English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Schwarzschild's 'interior solution' is a space-time metric that satisfiesEinstein's gravitational field equations with a source term that Einsteincreated on the basis of an unjustified identification of the conceptuallydistinct notions of the passive gravitational mass of matter and the activegravitational mass of matter. Giving up that assumption allows deriving from avariational principle new and better (because logically obtained) fieldequations that more faithfully extend the Poisson equation for Newton's gravitythan do Einstein's, with an active gravitational mass density providing thesource term. Solving these equations for a nonrotating spherical ball of matterwith uniform mass density produces a new, improved interior metric matched atthe surface of the ball to Schwarzschild's 'exterior' solution metric. This newmetric can then be used to address questions about the flight times of photonsand neutrinos through such a ball of matter.

Gravity Inside a Nonrotating, Homogeneous, Spherical Body