are expelled, but the central region, being massive enough, collapses to a black hole. These “stellar mass” black holes, spanning an approximate range from 8-to-40 solar masses, will grow over time, as they consume any matter or energy that dares to venture too nearby. Even if you move at the speed of light when you cross the event horizon, you’ll never get out again.

The anatomy of a very massive star throughout its life, culminating in a Type II Supernova. At the end of its life, if the core is massive enough, the formation of a black hole is absolutely unavoidable.

Nicole Rager Fuller for the NSF

In fact, once you cross the event horizon, it’s an inevitability that you’ll encounter the central singularity. And from the perspective of an outside observer, once you cross the event horizon’s boundary, all you do is add to the mass, energy, charge, and angular momentum of the black hole.

From outside a black hole, we have no way to gain information about what it was initially composed of. A (neutral) black hole made from protons and electrons, neutrons, dark matter, or even antimatter would all appear identical. In fact, there are only three properties at all that we can observe about a black hole from an external location:

its mass,

its electric charge,

and its angular momentum (or intrinsic rotational spin).

An illustration of heavily curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. The radius of that location is set by the mass, charge, and angular momentum of the black hole, the speed of light, and the laws of General Relativity alone.

Pixabay user JohnsonMartin

Dark matter, even though we know what it is, is known to have mass but not electric charge. The angular momentum it adds to the black hole is entirely dependent on its initial infalling trajectory. If you were interested in other quantum numbers — for example, because you were thinking about the black hole information paradox — you’d be chagrined to learn that dark matter doesn’t have them.

Dark matter has no color charge, baryon number, lepton number, lepton family number, etc. And because black holes form from the deaths of supermassive stars (i.e., normal, baryonic matter), the initial composition of a newly-formed black hole is always approximately 100% normal matter and 0% dark matter. Even though there’s no definitive way to tell what black holes are made of from the outside alone, we’ve witnessed the direct formation of a black hole from a progenitor star; no dark matter was involved.

The visible/near-IR photos from Hubble show a massive star, about 25 times the mass of the Sun, that has winked out of existence, with no supernova or other explanation. Direct collapse is the only reasonable candidate explanation, and is one known way, in addition to supernovae or neutron star mergers, to form a black hole for the first time.

NASA/ESA/C. Kochanek (OSU)

There’s a good reason to believe that dark matter doesn’t play a role in the initial formation of black holes, but will play a role in the growth of black holes over time: from the ways it does and does not interact.

Remember that dark matter interacts only gravitationally, unlike normal matter, which interacts via the gravitational, weak, electromagnetic and strong forces. Yes, there’s perhaps five times as much dark matter total in large galaxies and clusters as there is normal matter, but that’s summed up over the entire huge halo. In a typical galaxy, that dark matter halo extends for a million light-years or more, spherically, in all directions. Contrast that with the normal matter, which is concentrated in a disk that occupies just 0.01% the dark matter’s volume.

A clumpy dark matter halo with varying densities and a very large, diffuse structure, as predicted by simulations, with the luminous part of the galaxy shown for scale. Since dark matter is everywhere, it should affect the motion of everything around it. The volume occupied by a typical dark matter halo is around 10,000 times as great as the volume occupied by the normal matter.

NASA, ESA, and T. Brown and J. Tumlinson (STScI)

Black holes tend to form in the inner regions of the galaxy, where the normal matter is dominant over dark matter. Consider just the region of space where we’re located: around our Sun. If we drew a sphere that was 100 AU in radius (where one AU is the distance of the Earth from the Sun) around our Solar System, we’d enclose all the planets, moons, asteroids and pretty much the entire Kuiper belt. We’d also enclose a fair amount of dark matter in that volume.

Quantitatively, though, the baryonic mass — the normal matter — inside this sphere would be dominated by our Sun, and would weigh about 2 × 1030 kg. (Everything else, combined, adds just another 0.2% to that total.) On the other hand, the total amount of dark matter in that same sphere? Only about 1 × 1019 kg, or just 0.0000000005% the mass of the normal matter in that same region. All the dark matter combined is about the same mass as a modest asteroid like Juno.

