Category Archives: Singularity

Professor of Particle Physics, University of Liverpool I was head of Particle Physics at Liverpool, from 2011-2019. My aim was to support the group to tackle the most fundamental of problems in Physics.

The group has experiments at CERN, Fermilab and in Tokai (Japan) as well as SNOlab in Canada. We work at the energy frontier (ATLAS) and precision frontiers (LHCb) at CERN and g-2 (FNAL). We have a program understanding the properties of neutrinos at T2K and HK (Japan), Proto-Dune and DUNE. The group has played in important role in terrestrial measurements of Dark Energy/Matter and Gravitational Waves using Quantum Technologies and has joined the MAGIS experiment at FNAL and LZ experiment for DM (dark matter). All these experiments should lead us to a better understanding of the nature of matter (luminous and dark), to understand the predominance of matter over anti-matter, to understand the properties of neutrinos, and to make first measurements of DE. I initiated Liverpool's muon program which now includes mu2e and mu3e as experiments.

I strongly believe that the group must be involved closely with both theoretical developments and enabling technologies and am actively involved in building relationships between our engineering departments and CERN and other international partner laboratories.

From 1997-2011 my LHCb group to build the VELO detectors which is one of the highest precision detectors at the LHC and has enabled the LHCb experiment to make critical measurements of the properties of B meson days. Previously I was a member of the DELPHI group where I made precision measurements of B-lifetimes and WW couplings.

I am currently working on the LHCb upgrade due to take data early 2022. I am also working on the g-2 experiment at FNAL, where Liverpool built the tracking detectors, and hopes is studying the anomalous magnetic moment of the muon and its electric dipole moment (EDM). I am also trying to build a small lab experiment to attempt to look for evidence of the foam like nature of space and time at the Planck scale.

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Professor of Particle Physics, University of Liverpool - Singularity Hub

Genealogy services have grown in popularity in recent years. Ancestry.com and 23andMe let users analyze their DNA to show their ethnic makeup, connect with relatives they didnt know they had, create online family trees, and search databases for information about ancestors. Now a third service, called MyHeritage, has added a particularly unique feature to this list: bringing photos of your deceased relatives alive by adding animations like blinking, nodding, head-bopping, and a number of other gestures.

The feature is called Deep Nostalgia, and it was launched in late February of this year. It initially let users animate one person in a photo for a few seconds, in a way that made it seem like you could see their face right before or after the photo was takensort of like the iPhones live photos feature. Photo subjects would move their heads, blink, or smile in a way that looked pretty darn realistic. Far from being weirded out, MyHeritage users seemed to embrace the feature wholeheartedly; the site claims that in just five weeks, people created over 72 million photo animations.

This week MyHeritage added 10 new drivers, or videos of actions you can make the pictures do, to the Deep Nostalgia service; people in photos can now be made to blow a kiss, nod approval, and bop their heads in a dance-y way, to name just a few.

Deep Nostalgia uses a deep learning algorithm created by a company called D-ID, short for de-identification. The software analyzes a photo to determine which way the subject is looking and which direction their head is facing. Then it finds a compatible drivera video of a face doing whatever the person in the photo will end up doingto guide how the photo is animated.

You can use Deep Nostalgia for free to animate up to five photos if you have a MyHeritage account. The sites blog says its users were moved to tears to see their ancestors look around and smile at them. Though its on a whole different level, this brings to mind the chatbots or digital avatars of deceased people that can be created using their old texts, emails, and recorded conversations.

We can call these things bizarre, creepy, or ethically questionable, as theyre using technology to play to peoples emotions with products that, at the end of the day, arent real. But if they make people feel good or help ease the loss of a loved one, perhaps theyre not all bad (the chatbot is up for debate, IMO). Many MyHeritage users tweeted their photo animations and expressed how moved they were by them.

The animated photos dont quite qualify as deepfakes. Deepfakes typically map someones facial expressions (e.g., an actor) onto someone else to make it seem like the person said or did something they did not in fact say or do. In this case, theres no actor and no intention to deceive. But Deep Nostalgia shows how this sort of technology is slowly creeping into unexpected places; whod have thought youd ever be able to make a photo of your great-grandmother wink at you?

Some uses of the technology, like this one, will be fun and harmless. While we enjoy these, we must also be cautious of applications that are meant to deceive, and keep a close eye on whether even the harmless uses are emotionally healthy for us.

In the meantime, why limit the photo animations to deceased relatives? They seem like the perfect way to spice up a school picture, add some flare to a birthday or anniversary card, or just make someone laugh.

Image Credit: MyHeritage

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'Deep Nostalgia' Uses AI to Make Old Photos of Your Relatives Wink, Nod, Dance, and More - Singularity Hub

Seven years ago, a huge magnet was transported over 3,200 miles (5,150km) across land and sea, in the hope of studying a subatomic particle called a muon.

