Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy, including planets, stars, galaxies, and even light, are attracted to (or gravitate toward) one another.

On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the tides of the oceans. The gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing and forming stars and caused the stars to group together into galaxies, so gravity is responsible for many of the large-scale structures in the Universe. Gravity has an infinite range, although its effects become weaker as objects get farther away.

Spaceflight I

Spaceflight (or space flight) applies astronautics to fly spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth and includes space probes for flights beyond Earth orbit. Such spaceflight operates either by telerobotic or autonomous control.