"All conservative forces have potential energy associated with them. The force of gravity is no exception. Gravitational potential energy is usually given the symbol UgU_gUgU, start subscript, g, end subscript. It represents the potential an object has to do work as a result of being located at a particular position in a gravitational field."
https://www.khanacademy.org/science/physics/work-and-energy/work-and-energy-tutorial/a/what-is-gravitational-potential-energy
"Gravitational energy is the energy stored in an object due to its height above the Earth (e.g. if it's further away or closer to the ground). It is a form of potential energy."
https://www.solarschools.net/knowledge-bank/energy/types/gravitational
"GPE depends on two key factors: the object’s position relative to a gravitational field and the mass of the object. The center of mass of the body creating the gravitational field (on Earth, the center of the planet) is the lowest-energy point in the field (although in practice the actual body will stop the falling before this point, as the Earth’s surface does), and the farther from this point an object is, the more stored energy it has due to its position. The amount of stored energy also increases if the object is more massive."
https://sciencing.com/gravitational-potential-energy-definition-formula-units-w-examples-13720808.html
"Gravitational waves are distortions in the fabric of space and time caused by the movement of massive objects"
https://www.nationalgeographic.com/science/article/gravitational-waves
"Gravitational waves, also known as gravitational radiation, were predicted by Albert Einstein as a consequence of his theory of general relativity. This theory describes gravity as distortions in the structure of spacetime created by matter and energy. Einstein realized those distortions would travel at the speed of light in the form of waves, much like light itself can be described as a wave."
https://www.cfa.harvard.edu/research/topic/gravitational-waves
"A gravitational wave is an invisible (yet incredibly fast) ripple in space. Gravitational waves travel at the speed of light (186,000 miles per second). These waves squeeze and stretch anything in their path as they pass by."
https://spaceplace.nasa.gov/gravitational-waves/en/
"The "energy receiver" (gravitational energy converter) had been built by Tesla himself"
http://waterpoweredcar.com/teslascar.html