In the solar system, to a first approximation, the Sun determines the orbits of the planets. To a second approximation, all the other masses (like planets, moons, asteroids, etc.) play a large role. But to add in dark matter, we’d have to get incredibly sensitive: the entire contribution of all the dark matter within 100 AU of the Sun is about the same contribution as the mass of Juno, the asteroid belt’s 11th largest asteroid (by volume).

Wikipedia user Dreg743

Over time, dark matter and normal matter both will collide with this black hole, getting absorbed and adding to its mass. The vast majority of black hole mass growth will come from normal matter and not dark matter, although at some point, about 1022 years into the future, the rate of black hole decay will finally surpass the rate of black hole growth.

The Hawking radiation process results in the emission of particles and photons from outside the black hole’s event horizon, conserving all the energy, charge and angular momentum from the black hole’s insides. Perhaps the information encoded on the surface is somehow encoded in the radiation, too: this is the essence of the black hole information paradox.

Encoded on the surface of the black hole can be bits of information, proportional to the event horizon’s surface area. When the black hole decays, it decays to a state of thermal radiation. Whether that information survives and is encoded in the radiation or not, and if so, how, is not a question that our current theories can provide the answer to.

T.B. Bakker / Dr. J.P. van der Schaar, Universiteit van Amsterdam

This process may take anywhere from 1067 to 10100 years, depending on the black hole’s mass. But what comes out is simply thermal, blackbody radiation.

This means that some dark matter will come out of black holes, but that’s expected to be completely independent of whether a substantial amount of dark matter went into the black hole in the first place. All a black hole has memory of, once things have fallen in, is a small set of quantum numbers, and the amount of dark matter that went into it isn’t one of them. What comes out, at least in terms of particle content, isn’t going to be the same as what you put in!

The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. Although conventional blackbody radiation is emitted from outside the event horizon, it is unclear where, when, or how the entropy/information encoded on the surface behaves in a merger scenario.

NASA; Dana Berry, SkyWorks Digital, Inc.

If you do the math, you’ll find that black holes will use both normal matter and dark matter as a food source, but that normal matter will dominate the rate of growth of the black hole, even over long, cosmic timescales. When the Universe is more than a billion times as old as it is today, black holes will still owe more than 99% of their mass to normal matter, and less than 1% to dark matter.

Dark matter is neither a good food source for black holes, nor is it (information-wise) an interesting one. What a black hole gains from eating dark matter is no different than what it gains from shining a flashlight into it. Only the mass/energy content, like you’d get from E = mc2, matters. Black holes and dark matter do interact, but their effects are so small that even ignoring dark matter entirely still gives you a great description of black holes: past, present, and future.

Send in your Ask Ethan questions to startswithabang at gmail dot com!

  Ethan Siegel

#News

[livioacerbo]

Stephen Hawking's last paper on black holes is now online

Stephen Hawking’s last paper on black holes is now online

The information paradox arose from Hawking’s theoretical argument back in the 1970s that black holes have a temperature. As such, they’re bound to evaporate over time until there’s nothing left, releasing energy now called the “Hawking Radiation.” See, it’s believed that when an object enters a black hole, its information gets preserved on its surface forever even if it vanishes from sight. If a…

[mysticstronomy]

WHAT IS THE BLACK HOLE INFORMATION PARADOX??

Blog#256

Saturday, December 24th, 2022

Welcome back,

A black hole’s event horizon is the ultimate last-chance saloon: beyond this boundary nothing, not even light, can escape. But does this “anything” include information itself? Physicists have spent the best part of four decades grappling with the “information paradox”, but a group of researchers from the UK thinks it can offer a solution.

The researchers have created a theoretical model for the event horizon of a black hole that eschews space–time altogether. Their work also supports a controversial theory proposed in 2010 suggests that gravity is an emergent force rather than a universal fundamental interaction.

