## Seminars

**Forthcoming Seminar**

**The Origin of Inertia in FRW Universes**

Friday, March 24, 2017, 12:00

**Dr. Demosthenis Kazanas**** **

**NASA Goddard Spaceflight Center & Academy of Athens**

**Abstract:**

Using Sciama’s law of inertial induction and the fact that gravitational interactions are subject to retardation, we compute the effective force on an accelerating particle due to the contributions by the entire universe. Because the accelerating particle fields contain a term proportional to 1/*r*, in addition to the more conventional 1/*r*^{2} of the static field, the contribution of gravitational interactions by the rest of the universe onto an accelerating mass *m *(interior to the spherical distribution of cosmic matter) does not vanish. The resulting gravitational force has the form* F* = −*kma*, where *k* ~ 1, thereby indicating that inertial forces are due to gravitational interactions with the distant objects, as posited by Mach's principle. We will discuss whether these considerations support the presence of a characteristic universal acceleration of order *c* *H*_{0} (the speed of light divided by the age of the Universe) that can account for the galactic rotation curves and the apparent acceleration of the Universe in violation of the strong equivalence principle.

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#### Στην αίθουσα διαλέξεων "Β. Ξανθόπουλος" στο Εργαστήριο Αστρονομίας, ΑΠΘ

Το σεμινάριο θα μεταδοθεί στη σελίδα http://www.astro.auth.gr/seminars/live/live.html.

**See the 2016 video archive of previous seminars.**

**See the 2000-2015 list of previous seminars.**