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Category: space

Laser experiments push helium to record shock pressures

Deep inside gas giants like Jupiter and Saturn, hydrogen and helium coexist under pressures millions of times greater than Earth’s atmosphere. Under those conditions, helium may separate from hydrogen and influence a planet’s internal heat flow, structure and magnetic field. Understanding these processes and how these materials behave under extreme conditions is essential to building accurate models of planetary evolution.

New experimental results, published in Physical Review Research, reveal the behavior of helium at unprecedented pressures. The research, conducted by scientists at Lawrence Livermore National Laboratory (LLNL), the University of California, Berkeley, the French Commissariat à l’Énergie Atomique et aux Energies Alternatives (CEA) and the University of Rochester’s Laboratory for Laser Energetics (LLE), shows that helium behaves differently from what most broad-range theoretical models predicted.

Scientists catch classical space-time crystals moving like Majorana quasiparticles

A research team from Hiroshima University, the University of Colorado, and other collaborators have demonstrated that space-time crystals—exotic structures that, under external drive, loop endlessly through both space and time—can be created using everyday liquid-crystal materials.

For the past decade, physicists have been fascinated by time crystals. Unlike normal crystals (such as salt or diamonds), which have repeating molecular patterns in space, time crystals have patterns that repeat at regular intervals in time. Previously, scientists believed these bizarre structures could exist only in highly complex, fragile quantum systems at near-absolute-zero temperatures, such as trapped ions or quantum simulators. However, in a collaborative study published in Nature Communications, researchers successfully created them in a classical, room-temperature liquid-crystal system.

To achieve this, the team took a liquid-crystal material—similar to the fluid used in smartphones and television screens—and doped it with ionic substances. They then applied a rhythmic, repeating electrical signal to the fluid. Using advanced computer models and optical microscopes, the researchers observed a surprising phenomenon known as period-doubling. Even though the electrical drive pumped energy into the fluid at a set internal rhythm, the liquid crystals spontaneously locked into a pattern that repeated only every two cycles of the electricity.

ALMA spots a nine-member stellar family in the act of formation

Massive stars much bigger than our sun always come in pairs or groups, not alone. But astronomers don’t fully understand how these groupings form. In a new study, astronomers using ALMA have serendipitously discovered a young system containing nine baby stars forming together, and they have detailed a rare glimpse of the formation of such a stellar family in its earliest assembly stage in a paper submitted to the arXiv preprint server on June 2.

There are a few competing theories of how groups of stars form: disk, core and filament fragmentation. That is, a spinning disk of gas around a young star breaks apart into multiple pieces, or a big core of gas fragments into multiple star-forming clumps before the stars even form, or a long filamentary cloud of gas breaks into clumps along its length, each clump forming a star.

Massive stars, growing together as a group, are hard to study because they are far away, buried in thick dust and grow up fast while still in dense clouds. So astronomers have not caught many of them “in the act” of forming.

Next-Latent Prediction Transformers Learn Compact World Models

View recent discussion. Abstract: Transformers replace recurrence with a memory that grows with sequence length and self-attention that enables ad-hoc lookups over past tokens. Consequently, they lack an inherent incentive to compress history into compact latent states with consistent transition rules. This often leads to learning solutions that generalize poorly. We introduce Next-Latent Prediction (NextLat), which extends standard next-token training with self-supervised predictions in the latent space. Specifically, NextLat trains a transformer to learn latent representations that are predictive of its next latent state given the next token. Theoretically, we show that these latents provably converge towards belief states, compressed information about the history necessary to predict the future.

Einstein Probe detects mysterious X-ray transient that doesn’t fit any known class

Astronomers have reported the discovery of an unusual X-ray transient detected by the Einstein Probe that does not fit any known class of cosmic explosions. The paper presenting its multiwavelength analysis was published in the journal Monthly Notices of the Royal Astronomical Society on June 13.

On March 5, 2024, a space telescope called the Einstein Probe—designed to scan the sky for sudden X-ray flashes—caught a brief, never-before-seen source called EP240305a. It produced two brief X-ray flares, one right after the other, separated by about 200 seconds of quiet.

Researchers quickly pointed several telescopes at this source to gather more data in X-rays, infrared, optical and radio wavelengths; the analysis of these multiwavelength data is presented in the new study.

Homing pigeon navigation relies on superparamagnetic macrophages under overcast conditions

Birds use a variety of navigational strategies, including the geomagnetic field, especially when other cues are not available, such as under overcast or nocturnal conditions. Magnetite particles in the beak, cryptochromes in the eye, cellular ion-channel alterations, and changes in the vestibular system have been proposed to explain magnetoreception, but the exact mechanisms remain debated. Here, we used physical, morphological, functional, and genomic assays to identify the presence of superparamagnetic macrophages in the liver. We found that after macrophage depletion, pigeons flying under overcast conditions lacked their usual orientation capabilities. Orientation was unimpaired in birds without macrophages when the sun was visible, suggesting that this was their primary cue.

NASA to Cover US Spacewalk 95, Host Preview News Conference

NASA astronauts will venture outside the International Space Station on Tuesday, June 30, to replace a wrist joint on the orbital complex’s Canadarm2 robotic arm. The spacewalk is scheduled to begin at approximately 8:35 a.m. EDT.

Experts from NASA and CSA (Canadian Space Agency) will preview the upcoming spacewalk during a news conference at 2 p.m. on Thursday, June 25, on the agency’s YouTube channel. The briefing will take place at NASA’s Johnson Space Center in Houston. Learn how to watch NASA content through a variety of platforms, including social media.

Participants include:

No spacecraft has ever landed in the outer solar system — except one: the Huygens probe

Two decades on, it is still the most distant landing ever made, and it remains the only one in the outer solar system.

Seven years to get there

Huygens was the lander half of the Cassini-Huygens mission, a joint venture between NASA, the European Space Agency and the Italian space agency. The European-built probe rode piggyback on NASA’s Cassini orbiter, which launched in 1997 and spent nearly seven years crossing the solar system before slipping into orbit around Saturn in 2004.

NASA selects mission to study space weather interaction with Earth’s atmosphere

WASHINGTON — NASA has selected for development a space science mission that will study how space weather interacts with Earth’s atmosphere.

NASA announced June 18 that the Dynamic Atmosphere-Ionosphere Explorer, or DAPHNE, mission will proceed into the next phase of development, with a launch planned for no earlier than 2029.

DAPHNE was one of three concepts selected by NASA for study in 2024 for a mission concept called Dynamical Neutral Atmosphere-Ionosphere Coupling, or DYNAMIC, that was recommended by the heliophysics decadal survey in 2013 to examine the coupling between regions of the atmosphere and space weather.

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