The information paradox first surfaced in the early 1970s when Stephen Hawking of Cambridge University, building on earlier work by Jacob Bekenstein at the Hebrew University of Jerusalem, suggested that black holes are not totally black.

Hawking showed that particle–antiparticle pairs generated at the event horizon – the outer periphery of a black hole – would be separated. One particle would fall into the black hole while the other would escape, making the black hole a radiating body.

Hawking’s theory implied that, over time, a black hole would eventually evaporate away, leaving nothing. This presented a problem for quantum mechanics, which dictates that nothing, including information, can ever be lost. If black holes withheld information forever in their singularities, there would be a fundamental flaw with quantum mechanics.

The significance of the information paradox came to a head in 1997 when Hawking, together with Kip Thorne of the California Institute of Technology (Caltech) in the US, placed a bet with John Preskill, also of Caltech. At the time, Hawking and Thorne both believed that information was lost in black holes, while Preskill thought that it was impossible. Later, however, Hawking conceded the bet, saying he believed that information is returned – albeit in a disguised state.

At the turn of this century, Maulik Parikh of the University of Utrecht in the Netherlands, together with Frank Wilczek of the Institute of Advanced Study in Princeton, US, showed how information could leak away from a black hole. In their theory, information-carrying particles just within the event horizon could tunnel through the barrier, following the principles of quantum mechanics. But this solution, too, remained debatable.

Now, Samuel Braunstein and Manas Patra of the University of York in the UK think they have formulated a tunnelling theory that looks rather more attractive than Parikh and Wilczek’s theory.

“We cannot claim to have proven that escape from a black hole is truly possible,” they explain, “but that is the most straightforward interpretation of our results.

Normally, theorists dealing with black holes have to wrestle with the complex geometries of space–time arising from Einstein’s theory of gravitation – the theory of general relativity. In their model, Braunstein and Patra say that the event horizon is purely quantum mechanical in nature, with bits of quantum “Hilbert” space tunnelling through the barrier.

Originally published on physicsworld.com

COMING UP!!

(Wednesday, December 28th, 2022)

"WHAT IS THE BOOTSTRAP PARADOX??"

[computerguideworld-blog]

Quantum Computer Experiment Suggests How To Get Information Out Of Black Holes

New Post has been published on https://computerguideto.com/must-see/quantum-computer-experiment-suggests-how-to-get-information-out-of-black-holes/

Quantum Computer Experiment Suggests How To Get Information Out Of Black Holes

Black holes are one of those physical objects whose complete description escapes our theories. Quantum mechanics and general relativity don’t work particularly well together and this leads to paradoxes. According to relativity, nothing can escape a black hole, but in quantum mechanics, no information is ever lost.

This is the information paradox that physicists, including the late Stephen Hawking, have tried to find a solution to. In a paper published in Nature, researchers used a seven-qubit quantum computer to simulate whether or not information can be retrieved when something falls into a black hole. Now, researchers think that it is indeed possible.

Black holes emit a small amount of radiation from the region just outside the event horizon, the point of no return. This is known as Hawking radiation, and it leads over an incredible amount of time to black holes evaporating. Physicists believe that if they were able to study the black holes for this amount of time, the information would all be there.

But there might be another way. These Hawking photons are entangled with particles that fell in the black hole, which is very useful. Entangled particles are in a single quantum state even if they are separated by huge distances, so the properties of one affects the properties of the other.

Since quantum information is the same everywhere, the team was able to construct an analogous black hole. Researchers supposed that it would be possible to drop an entangled qubit inside a black hole to get some useful information from the escaping Hawking radiation.

“One can recover the information dropped into the black hole by doing a massive quantum calculation on these outgoing Hawking photons,” co-author Norman Yao, a UC Berkeley assistant professor of physics, said in a statement. “This is expected to be really, really hard, but if quantum mechanics is to be believed, it should, in principle, be possible. That’s exactly what we are doing here, but for a tiny three-qubit ‘black hole’ inside a seven-qubit quantum computer.”

