Monthly Archives: April 2017

A team of scientists at the Tata Institute of Fundamental Research (TIFR), Mumbai, India, have found new ways to detect a bare or naked singularity, the most extreme object in the universe.

When the fuel of a very massive star is spent, it collapses due to its own gravitational pull and eventually becomes a very small region of arbitrarily high matter density, that is a`Singularity', where the usual laws of physics may breakdown. If this singularity is hidden within an event horizon, which is an invisible closed surface from which nothing, not even light, can escape, then we call this object a black hole. In such a case, we cannot see the singularity and we do not need to bother about its effects. But what if the event horizon does not form? In fact, Einstein's theory of general relativity does predict such a possibility when massive stars collapse at the end of their life-cycles. In this case, we are left with the tantalizing option of observing a naked singularity.

An important question then is, how to observationally distinguish a naked singularity from a black hole. Einstein's theory predicts an interesting effect: the fabric of spacetime in the vicinity of any rotating object gets `twisted' due to this rotation. This effect causes a gyroscope spin and makes orbits of particles around these astrophysical objects precess. The TIFR team has recently argued that the rate at which a gyroscope precesses (the precession frequency), when placed around a rotating black hole or a naked singularity, could be used to identify this rotating object. Here is a simple way to describe their results. If an astronaut records a gyroscope's precession frequency at two fixed points close to the rotating object, then two possibilities can be seen: (1) the precession frequency of the gyroscope changes by an arbitrarily large amount, that is, there is a wild change in the behaviour of the gyroscope; and (2) the precession frequency changes by a small amount, in a regular well-behaved manner. For the case (1), the rotating object is a black hole, while for the case (2), it is a naked singularity.

The TIFR team, namely, Dr. Chandrachur Chakraborty, Mr. Prashant Kocherlakota, Prof. Sudip Bhattacharyya and Prof. Pankaj Joshi, in collaboration with a Polish team comprising Dr. Mandar Patil and Prof. Andrzej Krolak, has infact shown that the precession frequency of a gyroscope orbiting a black hole or a naked singularity is sensitive to the presence of an event horizon. A gyroscope circling and approaching the event horizon of a black hole from any direction behaves increasingly 'wildly,' that is, it precesses increasingly faster, without a bound. But, in the case of a naked singularity, the precession frequency becomes arbitrarily large only in the equatorial plane, but being regular in all other planes.

The TIFR team has also found that the precession of orbits of matter falling into a rotating black hole or a naked singularity can be used to distinguish these exotic objects. This is because the orbital plane precession frequency increases as the matter approaches a rotating black hole, but this frequency can decrease and even become zero for a rotating naked singularity. This finding could be used to distinguish a naked singularity from a black hole in reality, because the precession frequencies could be measured in X-ray wavelengths, as the infalling matter radiates X-rays.

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Materials provided by Tata Institute of Fundamental Research. Note: Content may be edited for style and length.

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Can we see a singularity, the most extreme object in the universe ... - Science Daily

Black holes are weird: insanely dense objects that are crammed into such a small space they cause space-time to distort and the laws of physics to break down into a singularity.

Fortunately, the Universe shields us from this weirdness by wrapping black holes in event horizons. But now, physicists say they've found a way we could detect something even more extreme - a naked singularity - and most likely bend the laws of physics in the process.

"A naked singularity, if such a thing exists, would be an abrupt hole in the fabric of reality - one that would not just distort space-time, but would also wreak havoc on the laws of physics wherever it goes and lead to a catastrophic loss of predictability," explains Avaneesh Pandey for IB Times.

If that sounds a little too confronting, don't worry, this whole study is purely theoretical, and is hinged on one very big assumption - that naked singularities actually exist in our Universe, something that scientists have never confirmed.

But according to Einstein's theory of general relativity at least, and our best computer models to date, naked singularitiesarepossible.

So, what are they?A singularity can form when huge stars collapse at the end of their lives into regions so small and dense, physics as we know it fails to explain what could happen there.

There are two general laws of physics that govern our understanding of reality: quantum mechanics, which explains all the small stuff, such as the behaviour of subatomic particles; and general relativity, which describes the stuff we can see, such as stars and galaxies.

When applied to singularities, both these schools of thought predict different and incompatible outcomes.

And we've never really had to deal with that conundrum, because all the singularities we know of are inside black holes, wrapped in an event horizon from which not even light can escape - or at the very birth of our Universe, shrouded by radiation we can't see past. Out of sight, out of mind, right?

