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:
“Given that external reality is a fiction, the writer’s role is almost superfluous. He does not need to invent the fiction because it is already there.”
—J.G. (James Graham)
“An enormously vast field lies between “God exists” and “there is no God.” The truly wise man traverses it with great difficulty. A Russian knows one or the other of these two extremes, but is not interested in the middle ground. He usually knows nothing, or very little.”
—Anton Pavlovich Chekhov (1860–1904)
“As soon as I suspect a fine effect is being achieved by accident I lose interest. I am not interested ... in unskilled labor.... The scientific actor is an even worker. Any one may achieve on some rare occasion an outburst of genuine feeling, a gesture of imperishable beauty, a ringing accent of truth; but your scientific actor knows how he did it. He can repeat it again and again and again. He can be depended on.”
—Minnie Maddern Fiske (1865–1932)