Tag: physics

Neutron Star Smash-Up Produces Gravitational Waves And Light In Unprecedented Stellar Show​

The 2015 detection of gravitational waves – ripples in the very fabric of space and time – was one of the biggest scientific breakthroughs in a century.

But because it was caused by two black holes merging, the event was all but invisible, detectable indirectly via the LIGO facility.

Now a team of scientists has announced the fifth detection of gravitational waves, but there’s a groundbreaking difference this time around.

The ripples were caused by the collision of two neutron stars, meaning the event was accompanied by light, radio, and other electromagnetic signals for the first time.

First predicted by Albert Einstein over 100 years ago, gravitational waves are caused by cosmic cataclysms like the collision of two black holes, but because of the immense distance.




By the time they reach us here on Earth the distortions are occurring on the subatomic scale.

To observe waves that tiny, LIGO beams lasers down a 4-km (2.5-mi) long tunnel and measures how gravitational waves might warp the beam as they wash over our local corner of spacetime.

That delicate process is effective at confirming the phenomenon, but still somewhat indirect.

This is the first time that the collision of two neutron stars has been detected, and this is the closest and most precisely located gravitational wave signal we’ve received,” says Susan Scott, the Leader of the General Relativity Theory and Data Analysis Group at Australian National University (ANU), which played a key role in the observation.

It is also the loudest gravitational wave signal we’ve detected.

The collision occurred in a galaxy called NGC 4993, which lies about 130 million light-years away – that might sound far, but it’s much closer than previous observations, which occurred at distances of billions of light-years.

As well as producing gravitational waves, the neutron stars’ collision sent a host of electromagnetic signals sweeping across the universe, including a short gamma ray burst, X-rays, light and radio waves.

These were picked up by observatories all over the world, helping pinpoint the source.

ANU was among those, using SkyMapper and the Siding Spring Observatory in New South Wales, Australia, to observe the brightness and color of the light signals given off.

Along with learning more about gravitational waves, the discovery can teach astronomers about neutron stars.

Created when larger stars collapse, neutron stars are relatively tiny – only about 10 km (6.2 mi) wide – and incredibly dense, with very strong magnetic fields. Other than that, not a whole lot is known about them.

With this discovery we have the opportunity to learn so much more about neutron stars, which have been quite a mystery to us,” says Scott.

Unlike black holes, neutron star collisions emit other signals such as gamma rays, light and radio waves so astronomers around the world were able to observe the event through telescopes. This is an amazing time to be a scientist.

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Pass it on: New Scientist

The Quantum Computer That Could Spell The End Of Encryption

The researchers from Massachusetts Institute of Technology (MIT) and Austria’s University of Innsbruck call it “the beginning of the end for encryption schemes“.

Most encryption used today uses integer factorisation, or “the factoring problem“, and its security comes from the difficulty of factoring large numbers.

For example, finding the prime factors, or multipliers, for the number 15 is fairly easy as it’s a small number.

However, a larger number such as 91, may take some pen and paper.

An even larger number, say with 232 digits, has taken scientists two years to factor, using hundreds of classical computers operating in parallel.

In encryption, two different, but intimately related numbers, are used for the encryption and decryption, making it easy to calculate but hard to reverse.




However, a quantum computer is expected to outperform traditional computers and crack this problem by using hundreds of atoms, essentially in parallel, to quickly factor huge numbers because data is encoded in the ‘spin’ of individual electrons.

Unlike standard computers, quantum bits, or qubits can exist in multiple states at once rather than the binary 1 or 0 of conventional bits.

This means they can perform multiple calculations in parallel and hold far more information than normal bits.

For example, a computer with just 1,000 qubits could easily crack modern encryption keys while smartphone games like Angry Birds typically use 40,000 conventional bits to run.

It typically takes about 12 qubits to factor the number 15, but researchers at MIT and the University of Innsbruck in Austria have found a way to pare that down to five qubits, each represented by a single atom.

