Month: January 2018

08 Jan 2018
Manahel Thabet

Scientists Are Rethinking the Very Nature of Space and Time

The Nature of Space and Time

A pair of researchers have uncovered a potential bridge between general relativityand quantum mechanics — the two preeminent physics theories — and it could force physicists to rethink the very nature of space and time.

Albert Einstein’s theory of general relativity describes gravity as a geometric property of space and time. The more massive an object, the greater its distortion of spacetime, and that distortion is felt as gravity.

In the 1970s, physicists Stephen Hawking and Jacob Bekenstein noted a link between the surface area of black holes and their microscopic quantum structure, which determines their entropy. This marked the first realization that a connection existed between Einstein’s theory of general relativity and quantum mechanics.

Less than three decades later, theoretical physicist Juan Maldacena observed another link between between gravity and the quantum world. That connection led to the creation of a model that proposes that spacetime can be created or destroyed by changing the amount of entanglement between different surface regions of an object.

In other words, this implies that spacetime itself, at least as it is defined in models, is a product of the entanglement between objects.

To further explore this line of thinking, ChunJun Cao and Sean Carroll of the California Institute of Technology (CalTech) set out to see if they could actually derive the dynamical properties of gravity (as familiar from general relativity) using the framework in which spacetime arises out of quantum entanglement. Their research was recently published in arXiv.

Using an abstract mathematical concept called Hilbert space, Cao and Carroll were able to find similarities between the equations that govern quantum entanglement and Einstein’s equations of general relativity. This supports the idea that spacetime and gravity do emerge from entanglement.

Carroll told Futurism the next step in the research is to determine the accuracy of the assumptions they made for this study.

“One of the most obvious ones is to check whether the symmetries of relativity are recovered in this framework, in particular, the idea that the laws of physics don’t depend on how fast you are moving through space,” he said.

A Theory of Everything

Today, almost everything we know about the physical aspects of our universe can be explained by either general relativity or quantum mechanics. The former does a great job of explaining activity on very large scales, such as planets or galaxies, while the latter helps us understand the very small, such as atoms and sub-atomic particles.

However, the two theories are seemingly not compatible with one another. This has led physicists in pursuit of the elusive “theory of everything” — a single framework that would explain it all, including the nature of space and time.

Because gravity and spacetime are an important part of “everything,” Carroll said he believes the research he and Cao performed could advance the pursuit of a theory that reconciles general relativity and quantum mechanics. Still, he noted that the duo’s paper is speculative and limited in scope.

“Our research doesn’t say much, as yet, about the other forces of nature, so we’re still quite far from fitting ‘everything’ together,” he told Futurism.

Still, if we could find such a theory, it could help us answer some of the biggest questions facing scientists today. We may be able to finally understand the true nature of dark matter, dark energy, black holes, and other mysterious cosmic objects.

Already, researchers are tapping into the ability of the quantum world to radically improve our computing systems, and a theory of everything could potentially speed up the process by revealing new insights into the still largely confusing realm.

While theoretical physicists’ progress in pursuit of a theory of everything has been “spotty,” according to Carroll, each new bit of research — speculative or not — leads us one step closer to uncovering it and ushering in a whole new era in humanity’s understanding of the universe.

Source: Futurism

06 Jan 2018
Manahel Thabet

Parallel Universes Could Solve One of the Biggest Mysteries in Physics

IN BRIEF

Black holes have long since presented something of a contradiction considering our current understanding of physics. Now, the many worlds interpretation offers a convincing explanation.

BLACK HOLES AND REVELATIONS

Black holes are the source of a major quandary when it comes to our understanding of physics; either they can destroy information, which contradicts what we know about quantum mechanics, or they seemingly disregard Einstein’s theory of relativity. However, it’s now thought by some that the many worlds interpretation might help explain the situation.

It suggests that each one of the multiple possible outcomes of a quantum event splinters off into its own discrete world.

Now, a team of researchers at the California Institute of Technology led by Sean Carroll has suggested that this interpretation can explain away inconsistencies pertaining to black holes. They say that general relativity is upheld within each single possible world, while information is preserved across the entire global wave function, if not among individual branches.

MANY WORLDS

Aidan Chatwin-Davies, a member of Carroll’s team, told Futurism that other scientists have already suggested applying the many worlds theory, also known as Everettian, to the black hole information problem. “Cosmetically, we’re perhaps the first to cleanly label our perspective as Everettian,” he said. “More substantively, we wanted to perform some concrete calculations to mathematize otherwise abstract ideas.”

“Previous attempts considered statements of general relativity and quantum mechanics to be applicable to the same world,” Yasunori Nomura, professor of physics at the University of California, Berkeley told Futurism. “My approach separates the two – quantum mechanics allows for a quantum state to be a ‘superposition’ of many classical worlds; statements of quantum mechanics apply to the entirety of these many worlds while those of general relativity apply only to each of these worlds.”

This line of thinking is important because it could potentially explain more about the nature of gravity and spacetime. Nomura suggests that these ideas have a broader relevance to how quantum gravity works at a fundamental level, particular in relation to the origins of the universe.

“We know that we need both general relativity and quantum mechanics to understand black holes, and so they are a good starting point for testing out ideas about quantum gravity,” explained Chatwin-Davies. “If we really understood how to describe black holes, then we would be a great deal closer to being able to describe quantum gravity in broad generality.”

By using the many worlds interpretation, scientists and astronomers are finding new ways to approach longstanding questions about black holes. With further study, this research might offer up further information about the very fabric of our universe that could fill in some persistent gaps in our knowledge.

