A new theoretical study argues that many standard beliefs about consciousness are rooted in a misleading concept of how the brain functions.
Category: physics
Image: Ball bearings as tools for studying physics in microgravity
In this Oct. 20, 2025, photo, tiny ball bearings surround a larger central bearing during the Fluid Particles experiment, conducted inside the Microgravity Science Glovebox (MSG) aboard the International Space Station’s Destiny laboratory module.
A bulk container installed in the MSG, filled with viscous fluid and embedded particles, is subjected to oscillating frequencies to observe how the particles cluster and form larger structures in microgravity. Insights from this research may advance fire suppression, lunar dust mitigation, and plant growth in space. On Earth, the findings could inform our understanding of pollen dispersion, algae blooms, plastic pollution, and sea salt transport during storms.
In addition to uncovering potential benefits on Earth, research done aboard the space station helps inform long-duration missions like Artemis and future human expeditions to Mars.
Boosting the Coherence of X-Ray Free-Electron Lasers
Mode locking—a laser technique that revolutionized optical physics—has been extended to x rays, producing stable trains of attosecond pulses with unprecedented phase coherence.
X-ray free-electron lasers (XFELs) have transformed the study of matter by delivering femtosecond and attosecond pulses at angstrom wavelengths, enabling direct observation of ultrafast structural and electronic dynamics. Despite these successes, XFELs have long lacked a capability central to precision optical science: stable temporal phase coherence. Most XFEL facilities operate in the self-amplified spontaneous-emission (SASE) regime, in which radiation originates from microscopic shot noise in an electron beam. This mechanism produces extremely bright pulses, but shot-to-shot fluctuations in their temporal structure limit their use in phase-sensitive experiments useful for metrology, interferometry, and ultrafast spectroscopy [1].
How do I make clear ice at home? A food scientist shares easy tips
When you splurge on a cocktail in a bar, the drink often comes with a slab of aesthetically pleasing, perfectly clear ice. The stuff looks much fancier than the slightly cloudy ice you get from your home freezer. How do they do this?
Clear ice is actually made from regular water—what’s different is the freezing process.
With a little help from science, you can make clear ice at home, and it’s not even that tricky. However, there are quite a few hacks on the internet that won’t work. Let’s dive into the physics and chemistry involved.
New materials, old physics—the science behind how your winter jacket keeps you warm
As the weather grows cold this winter, you may be one of the many Americans pulling their winter jackets out of the closet. Not only can this extra layer keep you warm on a chilly day, but modern winter jackets are also a testament to centuries-old physics and cutting-edge materials science.
Winter jackets keep you warm by managing heat through the three classical modes of heat transfer —conduction, convection and radiation—all while remaining breathable so sweat can escape.
The physics has been around for centuries, yet modern material innovations represent a leap forward that let those principles shine.
The Causal Accessibility Horizon: A Structural Limit on Finite-Time Reachability
Across physics, chemistry, biology, and engineered systems, the operationally significant questionis often not whether a system will eventually reach a particular state, but whether it can be broughtthere within the time available. This paper establishes a single structural necessity: when causalresponse propagates at finite speed, there exist states that are theoretically admissible but practicallyunreachable within any finite time horizon. We formalize this as the causal accessibility horizon—ageometric boundary determined solely by propagation speed and actuation geometry, beyond whichno control action can have effect by a given time T. This constraint is categorical: it arises fromthe hyperbolic structure of finite-speed dynamics and is logically independent of dissipation, whichgoverns amplitude decay within the accessible region but does not determine its boundary. Theresult reframes questions of control, safety, and stabilization as finite-time reachability problemssubject to irreducible geometric limits.
Behold the Manifold, the Concept that Changed How Mathematicians View Space
The world is full of such shapes—ones that look flat to an ant living on them, even though they might have a more complicated global structure. Mathematicians call these shapes manifolds. Introduced by Bernhard Riemann in the mid-19th century, manifolds transformed how mathematicians think about space. It was no longer just a physical setting for other mathematical objects, but rather an abstract, well-defined object worth studying in its own right.
This new perspective allowed mathematicians to rigorously explore higher-dimensional spaces—leading to the birth of modern topology, a field dedicated to the study of mathematical spaces like manifolds. Manifolds have also come to occupy a central role in fields such as geometry, dynamical systems, data analysis, and physics.