The experimental set up has demonstrated the phenomenon of quantum information scrambling for the first time. Quantum scrambling is a chaotic shuffling of the information stored among a system made of many quantum particles. By measuring scrambling, the team can directly probe the dynamics of this process as well as create a good analogous for black holes.

This approach could be used to potentially diagnose complex noise in quantum computers and improve them.

Read more: http://www.iflscience.com

[tech-only-blog]

Stephen Hawking's last paper on black holes is now online

Stephen Hawking’s last paper on black holes is now online

The information paradox arose from Hawking’s theoretical argument back in the 1970s that black holes have a temperature. As such, they’re bound to evaporate over time until there’s nothing left, releasing energy now called the “Hawking Radiation.” See, it’s believed that when an object enters a black hole, its information gets preserved on its surface forever even if it vanishes from sight. If…

[princeashy]

Stephen Hawking's last paper on black holes is now online

Stephen Hawking's last paper on black holes is now online

[ad_1]

The information paradox arose from Hawking’s theoretical argument back in the 1970s that black holes have a temperature. As such, they’re bound to evaporate over time until there’s nothing left, releasing energy now called the “Hawking Radiation.” See, it’s believed that when an object enters a black hole, its information gets preserved on its surface forever even if it vanishes from…

[theliterateape]

We're All Going To Die!

By Chris Churchill

If the experience of life has taught me anything, it has taught me that people like staying alive. Somewhere in the very essence of what it is to be alive is that special feeling that philosophers call “qualia of consciousness." Being alive feels like something. Here we are, inside our little meatboxes, looking out at all the other meatboxes and we know they’re feeling like they’re alive too. Most all of us like being alive. At the most primitive level, we hate that we won’t be alive at some point. The fear of not being alive anymore is huge. We don’t want to die.

But we’re all going to die!

I don’t just mean that, someday, eventually, we will all, individually, one-by-one, in our own time, die. Cue tiny voice in your head, saying, “Well the species will carry on.”

No it won’t.

We’re all gonna die! The animals? Yes. The plants? Yes? Those new tardigrades they discovered? Yes. The mushrooms? Yep. We’re all gonna die. Here’s what you need to know:

First off, we’re very lucky to even still be here. According to a group of Oxford geneticists, it was shown that in the early history of ancient man, we were down to merely 4,000 individuals.  According to science writer Sam Kean in his book The Violinist’s Thumb our ancestors almost went completely extinct (possibly 40 humans) in 70,000 BC. when a volcano called Toba on the island of Sumatra blew up. It was 2,800 times stronger than Mt. Saint Helen’s in 1980 and nearly 1,000 times stronger than Mt. Vesuvius in 79 AD. It caused a layer of ash 6cm deep all over the globe and it likely blotted out the sun for six years. In 1816, Mount Tambora in Indonesia blew and caused “A Year Without a Summer” in the Northern Hemisphere because it shot 80 cubic kilometers of volcano vomit into the sky. That’s compared to Mont Toba’s 2,800 cubic kilometers in 70,000 BC.

So think of that. In very recent history, we almost ceased to exist as a species. If it were to happen again (I’m looking at you, Yellowstone Super Volcano), there would be nothing we could do about it. Like Clubber Lang in Rocky III, the earth has “got a lotta mo” for us.

But if that doesn’t do us in, there are a lot of other options for erasing us and everything our species every accomplished, figured out, learned, loved, hated, created, developed… whatever. Here we go:

CERN. Some people think CERN already had an accident and that’s why the Cubs won the 2016 World Series and Trump got elected president of the United States of America. In doing whatever the hell it was supposed to be doing, smashing subatomic particles together to see what happens, I guess, it caused our universe and neighboring parallel universe to bump into each other, causing events from the two universes to be intermingled and the Mandela Effect was born. Look it up. It’s fun, if you like going insane. The problem with saying CERN destroyed us is, well, we’re still here. Regardless of the universe we are currently experiencing, we are still experiencing something, which is what living things do. So… we’re not dead yet. But CERN could screw up worse. It could blow us up, or what could happen is that CERN or whatever comes next in that technology could cause a mini black hole. A small enough one will evaporate due to Hawking radiation but a big enough one just swallows us up into nothing. Or what if the reaction just scrambles the laws of physics and speilking (sp? OH NO! IT’S HAAPPENING!). How many times do we get lucky before some scientists make a tiny error that kills us all?