Muons are closely related to electrons, which orbit every atom and form the building blocks of matter. The electron and muon both have properties precisely predicted by our current best scientific theory describing the subatomic quantum world, the standard model of particle physics.

A whole generation of scientists have dedicated themselves to measuring these properties in exquisite detail. In 2001, an experiment hinted that one property of the muon was not exactly as the standard model predicted, but new studies were needed to confirm. Physicists moved part of the experiment to a new accelerator, at Fermilab, and started taking more data.

A new measurement has now confirmed the initial result. This means new particles or forces may exist that arent accounted for in the standard model. If this is the case, the laws of physics will have to be revised and no one knows where that may lead.

This latest result comes from an international collaboration, of which we are both a part. Our team has been using particle accelerators to measure a property called the magnetic moment of the muon.

Each muon behaves like a tiny bar magnet when exposed to a magnetic field, an effect called the magnetic moment. Muons also have an intrinsic property called spin, and the relation between the spin and the magnetic moment of the muon is known as the g-factor. The g of the electron and muon is predicted to be two, so g minus two (g-2) should be measured to be zero. This is whats were testing at Fermilab.

For these tests, scientists have used accelerators, the same kind of technology CERN uses at the LHC. The Fermilab accelerator produces muons in very large quantities and measures, very precisely, how they interact with a magnetic field.

The muons behavior is influenced by virtual particles that pop in and out of existence from the vacuum. These exist fleetingly, but for long enough to affect how the muon interacts with the magnetic field and change the measured magnetic moment, albeit by a tiny amount.

The standard model predicts very precisely, to better than one part in a million, what this effect is. As long as we know what particles are bubbling in and out of the vacuum, experiment and theory should match. But, if experiment and theory dont match, our understanding of the soup of virtual particles may be incomplete.

The possibility of new particles existing is not idle speculation. Such particles might help in explaining several of the big problems in physics. Why, for example, does the universe have so much dark mattercausing the galaxies to rotate faster than wed expectand why has nearly all the anti-matter created in the Big Bang disappeared?

The problem to date has been that nobody has seen any of these proposed new particles. It was hoped the LHC at CERN would produce them in collisions between high energy protons, but theyve not yet been observed.

The new measurement used the same technique as an experiment at Brookhaven National Laboratory in New York, at the beginning of the century, which itself followed a series of measurements at CERN.

The Brookhaven experiment measured a discrepancy with the standard model that had a 1 in 5,000 chance of being a statistical fluke. This is approximately the same probability as throwing a coin 12 times in a row, all heads up.

This was tantalizing, but way below the threshold for discovery, which is generally required to be better than one in 1.7 millionor 21 coin throws in a row. To determine whether new physics were in play, scientists would have to increase the sensitivity of the experiment by a factor of four.

To make the improved measurement, the magnet at the heart of the experiment had to be moved in 2013 3,200 miles from Long Island along sea and road, to Fermilab, outside Chicago, whose accelerators could produce a copious source of muons.

Once in place, a new experiment was built around the magnet with state of the art detectors and equipment. The muon g-2 experiment began taking data in 2017, with a collaboration of veterans from the Brookhaven experiment and a new generation of physicists.

The new results, from the first year of data at Fermilab, are in line with the measurement from the Brookhaven experiment. Combining results reinforces the case for a disagreement between experimental measurement and the standard model. The chances now lie at about one in 40,000 of the discrepancy being a flukestill shy of the gold standard discovery threshold.

Intriguingly, a recent observation by the LHCb experiment at CERN also found possible deviations from the standard model. Whats exciting is that this also refers to the properties of muons. This time its a difference in how muons and electrons are produced from heavier particles. The two rates are expected to be the same in the standard model, but the experimental measurement found them to be different.

Taken together, the LHCb and Fermilab results strengthen the case that weve observed the first evidence of the standard model prediction failing, and that there are new particles or forces in nature out there to be discovered.

For the ultimate confirmation, this needs more data both from the Fermilab muon experiment and from CERNs LHCb experiment. Results will be forthcoming in the next few years. Fermilab already has four times more data than was used in this recent result, currently being analyzed, CERN has started taking more data and a new generation of muon experiments is being built. This is a thrilling era for physics.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Image Credit: Fermilab/Reidar Hahn

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Scientists Found Hints of New Particles or Forces of Nature, and It Could Change Physics - Singularity Hub

This may be the era of the home run. But in one way roster construction five American League teams are summoning the ghosts of the MLB dead ball era.

The Orioles, Red Sox, Blue Jays, Mariners, and Rangers all entered play Friday carrying just a dozen position players on their 26-man roster. Subtracting 14-man pitching staffs plus their regulars and their DH, that leaves the managers of those teams with just three every-day substitutes.

Thats the kind of roster constriction big league managers havent faced since the days when clubs traveled by rail, only washed woolen uniforms twice a week, and drew crowds of a few thousand to wooden stadiums.

