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New tool allows scientists to peer inside neutron stars

Imagine taking a star twice the mass of the sun and crushing it to the size of Manhattan. The result would be a neutron star—one of the densest objects found anywhere in the universe, exceeding the density of any material found naturally on Earth by a factor of tens of trillions. Neutron stars are extraordinary astrophysical objects in their own right, but their extreme densities might also allow them to function as laboratories for studying fundamental questions of nuclear physics, under conditions that could never be reproduced on Earth.

Because of these exotic conditions, scientists still do not understand what exactly themselves are made from, their so-called “equation of state” (EoS). Determining this is a major goal of modern astrophysics research. A new piece of the puzzle, constraining the range of possibilities, has been discovered by a pair of scholars at IAS: Carolyn Raithel, John N. Bahcall Fellow in the School of Natural Sciences; and Elias Most, Member in the School and John A. Wheeler Fellow at Princeton University. Their work was recently published in The Astrophysical Journal Letters.

Ideally, scientists would like to peek inside these exotic objects, but they are too small and distant to be imaged with standard telescopes. Scientists rely instead on indirect properties that they can measure—like the mass and radius of a neutron star—to calculate the EoS, the same way that one might use the length of two sides of a right-angled triangle to work out its hypotenuse. However, the radius of a neutron star is very difficult to measure precisely. One promising alternative for future observations is to instead use a quantity called the “peak spectral frequency” (or f2) in its place.

Shortly Before They Collided, two Black Holes Tangled Spacetime up Into Knots

In February 2016, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) announced the first-ever detection of gravitational waves (GWs). Originally predicted by Einstein’s Theory of General Relativity, these waves are ripples in spacetime that occur whenever massive objects (like black holes and neutron stars) merge. Since then, countless GW events have been detected by observatories across the globe – to the point where they have become an almost daily occurrence. This has allowed astronomers to gain insight into some of the most extreme objects in the Universe.

In a recent study, an international team of researchers led by Cardiff University observed a binary black hole system originally detected in 2020 by the Advanced LIGO, Virgo, and Kamioki Gravitational Wave Observatory (KAGRA). In the process, the team noticed a peculiar twisting motion (aka. a precession) in the orbits of the two colliding black holes that was 10 billion times faster than what was noted with other precessing objects. This is the first time a precession has been observed with binary black holes, which confirms yet another phenomenon predicted by General Relativity (GR).

The team was led by Professor Mark Hannam, Dr. Charlie Hoy, and Dr. Jonathan Thompson from the Gravity Exploration Institute at Cardiff University. They were joined by researchers from the LIGO Laboratory, the Barcelona Institute of Science and Technology, the Max Planck Institute for Gravitational Physics, the Institute for Gravitational Wave Astronomy, the ARC Centre of Excellence for Gravitational Wave Discovery, the Scottish Universities Physics Alliance (SUPA), and other GW research institutes.

Spacecraft Makes Progress on Solar Heating Mystery

Data from the Parker Solar Probe confirms a long-suspected heat source for the Sun’s surprisingly hot corona, but there may be others.

The Sun’s surface temperature is around six thousand degrees kelvin, but the solar atmosphere—the corona and the solar wind—can reach a million degrees kelvin, a long-standing mystery in solar physics. Now, with data from the Parker Solar Probe, researchers have found evidence supporting a partial explanation for this mystery: magnetic waves driven by subsurface turbulence can impart energy to ions in these regions [1].

The exact mechanism of heating has been debated for decades, but the story appears to start with turbulent flow in the Sun’s convection zone, the outermost layer below the surface. In fluid dynamics, turbulence causes heating through a process known as turbulent energy cascade, where large eddies are converted into progressively smaller eddies. The energy in the smallest eddies is converted into heat through collisions between molecules.

What Drives Galaxies? The Milky Way’s Black Hole May Be the Key

On May 12, at nine simultaneous press conferences around the world, astrophysicists revealed the first image of the black hole at the heart of the Milky Way. At first, awesome though it was, the painstakingly produced image of the ring of light around our galaxy’s central pit of darkness seemed to merely prove what experts already expected: The Milky Way’s supermassive black hole exists, it is spinning, and it obeys Albert Einstein’s general theory of relativity.

And yet, on closer inspection, things don’t quite stack up.

Danish Physicist Lene Hau was Able to Slow Down the Speed of Light to 38 mph and was Eventually Able to Manipulate it

The speed of light is a universal physical constant that is important in many aspects of physics. Light travels at a continuous and finite speed of 186,000 miles per second. But did you have note that the speed of light can be manipulated?