This has been designed and built by a quantum computer from five atoms in an ion trap. The computer uses laser pulses to carry out algorithms on each atom, to correctly factor the number 15.

The approach thus provides the potential for designing a powerful quantum computer, but with fewer resources,” said the research paper.

We factor the number 15 by effectively employing and controlling seven qubits and four ‘cache qubits’ and by implementing generalised arithmetic operations, known as modular multipliers.

The system is designed in a way that more atoms and lasers can be added to build a bigger and faster quantum computer, able to factor much larger numbers.

The scientists said the results represent the first scalable implementation of Shor’s algorithm, a quantum algorithm named after mathematician Peter Shor in 1994 to solve the factorisation problem.

We show that Shor’s algorithm, the most complex quantum algorithm known to date, is realisable in a way where, yes, all you have to do is go in the lab, apply more technology, and you should be able to make a bigger quantum computer,” said Isaac Chuang, professor of physics and professor of electrical engineering and computer science at MIT.

It might still cost an enormous amount of money to build – you won’t be building a quantum computer and putting it on your desktop anytime soon – but now it’s much more an engineering effort, and not a basic physics question.

The researchers claimed the ion-trap quantum computer returns the correct factors with a confidence level exceeding 99 per cent.

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Gravitational Waves Just Led Us To The Incredible Origin Of Gold In The Universe

The Nobel Prize–winning Laser Interferometer Gravitational-Wave Observatory (LIGO) observatory has already changed the world of astronomy.

When the scientists in the LIGO collaboration announced the first detection of gravitational waves in 2016, it meant they’d discovered a new way to observe the universe.

For the first time, scientists could “listen” to ripples in spacetime created by the collision of massive objects like black holes.

But that was just the beginning. The dream, all along, was to combine gravitational wave detections with observations from more traditional telescopes.

On Monday, a team of thousands of LIGO scientists around the globe published an incredible finding spread throughout several papers in the journal Physical Review Letters.

Not only did these scientists detect, for the first time, the gravitational waves produced from two colliding neutron stars, but they were able to pinpoint their location in the sky and witness the event with optical and electromagnetic telescopes.




The gravitational waves tell physicists how large and how far away the objects are, and allow scientists to recreate the moments before they collided.

Then the observations in optical light and electromagnetic waves fill in the blanks that gravitational waves can’t answer.

They help astronomers nail down exactly what the objects were made out of, and which elements their collisions produced.

In this case, the scientists were able to conclude that the resulting explosion from a neutron star merger produces heavy elements like gold, platinum, and uranium.

On August 17 at 8:41 am, LIGO detected gravitational waves — literal distortions in space and time — passing through Earth.

LIGO is a pair of L-shaped observatories in Washington state and Louisiana that can detect when these waves temporarily squish and stretch the fabric of spacetime around us.

In the past two years, LIGO had detected gravitational waves generated by black holes that had crashed into one another.

When LIGO detects gravitational waves, it automatically sends out alerts to hundreds of scientists across the world. Brown was one of them.

We got on the phone very quickly, and we realized this was a very loud gravitational wave signal. It blew our socks off,” he says.

On the day of the gravitational wave detection, the scientists immediately got another clue that something big was happening.

Two seconds after LIGO detected the gravitational waves, Fermi, a NASA satellite, detected a gamma-ray burst, one of the most powerful explosions of energy we know of in the universe.

It had long been theorized that neutron star mergers could create gamma-ray bursts. This couldn’t be a coincidence.

But light from the neutron star merger and subsequent explosion would soon dim. And so the LIGO collaboration scientists were suddenly under intense pressure to move quickly.

The sooner you get telescopes on this thing, the more information you get,” Brown says.

Studying that light, and how it changes, would teach scientists a huge amount about neutron stars and how their collisions transform matter.

This discovery is so exciting because it means we’re truly in a new age of astronomy.

It means scientists can study celestial objects not just in terms of the light or radiation they emit they can also combine those observations with data from gravitational waves.