Just one week into the season, teams are already beginning to see the kinds of problems those roster limitations can create.

Toronto Blue Jays manager Charlie Montoyo faced that circumstance for the first but likely not the last time Thursday in the teams home opener in Dunedin. Facing the Los Angeles Angels, Montoyo began the game with only outfielder Jonathan Davis, backup catcher Alejandro Kirk and DH Rowdy Tellez available to him.

Virtually from the outset of what developed into a tight 5-5 battle, the limited options appeared to influence Montoyos decisions. After Joe Panik led off the seventh inning with a double, Montoyo held off pinch hitting for his ninth hitter catcher Danny Jansen who is hitting .143 not wanting to burn his limited options too quickly. Jansen grounded out, Panik did not advance and the Jays did not push across the lead run.

Two innings later, the game still tied, Montoyo made his move. With none on and two out, he sent Tellez up to pinch hit for Jansen in the hope of averting extra innings. Then when Tellez walked, he burned Davis as a pinch runner. That move backfired when Angels pitcher Steve Cishek picked Davis off to send the game into extra innings.

After the Angels failed to score, Montoyo used his final option, pinch running Kirk for Davis at second base. But the Jays could not move Kirk, sending the game to an 11th inning with Montoyo out of substitutes.

The Angels scored twice in the 11th and won the game 7-5.

All five of the teams operating with just three every-day subs are applying essentially the same formula: One extra catcher, one utility infielder and a fourth outfielder. They are all carrying 14 pitchers, one more than the 13 being carried by most teams.

The spare infielder can almost always play multiple positions, and the spare outfielder sometimes packs a first basemans glove.

The Los Angeles Angels are also carrying 14 pitchers, but of course one of them is Shohei Ohtani, who theoretically could play in the outfield. That singularity gives Angels manager Joe Maddon four available bodies, typically catcher Kurt Suzuki, infielder Jose Rojas, outfielder Juan Lagares, and either Ohtani or Albert Pujols, whichever isnt in that days lineup.

One has to go back nearly 90 years to find a successful team that carried that few bench regulars. During his teams 1929 World Championship run, Athletics manager (and team owner) Connie Mack often traveled with as few as 18 players, 11 regulars and seven pitchers.

That year only nine non-pitchers catcher Mickey Cochrane, first baseman Jimmie Foxx, second baseman Max Bishop, shortstop Joe Boley, third baseman Sammy Hale, outfielders Al Simmons, Bing Miller, and Mule Haas, and utility man Jimmy Dykes got as many as 90 plate appearances during the 154-game regular season. In that years World Series which Macks team won in five games he used just 11 regulars and six pitchers.

But to find a large group of teams as routinely personnel-strapped as those five AL teams are at present, it is necessary to go back to the first decade of the 20th Century. In 1902, only 186 non-pitchers on the 16 existing teams thats an average of about 11.6 per team got as many as 100 plate appearances.

While MLB plate appearances is an imperfect method of estimating normal roster size, its the best we have and it suggests that several current managers are dealing with the kinds of limited in-game personnel options that havent confounded their peers in more than a century.

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MLB roster moves: The vanishing bench player - Call to the Pen

Though we dont quite have the technology to make three-dimensional holograms a reality yet, companies like PORTL and Microsoft are working on it. But a third company decided to forego the traditional approach and came up with a whole new way to create 3D shapes made of light.

LED Pulse uses thousands of strings of LED lights to make volumetric displays that, while not technically holograms, look a lot like them. The latest iteration of their technology is called Dragon O, and it can be as big as a room and display any sort of content its creators can dream up.

Writing in Digital Trends, Luke Dormehl likens the setup to 100 beaded string curtains where every bead is a tiny light, with dozens of curtains positioned one in front of the other. The company calls the individual lights LED neurons, and compares their function to that of neurons in the human brain; both receive information through electrical impulses, and while capable of functioning independently, can only create an idea (or, in this case, an image) when working cohesively.

Our brain is a machine that constructs reality, selects and filters the necessary information, the companys website says. Similarly, the light displays they create can be configured to produce any sort of visual they choose, including moving images.

While LED neurons may be an interesting approximation, the lights can also be called voxels. You can think of a voxel as the 3D version of a pixel; if a pixel is a square or a point on a flat, two-dimensional image on a screen, a voxel is a point on a grid in three-dimensional space. Put in a way thats easier to picture, its a cube inside a 3D model. The layered setup of voxels means LED Pulses installations are truly three-dimensional; any different angle you view them from, youll see something different, same as viewing an object or a person in real life.

If you have a volumetric human made out of light, and you walk around the back, you will see their back. If you go to the left, you will see the left arm. Its all exactly how it would be in the real world, said LED Pulses founder, Danilo Grande. Every time we create an exhibition, we invite people to walk around, not to stay in one place only.

