Gravitational

The observation of gravitational waves will start a new phase in the study of the universe.

Tycho's painstakingly collected data was reduced by Kepler to become grist for the mill that ground out Newton's gravitational theory.

The net gravitational field at any point on the surface of the earth is the sum of the gravitational fields of all the masses in the universe; hence it displays diurnal and seasonal variations and variations with the phases of the moon and Jupiter; and those variations vary with latitude: if you live far from the poles, you weigh more at night.

The sun exerts a stronger gravitational pull on the moon than does the earth.

Mars has two moons, Phobos and Deimos, which have unusual shapes. Scientists think these potato-shaped moons were once asteroids captured by Mars' gravitational pull.

The Martian atmosphere is composed of over 95% carbon dioxide. Solar winds carry the thin, weak atmosphere away because Mars has a weak gravitational and magnetic field.

Mars has two small natural satellites, Phobos and Deimos. They are highly irregular in shape and are believed to be asteroids captured by Mars' weak gravitational field.

Scientists believe that the particles in Saturn's rings came from the destruction of moons circling the planet. As comets and meteorites smashed the moons, Saturn's gravitational pull shaped the particles into rings.

Neptune was discovered because Uranus did not follow the orbital path predicted by astronomers. Astronomers assumed that the gravitational pull of another object was affecting the orbit of Uranus. This led them to look for, and find, Neptune.

Due to Triton's retrograde orbit, its density, and its composition, astronomers theorize that Triton was not originally a satellite of Neptune, but was captured by Neptune's gravitational pull, forcing it into an orbit around the planet.