In 1999, Lene Hau, a physicist from Denmark, was the first to slow light down to only 38 mph. Later, she could totally stop, control, and move it.

Researchers resolve decades-long debate about shock-compressed silicon with unprecedented detail

Silicon, an element abundant in Earth’s crust, is currently the most widely used semiconductor material and is important in fields like engineering, geophysics and plasma physics. But despite decades of studies, how the material transforms when hit with powerful shockwaves has been a topic of longstanding debate.

“One might assume that because we have already studied in so many ways there is nothing left to discover,” said Silvia Pandolfi, a researcher at the Department of Energy’s SLAC National Accelerator Laboratory. “But there are still some important aspects of its behavior that are not clear.”

Now, researchers at SLAC have finally put this controversy to rest, providing the first direct, high-fidelity view of how a single silicon crystal deforms during shock compression on nanosecond timescales. To do so, they studied the crystal with X-rays from SLAC’s Linac Coherent Light Source (LCLS) X-ray laser. The team published their results in Nature Communications on September 21st. What they learned could lead to more accurate models that better predict what will happen to certain materials in .

Matter Ejected From Crashing Neutron Stars Appeared to Break Light Speed

When astronomers around the world watched the epic collision between two neutron stars in 2017, the main event was just the beginning. The after-effects, both immediate and longer-term, of such a massive, never-before-seen merger were bound to be exciting, interesting, and deeply informative.

And now scientists have revealed a doozy. As the two neutron stars slammed together, they ejected a jet of material that, to our eyes, appeared to blast into space at seven times the speed of light.

This, of course, is impossible, according to our current understanding of physics. It’s a phenomenon known as superluminal speed, which in spite of its name is actually an illusion based on our viewing angle.

#16 David Chalmers PHD — THE SIMULATION HYPOTHESIS AND VIRTUAL WORLDS

How likely is it that we live in a simulation? Are virtual worlds real?

In this first episode of the 2nd Series we delve into the fascinating topic of virtual reality simulations and the extraordinary possibility that our universe is itself a simulation. For thousands of years some mystical traditions have maintained that the physical world and our separated ‘selves’ are an illusion, and now, only with the development of our own computer simulations and virtual worlds have scientists and philosophers begun to assess the statistical probabilities that our shared reality could in fact be some kind of representation rather than a physical place.
As we become more open to these possibilities, other difficult questions start to come into focus. How can we create a common language to talk about matter and energy, that bridges the simulated and simulating worlds. Who could have created such a simulation? Could it be an artificial intelligence rather than a biological or conscious being? Do we have ethical obligations to the virtual beings we interact with in our virtual worlds and to what extent are those beings and worlds ‘real’? The list is long and mind bending.

Fortunately, to untangle our thoughts on this, we have one of the best known philosophers of all things mind bending in the world, Dr. David Chalmers; who has just released a book ‘Reality+: virtual worlds and the problems of philosophy’ about this very topic. Dr. Chalmers is an Australian philosopher and cognitive scientist specialising in the areas of philosophy of mind and philosophy of language. He is a Professor of Philosophy and Neuroscience at New York University, as well as co-director of NYU’s Center for Mind, Brain and Consciousness. He’s the founder of the ‘Towards a Science of Consciousness Conference’ at which he coined the term in 1994 The Hard Problem of Consciousness, kicking off a renaissance in consciousness studies, which has been increasing in popularity and research output ever since.

Donate here: https://www.chasingconsciousness.net/episodes.

What we discuss in this episode:
00:00 Short Intro.
06:00 Synesthesia.
08:27 The science of knowing the nature of reality.
11:02 The Simulation Hypothesis explained.
15:25 The statistical probability evaluation.
18:00 Knowing for sure is beyond the reaches of science.
19:00 You’d only have to render the part you’re interacting with.
20:00 Clues from physics.
22:00 John Wheeler — ‘It from bit’
23:32 Eugene Wigner: measurement as a conscious observation.
27:00 Information theory as a useful but risky hold-all language tool.
34:30 Virtual realities are real and virtual interactions are meaningful.
37:00 Ethical approaches to Non-player Characters (NPC’s) and their rights.
38:45 Will advanced AI be conscious?
42:45 Is god a hacker in the universe up? Simulation Theology.
44:30 Simulation theory meets the argument for the existence of God from design.
51:00 The Hard problem of consciousness applies to AI too.
55:00 Testing AI’s consciousness with the Turing test.
59:30 Ethical value applied to immoral actions in virtual worlds.

References: