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Category: physics – Page 306

SC18: HPC Demand Surges, Accelerated

NVIDIA’s playing a bigger role in high performance computing than ever, just as supercomputing itself has become central to meeting the biggest challenges of our time.

Speaking just hours ahead of the start of the annual SC18 supercomputing conference in Dallas, NVIDIA CEO Jensen Huang told 700 researchers, lab directors and execs about forces that are driving the company to push both into “scale-up” computing — focused on large supercomputing systems — as well as “scale-out” efforts, for researchers, data scientists and developers to harness the power of however many GPUs they need.

“The HPC industry is fundamentally changing,” Huang told the crowd. “It started out in scientific computing, and the architecture was largely scale up. Its purpose in life was to simulate from first principles the laws of physics. In the future, we will continue to do that, but we have a new tool — this tool is called machine learning.”

Ripples in Space-Time Could Reveal the Shape of Wormholes

Wormholes — yawning gateways that could theoretically connect distant points in space-time — are usually illustrated as gaping gravity wells linked by a narrow tunnel.

But their precise shape has been unknown.

Now, however, a physicist in Russia has devised a method to measure the shape of symmetric wormholes — even though they have not been proven to exist — based on the way the objects may affect light and gravity. [8 Ways You Can See Einstein’s Theory of Relativity in Real Life].

Does antimatter fall upwards? New CERN gravity experiments aim to get to the bottom of the matter

Physics tells us that a hammer and a feather, dropped in a vacuum, will fall at the same rate – as famously demonstrated by an Apollo 15 astronaut on the Moon. Now, CERN scientists are preparing to put a spooky new spin on that experiment, by dropping antimatter in a vacuum chamber to see if gravity affects it the same way it does matter – or if antimatter falls upwards instead.

Exclusive: Grave doubts over LIGO’s discovery of gravitational waves

The news we had finally found ripples in space-time reverberated around the world in 2015. Now it seems they might have been an illusion.

LIGO’s detectorsEnrico Sacchetti

THERE was never much doubt that we would observe gravitational waves sooner or later. This rhythmic squeezing and stretching of space and time is a natural consequence of one of science’s most well-established theories, Einstein’s general relativity. So when we built a machine capable of observing the waves, it seemed that it would be only a matter of time before a detection.

Danish physicists claim to cast doubt on detection of gravitational waves

“The first direct detection of gravitational waves was announced on February 11, 2016, spawned headlines around the world, snagged the 2017 Nobel Prize in Physics, and officially launched a new era of so-called “multi-messenger” astronomy. But a team of physicists at the Niels Bohr Institute in Copenhagen, Denmark, is calling that detection into question…”

“Andrew Jackson and his group have been saying for the past few years that LIGO’s detections are not real,” says LIGO Executive Director David Reitze of Caltech. “Their analysis has been looked at by many people who have all concluded there is absolutely no validity to their claims.” Reitze characterized the New Scientist article as “very biased and sensational.”

“Nothing they’ve done gives us any reason to doubt our results.”

This Bizarre Form of Ice Grows at Over 1,000 mph, And Now Physicists Know How

New research into a very weird type of ice known as Ice VII has revealed how it can form at speeds over 1,000 miles per hour (1,610 kilometres per hour), and how it might be able to spread across yet-to-be-explored alien worlds.

This ice type was only discovered occurring naturally in March, trapped inside diamonds deep underground, and this latest study looks in detail at how exactly it takes shape – apparently in a way that’s completely different to how water usually freezes into ice.

Based on a mathematical model devised by researchers from the Lawrence Livermore National Laboratory in California, there’s a certain pressure threshold across which Ice VII will spread with lightning speed. This process of near-instantaneous transformation is known as homogeneous nucleation.