It means scientists have data on the entirety of this collision. They have data on how the two neutron stars danced around each other, they have data on the moment of impact, and they have extensive data on the aftermath.

Scientists expect to observe more black hole mergers, more neutron star mergers. But stranger, cooler observations may come through as well.

If LIGO and VIRGO continue to be upgraded, it’s possible they could detect gravitational waves still rippling away from the Big Bang.

Or, more excitingly, they could detect sources of gravitational waves that have never been predicted or observed.

I was a little sad I was not alive for the first moon landing,” Thomas Corbitt, a physicist and LIGO collaborator at Louisiana State University, says.

But when you see things like this, which are a testament to what people can do when they work together, it really is inspiring, and it teaches us about the universe.

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What Came Before The Big Bang?

It is difficult enough to imagine a time, roughly 13.7 billion years ago, when the entire universe existed as a singularity.

According to the big bang theory, one of the main contenders vying to explain how the universe came to be, all the matter in the cosmos – all of space itself – existed in a form smaller than a subatomic particle.

Once you think about that, an even more difficult question arises: What existed just before the big bang occurred?

The question itself predates modern cosmology by at least 1,600 years. Fourth-century theologian St. Augustine wrestled with the nature of God before the creation of the universe.




His answer? Time was part of God’s creation, and there simply was no “before” that a deity could call home.

Armed with the best physics of the 20th century, Albert Einstein came to very similar conclusions with his theory of relativity.

Just consider the effect of mass on time. A planet’s hefty mass warps time — making time run a tiny bit slower for a human on Earth’s surface than a satellite in orbit.

The difference is too small to notice, but time even runs more slowly for someone standing next to a large boulder than it does for a person standing alone in a field.

The pre-big bang singularity possessed all the mass in the universe, effectively bringing time to a standstill.

Following this line of logic, the title of this article is fundamentally flawed.

According to Einstein’s theory of relativity, time only came into being as that primordial singularity expanded toward its current size and shape.

Case closed? Far from it. This is one cosmological quandary that won’t stay dead.

In the decades following Einstein’s death, the advent of quantum physics and a host of new theories resurrected questions about the pre-big bang universe. Keep reading to learn about some of them.

Here’s a thought: What if our universe is but the offspring of another, older universe? Some astrophysicists speculate that this story is written in the relic radiation left over from the big bang: the cosmic microwave background (CMB).

Astronomers first observed the CMB in 1965, and it quickly created problems for the big bang theory — problems that were subsequently addressed (for a while) in 1981 with the inflation theory.

This theory entails an extremely rapid expansion of the universe in the first few moments of its existence.

It also accounts for temperature and density fluctuations in the CMB, but dictates that those fluctuations should be uniform.

In chaotic inflation theory, this concept goes even deeper: an endless progression of inflationary bubbles, each becoming a universe, and each of these birthing even more inflationary bubbles in an immeasurable multiverse.

Other scientists place the formation of the singularity inside a cycle called the big bounce in which our expanding universe will eventually collapse back in on itself in an event called the big crunch.

A singularity once more, the universe will then expand in another big bang.

This process would be eternal and, as such, every big bang and big crunch the universe ever experiences would be nothing but a rebirth into another phase of existence.

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The Physics Nobel Goes To The Detection Of Ripples In Space And Time

The way the Nobel Committee tells it, the story of this year’s physics prize begins like a certain 1970s space opera.

Once upon a time, a long time ago, in a galaxy far, far away, two massive black holes engaged in a deadly dance,” said physicist and Nobel committee member Olga Botner at today’s prize announcement.

The pair spiraled toward each other, colliding to form an even bigger black hole with a mass 62 times that of Earth’s sun.

The impact shook the universe, generating ripples known as gravitational waves that warped the fabric of spacetime as they pulsed through.

By the time the collision’s reverberations reached Earth, they had quieted to a quiver.

Some 1.3 billion years after that ferocious black hole do-si-do, physicists at two observatories in the US simultaneously detected a ripple as a tiny compression and expansion in length in their machines.




