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.

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.

If mass curves space, then very large masses moving quickly through space would create ripples in space. These are called gravitational waves.

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.

Scientists have announced that they have discovered gravitational waves.

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.

Because their rapid pulse of radio emission is so predictable, a large array of well-understood pulsars can be used to measure extremely subtle abnormalities, such as gravitational waves.

The strength of the gravitational force reduces quickly with distance.

Tides are caused by gravitational pull of the moon and the sun.

So far, there have been five detections of gravitational waves, thanks to the Laser Interferometer Gravitational-Wave Observatory (LIGO) and, more recently, the European Virgo gravitational-wave detector.