Alternative Theories
Although dark matter is the most popular theory to explain the various astronomical observations of galaxies and galaxy clusters, there has been no direct observational evidence of dark matter. Some alternative theories have been proposed to explain these observations without the need for a vast amount of undetected matter. They broadly fall into the categories of modified gravity laws and quantum gravity laws. The difference between modified gravity laws and quantum gravity laws is that modified gravity laws simply propose alternative behaviour of gravity at astrophysical and cosmological scales, without any regard to the quantum scale. Both posit that gravity behaves differently at different scales of the universe, making the laws established by Newton and Einstein insufficient.
Read more about this topic: Dark Matter
Famous quotes containing the words alternative and/or theories:
“Our mother gives us our earliest lessons in love—and its partner, hate. Our father—our “second other”Melaborates on them. Offering us an alternative to the mother-baby relationship . . . presenting a masculine model which can supplement and contrast with the feminine. And providing us with further and perhaps quite different meanings of lovable and loving and being loved.”
—Judith Viorst (20th century)
“The two most far-reaching critical theories at the beginning of the latest phase of industrial society were those of Marx and Freud. Marx showed the moving powers and the conflicts in the social-historical process. Freud aimed at the critical uncovering of the inner conflicts. Both worked for the liberation of man, even though Marx’s concept was more comprehensive and less time-bound than Freud’s.”
—Erich Fromm (1900–1980)