The company measures its light displays in cuboids (like cubes, except rectangular instead of square-shaped, meaning not all sides are the same length). Each cuboid has a volume of three cubic meters and contains 24,000 voxels. Cuboids can be put together to make larger displays, with the largest thus far consisting of 6 cuboids and a corresponding 144,000 voxels.

Dragon O has been used in a Lancome perfume launch, a game called Virus Killer, a nightclub in Berlin, and events in Shenzhen, Barcelona, and Munich.

The Munich event was an anniversary party for a German company called BrainLab, which makes hardware and software to enhance medical data collection and presentation. Dragon O created 3D images of the brain, exploring potential applications of its technology in scientific or medical fields.

Though Dragon O is, at the moment, mostly just an artistic experience, LED Pulse is optimistic about finding practical applications for its technology, including the same thing PORTL and Microsoft are working on: teleporting real-time 3D images of people to different locations to meet and collaborate with others.

In the meantime, as the world starts to open up again, we hope to see Dragon O lighting up the night (or day) at events and exhibitions around the world.

Image Credit: LED Pulse

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This Huge Hologram-Like 3D Display Is Made of Thousands of Tiny LED Lights - Singularity Hub

There are many methods that can be used to break people out of their comfort zones. What is not as common, are methods that achieve this while training teams and pulling people out of isolation. Techpreneur Marshall Moser has achieved all of the above thanks to virtual reality (VR).

After graduating from the University of Georgia in 2015 with a triple major in biology, psychology, and economics, followed by a masters degree in public health administration, Marshall put his impressive education to use in the tech sector. He participated in a program called Singularity Universitya joint venture between NASA and Googlewhere he build VR environments triggered by variations in heart rates. Marshall then tested this data to see if it could be used in adaptable VR adventure environments.

Fueled by this virtual innovation and his love for action sports, Marshall founded Vestigo. Though a young company, it boasts clients such as CNN, Microsoft, and Home Depot. Vestigo builds VR environments for intense and unconventional corporate leadership training. These environments mimic the worlds most challenging and inspiring sports adventures. Marshall has created these programs to help people overcome the innate human need for comfort and stability. In a business sense, this VR training results in greater team adaptability and innovation.

This falls in line with Marshalls deep desire to give back to his community. He was the VP of the Student Government Association at UGA and a guide for the colleges outdoor recreation program. He helps students step outside their comfort zones and overcome their limits through outdoor activities. Marshall, an avid adventure-sports athlete himself, maintains a mindset of peak performance and innovation through these sports. With Vestigo and the dedication to his alma mater, Marshall has turned his passions and mentality into a sought-after business service.

These VR adventures are also immensely helpful for helping people overcome isolation created by the COVID-19 pandemic. They can paraglide, snowboard, scuba dive, or explore caves without leaving their homes. As for corporate team training, Marshall has created environments where coworkers build trust and powerful relationships through walking a plank high above the ground and working together to detonate a virtual time bomb to hone communication skills when time is of the essence.

This permits socially distanced learning with not only excellent results, but the nature of the instruction makes what could be a mundane activity new, exciting, and memorable. The VR component tricks a persons mind into believing they are in an unknown and potentially uncomfortable situation, thus removing that person from their comfort zone. Obstacles can be treated as opportunities, and the element of the unknown requires innovative thinking. Together, these activities can increase performance and adaptability, two very desirable characteristics for almost any setting.

As for the reality of Vestigos VR experiences, participants are fully immersed thanks to small details that touch on all five senses. Marshall is currently developing two new environments, including a crevasse crossing on Mount Everest. If that doesnt help people overcome their desire for stability and comfort, the brilliant minds at Vertigo are up to the challenge of creating something that will.

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I want to help people overcome the biological desire for stability and co - The Jerusalem Post

For five years running, Rancho Santa Fes Team Singularity earned the opportunity to compete at the San Diego Regional Championship. Due to the ongoing COVID-19 pandemic the competition format has gone virtual. Previously a one-day League tournament, the competition stretched over four days with uploading of the team engineering notebook on Day 1, judging taking place via Zoom on Day 2, completing six 2-1/2 minute match runs at home with the team robot on Day 3, and a virtual awards ceremony via Zoom and Twitch on Day 4.

Team Singularitys Game Changer Robot 1

(Courtesy)

The entire FIRST Tech Challenge 2020-21 Game Changer Tournament season has been reformatted to a virtual setting. Sponsored by Qualcomm, FIRST Robotics teamed up with Disney and Lucasfilm and had all teams compete with their robots by video conferencing, in contrast to a traditional four robotics team match with two opposing alliances made up of two teams in each alliance held at a host school site. Part of the STEM (Science Technology Engineering and Math) experience this season was to adapt to the challenges a global pandemic requires. Preparation for the competition required many virtual calls via Zoom, Discord and other forms of social media. Design of the robot had to be done virtually. Building, assembling, testing, troubleshooting and driving the robot had to comply with masks, hand sanitizer and physical distancing measures. Competing was conducted independent of an alliance partner and absent from an opposing competitor in the same room or garage. Scores were submitted online. Even community outreaches had to be creative and conducted either virtually and with social distancing measures in compliance with the CDC recommendations.