But naked singularities are theoretical singularities that are exposed to the rest of the Universe for some reason.

Below you can see an illustration of a black hole wrapped in its event horizon (dotted line) on the left, and a naked singularity on the right. The arrows indicate light, which would be able to escape a naked singularity, but not a black hole.

Sudip Bhattacharyya/Pankaj Joshi

Assuming they do exist, the big question then is how would we be able to distinguish a naked singularity from a regular black hole, and this is where the new study comes in.

Researchers from the Tata Institute of Fundamental Research in Indiahave come up with a two-step plan based on the fact that singularities, as far as we know, are rotating objects, just like black holes.

According to Einstein's theory of general relativity, the fabric of space-time in the vicinity of any rotating objects gets 'twisted' due to this rotation. And this effect causes a gyroscopic spin and makes the orbits of particles around the rotating objects 'precess', or change their rotational axis.

You can watch the hypnotic precession of a gyroscope below to see what we mean - its axis is no longer straight:

LucasVB/WikimediaCommons

Based on this, the researchers say that we could figure out the nature of a rotating objects by measuring the rate at which a gyroscope precesses - its precession frequency - at two fixed points close to the object.

According to the new paper, there are two possibilities:

Obviously getting a gyroscope close enough to a black hole to perform these experiments isn't exactly easy.

But that's okay, because the team has also come up with a way to observe the same effect from here on Earth - measuring the precession frequencies of matter falling into either black holes or naked singularities using X-ray wavelengths.

"This is because the orbital plane precession frequency increases as the matter approaches a rotating black hole, but thisfrequencycan decrease and even become zero for a rotating naked singularity," the team's press release explains.

Again, we have to make it clear that all of this is wildly speculative at this time - we have never found any candidate naked singularities, and we're only just beginning to truly understand regular black holes.

It's also worth noting thatlast week, another team of researchers suggested that even if naked singluarities exist, strange quantum effects could keep them hidden from us.

So there's definitely no consensus right now on whether we'll ever get the chance to study naked singularities.

And that's not a terrible thing for now, because are we really ready to observe what goes on at the edge of our Universe?

Maybe, in our lifetime, we'll find out.

The research has been published in Physical Review D.

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Physicists Say They've Found a Way to Detect Naked Singularities... if They Exist - ScienceAlert

Two basic types of encryption schemes are used on the internet today. One, known as symmetric-key cryptography, follows the same pattern that people have been using to send secret messages for thousands of years. If Alice wants to send Bob a secret message, they start by getting together somewhere they cant be overheard and agree on a secret key; later, when they are separated, they can use this key to send messages that Eve the eavesdropper cant understand even if she overhears them. This is the sort of encryption used when you set up an online account with your neighborhood bank; you and your bank already know private information about each other, and use that information to set up a secret password to protect your messages.

The second scheme is called public-key cryptography, and it was invented only in the 1970s. As the name suggests, these are systems where Alice and Bob agree on their key, or part of it, by exchanging only public information. This is incredibly useful in modern electronic commerce: if you want to send your credit card number safely over the internet to Amazon, for instance, you dont want to have to drive to their headquarters to have a secret meeting first. Public-key systems rely on the fact that some mathematical processes seem to be easy to do, but difficult to undo. For example, for Alice to take two large whole numbers and multiply them is relatively easy; for Eve to take the result and recover the original numbers seems much harder.

Public-key cryptography was invented by researchers at the Government Communications Headquarters (GCHQ) the British equivalent (more or less) of the US National Security Agency (NSA) who wanted to protect communications between a large number of people in a security organization. Their work was classified, and the British government neither used it nor allowed it to be released to the public. The idea of electronic commerce apparently never occurred to them. A few years later, academic researchers at Stanford and MIT rediscovered public-key systems. This time they were thinking about the benefits that widespread cryptography could bring to everyday people, not least the ability to do business over computers.

Now cryptographers think that a new kind of computer based on quantum physics could make public-key cryptography insecure. Bits in a normal computer are either 0 or 1. Quantum physics allows bits to be in a superposition of 0 and 1, in the same way that Schrdingers cat can be in a superposition of alive and dead states. This sometimes lets quantum computers explore possibilities more quickly than normal computers. While no one has yet built a quantum computer capable of solving problems of nontrivial size (unless they kept it secret), over the past 20 years, researchers have started figuring out how to write programs for such computers and predict that, once built, quantum computers will quickly solve hidden subgroup problems. Since all public-key systems currently rely on variations of these problems, they could, in theory, be broken by a quantum computer.

