Showing posts with label fundamental symmetries. Show all posts
Showing posts with label fundamental symmetries. Show all posts

Tuesday, June 02, 2026

How does a spherical robot with 20 legs move?

Amazing stuff!

"... Researchers took inspiration from the symmetry in nature to build a variety of Argus bots with 16 to 22 legs. Each leg had a motor and a camera for seeing a near-360-degree picture of its surroundings, which made the robot capable of moving in any direction without adjustment. Across tests, the team found that more symmetrical robots were more successful on tasks, more energy efficient, and more resilient against injury. A 20-legged Argus, specifically, was especially successful at navigating diverse terrains, self-stabilizing, and responding to mechanical failures. ..."

"Symmetry is a central organizing principle in natural systems, yet its use as a unifying design strategy in robotics has largely remained limited to geometric form.
We show that symmetry can instead be leveraged at the level of dynamic actuation capability. We introduce dynamic symmetry, the uniformity of a robot's attainable center-of-mass accelerations, and formalize it through a measure coined as dynamic isotropy.
Across more than 1,000 simulated morphologies, we found that higher dynamic symmetry consistently improves trajectory tracking, task success, robustness, resiliency, and energy efficiency, with the benefits becoming most pronounced as dynamic isotropy approaches its theoretical limit.
To study this regime systematically, we developed Argus, a family of spherical robots designed to explore the effects of increasing dynamic symmetry.
Members of the Argus family vary in their actuation geometry and dynamic symmetry level, while sharing a common architectural principle: radially oriented linear actuators that directly shape the robot's center-of-mass dynamics. Among them, we build a physical 20-leg Argus variant that achieves near-extreme dynamic isotropy and demonstrates orientation-invariant locomotion, agile traversal of cluttered and deformable terrain, rapid self-stabilization, and resilience to partial actuator failures.
Its distributed sensing further enables omnidirectional perception and object interaction during continuous motion.
These results show that designing robots for symmetry not only in morphology but also in their attainable dynamics provides a powerful and general pathway toward agility, robustness, and multifunctionality in uncertain terrestrial and extraterrestrial environments."

From the abstract:
"Symmetry is a central organizing principle in natural systems, yet its use as a unifying design strategy in robotics has largely remained limited to geometric form.
We show that symmetry can instead be leveraged at the level of dynamic actuation capability. We introduce dynamic symmetry, the uniformity of a robot’s attainable center-of-mass accelerations, and formalize it through a measure coined as dynamic isotropy.
Across more than 1000 simulated morphologies, we found that higher dynamic symmetry consistently improved trajectory tracking, task success, robustness, resiliency, and energy efficiency, with the benefits becoming most pronounced as dynamic isotropy approached its theoretical limit.
To study this regime systematically, we developed Argus, a family of spherical robots designed to explore the effects of increasing dynamic symmetry. Members of the Argus family vary in their actuation geometry and dynamic symmetry level while sharing a common architectural principle: radially oriented linear actuators that directly shape the robot’s center-of-mass dynamics.
Among them, we built a physical 20-leg Argus variant that achieved near-extreme dynamic isotropy and demonstrated orientation-invariant locomotion, agile traversal of cluttered and deformable terrain, rapid self-stabilization, and resilience to partial actuator failures. Its distributed sensing further enabled omnidirectional perception and object interaction during continuous motion.
These results show that designing robots for symmetry not only in morphology but also in their attainable dynamics provides a powerful and general pathway toward agility, robustness, and multifunctionality in uncertain terrestrial and extraterrestrial environments."

ScienceAdviser





Wednesday, October 29, 2025

With a new molecule-based method, physicists peer inside an atom’s nucleus

Amazing stuff! However, can this approach be transferred to atoms of other elements?

"Physicists at MIT have developed a new way to probe inside an atom’s nucleus, using the atom’s own electrons as “messengers” within a molecule.

In a study appearing today in the journal Science, the physicists precisely measured the energy of electrons whizzing around a radium atom that had been paired with a fluoride atom to make a molecule of radium monofluoride. They used the environments within molecules as a sort of microscopic particle collider, which contained the radium atom’s electrons and encouraged them to briefly penetrate the atom’s nucleus. ... 

The team’s new molecule-based method offers a table-top alternative to directly probe the inside of an atom’s nucleus.
Amazing stuff!

Within molecules of radium monofluoride, the team measured the energies of a radium atom’s electrons as they pinged around inside the molecule. They discerned a slight energy shift and determined that electrons must have briefly penetrated the radium atom’s nucleus and interacted with its contents. As the electrons winged back out, they retained this energy shift, providing a nuclear “message” that could be analyzed to sense the internal structure of the atom’s nucleus.

The team’s method offers a new way to measure the nuclear “magnetic distribution.” In a nucleus, each proton and neutron acts like a small magnet, and they align differently depending on how the nucleus’ protons and neutrons are spread out. The team plans to apply their method to precisely map this property of the radium nucleus for the first time. What they find could help to answer one of the biggest mysteries in cosmology: Why do we see much more matter than antimatter in the universe? ..."

From the editor's summary and the abstract:
"Editor’s summary
Precision molecular spectroscopy is increasingly being used to probe symmetry violations relevant to fundamental physics studies. Of particular interest are molecules containing heavy radioactive nuclei, such as the pear-shaped radium isotope 225Ra. Wilkins et al. performed laser spectroscopy measurements of the hyperfine structure of the radium monofluoride molecule, which is especially challenging given the molecule’s short lifetime. In combination with calculations, the researchers were able to test models of magnetization distribution inside the radium nucleus. Their findings may lead to improved tests of fundamental symmetries. ...

Abstract
Precise experimental control and interrogation of molecules and calculations of their structure are enriching the investigation of nuclear and particle physics phenomena. Molecules containing heavy, octupole-deformed nuclei, such as radium, are of particular interest.
Here, we report precision laser spectroscopy measurements and theoretical calculations of the structure of the radioactive radium monofluoride molecule 225Ra19F.
Our results reveal fine details of the short-range electron-nucleus interaction, indicating the high sensitivity of this molecule to the distribution of magnetization, within the radium nucleus.
These results provide a stringent test of the description of the electronic wave function inside the nuclear volume, highlighting the suitability of these molecules for investigating subatomic phenomena."

With a new molecule-based method, physicists peer inside an atom’s nucleus | MIT News | Massachusetts Institute of Technology "An alternative to massive particle colliders, the approach could reveal insights into the universe’s starting ingredients."