There are also rogue black holes. They exist and we wouldn’t be able to notice them until we were past the event horizon and onto that matterfall fun ride to spaghettification.

Have you heard of gamma ray bursts? Not the kind that make you the Incredible Hulk. An incredible burst of gamma radiation across the universe caused by a collision of two collapsed stars. It has 10 quadrillion times more energy than our sun. By the time we see it, because it’s a time of light energy, we will be in the process of quickly dying. Every last one of us. We’d never see it coming. It could happen right now. Or… NOW! Grrrrr… NOW!! Or in two weeks. Or after you're dead from head injuries from all your street brawling.

But I supposed some of you don’t feel science stuff like that. Here are some more threats to ruin your day. The sun, absolutely will destroy the Earth in five billion years when it dies and, selfishly, takes us with it. It will expand into a red dwarf and burn up everything, including your favorite ice cream shop. The one where they know what you like and they call you by name and sometimes they forget to charge you. That one. It’ll be all burned up. Thanks, Sun.

But we probably won’t make it that far anyway. Get this: Our success as a species could kill us. Harvard Biologist E.O. Wilson has shown that we make up 100 times the biomass of any large animal in Earth’s history. We weigh 750 billion pounds. So there. Now you know how much all of us weigh. There are currently seven billion of us, but we keep expanding. The UN website projects that we’ll hit 10 billion by 2044 and could hit 36 fothermucking billion by 2300. If that sounds crowded and you worry about how you’ll feel in a crowd like that after medical science allows you to live to the year 2300, don’t worry. You’ll be dead anyway.    

According to David Quammen’s book, Spillover, we might not get that far because at population densities like that we are likely to see deadly viruses being easily transmitted at a speed we’ve never seen. Walking Dead time, people. Except, no sheriff can save us.

Quammen says the next big plague will be worse than the Black Death and Spanish Flu and nut allergies combined!

Asteroids! NASA’s Near Earth Object Program predicts that on April 23, 2029 and April 23, 2036 (exactly seven years apart—just enough time for the Rapture and the Tribulation to start and finish, if you like to think about that stuff), an asteroid called Apophis will come within 18,300 miles of Earth. Lucky… this time.

Of course, as anyone who’s ever spoken to or even seen another human in action can tell you, we’re most likely to all die from our own stupidity as a species. To elicit Halloween style fright, “It’s coming from inside the house!” We're the ones that will kill us! Obviously, wars, poisons, environmental issues. All we can do to escape our fate, if it is at all possible, is to work together as a species to delay or completely prevent these events from affecting us.

We got to the moon only 65 years after the invention of the airplane and the moon landing set in A Trip to the Moon (for those who believe it was staged). We’ve landed probes on Mars. We’ve shot stuff way out in space. Ultimately, we’ll have to speed through Michio Kaku’s  3 Civilization Types to solve all these problems. Type 1 is when a species masters a planet and the energy resources within. Type 2 is when a species masters the power of the solar system. Type 3 is when we master the power of the galaxy.

But we will have to figure out all of our species specific problems before we can even become a Type 1 civilization. And, in this time of year when all is focused on death and darkness, death and darkness is what I currently predict for life on Earth.

WE ARE ALL GOING TO DIE! Happy Halloween!

[sciencespies]

Ask Ethan: Can Black Holes And Dark Matter Interact?

https://sciencespies.com/news/ask-ethan-can-black-holes-and-dark-matter-interact/

Ask Ethan: Can Black Holes And Dark Matter Interact?

