Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: physics

From ship wakes to soft tissues: Exploring fluid and solid surface-wave physics

A new study by scientists in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) shows that when a pressure disturbance moves across an ultrasoft elastic material, such as a gel or a biological tissue, it generates a V-shaped wake that’s strikingly similar to the waves that travel behind a boat.

Published in Physical Review Letters, the study offers a unified perspective, combining experiments and theory, on surface motion that spans fluids, solids, and the soft materials that lie between. It opens the door to new approaches to imaging and understanding the behavior of both natural and engineered soft materials.

The research was led by L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, Organismic and Evolutionary Biology, and Physics, in SEAS and FAS, and includes first author and former postdoctoral researcher Aditi Chakrabarti; postdoctoral researcher Divya Jaganathan, and SEAS research associate Robert Haussman.

Rapid method uncovers hidden structures in materials—including elusive quasicrystals

An international team of scientists, including researchers from Loughborough University, has developed a method to dramatically speed up the discovery and design of advanced materials. The study, published in Physical Review Letters, shows how the new approach can map complex phase diagrams in as little as a day—rather than weeks or months—and pinpoint where important structures, including crystals and quasicrystals, are likely to form.

The method will enable scientists to “scout ahead” and identify where promising structures are likely to form and the conditions needed to create them, rather than using a trial-and-error approach. It could help accelerate the development of advanced materials and technologies that harness the unique properties of quasicrystal structures.

“Our approach is a day’s work for an expert—it’s much faster,” said Professor Andrew Archer, an expert in applied mathematics and theoretical physics at Loughborough University and one of the paper’s authors.

How young galaxies grew magnetic fields faster than expected

How fast can a galaxy build ordered magnetic fields spanning thousands of light-years? Existing theories say several billion years, but observations of galaxies in our universe imply shorter timescales. In a study published in the Physical Review Letters and highlighted in the Physics magazine, scientists propose an explanation that resolves this contradiction. They say that the collapse of plasma clouds during the formation of galaxies could significantly accelerate the growth of these magnetic fields.

Almost all visible matter in our universe is in the form of plasma, which can be stirred by forces related to gravity, temperature gradients and rotation. If these lead to turbulent flow, the dynamo theory predicts that the existing magnetic fields in the plasma are amplified. The dynamo theory is our primary framework for understanding the origin of cosmic magnetic fields.

“However, dynamo theory has its limitations,” says Pallavi, an assistant professor at the International Centre for Theoretical Sciences (ICTS) and an author of the study. “In particular, it struggles to explain observations of young galaxies with robust magnetic fields across thousands of light-years.”

Astronomers discover Andromeda XXXVI, an ultra-faint dwarf satellite galaxy

By analyzing the data from the Pan-Andromeda Archaeological Survey (PandAS), European astronomers have discovered a new satellite of the Andromeda galaxy. The newfound object, which received the designation Andromeda XXXVI, appears to be an ultra-faint dwarf galaxy. The finding is reported in a paper published March 30 on the arXiv preprint server.

The so-called ultra-faint dwarf galaxies (UFDs) are the least luminous, most dark matter-dominated, and least chemically evolved galaxies known. Therefore, they are perceived by astronomers as the best candidate fossils from the universe at its early stages.

Now, a team of astronomers, led by Joanna D. Sakowska of the Institute of Astrophysics of Andalusia in Spain, reports the finding of a new UFD. Andromeda XXXVI was first spotted and classified as a candidate UFD by amateur astronomer Giuseppe Donatiello during a systematic, visual inspection search of public images from the full PAndAS footprint. Sakowska and her colleagues recently performed follow-up deep imaging of Andromeda XXXVI with the Roque de los Muchachos Observatory, which confirmed the UFD nature of this galaxy.

New AI video tool removes objects without breaking the laws of physics

When movie and TV directors want to tinker with their footage in post-production, they have an array of tools at their disposal to perfect a scene if it wasn’t shot exactly how they liked. That includes removing objects like stray equipment or unwanted background actors. But the tech has its limits when it comes to more complex physical interactions.

For example, if you want to remove an object that was bumping into or supporting something else, traditional tools often leave the remaining objects behaving in ways that defy the laws of physics, like a character hovering mid-air if the chair they were sitting on is deleted.

Physicists trace the sun’s magnetic engine, 200,000 kilometers below its surface

Every eleven years, the sun’s magnetic field flips. Sunspots—dark, cooler regions on the sun’s surface that mark intense magnetic activity and often trigger solar eruptions—appear at mid-latitudes and migrate toward the star’s equator in a butterfly-shape pattern before fading as the cycle resets. While this spectacle on the star’s surface has long been visible to astronomers, where this powerful cycle begins inside the star has remained hidden until now.

Researchers at the New Jersey Institute of Technology (NJIT) have analyzed nearly three decades of solar oscillation data to trace the sun’s interior dynamics, and have now pointed to the likely location of the star’s magnetic engine deep beneath its surface: roughly 200,000 kilometers down, about the length of stacking 16 Earths end to end.

The findings, published in Scientific Reports, provide one of the clearest observational windows yet into the sun’s magnetic engine—the solar dynamo—shedding light on hidden forces shaping space weather patterns linked to the solar cycle, not only on Earth’s nearest star, but potentially on other stars across the galaxy.

Physicists Found Something That Can Move Faster Than Light: The Darkness Inside It

For the first time, physicists have observed that ‘holes’ in light can move faster than the light itself.

They’re known as phase singularities or optical vortices, and since the 1970s, scientists have predicted that, just as eddies in a river can move faster than the flowing water around them, so too can whirlpools in a wave of light outrun the light they’re embedded within.

This does not break relativity, which states that nothing can travel faster than the speed of light. That’s because the vortices carry no mass, energy, or information, and their motion is based on the evolving geometry of the wave pattern rather than any physical motion through space.

Some black holes are ‘forbidden,’ ripples in spacetime reveal

How do you prove that in the unimaginably vast universe, certain objects don’t exist?

That’s a question that has plagued scientists studying gravitational waves—ripples in spacetime set off when two massive objects such as black holes swirl together and merge.

For decades, theorists have thought that, ironically, stars in a certain very heavy mass range simply cannot collapse to form black holes.

But gravitational wave astronomers had spotted no evidence of such a “mass gap”—until now.

Analysis of gravitational waves supports theory that some stars explode without leaving behind black holes.

/* */