Theoretical Models
Of the four fundamental interactions, gravitation is dominant at cosmological length scales; that is, the other three forces play a negligible role in determining structures at the level of planetary systems, galaxies and larger-scale structures. Because all matter and energy gravitate, gravity's effects are cumulative; by contrast, the effects of positive and negative charges tend to cancel one another, making electromagnetism relatively insignificant on cosmological length scales. The remaining two interactions, the weak and strong nuclear forces, decline very rapidly with distance; their effects are confined mainly to sub-atomic length scales.
Read more about this topic: Universe
Famous quotes containing the words theoretical and/or models:
“The desire to serve the common good must without fail be a requisite of the soul, a necessity for personal happiness; if it issues not from there, but from theoretical or other considerations, it is not at all the same thing.”
—Anton Pavlovich Chekhov (1860–1904)
“Today it is not the classroom nor the classics which are the repositories of models of eloquence, but the ad agencies.”
—Marshall McLuhan (1911–1980)