“What is spacetime made out of?” asks physicist Aron Wall at the Stanford Institute for Theoretical Physics . During the past several years, physicists have begun thinking about spacetime in a radically different way, not as just an empty backdrop for the unfolding story of the universe, but rather treating spacetime as the flow of quantum information from one point to another.
Since 2009 the European Space Agency’s Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been mapping the Earth’s gravitational field. More potato-shaped than spherical, the latest images shows just how different gravity can be at different points on our planet.
An international group of astronomers has revived a previously debunked theory of gravity, arguing that motions within dwarf galaxies would be slower if close to a massive galaxy. The theory, MOND, is a controversial alternative to general relativity, the prevailing Einstein-inspired understanding of the phenomenon of gravity, that requires dark matter to exist, but this has never been proved. MOND does not require dark matter.