An illustration of an active black hole, one that accretes matter and accelerates a portion of it outwards in two perpendicular jets. The normal matter undergoing an acceleration like this describes how quasars work extremely well. The matter that falls into a black hole, of any variety, will be responsible for additional growth in both mass and event horizon size for the black hole, whether it’s normal matter or dark matter.

Mark A. Garlick

Black holes are some of the most extreme objects in the Universe: the only locations where there’s so much energy in a tiny volume of space that an event horizon gets created. When they form, atoms, nuclei, and even fundamental particles themselves are crushed down to an arbitrarily small volume — to a singularity — in our three-dimensional space. At the same time, everything that falls past the event horizon is forever doomed, simply adding to the black hole’s gravitational pull. What does that mean for dark matter? Patreon supporter kilobug asks:

How does dark matter interact with black holes? Does it get sucked into the singularity like normal matter, contributing to the mass of the black hole? If so, when the black hole evaporates through Hawking radiation, what happens to [it]?

To answer this, we have to start at the beginning: with what a black hole actually is.

The very first launch from NASA’s Cape Kennedy space center was of the Apollo 4 rocket. Although it accelerated no faster than a sportscar, the key to its success was that the acceleration was sustained for so long, enabling payloads to escape Earth’s atmosphere and enter orbit. Eventually, multi-stage rockets would enable humans to escape the gravitational pull of the Earth entirely. The Saturn V rockets later took humanity to the Moon.

NASA

Here on Earth, if you want to send something into space, you need to overcome the Earth’s gravitational pull. The way we normally think about this is in terms of balancing two forms of energy: the gravitational potential energy provided by the Earth itself at its surface, compared with the kinetic energy you’d have to add to your payload to escape from Earth’s gravitational pull.

If you balance these energies, you can derive your escape velocity: how fast you’d have to make an object go for it to eventually achieve an arbitrarily large distance away from the Earth. Even though the Earth has an atmosphere, providing resistance to that motion and requiring us to impart even more energy to a payload than the escape velocity would imply, escape velocity is still a useful physical concept for us to consider.

If the Earth had no atmosphere, then firing a cannonball at a particular speed would be enough to determine whether it fell back to Earth (A, B), remained in a stable orbit around Earth (C, D), or escaped from Earth’s gravitational pull (E). For all objects that aren’t black holes, all five of these trajectories are possible. For objects that are black holes, trajectories like C, D, and E are impossible inside the event horizon.

Wikimedia Commons user Brian Brondel

For our planet, that calculated speed — or escape velocity — is somewhere around 25,000 mph (or 11.2 km/s), which the rockets we’ve developed on Earth can actually achieve. Multi-stage rockets have been launching spacecraft beyond the reach of Earth’s gravity since the 1960s, and out of even the Sun’s gravitational reach since the 1970s. But this is still only possible because of how far away we are from the surface of the Sun at the location of Earth’s orbit.

If we were instead on the surface of the Sun, the speed we’d need to achieve to escape the Sun’s gravitational pull — escape velocity — would be much greater: about 55 times as great, or 617.5 km/s. When our Sun dies, it will contract down to a white dwarf, of about 50% the Sun’s current mass but only the physical size of Earth. In this case, its escape velocity will be about 4.570 km/s, or about 1.5% the speed of light.

Sirius A and B, a normal (Sun-like) star and a white dwarf star. There are stars that get their energy from gravitational contraction, but they are the white dwarfs, which are millions of times fainter than the stars we’re more familiar with. It wasn’t until we understood nuclear fusion that we began to comprehend how stars shine.

NASA, ESA and G. Bacon (STScI)

There’s a valuable lesson in comparing the Sun, as it is today, to the Sun’s far-future fate as a white dwarf. As more and more mass gets concentrated into a small region of space, the speed required to escape this object rises. If you allowed that mass density to rise, either by compressing it into a smaller volume or adding more mass to the same volume, your escape velocity would get closer and closer to the speed of light.

