the sphere

Sting Won’t Make the Sphere His Hive

Unlike his peers, the musician doesn’t see the appeal of the world’s hottest venue: “I don’t want to be overpowered by visuals.”




the sphere

Liturgy, Logos, and the Harmony of the Spheres

After sharing three commentaries on the Prologue of St. John, Fr. Anthony talks about the pattern of sound and how it works to perfect us and our community in Christ. This was first shared via Fr. Anthony's "My Fool Head" YouTube livestream on 04 December 2021. The Jonathan Pageau interview he couldn't remember was with Samuel Andreyev; "Patterns and Meaning in Music". Enjoy the show!




the sphere

Music of the Spheres: Star Songs

Plato, the Greek philosopher and mathematician, described music and astronomy as “sister sciences” that both encompass harmonious motions, whether of instrument strings or celestial objects. […]

The post Music of the Spheres: Star Songs appeared first on Smithsonian Insider.



  • Science & Nature
  • Space
  • astronomy
  • astrophysics
  • Center for Astrophysics | Harvard & Smithsonian
  • Chandra X-Ray Observatory
  • music
  • Smithsonian Astrophysical Observatory

the sphere

A Local Spectral Exterior Calculus for the Sphere and Application to the Shallow Water Equations. (arXiv:2005.03598v1 [math.NA])

We introduce $Psimathrm{ec}$, a local spectral exterior calculus for the two-sphere $S^2$. $Psimathrm{ec}$ provides a discretization of Cartan's exterior calculus on $S^2$ formed by spherical differential $r$-form wavelets. These are well localized in space and frequency and provide (Stevenson) frames for the homogeneous Sobolev spaces $dot{H}^{-r+1}( Omega_{ u}^{r} , S^2 )$ of differential $r$-forms. At the same time, they satisfy important properties of the exterior calculus, such as the de Rahm complex and the Hodge-Helmholtz decomposition. Through this, $Psimathrm{ec}$ is tailored towards structure preserving discretizations that can adapt to solutions with varying regularity. The construction of $Psimathrm{ec}$ is based on a novel spherical wavelet frame for $L_2(S^2)$ that we obtain by introducing scalable reproducing kernel frames. These extend scalable frames to weighted sampling expansions and provide an alternative to quadrature rules for the discretization of needlet-like scale-discrete wavelets. We verify the practicality of $Psimathrm{ec}$ for numerical computations using the rotating shallow water equations. Our numerical results demonstrate that a $Psimathrm{ec}$-based discretization of the equations attains accuracy comparable to those of spectral methods while using a representation that is well localized in space and frequency.




the sphere

On Sobolev tests of uniformity on the circle with an extension to the sphere

Sreenivasa Rao Jammalamadaka, Simos Meintanis, Thomas Verdebout.

Source: Bernoulli, Volume 26, Number 3, 2226--2252.

Abstract:
Circular and spherical data arise in many applications, especially in biology, Earth sciences and astronomy. In dealing with such data, one of the preliminary steps before any further inference, is to test if such data is isotropic, that is, uniformly distributed around the circle or the sphere. In view of its importance, there is a considerable literature on the topic. In the present work, we provide new tests of uniformity on the circle based on original asymptotic results. Our tests are motivated by the shape of locally and asymptotically maximin tests of uniformity against generalized von Mises distributions. We show that they are uniformly consistent. Empirical power comparisons with several competing procedures are presented via simulations. The new tests detect particularly well multimodal alternatives such as mixtures of von Mises distributions. A practically-oriented combination of the new tests with already existing Sobolev tests is proposed. An extension to testing uniformity on the sphere, along with some simulations, is included. The procedures are illustrated on a real dataset.




the sphere

Wavelet Analysis on the Sphere: Spheroidal Wavelets / Anouar Ben Mabrouk, Sabrine Arfaoui, Imen Rezgui

Online Resource