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Category: physics – Page 2

Two Dead Stars Are Racing Around Each Other Every 6.2 Minutes

A pair of white dwarfs race around each other every 374 seconds, creating a rhythmic X-ray beacon that could reveal powerful gravitational waves.

Every 6.2 minutes, two dead stars complete an entire orbit around each other.

The system, eRASSU J060839.5–704014, or eRASSU J0608, is so compact that material from one white dwarf appears to strike the other directly, producing a strong X-ray pulse on every orbit. Astronomers have now found that the orbit is also shrinking unusually fast, making the system a promising target for future gravitational wave observatories.

X-ray light is like guitar music, with frequencies sliding continuously between harmonics

Ultrashort laser pulses can be used to generate X-rays. Normally, however, only certain specific frequencies are produced. A team from TU Wien and the University of California San Diego has developed a method that makes it possible to tune the frequency continuously.

Using a six-meter-long gas-filled waveguide (20 feet long) containing the appropriate gas, the researchers can “detune” the light frequencies so that, in the end, exactly the required X-ray frequency is produced. The results have been published in the journal Communications Physics.

‘Crisis averted’ as experts confirm universe’s expansion IS accelerating

Our universe’s expansion is still accelerating despite recent claims suggesting otherwise, an international team of astrophysicists say.

They refuted a study published last year claiming the growth of the universe is slowing and insist there is no flaw in the widely-accepted theory that a mysterious force known as dark energy is driving the expanding cosmos.

The researchers, who include two Nobel Laureates and represent institutions worldwide, say the debate that followed last November’s revelations was the result of a scientific misunderstanding rather than a cosmic grenade threatening to blow apart everything we know about the universe.

Laser experiments recreate solar flare physics and reveal consistent magnetic reconnection rates

Magnetic reconnection is a process that occurs when the magnetic fields of a conductive plasma quickly rearrange and release massive amounts of stored magnetic energy. It is widely thought to be the underlying mechanism behind cosmic events such as solar flares and substorms in Earth’s magnetosphere.

Now, researchers from Kyushu University have used high-power lasers to recreate and investigate this puzzling physical phenomenon of magnetic reconnection in a controlled environment. Their results indicate that fast magnetic reconnection is governed by the local physics of the reconnection layer rather than the properties of the surrounding plasma.

Briefly, magnetic reconnection involves the splicing and reconnection of magnetic field lines pointing in opposite directions as two plasma flows meet, causing plasma heating and high-speed plasma outflows.

Pilot system couples seawater desalination with hydrogen production

Seawater holds enormous potential for green hydrogen production, but realizing that potential remains far from straightforward. Direct seawater electrolysis can damage electrodes, whereas conventional freshwater electrolysis loses much of its energy as low-grade waste heat. Researchers have now found a way to harness this otherwise wasted heat, using it to desalinate seawater and produce fresh water alongside hydrogen.

In a study published in Nature Energy on Sept. 15, a team led by Prof. Deng Dehui and Associate Prof. Liu Yanting from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) proposed a “seawater to hydrogen and fresh water (STHW)” route that couples alkaline water electrolysis (AWE) with low-temperature vacuum distillation desalination.

The STHW process uses waste heat generated during AWE to drive low-temperature seawater desalination, producing fresh water for electrolysis and external use. The resulting concentrated brine can also be used for resource recovery, including salt, uranium and bromine.

New krypton-88 data narrow a key gap in stellar strontium models

An international research team has reported the first experimental investigation of a nuclear physics reaction essential for understanding how the element strontium is produced in stars—specifically in stellar environments where traditional explanations for its formation fall short. The study, published June 8 in Communications Physics, reports that the team used indirect experimental techniques to extract previously inaccessible information about how an isotope of a separate element—krypton—absorbs, or captures, neutrons.

Their measurements reduced the uncertainty of the neutron-capture rate of this isotope, krypton-88, from at least a factor of eight to about a factor of three. The team showed that the true rate of neutron capture by krypton-88 is consistently lower than theoretical predictions. When they incorporated these observations into leading models of how stars forge heavy elements—the intermediate neutron-capture process (i-process)—they discovered that the new rate increased the predicted amount of strontium, bringing simulations into better agreement with astronomical observations.

A finely tuned mess—how disorder can make networks more stable

Perfection is overrated—at least when it comes to complex systems like the power grid, food webs and advanced materials. For decades, scientists generally assumed that networks function most reliably when their individual components are as similar as possible. But real-world networks are rarely uniform.

Generators in a power grid, neurons in a brain, animals in a food web and components in a material all differ in ways that scientists traditionally treated as imperfections.

Now, Northwestern University physicists are overturning that long-held assumption.

Disorder is key to tuning a high-temperature superconductor

Cornell physicists have discovered that minimizing disorder, not varying electron count, is the key factor for controlling superconductivity in the unique material iron selenide (FeSe), a new insight for understanding high-temperature superconductors.

Using a new technique to control this iron-based superconductor, researchers in Kyle Shen’s lab have found that iron selenide’s superconducting “dome”—the curve tracing how superconductivity strengthens and then weakens as the properties are tuned—is more closely linked to resistance caused by imperfections in its crystal lattice than to the number of electrons flowing through the crystal. Iron selenide could be fundamentally different from other high-temperature (or unconventional) superconductors, the finding suggests.

“We found that in this material, that dome is driven by factors much different than what you see normally,” said postdoctoral researcher Paul Malinowski, a former Klarman Postdoctoral Fellow in the College of Arts and Sciences (A&S). “It’s not driven by how many electrons you’re adding in, but rather, it’s driven by the obstacles the electrons are hitting—how perfect or imperfect is the crystal lattice?”

Mysterious Gamma Rays Reveal Hidden Magnetism Inside Atomic Nuclei

Scientists have traced a decades-old gamma-ray mystery to hidden magnetic transitions inside atomic nuclei.

For decades, nuclear physicists have faced a puzzling question: why do some atomic nuclei release far more low-energy gamma rays than expected?

A new study led by the Facility for Rare Isotope Beams (FRIB), with contributions from scientists at Lawrence Livermore National Laboratory (LLNL), may finally provide the answer. Published in Nature, the research offers new insight into the inner workings of atomic nuclei and could have important implications for astrophysics, nuclear energy, national security, and nuclear forensics.

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