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Despite these challenges, Team Singularity was up to the task, even during this COVID-19 pandemic. Not only did they earn the privilege of qualifying for the virtual Regional competition on April 25, 2021, Singularity took 1st place in the Collins Aerospace Innovate Award with their 3D printed robot design; 2nd place Deans List Semi-Finalist; 3rd place Think Award for their engineering notebook; 3rd place Connect Award for their virtual outreaches in fundraising and donating face shields to healthcare heroes around the country and designing 3D printed nasal swabs for COVID-19 testing and submitting their research to the American Society of Human Genomics Conference while mentoring a FIRST Lego League team and a fellow FTC team. Singularity also ranked as the 2nd highest scoring team in the Euclid League.

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Robotics Team Singularity qualifies virtually for the San Diego FTC Regional Championship - Rancho Santa Fe Review

One of the primary capabilities separating human intelligence from artificial intelligence is our ability to be creativeto use nothing but the world around us, our experiences, and our brains to create art. At present, AI needs to be extensively trained on human-made works of art in order to produce new work, so weve still got a leg up. That said, neural networks like OpenAIs GPT-3 and Russian designer Nikolay Ironov have been able to create content indistinguishable from human-made work.

Now theres another example of AI artistry thats hard to tell apart from the real thing, and its sure to excite 90s alternative rock fans the world over: a brand-new, never-heard-before Nirvana song. Or, more accurately, a song written by a neural network that was trained on Nirvanas music.

The song is called Drowned in the Sun, and it does have a pretty Nirvana-esque ring to it. The neural network that wrote it is Magenta, which was launched by Google in 2016 with the goal of training machines to create artor as the tools website puts it, exploring the role of machine learning as a tool in the creative process. Magenta was built using TensorFlow, Googles massive open-source software library focused on deep learning applications.

The song was written as part of an album called Lost Tapes of the 27 Club, a project carried out by a Toronto-based organization called Over the Bridge focused on mental health in the music industry.

Heres how a computer was able to write a song in the unique style of a deceased musician. Music, 20 to 30 tracks, was fed into Magentas neural network in the form of MIDI files. MIDI stands for Musical Instrument Digital Interface, and the format contains the details of a song written in code that represents musical parameters like pitch and tempo. Components of each song, like vocal melody or rhythm guitar, were fed in one at a time.

The neural network found patterns in these different components, and got enough of a handle on them that when given a few notes to start from, it could use those patterns to predict what would come next; in this case, chords and melodies that sound like they couldve been written by Kurt Cobain.

To be clear, Magenta didnt spit out a ready-to-go song complete with lyrics. The AI wrote the music, but a different neural network wrote the lyrics (using essentially the same process as Magenta), and the team then sifted through pages and pages of output to find lyrics that fit the melodies Magenta created.

Eric Hogan, a singer for a Nirvana tribute band who the Over the Bridge team hired to sing Drowned in the Sun, felt that the lyrics were spot-on. The song is saying, Im a weirdo, but I like it, he said. That is total Kurt Cobain right there. The sentiment is exactly what he would have said.

Cobain isnt the only musician the Lost Tapes project tried to emulate; songs in the styles of Jimi Hendrix, Jim Morrison, and Amy Winehouse were also included. What all these artists have in common is that they died by suicide at the age of 27.

The project is meant to raise awareness around mental health, particularly among music industry professionals. Its not hard to think of great artists of all persuasionsmusicians, painters, writers, actorswhose lives are cut short due to severe depression and other mental health issues for which it can be hard to get help. These issues are sometimes romanticized, as suffering does tend to create art thats meaningful, relatable, and timeless. But according to the Lost Tapes website, suicide attempts among music industry workers are more than double that of the general population.

How many more hit songs would these artists have written if they were still alive? Well never know, but hopefully Lost Tapes of the 27 Club and projects like it will raise awareness of mental health issues, both in the music industry and in general, and help people in need find the right resources. Because no matter how good computers eventually get at creating music, writing, or other art, as Lost Tapes website pointedly says, Even AI will never replace the real thing.

Image Credit: Edward Xu on Unsplash

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There's a New Nirvana Song Out, and It Was Written by Google's AI - Singularity Hub

Black holes are cosmic bodies that pack an immense amount of mass into a surprisingly small space. Due to their extremely intense gravity, nothing can escape their grasp not even light which defines the universes speed limit.

April 10th, 2019 marked a milestone in science history when the team at the Event Horizon Telescope revealed the first image of a supermassive black hole. As a result, these areas of space created when stars reach the end of their nuclear fuel burning and collapse creating massive gravitational wells, completed their transition from theory to reality.

