The External Field Effect (EFE)
In MOND it turns out that if a weakly gravitationally bound system s, whose inner accelerations are expected to be of the order of 10−10 m s−2 from a Newtonian calculation, is embedded in an external gravitational field generated by a larger array of masses S, then, even if is uniform throughout the spatial extension of s, the internal dynamics of the latter is influenced by in such a way that the total acceleration within s is, actually, larger than 10−10 m s−2. In other words, the Strong Equivalence Principle is violated. Milgrom originally introduced such a concept to explain the fact that the expected phenomenology of dark matter—-to be explained in terms of MOND—-was absent just in some systems (open clusters) in which it should have, instead, been present. It was shown later by R. Scarpa and collaborators that also a number of globular clusters in the neighborhood of the Milky Way behave in the same way, that is MOND effects are seen even though the total (internal+external) field is above MOND acceleration limit.
Read more about this topic: Modified Newtonian Dynamics
Famous quotes containing the words external, field and/or effect:
“Language disguises the thought; so that from the external form of the clothes one cannot infer the form of the thought they clothe, because the external form of the clothes is constructed with quite another object than to let the form of the body be recognized.”
—Ludwig Wittgenstein (1889–1951)
“And they wonder, as waiting the long years through
In the dust of that little chair,
What has become of our Little Boy Blue,
Since he kissed them and put them there.”
—Eugene Field (1850–1895)
“The whole theory of modern education is radically unsound. Fortunately in England, at any rate, education produces no effect whatsoever. If it did, it would prove a serious danger to the upper classes, and probably lead to acts of violence in Grosvenor Square.”
—Oscar Wilde (1854–1900)