This first detection of a gravitational wave took four decades of calculations, simulations, and engineering—and more than a billion dollars of US taxpayer money.

Today, physicists Rainer Weiss, Barry Barish, and Kip Thorne won the Nobel Prize in Physics for the pioneering work that led to this discovery.

They’ll split 9 million Swedish krona in prize money, or 1.1 million dollars; Weiss will receive half the prize while Barish and Thorne will split the other half.

Weiss and Thorne began to search for gravitational waves back in the ’70s, 50 years after Albert Einstein first predicted their existence in his theory of general relativity.

No one had seen a gravitational wave yet, so it was possible that Einstein had gotten some of his theory wrong.

Weiss, working at MIT, and Thorne, at Caltech, developed prototypes of a laser interferometer—a machine that could measure minuscule fluctuations in length.

Weiss brought the craftsmanship and engineering, while Thorne specialized in theoretical calculations.

Their designs led to machines that could detect compressions in spacetime thousands of times smaller than the width of a proton.

The descendants of those prototypes, one located in Louisiana and the other in Washington, detected the first gravitational wave in 2015.

But a sophisticated machine is only as clever as its operators. The Nobel Committee credits Barish, a physicist at Caltech, for assembling and managing the team—the Laser Interferometer Gravitational Wave Observatory collaboration—that made the discovery.

When Barish became LIGO’s leader in 1994, he expanded the group from about 40 researchers to more than a thousand people from all over the world.

He gathered experts specializing in black holes, gravity, lasers, statistics, vacuum systems, and everything else that goes into a giant, L-shaped observatory that can measure tiny contractions in its two 2.5-mile-long arms.

Since that first detection in 2015, LIGO has identified three other gravitational waves, also from black hole collisions. So far, all the measurements confirm Einstein’s theory of general relativity.

Now, physicists are trying to learn more details about these collisions and the black holes that produce them. This August, a similar observatory called VIRGO came online in Italy to collaborate with LIGO.

With VIRGO’s additional data, physicists will be able to more precisely locate where gravitational waves originate.

They want to find spacetime-warping effects from other types of collisions, such as ones between collapsed stars, known as neutron stars.

They want to observe tens of these per year and investigate their paths as they ripple toward Earth.

By studying how they move through space, physicists think they might be able to observe the waves interacting with new astronomical objects previously invisible to telescopes.

A hundred years after Einstein predicted their existence, the story of gravitational waves and their effects on the fabric of spacetime is only just beginning.

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New Gravitational Wave Detection Shows Shape Of Ripples From Black Hole Collision

Astronomers have made a new detection of gravitational waves and for the first time have been able to trace the shape of ripples sent through spacetime when black holes collide.

The announcement, made at a meeting of the G7 science ministers in Turin, marks the fourth cataclysmic black-hole merger that astronomers have spotted using Ligo, the Laser Interferometer Gravitational-Wave Observatory.

The latest detection is the first to have also been picked up by the Virgo detector, located near Pisa, Italy, providing a new layer of detail on the three dimensional pattern of warping that occurs during some of the most violent and energetic events in the universe.

A tiny wobble in the signal, picked up by Ligo’s twin instruments and the Virgo detector on 14 August, could be traced back to the final moments of the merger of two black holes about 1.8bn years ago.




The black holes, with masses about 31 and 25 times the mass of the sun, combined to produce a newly spinning black hole with about 53 times the mass of the sun.

The remaining three solar masses were converted into pure energy that spilled out as deformations that spread outwards across spacetime like ripples across a pond.

Detecting these tiny distortions has required detectors sensitive enough to measuring a discrepancy of just one thousandth of the diameter of an atomic nucleus across a 4km laser beam.

What is a gravity wave?

Rippling out from a super- massive collision, for example between two black holes, gravity waves could be detected through the stretching and contracting of space and time.

How Ligo and Virgo’s detectors work?