Source: Futurism

04 Jan 2018
Manahel Thabet

Off World New Data Finally Reveals That, No, There Is No Alien Megastructure

IN BRIEF

New data collected on Tabby’s Star indicates that the strange dimming observed by researchers is likely caused by dust and not alien technology. The data was collected using the more than $100,000 donated through a Kickstarter campaign.

ANSWERS IN DATA

In 2015, researchers first noticed that KIC 8462852, better known as “Tabby’s Star,” was inexplicably dimming with no clear indication as to what might be causing this strange light pattern.

Now, thanks to a wildly successful Kickstarter campaign, researchers led by Louisiana State University (LSU) Department of Physics & Astronomy Assistant Professor Tabetha Boyajian were able to collect additional data on Tabby’s Star.

That data has produced new insights into the mysterious celestial body, which the researchers have overviewed in a paper published in The Astrophysical Journal Letters.

Some had speculated that the dimming of Tabby’s Star was caused by some kind of orbiting alien megastructure. No doubt those SETI hopefuls will be dismayed to find out that the new data points to dust as being the cause of the strange light patterns.

According to the paper, various colors of light emanating from the star are being blocked at different intensities. If something opaque, such as an alien megastructure or planet, was passing between the Earth and the star, that would not be the case.

STRANGE AND EXCITING

Anomalies like Tabby’s Star are best examined with a healthy dose of skepticism. As previously reported, the cause of the dimming had plenty of possible explanations far more plausible than aliens. Discussing the possibility of alien involvement or even hoping for such involvement isn’t necessarily problematic, though.

Allowing far-fetched hopes of aliens to get in the way of the actual gathering of data would discredit the scientific community, and we must always focus on what we can prove factually using the scientific method. Still, there is no harm in hoping the line between the factual and the fantastic gets blurred every once in a while.The place where imagination and science intersect has lead to some truly fantastic developments, such as all of the technology that has been, in part, influenced by “Star Trek” or other works of science fiction. Plus, remarkable discoveries like Tabby’s Star can encourage otherwise indifferent people to take an interest in science.

Source: Futurism

02 Jan 2018
Manahel Thabet

New Calculations May Finally Make Fusion Energy a Reality

It’s well established that nuclear fusion — the reaction that powers our Sun — could be the key to unlocking clean, limitless energy here on Earth.

But one of the biggest challenges of modern science is how to harness the fusion reaction so that it produces more energy than it consumes. And a new paper claims to have found a way to do just that.

Instead of looking at how to optimize common fusion reactor designs, such as tokamaks or stellerators, a group of physicists experimentally tested some novel reactor types.

They found that a strange-looking sphere design could be the key to achieving net-positive nuclear fusion because, surprisingly, it has the potential to generate more energy than it uses.

The key difference, aside from its shape, is that this nuclear sphere would fuse hydrogen and boron, rather than hydrogen isotopes such as deuterium and tritium. And it uses lasers to heat the core up to 200 times hotter than the center of the Sun.

If the team’s calculations are correct, the hydrogen-boron reactor device could be built and producing net-positive energy way before any of the reactors currently being tested reach completion.

Even better, the hydrogen-boron reaction produces no neutrons, and therefore doesn’t create any radioactive waste as a byproduct.

“It is a most exciting thing to see these reactions confirmed in recent experiments and simulations,” says lead researcher Heinrich Hora, from the University of New South Wales in Australia.

“I think this puts our approach ahead of all other fusion energy technologies.”

Fusion reactions take the opposite approach to the nuclear fission reactions we rely on for our nuclear power today: instead of atoms being split, they’re combined, or fused, together.

It’s similar to the reactions that power the Sun, as lighter nuclei are fused to build heavier ones with the help of incredible temperatures and pressures.

As great as it sounds in theory, it’s proving very difficult to harness in practice. The past two years have been record-breaking for fusion reactors around the world, with Germany switching on their much-hyped Wendelstein 7-X stellerator reactor.

But despite all our advances, we’re not a whole lot closer to creating net-positive nuclear fusion. Put simply, that’s because these machines just take so much energy to generate plasma.

In fact, Wendelstein 7-X isn’t even intended to generate usable amounts of energy, ever. It’s just a proof of concept.

But for years, Hora and her team have been working on alternative designs. And in this study, they tested them out experimentally as well as through simulations.

Their hydrogen-boron reactor works by triggering an “avalanche” fusion reaction from a laser beam packing a quadrillion watts of power in just a trillionth of a second.

You can see what it would look like below.

hb fus 02
Diagram showing a hydrogen-boron reaction. Image Credit: UNSW

The latest tests put the hydrogen-boron approach ahead of other similar technologies, including deuterium-tritium fusion, which is being explored at the National Ignition Facility in the US (and also has the drawback of producing radioactive waste).

The team also put together a roadmap for further development of hydrogen-boron fusion.

The best news? If future research doesn’t reveal any major engineering hurdles to this approach, the scientists reckon that a prototype reactor could be built within a decade.

While plenty of challenges remain in optimizing the necessary reactions and keeping them stable enough to generate electricity, if this new fusion technique can be made to work, the benefits could be huge.

“The fuels and waste are safe, the reactor won’t need a heat exchanger and steam turbine generator, and the lasers we need can be bought off the shelf,” says Warren McKenzie, managing director of HB 11, which owns the patents to the new technology.

The research has been published in Laser and Particle Beams.

Source: Futurism