This transition has been further solidified since with the revelation of a second, much clearer image of the supermassive black hole (SMBH) at the centre of the galaxy Messier 87 (M87). This second image revealing details such as the orientation of the magnetic fields that surround it and drive its powerful jets that extend for light-years.

The study of black holes could teach us much more than about these spacetime events and the environments that home them, however. Because cosmologists believe that most galaxies have an SMBH sat at their centre, greedily consuming material like a fat spider lurking at the centre of a cosmic web, learning more about these spacetime events can also teach us how galaxies themselves evolve.

The origin of black holes is one that runs in reverse to that of most astronomical objects. We didnt discover some mysterious object in the distant cosmos and then began to theorise about it whilst making further observations.

Rather, black holes entered the scientific lexicon in a way that is more reminiscent of newly theorised particles in particle physics; emerging first from the solutions to complex mathematics. In the case of black holes, the solutions to the field equations employed by Einstein in his most important and revolutionary theory.

Just as a physical black hole forms from the collapse of a star, the theory of black holes emerged from the metaphorical collapse of the field equations that govern the geometrical theory of gravity; better known as general relativity.

One of the most common misconceptions about black holes arises from their intrinsic uniqueness and the fact that there really isnt anything else like them in the Universe.

General relativity introduced the idea that mass has an effect on spacetime, a concept fundamental to the idea that space and time are not passive stages upon which the events of the universe play out. Instead, those events shape that stage. As John Wheeler brilliantly and simply told us; when it comes to general relativity:

Matter tells space how to curve. Space tells matter how to move.

The most common analogy is for this warping of space is that of placing objects on a stretched rubber sheet. The larger the object the deeper the dent and the more extreme the curvature it creates. In our analogy, a planet is a marble, a star an apple, and a black hole a cannonball.

Thus, considering this a black hole isnt really an object at all but, is actually better described as a spacetime event. When we say black hole what we really mean is an area of space that is so warped by a huge amount of mass condensed into a finite point that even light itself doesnt have the necessary velocity to escape it.

This point at which light can no longer escape marks the first of two singularities that define black holespoints at which solutions of the equations of general relativity go to infinity.

The event horizon of a black hole is the point at which its escape velocity exceeds the speed of light in vacuum (c). This occurs at a radius called the Schwarzchild radiusnamed for astrophysicist Karl Schwarzschild, who developed a solution for Einstiens field equations whilst serving on the Eastern Front in the First World War.

His solution to Einsteins field equationswhich would unsurprisingly become known as theSchwarzschild solution described the spacetime geometry of an empty region of space. It had two interesting features two singularities one a coordinate singularity the other, a gravitational singularity. Both take on significance in the study of black holes.

Dealing with the coordinate singularity, or the Schwarzchild radius first.

The Schwarzchild radius(Rs)also takes on special meaning in cases where the radius of a body shrinks within this Schwarzschild radius (ie.Rs >r). When a bodys radius shrinks within this limit, it becomes a black hole.

All bodies have a Schwarzschild radius, but as you can see from the calculation below for a body like Earth, Rs falls well-within its radius.

Thats part of what makes black holes unique; their Schwartzchild radius is outside their physical radius because their mass is compressed into such a tiny space.

Because the outer edge of the event horizon is the last point at which light can escape it also marks the last point at which events can be seen by distant observers. Anything past this point can never be observed.

The reason the Schwarzschild radius is called a coordinate singularity is that it can be removed with a clever choice of coordinate system. The second singularity cant be dealt with in this way. This makes it the true physical singularity of the black hole itself.

This is known as the gravitational singularityand is found at the centre of the black hole (r=0). This is the end-point for every particle that falls into a black hole. Its also the point the Einstein field equations break down maybe even all the laws of physics themselves.

The fact that the escape velocity of the event horizon exceeds the speed of light means that no physical signal could ever carry information from the central singularity to distant observers. We are forever sealed off from this aspect of black holes, which will therefore forever remain in the domain of theory.

Weve already seen that for a body with the mass of Earth to become a black hole, its diameter would have to shrink to less than 2cm. This is obviously something that just isnt possible. In fact, not even our Sun has enough mass to end its life as a black hole. Only stars with around three times the mass of the Sun are massive enough to end their lives in this way.

But why is that the case?

It wont surprise you to learn that for an astronomical body to become a black hole it must meet and exceed a series of limits. These limits are created by outward forces that are resisting against the inward force that leads to gravitational collapse.

For planets and other bodies with relatively small masses, the electromagnetic repulsion between atoms is strong enough to grant them stability against total gravitational collapse. For large stars the situation is different.

During the main life cycle of starsthe period of the fusion of hydrogen atoms to helium atomsthe primary protection against gravitational collapse is the outward thermal and radiation pressures that are generated by these nuclear processes. That means that the first wave of gravitational collapse occurs when a stars hydrogen fuel is exhausted and inward pressure can no longer be resisted.

