"Gravity (from Latin gravitas 'weight') is a fundamental interaction which causes mutual attraction between all things that have mass."
Theory of gravitation, Kepler's laws of planetary motion, Newton's laws of motion and gravity, Einstein's theory of general relativity.
Newton's Law of Universal Gravitation: This law describes the attractive force between two masses in the universe.
Gravitational Field: The region around an object in which it exerts a force of gravitational attraction.
Inverse-Square Law: The intensity of gravity decreases with the square of the distance from the source.
Celestial Mechanics: Describes the motion of celestial bodies, including gravity's effect on their orbits.
Escape Velocity: The velocity an object needs to escape the gravitational pull of another object.
Black Holes: A region of space exhibiting gravitational force so strong that nothing, including light, can escape it.
Dark Matter: A hypothetical form of matter that is thought to make up approximately 85% of the matter in the universe.
General Relativity: A theory of gravitation that describes the curvature of spacetime caused by the presence of matter and energy.
Kepler's Laws of Planetary Motion: These laws describe the motion and orbits of planets around the sun.
Schwarzschild Radius: The radius at which the escape velocity from a black hole is equal to the speed of light.
Gravitational Waves: Ripples in the fabric of spacetime caused by the acceleration of massive objects.
Cosmology: The study of the structure, origins, and evolution of the universe, including the role of gravity.
Gravitational Lensing: The bending of light by the gravity of massive objects, which can be used to study the universe.
Dark Energy: A form of energy that is thought to be driving the accelerating expansion of the universe.
Chandrasekhar Limit: The maximum mass a white dwarf star can reach before collapsing into a neutron star or black hole.
Orbital Perturbations: Small changes to the orbit of a celestial body caused by the gravitational attraction of other objects in the system.
Newton's Laws of Motion: The three laws that describe the behavior of objects in motion, including the effects of gravity.
Escape Trajectory: The path a spacecraft takes to escape the gravitational pull of a planet or other celestial body.
Gravitational Redshift: The phenomenon in which the wavelength of light emitted from a source is stretched as it moves away from a gravitational field.
Orbital Resonance: A phenomenon in which the ratio of the orbital periods of two celestial bodies is a small integer, causing them to exert periodic perturbations on each other's orbit.
Newtonian gravity: This type of gravity was proposed by Sir Isaac Newton in the 17th century. Newton's law of gravitation states that any two objects with mass are attracted to each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This type of gravity is used to explain the motion of planets, stars, and other celestial bodies in the universe.
General Relativity: This is a theory of gravity proposed by Albert Einstein in the early 20th century. According to general relativity, gravity is not a force that allows objects to attract each other, but rather a curvature of space and time that is caused by the presence of mass and energy. This curvature of space and time is known as spacetime, and it describes how objects move and interact with each other in the universe. General relativity also predicts the existence of black holes and gravitational waves, which have been observed by modern astrophysical instruments.
"Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force, and 1029 times weaker than the weak interaction."
"As a result, it has no significant influence at the level of subatomic particles."
"Gravity is the most significant interaction between objects at the macroscopic scale, and it determines the motion of planets, stars, galaxies, and even light."
"On Earth, gravity gives weight to physical objects."
"The Moon's gravity is responsible for sublunar tides in the oceans (the corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another)."
"Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circulation of fluids in multicellular organisms."
"The gravitational attraction between the original gaseous matter in the universe caused it to coalesce and form stars which eventually condensed 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."
"Gravity is most accurately described by the general theory of relativity which describes gravity not as a force, but as the curvature of spacetime, caused by the uneven distribution of mass, and causing masses to move along geodesic lines."
"The most extreme example of this curvature of spacetime is a black hole, from which nothing—not even light—can escape once past the black hole's event horizon."
"For most applications, gravity is well approximated by Newton's law of universal gravitation, which describes it as a force causing any two bodies to be attracted toward each other, with magnitude proportional to the product of their masses and inversely proportional to the square of the distance between them."
"Current models of particle physics imply that the earliest instance of gravity in the universe, possibly in the form of quantum gravity, supergravity or a gravitational singularity, developed during the Planck epoch (up to 10−43 seconds after the birth of the universe)."
"Gravity developed during the Planck epoch, possibly from a primeval state, such as a false vacuum, quantum vacuum or virtual particle, in a currently unknown manner."
"Scientists are currently working to develop a theory of gravity consistent with quantum mechanics, a quantum gravity theory, which would allow gravity to be united in a common mathematical framework (a theory of everything) with the other three fundamental interactions of physics."