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Category: physics – Page 172

Toward next‐generation lava flow forecasting: Development of a fast, physics‐based lava propagation model

When a volcanic eruption occurs in an inhabited area, rapid and accurate lava flow forecasts can save lives and reduce infrastructure and property losses. To ensure that current lava forecasting models can provide outputs fast enough to be useful in practice, they unfortunately must incorporate physical simplifications that limit their accuracy.

To aid evacuation plans, forecast models must predict a ’s speed, direction, and extent. These attributes are intimately connected to how the lava solidifies as it cools. Yet to achieve real-time speed, most assume that a flow has a uniform temperature. This is a major simplification that directly influences modeled rates of cooling; generally, are much cooler at their boundaries, where they are in contact with air or the ground, than they are internally.

Aiming to strike a better compromise between speed and realism, David Hyman and a team developed a 2D, physics-based lava flow model called Lava2d. They extended the traditional, vertically averaged treatment of a lava packet by considering it as three distinct regions: the portion near the lava-air boundary, the portion near the lava-ground boundary, and the fluidlike central core. The top and bottom regions of a modeled flow cool based on the physics of heat transfer to the air and ground, while the temperature in the center remains uniform, as in prior approaches. This setup enables the model to account for a without requiring a computationally expensive 3D approach.

Machine learning could vastly speed up the search for new metals

The findings could help pave the way for greater use of machine learning in materials science, a field that still relies heavily on laboratory experimentation. Also, the technique of using machine learning to make predictions that are then checked in the lab could be adapted for discovery in other fields, such as chemistry and physics, say experts in materials science.

To understand why it’s a significant development, it’s worth looking at the traditional way new compounds are usually created, says Michael Titus, an assistant professor of materials engineering at Purdue University, who was not involved in the research. The process of tinkering in the lab is painstaking and inefficient.

Researchers compress light 12 times below the diffraction limit in a dielectric material

Until recently, it was widely believed among physicists that it was impossible to compress light below the so-called diffraction limit (see below), except when using metal nanoparticles, which unfortunately also absorb light. It therefore seemed impossible to compress light strongly in dielectric materials such as silicon, which are key materials in information technologies and come with the important advantage that they do not absorb light.

Interestingly, it was shown theoretically in 2006 that the diffraction limit also does not apply to dielectrics. Still, no one has succeeded in showing this in the , simply because no one has been able to build the necessary nanostructures until now.

A research team from DTU has successfully designed and built a structure, a so-called dielectric nanocavity, which concentrates light in a volume 12 times below the diffraction limit. The result is groundbreaking in optical research and has just been published in Nature Communications.

SpaceX to launch Europe’s next deep space telescope, first asteroid orbiter

On October 17th, a NASA official speaking at an Astrophysics Advisory Committee meeting revealed that the European Space Agency (ESA) had begun “exploring options” and studying the feasibility of launching the Euclid near-infrared space telescope on SpaceX’s Falcon 9 rocket.

In a major upset, director Josef Aschbacher confirmed less than three days later that ESA will contract with SpaceX to launch the Euclid telescope and Hera, a multi-spacecraft mission to a near-Earth asteroid, after all domestic alternatives fell through.

The European Union and, by proxy, ESA, are infamously insular and parochial about rocket launch services. That attitude was largely cultivated by ESA and the French company Arianespace’s success in the international commercial launch market in the 1980s, 1990s, and 2000s – a hard-fought position that all parties eventually seemed to take for granted. When that golden era slammed headfirst into the brick wall erected by SpaceX in the mid-2010s, Arianespace found itself facing a truly threatening competitor for the first time in 15+ years.

Is our planet surrounded by a giant magnetic tunnel? Let’s find out

It would consist of magnetic ropes.

A Dunlap Institute astronomer is speculating that our solar system may be surrounded by a magnetic tunnel that can be seen in radio waves, according to a press release by the institution published October 14.

Rope-like filaments surrounding our planet

Dr. Jennifer West, Research Associate at the Dunlap Institute for Astronomy and Astrophysics, is claiming that the two bright structures seen on opposite sides of the sky that were previously considered to be separate are actually connected. They are further made of rope-like filaments that form a tunnel around our solar system.

