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Using a spectral synthesis code designed to simulate conditions in interstellar matter, astronomers have explored a faint tidal disruption event (TDE) designated iPTF16fnl. Results of the study, published Dec. 29 on the pre-print server arXiv, deliver important insights into the properties of this TDE.

TDEs are astronomical phenomena that occur when a star passes close enough to a and is pulled apart by the black hole’s tidal forces, causing the process of disruption. Such tidally-disrupted stellar debris starts raining down on the black hole and radiation emerges from the innermost region of accreting debris, which is an indicator of the presence of a TDE. All in all, the debris stream-stream collision causes an energy dissipation, which may lead to the formation of an accretion disk.

Therefore, TDEs are perceived by as potentially important probes of strong gravity and accretion physics, providing answers about the formation and evolution of supermassive .

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A team of Chinese researchers used a novel theory to invent a new type of ultrathin optical crystal with high energy efficiency, laying the foundation for next-generation laser technology.

Prof. Wang Enge from the School of Physics, Peking University, recently told Xinhua that the Twist Boron Nitride (TBN) made by the team, with a micron-level thickness, is the thinnest optical crystal currently known in the world. Compared with traditional crystals of the same thickness, its is raised by 100 to 10,000 times.

Wang, also an academician of the Chinese Academy of Sciences, said this achievement is an original innovation by China in the theory of optical crystals and has created a new field of making optical crystals with two-dimensional thin-film materials of light elements.

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“The misperception of Neptune’s color, as well as the unusual color changes of Uranus, have bedeviled us for decades. This comprehensive study should finally put both issues to rest,” said Dr. Heidi Hammel.

In space, not everything is how it seems, and this might be the case with Uranus and Neptune, as a study scheduled to be published in February 2024 in the Monthly Notices of the Royal Astronomical Society examines how the colors of the two gas giants might be more similar that what NASA’s Voyager 2 spacecraft imaged in 1986 and 1989, respectively, as it flew past the gas giants during its mission. Originally, Voyager 2 imaged Uranus to exhibit a greenish-type color while Neptune appeared to be a strong blue, and this new study holds the potential to help scientists better understand how to estimate the true colors of planets throughout the cosmos.

“Although the familiar Voyager 2 images of Uranus were published in a form closer to ‘true’ color, those of Neptune were, in fact, stretched and enhanced, and therefore made artificially too blue,” said Dr. Patrick Irwin, who is a Professor of Planetary Physics at the University of Oxford and lead author of the study. “Even though the artificially-saturated color was known at the time amongst planetary scientists – and the images were released with captions explaining it – that distinction had become lost over time.”

For the study, the researchers used data obtained from the Lowell Observatory in Flagstaff, Arizona, between 1950 and 2016 and supplemental data obtained from NASA’s Hubble Space Telescope between 2016 and 2022 to determine that both Uranus and Neptune exhibit similar greenish-blue colors, with Neptune being slightly bluer than Uranus, which the team attributes to the planet’s possessing a thinner haze layer than Uranus. Additionally, the team might have also determined the color changes that Uranus experiences throughout its 84-year orbit, which they attributed to occurring during the planet’s equinoxes, when sunlight is directly over Uranus’ equator. When this happens, Uranus exhibits a slightly bluer color than during the rest of its orbit.

Continue reading “Revealing the True Colors of Neptune and Uranus: A Breakthrough Study” | >

Thanks to the LIGO and Virgo detectors, researchers now regularly observe ripples in spacetime known as gravitational waves, which are caused by catastrophic cosmic events such as black-hole mergers, star explosions, or the big bang itself.

Gravitational waves are ripples in the fabric of spacetime that travel at the speed of light. These are produced in some of the most violent events in the universe, such as black-hole mergers, supernovae, or the Big Bang itself. Since their first detection in 2015, and after three observing runs, the Advanced LIGO and Virgo detectors have detected around 100 such waves.

Thanks to these observations, we are starting to unveil the black-hole population of our universe, study gravity in its most extreme regime and even determine the formation of elements like gold or platinum during the merger of neutron stars.

The LIGO and Virgo detectors are nothing but the most precise rulers ever built by humankind, able to measure the subtle squeezing and stretching of spacetime produced by gravitational waves.

Continue reading “Scientists flip around gravitational-wave data analysis: Have LIGO and Virgo detected a merger of dark-matter stars?” | >

Scientists from the Technical University of Denmark (DTU) have confirmed the underlying physics of a newly discovered phenomenon of magnet levitation. In 2021, a scientist from Turkey published a research paper detailing an experiment where a magnet was attached to a motor, causing it to rotate rapidly. When this setup was brought near a second magnet, the second magnet began to rotate and suddenly hovered in a fixed position a few centimeters away.

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Researchers from the Helmholtz-Zentrum Dresden-Rossendorf and Dresden University of Technology have unraveled the water adsorption mechanism in certain microporous materials—so-called hierarchical metal-organic frameworks (MOFs)—while probing them on the atomic scale.

Discovered only about 25 years ago, their special properties quickly led to a reputation as “miracle materials”—which, as it turned out, can even harvest water from air. The researchers describe how the material achieves this in ACS Applied Materials & Interfaces.

“These very special materials are highly porous solids made of metals or metal-oxygen clusters which are connected in a modular way by pillars of organic chemicals. This 3D arrangement leads to networks of cavities reminiscent of the pores of a kitchen sponge. It is precisely these cavities that we are interested in,” says Dr. Ahmed Attallah of HZDR´s Institute of Radiation Physics.

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A new study reveals that magnetic fields are common in star systems with large blue stars, challenging prior beliefs and providing insights into the evolution and explosive nature of these massive stars.

Astronomers from the Leibniz Institute for Astrophysics Potsdam (AIP), the European Southern Observatory (ESO), and the MIT Kavli Institute and Department of Physics have discovered that magnetic fields in multiple star systems with at least one giant, hot blue star, are much more common than previously thought by scientists. The results significantly improve the understanding of massive stars and their role as progenitors of supernova explosions.

Characteristics of O-type Stars.

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University of Rochester astrophysicist Adam Frank explores the links between atmospheric oxygen and detecting extraterrestrial technology on distant planets.

In the quest to understand the potential for life beyond Earth, researchers are widening their search to encompass not only biological markers, but also technological ones. While astrobiologists have long recognized the importance of oxygen for life as we know it, oxygen could also be a key to unlocking advanced technology on a planetary scale.

In a new study published in Nature Astronomy, Adam Frank, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy at the University of Rochester and the author of The Little Book of Aliens (Harper, 2023), and Amedeo Balbi, an associate professor of astronomy and astrophysics at the University of Roma Tor Vergata, Italy, outline the links between atmospheric oxygen and the potential rise of advanced technology on distant planets.

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