- More Robotic physics: A coin vibrational motor powered hopper that can hop
across granular media. It turns out
that aerodynamics is important! A Light-weight High Froude Number Vibrational Motor Powered Recoil Robot that Hops Rapidly Across Granular Media
Click on this image to see high speed videos of the mechanism
hopping on poppy seeds
- A simple model for some structure seen with Gaia DR2
solar neighborhood stellar velocity
Spiral arm crossings inferred from ridges in Gaia DR2 stellar velocity distributions
Click on this image to see a movie showing an orbit
that grazes a spiral arm
- A seismic study of asteroid Bennu using a Bennu shape model
and the mass spring model:
Impact Excitation of a Seismic Pulse and Vibrational Normal Modes on Asteroid Bennu and Associated Slumping of Regolith
- The Galah survey stars show variations in the velocity distribution of stars
along different sight lines on the sky.
The Milky Way has lots of kinematic substructure changing across distances
of only a few hundred parsec, related to spiral structure and wobbling in the outer galaxy.
The GALAH Survey:
Stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere and metallicity
- Young supersolar open clusters might have been born in the inner galaxy
and moved outward. What type of spiral structure is needed to account for this?
Migration in the shearing sheet and estimates for young open cluster migration
- Originally developed for graphics applications, we modified mass spring models
to numerically explore a new field: Astro-Elastodynamics (aka Soft Astronomy).
For a talk (2017) on cracking moons and tidal evolution and spin dynamics
Astro-Elastodynamics (soft astronomy!)
- Explaining the weird high obliquities (spin tilts)
of Pluto and Charon's minor satellites, Styx, Nix, Kerberos and Hydra.
Obliquity evolution of the minor satellites of Pluto and Charon
- A new spin resonance model for the spin-secular/mean-motion resonance:
Tilting Styx and Nix but not Uranus with a Spin-Precession-Mean-motion resonance
- More Robotic Physics:
The motor vibration causes streaming in a fluid and if you break the rotational
symmetry the motor can swim! This paper illustrates a novel and low cost
robotic swimmer that has no external moving parts.
A coin vibrational motor swimming at low Reynolds number,
published in Regular and Chaotic Dynamics, 2016, Vol. 21, No. 7-8, pp 902-917.
Click on the figure to see the movie!
Showing the glycerin velocity field in the frame of the swimming motor.