Should a star have enough mass, this collapse forces together atoms in the nucleus enough to reignite nuclear fusion with helium atoms now fusing to create heavier elements. When this helium is exhausted, the process happens again, with the collapse again stalling if there is enough pressure to trigger the fusion of heavier elements still.

Stars like the Sun will eventually reach the point where their mass is no longer sufficient to kick start the nuclear burning of increasingly heavier elements. But if it isnt nuclear fusion that is generating the outward forces that prevent complete collapse, what is preventing these lower-mass stars from becoming black holes?

Lower-mass stars like the Sun will end their lives as white dwarf stars with a black hole form out of reach. The mechanism protecting these white dwarfs against complete collapse is a quantum mechanical phenomenon called degeneracy.

This degeneracy pressure is a factor of the Pauli exclusion principle, which states that certain particles known as fermions, which include electrons, protons, and neutrons are forbidden from occupying the same quantum states. This means that they resist being tightly crammed together.

This theory and the limitation it introduced led Indian-American astrophysicist Subrahmanyan Chandrasekhar to question if there was an upper cap at which this protection against gravitational collapse would fail.

Chandrasekhar awarded the 1983 Nobel Prize in physics for his work concerning stellar evolution proposed in 1931 that above 1.4 solar masses, a white dwarf would no longer be protected from gravitational collapse by degeneracy pressure. Past this limit termed the Chandrasekhar limitgravity overwhelms the Pauli exclusion principle and gravitational collapse can continue.

But there is another limit that prevents stars of even this greater mass from creating black holes.

Thanks to the 1932 discovery of neutronsthe neutral partner of protons in atomic nuclei Russian theoretical physicist Lev Landau began to ponder the possible existence of neutron stars. The outer part of these stars would contain neutron-rich nuclei, whilst the inner sections would be formed from a quantum fluid comprised of mostly neutrons

These neutron stars would also be protected against gravitational collapse by degeneracy pressurethis time provided by this neutron fluid. In addition to this, the greater mass of the neutron in comparison to the electron would allow neutron stars to reach a greater density before undergoing collapse.

By 1939, Robert Oppenheimer had calculated that the mass-limit for neutron stars would be roughly 3 times the mass of the Sun.

To put this into perspective, a white dwarf with the mass of the Sun would be expected to have a millionth of our stars volumegiving it a radius of 5000km, roughly that of the Earth. A neutron star of a similar mass though would have a radius of about 20kmroughly the size of a city.

Above the Oppenheimer-Volkoff limit, gravitational collapse begins again. This time no limits exist between this collapse and the creation of the densest possible state in which matter can exist. The state found at the central singularity of a black hole.

Weve covered the creation of black holes and the hurdles that stand in the way of the formation of such areas of spacetime, but theory isnt quite ready to hand black holes over to practical observations just yet. The field equations of general relativity can also be useful in the categorisation of black holes.

Categorising black holes is actually fairly straight-forward thanks to the fact that they possess very few independent qualities. John Wheeler had a colourful way of describing this lack of characteristics. The physicist once commented that black holes have no hair, meaning that outside a few characteristics they are essentially indistinguishable. This comment became immortalised as the no-hair theorem of black holes.

Black holes have only three independent measurable propertiesmass, angular momentum and electric charge. All black holes must have mass, so this means there are only four different types of a black hole based on these qualities. Each is defined by the metric or the function used to describe it.

This means that black holes can be quite easily catagorised by the properties they possess as seen below.

This isnt the most common or most suitable method of categorising black holes, however. As mass is the only property that is common to all black holes, the most straight-forward and natural way of listing them is by their mass. These mass categories are imperfectly defined and so far black holes in some of the categoriesmost notably intermediate black holes remain undetected.

Cosmologists believe that the majority of black holes are rotating and non-charged Kerr black holes. And the study of these spacetime events reveals a phenomenon that perfectly exemplifies their power and influence on spacetime.

The mathematics of the Kerr metric used to describe non-charged rotating black holes reveals that as they rotate, the very fabric of spacetime that surrounds them is dragged along in the direction of the rotation.

The powerful phenomenon is known as frame-dragging or the Lense-Thirring effect and leads to the violent churning environments that surround Kerr black holes. Recent research has revealed that this frame-dragging could be responsible for the breaking and reconnecting of magnetic field lines that in-turn, launch powerful astrophysical jets into the cosmos.

The static limit of a Kerr black hole also has an interesting physical significance. This is the point at which lightor any particle for that matter is no-longer free to travel in any direction. Though not a light-trapping surface like the event horizon, the static limit pulls light in the direction of rotation of the black hole. Thus, light can still escape the static limit but only in a specific direction.

British theoretical physicist and 2020 Nobel Laureate Sir Roger Penrose also suggested that the static limit could be responsible for a process that could cause black holes to leak energy into the surrounding Universe. Should a particle decay into a particle and its corresponding anti-particle at the edge of the static limit it would be possible for the latter to fall into the black hole, whilst its counterpart is launched into the surrounding Universe.