Cryptographers arent just giving up, however. Theyre exploring replacements for the current systems, in two principal ways. One deploys quantum-resistant ciphers, which are ways to encrypt messages using current computers but without involving hidden subgroup problems. Thus they seem to be safe against code-breakers using quantum computers. The other idea is to make truly quantum ciphers. These would fight quantum with quantum, using the same quantum physics that could allow us to build quantum computers to protect against quantum-computational attacks. Progress is being made in both areas, but both require more research, which is currently being done at universities and other institutions around the world.

Yet some government agencies still want to restrict or control research into cryptographic security. They argue that if everyone in the world has strong cryptography, then terrorists, kidnappers and child pornographers will be able to make plans that law enforcement and national security personnel cant penetrate.

But thats not really true. What is true is that pretty much anyone can get hold of software that, when used properly, is secure against any publicly known attacks. The key here is when used properly. In reality, hardly any system is always used properly. And when terrorists or criminals use a system incorrectly even once, that can allow an experienced codebreaker working for the government to read all the messages sent with that system. Law enforcement and national security personnel can put those messages together with information gathered in other ways surveillance, confidential informants, analysis of metadata and transmission characteristics, etc and still have a potent tool against wrongdoers.

In his essay A Few Words on Secret Writing (1841), Edgar Allan Poe wrote: [I]t may be roundly asserted that human ingenuity cannot concoct a cipher which human ingenuity cannot resolve. In theory, he has been proven wrong: when executed properly under the proper conditions, techniques such as quantum cryptography are secure against any possible attack by Eve. In real-life situations, however, Poe was undoubtedly right. Every time an unbreakable system has been put into actual use, some sort of unexpected mischance eventually has given Eve an opportunity to break it. Conversely, whenever it has seemed that Eve has irretrievably gained the upper hand, Alice and Bob have found a clever way to get back in the game. I am convinced of one thing: if society does not give human ingenuity as much room to flourish as we can manage, we will all be poorer for it.

This article was originally published at Aeon and has been republished under Creative Commons.

Banner Image Credit: Brewbooks/US Navy/Flickr

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Quantum Cryptography Is Unbreakable. So Is Human Ingenuity - Singularity Hub

Chief Photographer Melanie Hodges

UNA sophomore Karlee Mauk performs in The Singularity. The original ballet, created by UNA senior Jeremy Smith, took place at the Zodiac Theater April 21 and 22.

Posted: Friday, April 21, 2017 11:45 pm | Updated: 10:54 pm, Sat Apr 22, 2017.

"The Singularity" is 'on point' by Associate Life Editor Hannah Zimmer The Flor-Ala |

The wooden panel floorscreaked as UNA sophomore and ballerina KarleeMaukmoved across the stage.

The dancerperformed a lyrical piece entitled The Singularity atZodiac Theater indowntown Florence April 21 and will do so again April 22.

Mauksaid the performance was not her first time performing onstage,but the event was special because many of her friends and family members attended.

Ive been performing since I was three years old,Mauksaid. But for this crowd, it feels so incredible to be onstage.

The Singularity is "an epic that draws parallel to familiar characters such as Herculesand Odysseus," according to theprogram.

The performance also featured music to whichMaukdanced to. Instruments such as the clarinet, flute, drums, electric keyboard and xylophone sounded behind a black curtain as the ballerina danced on the tips of her toes.

The composer of The Singularity was senior Jeremy Smith, who hopes to obtaina degree at UNA in music theory and composition with a minor in philosophy. After the performance, audience members flocked to Smith outside the theatre to take pictures and ask him questions.

Mauksaid she, Smith andthe musiciansprepared for the balletfor four months. She described Smiths composition as "genius."

Freshmen Olivia Martinez said the performance played out in asophisticated and precise manner.

Ive never been to anything like this,but(the performance)was a fantastic first experience, Martinez said.

Tickets to The Singularity are $15 and are availableat the ticket window outside Zodiac Theatre.

I definitely think everyone should come out tomorrow to see the performance,Mauksaid. Jeremy is incredibly talented,and the story is beautiful.

Posted in Life on Friday, April 21, 2017 11:45 pm. Updated: 10:54 pm. | Tags: Dance, Ballet, Zodiac Theater

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"The Singularity" is 'on point' - Flor-Ala (subscription)