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Category: physics – Page 12

Cyanobacteria, an ancient lineage of bacteria that perform photosynthesis, have been found to regulate their genes using the same physics principle used in AM radio transmission.

New research published in Current Biology has found that cyanobacteria use variations in the amplitude (strength) of a pulse to convey information in single cells. The finding sheds light on how biological rhythms work together to regulate cellular processes.

In AM (amplitude modulation) radio, a wave with constant strength and frequency—called a carrier wave—is generated from the oscillation of an electric current. The audio signal, which contains the information (such as music or speech) to transmit, is superimposed onto the carrier wave. This is done by varying the amplitude of the carrier wave in accordance with the frequency of the .

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When laser energy is deposited in a target material, numerous complex processes take place at length and time scales that are too small to visually observe. To study and ultimately fine-tune such processes, researchers look to computer modeling. However, these simulations rely on accurate equation of state (EOS) models to describe the thermodynamic properties—such as pressure, density and temperature—of a target material under the extreme conditions generated by the intense heat of a laser pulse.

One process that is insufficiently addressed in current EOS models is ablation, where the irradiation from the laser beam removes solid material from the target either by means of vaporization or plasma formation (the fourth state of matter). It is this mechanism that launches a shock into the material, ultimately resulting in the high densities required for high pressure experiments such as (ICF).

To better understand laser–matter interactions with regard to ablation, researchers from Lawrence Livermore National Laboratory (LLNL), the University of California, San Diego (UCSD), SLAC National Accelerator Laboratory and other collaborating institutions conducted a study that represents the first example of using X-ray diffraction to make direct time-resolved measurements of an aluminum sample’s ablation depth. The research appears in Applied Physics Letters.

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In 2019, the High Energy Density Science (HEDS) Center at Lawrence Livermore National Laboratory (LLNL) launched its postdoctoral fellowship program, welcoming one new scientist annually to come and conduct research for a two-year term. Supported by LLNL’s Weapons Physics and Design program, HEDS fellows are encouraged to pursue their own research agenda as it relates to the study of matter and energy under extreme conditions.

The most recent postdoctoral fellows, physicist Elizabeth “Liz” Grace (2022 fellow) and plasma physicist Graeme Sutcliffe (2023 fellow), are using high-intensity lasers and advanced diagnostics to observe the behaviors of plasma. A plasma, known as the “fourth state of matter,” is a superheated, ionized gas that makes up the majority of visible matter in the universe, like stars and nebulae. Replicating these conditions is a key step to achieving robust igniting inertial fusion designs for energy resilience.

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Observations of the cosmic microwave background, leftover light from when the Universe was only 380,000 years old, reveal that our cosmos is not rotating. Infinitely long cylinders don’t exist. The interiors of black holes throw up singularities, telling us that the math of GR is breaking down and can’t be trusted. And wormholes? They’re frighteningly unstable. A single photon passing down the throat of a wormhole will cause it to collapse faster than the speed of light. Attempts to stabilize wormholes require exotic matter (as in, matter with negative mass, which isn’t a thing), and so their existence is just as debatable as time travel itself.

This is the point where physicists get antsy. General relativity is telling us exactly where time travel into the past can be allowed. But every single example runs into other issues that have nothing to do with the math of GR. There is no consistency, no coherence among all these smackdowns. It’s just one random rule over here, and another random fact over there, none of them related to either GR or each other.

If the inability to time travel were a fundamental part of our Universe, you’d expect equally fundamental physics behind that rule. Yet every time we discover a CTC in general relativity, we find some reason it’s im possible (or at the very least, implausible), and the reason seems ad hoc. There isn’t anything tying together any of the “no time travel for you” explanations.

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Astronomers have made a groundbreaking discovery of binary star systems, consisting of a white dwarf and a main sequence star, within young star clusters.

This discovery opens up new avenues for understanding stellar evolution and could provide insights into the origins of phenomena such as supernovas and gravitational waves.

Breakthrough Discovery in Star Clusters.

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Good news for anyone with a hankerin’ for going back in time to kill their grandfather before he had kids: a physicist named Germain Tobar from the University of Queensland in Australia says go for it since time travel paradoxes aren’t real. So feel free to kill your grandpappy without fear of deleting your own existence.

He didn’t explicitly frame it that way, but he does think that time travel paradoxes are bullshit. Tobar’s work uses Einstein’s theory of general relativity as a foundation and then builds from there. He says that, according to his calculations, events can exist both in the past and in the future simultaneously, independent of one another. Space-time will adjust itself to avoid paradoxes, thus allowing you to cause whatever mayhem you want throughout time without creating contradictions.

If true, famous time travel stories like The Terminator and Back to the Future wouldn’t be possible. A Terminator sent to the past to kill John Connor would not be killing John Connor in the future, theoretically. It would only kill John Connor in the past and space-time would find some way to adjust to ensure that John Connor is still alive in the future to continue to be a pain in every robot’s shiny metal ass.

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A new method enables researchers to analyze magnetic nanostructures with a high resolution. It was developed by researchers at Martin Luther University Halle-Wittenberg (MLU) and the Max Planck Institute of Microstructure Physics in Halle.

The new method achieves a resolution of around 70 nanometers, whereas normal light microscopes have a resolution of just 500 nanometers. This result is important for the development of new, energy-efficient storage technologies based on spin electronics. The team reports on its research in the current issue of the journal ACS Nano.

Normal optical microscopes are limited by the wavelength of light and details below around 500 nanometers cannot be resolved. The new method overcomes this limit by utilizing the anomalous Nernst effect (ANE) and a metallic nano-scale tip. ANE generates an electrical voltage in a magnetic metal that is perpendicular to the magnetization and a .

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For decades, scientists have used the Milky Way as a model for understanding how galaxies form. But three new studies raise questions about whether the Milky Way is truly representative of other galaxies in the universe.

“The Milky Way has been an incredible physics laboratory, including for the physics of galaxy formation and the physics of dark matter,” said Risa Wechsler, the Humanities and Sciences Professor and professor of physics in the School of Humanities and Sciences. “But the Milky Way is only one system and may not be typical of how other galaxies formed. That’s why it’s critical to find similar galaxies and compare them.”

To achieve that goal, Wechsler cofounded the Satellites Around Galactic Analogs (SAGA) Survey dedicated to comparing galaxies similar in mass to the Milky Way.

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