This has the net effect of reducing the black holes mass whilst increasing the mass content of the wider Universe.

Weve seen what happens to light at the edge of a black hole and explored the fate of particles that fall within a Kerr black holes static limit, but what would happen to an astronaut that strayed too close to the edge of such a spacetime event?

Of course, any astronaut falling into a black hole would be completely crushed upon reaching its central gravitational singularity, but the journey may spell doom even before this point has been reached. This is thanks to the tidal forces generated by the black holes immense gravitational influence.

As the astronauts centre of mass falls towards the black hole, the objects effect on spacetime around it causes their head and feet to arrive at significantly different times. The difference in the gravitational force at the astronauts head and feet gives rise to such a huge tidal force that means their body would be simultaneously compressed at the sides and stretched out.

Physicists refer to this process as spaghettification. A witty name for a pretty horrible way to die. Fortunately, we havent yet lost any astronauts to this bizarre demise, but astronomers have been able to watch stars meet the same fate.

For a stellar-mass black hole, spaghettification would occur not just before our astronaut reaches the central singularity, but also well before they even hit the event horizon. For a black hole 40 times the mass of our Sunspaghettification would occur at about 1,000 km out from the event horizon, which is, itself, 120 km from the central gravitational singularity.

As well as developing the Oppenheimer-Volkoff limit, Oppenheimer also used general relativity to describe how a total gravitational collapse should appear to a distant observer. They would consider the collapse to take an infinitely long time, the process appearing to slow and freeze as the stars surface shrinks towards the Schwarzschild radius.

An astronaut falling into a black hole would be immortalized in a similar way to a distant observer, though they themselvescould they have survived spaghettification they would notice nothing. The passing of Rs would just seem a natural part of the fall to them despite it marking the point of no return.

After emerging from the mathematics of general relativity at the earlier stages of the 20th Century, black holes have developed from a theoretical curiosity to the status of scientific reality. In the process, they have indelibly worked their way into our culture and lexicon.

Perhaps the most exciting thing about black holes is that there is so much we dont yet know about them. As a striking example of that, almost all the information listed above resulted just from theory and the interrogation of the maths of Einsteins field equations.

Unlocking the secrets held by black holes could, in turn, reveal how galaxies evolve and how the Universe itself has changed since its early epochs.

Relativity, Gravitation and Cosmology, Robert J. Lambourne, Cambridge Press, [2010].

Relativity, Gravitation and Cosmology: A basic introduction, Ta-Pei Cheng, Oxford University Press, [2005].

Extreme Environment Astrophysics, Ulrich Kolb, Cambridge Press, [2010].

Stellar Evolution and Nucleosynthesis, Sean G. Ryan, Andrew J. Norton, Cambridge Press, [2010].

Cosmology, Matts Roos, Wiley Publishing, [2003].

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What are Black Holes: The Journey From Theory to Reality - ZME Science

She warned us by holding up the box of Kleenex. Rev. Hannah was in the sanctuary at Minneola Lutheran Church near the town of Goodhue on Thursday evening, April 1, 2021, for their Holy Week worship service. It combined traditional elements depicting both Maundy Thursday and Good Friday.She shared a few passages from some of her recent meandering journaling with its insights, outlooks and hints of petulance.She and others have been considering the meaning of the cross. She feels strongly that it mustnt be seen merely as an ornament relegated to an accessory. It instructs us: Put your body where your values are.An entry online that had caught her attention referred to the crucifixion as a singularity creating a portal at the horizon. (That caught my attention because as she was live-streaming my husband and I were watching a two-part episode of a science fiction series with that very phenomenon as part of the story.)After officiating the institution of communion farther back from the camera beyond the rail, Jesus death on the cross was further dramatized up close and personal. Referring to his last breaths with words including battle and rattle and hole in my soul, Rev. Hannah said the atmosphere at that time and place had shifted from taunting to compassionate. Putting herself at the scene that followed as one who had sat at his feet and stood by his side, shed stepped into the cold tomb. Christs hand fell off the edge of the ledge where his body had been placed. She lovingly tucked it back into the folds of the linen.After putting a tissue to good use (while I had another sip of wine), she shifted smoothly into singing another refrain of stay with me, remain here with me, watch and pray changing the atmosphere for me from dire to dear.As at many other churches, the altar was ceremoniously stripped bare. Communion ware, candle sticks and colorful cloths were solemnly set aside. Earlier in the day during Minneolas community prayer time, there had been talk of hope and confidence starting to take shape along the periphery. But now, we focus on lack, loss and lifelessness ... for the time being.

Kate Josephson grew up in rural southwestern Minnesota going to a small town church every Sunday worked as a church secretary in Red Wing for seven years. She continues to seek out religious experiences wherever she goes.

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Church mouse: Setting things aside in Minneola Lutheran Church - RiverTowns