Physicists Baffled by Proton Structure Anomaly

Precision measurement of how a proton’s structure deforms in an electric field has revealed new details about an unexplained spike in proton data.

Nuclear physicists have confirmed that the current description of proton structure isn’t perfect. A bump in the data in probes of the proton’s structure has been revealed by a new precision measurement of the proton’s electric polarizability performed at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility. When this was seen in earlier measurements, it was widely thought to be a fluke. However, this new, more precise measurement has confirmed the presence of the anomaly and raises important questions about its origin. The research was published on October 19 in the journal Nature.

“There is something that we’re clearly missing at this point. The proton is the only composite building block in nature that is stable. So, if we are missing something fundamental there, it has implications or consequences for all of physics.” —

How our brain noises could make computers as imaginative as Shakespeare

It enables us to make extraordinary leaps of imagination.

We all have to make hard decisions from time to time. The hardest of my life was whether or not to change research fields after my Ph.D., from fundamental physics to climate physics. I had job offers that could have taken me in either direction — one to join Stephen Hawking’s Relativity and Gravitation Group at Cambridge University, another to join the Met Office as a scientific civil servant.

I wrote down the pros and cons of both options as one is supposed to do, but then couldn’t make up my mind at all. Like Buridan’s donkey, I was unable to move to either the bale of hay or the pail of water.

Metamorworks/iStock.

Since it was doing my head in, I decided to try to forget about the problem for a couple of weeks and get on with my life. In that intervening time, my unconscious brain decided for me. I simply walked into my office one day and the answer had somehow become obvious: I would make the change to studying the weather and climate.

Dr. Ezinne Uzo-Okoro, Ph.D. — Space Policy — Office of Science & Technology Policy, White House

Advancing Space For Humanity — Dr. Ezinne Uzo-Okoro, Ph.D. — Assistant Director for Space Policy, Office of Science and Technology Policy, The White House.

Dr. Ezinne Uzo-Okoro, Ph.D. is Assistant Director for Space Policy, Office of Science and Technology Policy, at the White House (https://www.whitehouse.gov/ostp/) where she focuses on determining civil and commercial space priorities for the President’s science advisor, and her portfolio includes a wide range of disciplines including Orbital Debris, On-orbit Servicing, Assembly, and Manufacturing (OSAM), Earth Observations, Space Weather, and Planetary Protection.

Previously, Dr. Uzo-Okoro built and managed over 60 spacecraft missions and programs in 17 years at NASA, in roles as an engineer, technical expert, manager and executive, in earth observations, planetary science, heliophysics, astrophysics, human exploration, and space communications, which represented $9.2B in total program value. Her last role was as a NASA Heliophysics program executive.

Dr. Uzo-Okoro has an undergraduate degree in Computer Science from Rensselaer Polytechnic Institute, and three masters degrees in Space Systems, Space Robotics, and Public Policy from Johns Hopkins University (APL), MIT (the Media Lab), and Harvard University, and a PhD in Space Systems from MIT, on the robotic assembly of satellites.

During her career, Dr. Uzo-Okoro also founded Terraformers.com to help grow affordable food through productive and networked backyard gardens, as a precursor to growing food in space. Her immigration story is profiled in President George W. Bush’s book, ‘Out of Many, One’.

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The most precise accounting yet of dark energy and dark matter

Astrophysicists have performed a powerful new analysis that places the most precise limits yet on the composition and evolution of the universe. With this analysis, dubbed Pantheon+, cosmologists find themselves at a crossroads.

Pantheon+ convincingly finds that the cosmos is composed of about two-thirds dark energy and one-third matter—mostly in the form of dark matter—and is expanding at an accelerating pace over the last several billion years. However, Pantheon+ also cements a major disagreement over the pace of that expansion that has yet to be solved.

By putting prevailing modern cosmological theories, known as the Standard Model of Cosmology, on even firmer evidentiary and statistical footing, Pantheon+ further closes the door on alternative frameworks accounting for dark energy and dark matter. Both are bedrocks of the Standard Model of Cosmology but have yet to be directly detected and rank among the model’s biggest mysteries. Following through on the results of Pantheon+, researchers can now pursue more precise observational tests and hone explanations for the ostensible cosmos.