  1. A single laser beam is split and directed down two identical tubes, 4km long
  2. Mirrors reflect the twin beams back to a detector
  3. Back inside the detector, the laser beams arrive perfectly aligned
  4. Recombined, they cancel each other out

How are gravity waves detected?

  1. When spacetime is distorted by a gravity wave, the two tubes change length. One tube stretches as the other contracts over and over until the wave has passed
  2. As the distances fluctuate the peaks and troughs of the two returning laser beams move in and out of alignment
  3. The recombined waves no longer cancel each other out. Light reaches the detector and the gravity wave can be measured

Ligo scientists’ historic observation of gravitational waves in September 2015, marked the first experimental proof of Einstein’s prediction a century ago that space itself can be stretched and squeezed.

However, the parallel orientation of the two Ligo detectors, one in Hanford, Washington state, the other in Livingston, Louisiana, has meant that scientists are effectively observing one flat plane through space, rather than getting a 3D picture.

It’s like if I give you just one slice of apple, you can’t guess what the fruit looks like,” said Prof Andreas Freise, a Ligo project scientist at the University of Birmingham.

This was intentional because it maximised the chances of detection – a discovery that is hotly tipped to be rewarded when the Physics Nobel Prize is announced next week.

However, the configuration made it impossible to test a second crucial prediction of Einstein’s theory – the shape of the path that the waves travel along.

Virgo’s arms are angled differently than the two Ligo detectors, allowing astronomers to extract new information about the polarisation of gravitational waves – essentially the path traced out by the vibrations.

Einstein’s theory predicts two polarisations of gravitational waves, but some competing theories of gravity predict up to six.

Prof Stefan Ballmer, a physics professor at Syracuse University, explains: “If you look at how you can bend the sheet of paper that spacetime is, there are many ways you can bend it. But if you look at [Einstein’s predictions], only two of those ways are present.

The new data – albeit based on a single detection – already appear to strongly favour Einstein’s predictions of how spacetime is expected to crumple.

Combining results from three detectors has also allowed scientists to more accurately triangulate the area of sky from which the waves are emanating.

In future, this could allow scientists to swing ground-based telescopes to the target locations to see whether there is any visible trace of the collision itself.

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The Secret Blue Ice Cloud In Every Champagne Bottle

Like ice cream and revenge, champagne is best served cold, ideally between 42.8 and 53.6 degrees Fahrenheit.

But if you’re forced to drink it at 68 degrees Fahrenheit, just below room temperature, something fleeting but amazing will happen.

Scientists at the University of Reims, in France’s Champagne region, used a super-high-speed camera to observe a short-lived, blue “mini-cloud” escaping the tepid bottle—a cloud that hangs around for just two to three thousandths of a second.

That plume of cyan gas is colder than ice, and blue as the circumstances (lukewarm champagne). Researchers published their work in the journal Scientific Reports earlier this week.




This cloud was “totally unexpected,” coauthor Gerard Liger-Belair, an expert in bubbles and foam said.

Most people who have popped a bottle of cold champagne will be familiar with the wisps of white fog that cascade from the bottleneck. Before it’s been opened, champagne is under high pressure, hence the cage on the cork.

But when it’s open and the pressure adjusts, carbon dioxide pours forth. At 68 degrees Fahrenheit, however, that white mist is very briefly replaced with blue.

If the color of the blue reminds you of the sky, there’s a reason for that. The sky gets its shade from molecules scattering blue light from the sun.

The bluish cloud forms when the CO2 transforms into miniature particles of dry ice which reflect the ambient light,” Liger-Belair said.

This blue cloud has the same physical origin as the blue color of the sky. Is that not extraordinary?

It is indeed extraordinary, but perhaps not wondrous enough to justify drinking your champagne at 68 degrees Fahrenheit—especially since you’re not going to see magic blue cloud without high-speed imaging.

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Airbus Conquers Physics With A Funky Super-Fast Helicopter

airbus-chopper

Emergency workers and the obscenely rich love helicopters, and for good reason. Unlike airplanes, whirlybirds can take off and land almost anywhere, making them just the thing for tight spots and urban areas.

