Geosynchronous orbit at the same point in the sky, i.e., not exhibit diurnal motion, while the Sun, Moon, and stars would traverse the skies behind it. The theoretical basis for this novel phenomenon of the sky goes back to Newton's theory of motion and gravity. In that theory, the existence of a geostationary satellite is made possible because the Earth rotates (with respect to an inertial frame in which Newton's laws of motion and gravity hold). However, as a practical device, the geostationary satellite owes much for its realisation to Arthur C. Clarke who proposed it during the 20th century and in
Three Roads to Quantum Gravity Three Roads to Quantum Gravity Three Roads to Quantum Gravity: A New Understanding of Space, Time and the Universe is the second non-fiction book by American theoretical physicist Lee Smolin. The book was initially published on May 30, 2001 by Basic Books as a part of "Science Masters" series. Smolin discusses three potential approaches by which a unified theory of quantum gravity, arguably the foremost issue in theoretical physics, may be realized. Approaches discussed include string theory, M-theory, and Smolin's preferred approach, loop quantum gravity. Smolin suggests that these approaches may be approximations of a single, underlying theory. —"The Guardian"