That’s the key limit. Once your escape velocity at the object’s surface reaches or exceeds the speed of light, it isn’t just that light can’t get out, it’s mandatory (in General Relativity) that everything within that object inevitably collapses down to and/or falls into the central singularity. The reason is simple: the fabric of space itself falls towards the central regions faster than the speed of light. Your speed limit is less than the speed at which the space beneath your feet moves, and hence, there’s no escape.

Both inside and outside the event horizon, space flows like either a moving walkway or a waterfall, depending on how you want to visualize it. At the event horizon, even if you ran (or swam) at the speed of light, there would be no overcoming the flow of spacetime, which drags you into the singularity at the center. Outside the event horizon, though, other forces (like electromagnetism) can frequently overcome the pull of gravity, causing even infalling matter to escape.

Andrew Hamilton / JILA / University of Colorado

So if you’re at any point away from a central singularity and you’re trying to hold a more distant object up against gravitational collapse, you can’t do it; collapse is inevitable. And the most common way to crest past this limit in the first place is simple: just begin with a star more massive than about 20-40 times the mass of our Sun.

Like all true stars, it lives its life by burning through the nuclear fuel in its core region. When that fuel gets used up, the center implodes under its own gravity, creating a catastrophic supernova explosion. The outer layers are expelled, but the central region, being massive enough, collapses to a black hole. These “stellar mass” black holes, spanning an approximate range from 8-to-40 solar masses, will grow over time, as they consume any matter or energy that dares to venture too nearby. Even if you move at the speed of light when you cross the event horizon, you’ll never get out again.

The anatomy of a very massive star throughout its life, culminating in a Type II Supernova. At the end of its life, if the core is massive enough, the formation of a black hole is absolutely unavoidable.

Nicole Rager Fuller for the NSF

In fact, once you cross the event horizon, it’s an inevitability that you’ll encounter the central singularity. And from the perspective of an outside observer, once you cross the event horizon’s boundary, all you do is add to the mass, energy, charge, and angular momentum of the black hole.

From outside a black hole, we have no way to gain information about what it was initially composed of. A (neutral) black hole made from protons and electrons, neutrons, dark matter, or even antimatter would all appear identical. In fact, there are only three properties at all that we can observe about a black hole from an external location:

its mass,

its electric charge,

and its angular momentum (or intrinsic rotational spin).

An illustration of heavily curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. The radius of that location is set by the mass, charge, and angular momentum of the black hole, the speed of light, and the laws of General Relativity alone.

Pixabay user JohnsonMartin

Dark matter, even though we know what it is, is known to have mass but not electric charge. The angular momentum it adds to the black hole is entirely dependent on its initial infalling trajectory. If you were interested in other quantum numbers — for example, because you were thinking about the black hole information paradox — you’d be chagrined to learn that dark matter doesn’t have them.

Dark matter has no color charge, baryon number, lepton number, lepton family number, etc. And because black holes form from the deaths of supermassive stars (i.e., normal, baryonic matter), the initial composition of a newly-formed black hole is always approximately 100% normal matter and 0% dark matter. Even though there’s no definitive way to tell what black holes are made of from the outside alone, we’ve witnessed the direct formation of a black hole from a progenitor star; no dark matter was involved.

The visible/near-IR photos from Hubble show a massive star, about 25 times the mass of the Sun, that has winked out of existence, with no supernova or other explanation. Direct collapse is the only reasonable candidate explanation, and is one known way, in addition to supernovae or neutron star mergers, to form a black hole for the first time.

NASA/ESA/C. Kochanek (OSU)

There’s a good reason to believe that dark matter doesn’t play a role in the initial formation of black holes, but will play a role in the growth of black holes over time: from the ways it does and does not interact.

Remember that dark matter interacts only gravitationally, unlike normal matter, which interacts via the gravitational, weak, electromagnetic and strong forces. Yes, there’s perhaps five times as much dark matter total in large galaxies and clusters as there is normal matter, but that’s summed up over the entire huge halo. In a typical galaxy, that dark matter halo extends for a million light-years or more, spherically, in all directions. Contrast that with the normal matter, which is concentrated in a disk that occupies just 0.01% the dark matter’s volume.