The drawback, though, is speed. Choppers are slow.

While Gulfstream’s G650 private jet streaks along at north of 600 mph, conventional choppers like the police or your local traffic reporter might use maxes out around 160 mph. Quick, but not that quick when talking about flight.

Airbus thinks it found a way of closing the speed gap without sacrificing a helicopter’s inherent advantages: add wings and props to create an aircraft that can take off and land vertically, hover, and cruise at a heady 250 mph.

Airbus calls it the Racer, for Rapid and Cost-Effective Rotorcraft.




The idea is to find a way around the physics that limit the speed of a conventional helo. With any helicopter, the top rotor provides lift as the blades slice the air.

When the helicopter is flying forward, air moves around the the blade spinning in the direction of travel faster than it does around the retreating blade on the opposite side, causing something aerodynamicists call dissymmetry of lift.

The faster you go, the more severe the effect and the less stable the helicopter. Aerodynamicists know how to compensate for most of that, but the challenge mounts as the blades approach the speed of sound. An advancing blade hitting the sound barrier creates aerodynamic instabilities engineers cannot compensate for.

So Airbus engineers added two short wings extending from each side of the fuselage. The wings meet at a point and support a rear-facing prop driven by the engines turning the main rotor.

airbus-chopper

In forward flight, the wings provide additional lift, and those small props provide additional propulsion. All of this allows the helo to achieve higher speeds without pushing the main rotor into an aerodynamic red zone.

“The concept of compound helicopters, using one or two pusher fans and small wings along with the main rotor, is not new,” says Mo Sammy, director of the Aerospace Research Center at Ohio State University. “What could be new is the claim of efficiency and affordability, if materialized.”

Although every futuristic aircraft seems to include electric motors these days, Airbus is sticking to a tried and tested powertrain here. Two Rolls-Royce turboprop engines power the main rotor and auxiliary propellers.

Airbus Helicopter

However, Airbus is exploring a “stop-start” system that will shut down one engine during low speeds or light loads. Think of it as “eco” mode for the sky.

Airbus sees a market for its machine that could rival private planes for city to city transport among jet setters in a hurry. Emergency services could benefit, too a higher top speed could mean a shorter flight to hospital.Airbus hopes to make the first flight in 2020. Commercial service could follow five to 10 years later. Just enough time to start saving up.

Airbus hopes to make the first flight in 2020. Commercial service could follow five to 10 years later. Just enough time to start saving up.

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How Physics Can Help You Achieve The Perfect Egg Crack

cracked egg

What’s the best way to crack an egg?

Physicists explain that we’re predisposed to hit the egg against a hard surface where the egg is flattest, or, its center, where its oblong shape widens; that’s the point at which an egg is weakest.




The egg puts up more of a fight at its round, arched ends. This curvature creates an even distribution of pressure, which may explain why it’s all but impossible to crack an egg when it’s held lengthwise between your fingers.

To game this correctly, then, you should create an initial crack in the center of your egg that opens a cavity small enough to fit your thumb through.

egg

What comes next requires quick, careful precision: You expand this ripple ever so slightly with your hands so that the egg’s yolk tumbles out. Go too fast and the shell will collapse in your hands.

So, there you go. Now you’ve got some new vocabulary, borrowed from the wild world of fracture mechanics, to apply to a deceptively simple cooking act. If this registers as completely useless information, consider that egg-cracking is a difficult art to master for the less dexterous among us.

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Want To Know What Happens When The Lightning Doesn’t Hit The Ground? Watch This!

lightning

Lightning is far more than just a sky-borne phenomenon: Remarkably, it can also form at ground level and shoot upwards.

This upside-down lightning is the subject of a paper published in the Journal of Atmospheric and Solar-Terrestrial Physics, in which the strange behavior of these inverted bolts is revealed.




Despite the fact that there are roughly 40-50 lightning strikes somewhere around the world every second, they are surprisingly poorly understood.

Watch the video to know how this upside down lightning works!


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