A clumpy dark matter halo with varying densities and a very large, diffuse structure, as predicted by simulations, with the luminous part of the galaxy shown for scale. Since dark matter is everywhere, it should affect the motion of everything around it. The volume occupied by a typical dark matter halo is around 10,000 times as great as the volume occupied by the normal matter.

NASA, ESA, and T. Brown and J. Tumlinson (STScI)

Black holes tend to form in the inner regions of the galaxy, where the normal matter is dominant over dark matter. Consider just the region of space where we’re located: around our Sun. If we drew a sphere that was 100 AU in radius (where one AU is the distance of the Earth from the Sun) around our Solar System, we’d enclose all the planets, moons, asteroids and pretty much the entire Kuiper belt. We’d also enclose a fair amount of dark matter in that volume.

Quantitatively, though, the baryonic mass — the normal matter — inside this sphere would be dominated by our Sun, and would weigh about 2 × 1030 kg. (Everything else, combined, adds just another 0.2% to that total.) On the other hand, the total amount of dark matter in that same sphere? Only about 1 × 1019 kg, or just 0.0000000005% the mass of the normal matter in that same region. All the dark matter combined is about the same mass as a modest asteroid like Juno.

In the solar system, to a first approximation, the Sun determines the orbits of the planets. To a second approximation, all the other masses (like planets, moons, asteroids, etc.) play a large role. But to add in dark matter, we’d have to get incredibly sensitive: the entire contribution of all the dark matter within 100 AU of the Sun is about the same contribution as the mass of Juno, the asteroid belt’s 11th largest asteroid (by volume).

Wikipedia user Dreg743

Over time, dark matter and normal matter both will collide with this black hole, getting absorbed and adding to its mass. The vast majority of black hole mass growth will come from normal matter and not dark matter, although at some point, about 1022 years into the future, the rate of black hole decay will finally surpass the rate of black hole growth.

The Hawking radiation process results in the emission of particles and photons from outside the black hole’s event horizon, conserving all the energy, charge and angular momentum from the black hole’s insides. Perhaps the information encoded on the surface is somehow encoded in the radiation, too: this is the essence of the black hole information paradox.

Encoded on the surface of the black hole can be bits of information, proportional to the event horizon’s surface area. When the black hole decays, it decays to a state of thermal radiation. Whether that information survives and is encoded in the radiation or not, and if so, how, is not a question that our current theories can provide the answer to.

T.B. Bakker / Dr. J.P. van der Schaar, Universiteit van Amsterdam

This process may take anywhere from 1067 to 10100 years, depending on the black hole’s mass. But what comes out is simply thermal, blackbody radiation.

This means that some dark matter will come out of black holes, but that’s expected to be completely independent of whether a substantial amount of dark matter went into the black hole in the first place. All a black hole has memory of, once things have fallen in, is a small set of quantum numbers, and the amount of dark matter that went into it isn’t one of them. What comes out, at least in terms of particle content, isn’t going to be the same as what you put in!

The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. Although conventional blackbody radiation is emitted from outside the event horizon, it is unclear where, when, or how the entropy/information encoded on the surface behaves in a merger scenario.

NASA; Dana Berry, SkyWorks Digital, Inc.

If you do the math, you’ll find that black holes will use both normal matter and dark matter as a food source, but that normal matter will dominate the rate of growth of the black hole, even over long, cosmic timescales. When the Universe is more than a billion times as old as it is today, black holes will still owe more than 99% of their mass to normal matter, and less than 1% to dark matter.

Dark matter is neither a good food source for black holes, nor is it (information-wise) an interesting one. What a black hole gains from eating dark matter is no different than what it gains from shining a flashlight into it. Only the mass/energy content, like you’d get from E = mc2, matters. Black holes and dark matter do interact, but their effects are so small that even ignoring dark matter entirely still gives you a great description of black holes: past, present, and future.

Send in your Ask Ethan questions to startswithabang at gmail dot com!

  Ethan Siegel

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