Feb 26 2025

Gravity

A force caused by the warping of space and time, as explained by Einstein's theory.

Newton's Inspiration

The legend of Isaac Newton being inspired by an apple falling from a tree, leading to insights about gravity.

Falling Apple and Moon

Newton's realization that both the falling apple and the moon are affected by gravitational forces.

Gravitational Attraction

The force by which two bodies attract each other; strength depends on their masses and distance.

Orbital Motion

The path of celestial bodies around others due to gravitational forces and motion.

Falling Moon Concept

The idea that the moon continues to fall towards Earth, maintaining its orbit due to tangential velocity.

Earth's Orbit

The movement of Earth around the sun, driven by gravitational attraction.

Observable Phenomena

Effects observed in planetary orbits as a result of gravitational interactions among celestial bodies.

Scientific Implications of Gravity

The understanding of gravity catalyzed the Age of Enlightenment and influenced scientific thought.

Expansion of the Universe

Speculations about the universe expanding, stemming from the foundational principles of gravity.

Force of Gravity

The force that pulls objects toward each other, dependent on their mass and distance.

Inertia and Gravity

Inertia is the resistance of an object to change its state of motion; gravity acts to overcome this inertia.

Kepler's Laws of Planetary Motion

Laws formulated by Johannes Kepler describing the motion of planets in elliptical orbits influenced by gravity.

Tidal Forces

Gravitational interactions between the Earth and the moon, causing ocean tides.

Black Holes

Regions in space where the gravitational pull is so strong that nothing, not even light, can escape.

Gravity Waves

Ripples in spacetime caused by some of the most violent and energetic processes in the universe.

Gravitational Lensing

The bending of light around massive objects, evident in the observation of distant galaxies.

General Relativity

Einstein's theory that describes gravity as a curvature of spacetime caused by mass.

Centripetal Force

The force required to make an object move in a circular path, directed towards the center of the circle.

Escape Velocity

The minimum speed needed for an object to break free from the gravitational attraction of a celestial body.

Weight

The force exerted by gravity on an object; calculated as mass times the acceleration due to gravity.

Mass vs Weight

Mass is a measure of the amount of matter in an object, while weight is the force of gravity acting on that mass.

Free Fall

The motion of an object where gravity is the only force acting upon it.

Frictional Forces

Forces that oppose the relative motion of two surfaces in contact, often affecting how gravity influences motion.

Projectile Motion

The motion of an object thrown or projected into the air, influenced by gravity and initial velocity.

Acceleration due to Gravity

The rate at which an object accelerates toward the Earth due to gravitational force, approximately 9.81 m/s².

Weightlessness

A condition where no net force is acting on an object, often experienced in free fall.

Gravitational Field

A region around a mass where other masses experience a force of gravitational attraction.

Escape Velocity Formula

The formula v = √(2GM/r) used to calculate escape velocity, where G is the gravitational constant, M is mass, and r is radius.

Gravitational Constant (G)

A fundamental constant used in the calculation of gravitational force, approximately 6.674×10⁻¹¹ N(m/kg)².

Non-Inertial Reference Frame

A frame of reference that is accelerating, leading to the appearance of forces like centrifugal force.

Centrifugal Force

An apparent force experienced in a rotating reference frame, pushing objects outward from the center.

Galileo's Contributions to Gravity

Galileo's experiments with inclined planes and falling objects led to foundational insights about gravity.

Cavendish Experiment

An experiment conducted by Henry Cavendish to measure the gravitational force between masses.

Newton's Law of Universal Gravitation

The law stating that every particle attracts every other particle with a force proportional to the product of their masses and inversely proportional to the square of their distance.

Surface Gravity

The acceleration due to gravity experienced at the surface of a celestial body like Earth or the Moon.

Kepler's First Law

States that planets move in elliptical orbits with the sun at one focus.

Kepler's Second Law

Describes how a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Kepler's Third Law

States that the square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

Gravity's Role in Structure Formation

Gravity plays a crucial role in the formation of galaxies, stars, and planetary systems.

Newton's Thought Experiment with Gravity

Considered how gravity might cause the moon to fall toward Earth to theorize its effects on celestial orbits.

Gravitational Collapse

The process by which an object's self-gravity causes it to decrease in size and increase in density.

Orbits in the Solar System

Most celestial bodies in the solar system follow elliptical orbits influenced by gravitational interactions.

Supernova and Gravity

During a supernova, a massive star's core collapse is heavily influenced by gravitational forces.

Antigravity Theory

Hypothetical concepts referring to technology or phenomena that counteract or manipulate gravitational effects.

Quantum Gravity

A theoretical framework attempts to describe gravity in terms of quantum mechanics.

Gravity and Time Dilation

According to general relativity, gravity can affect the passage of time, with stronger gravity slowing time.

Gravitational Equilibrium

A state where gravitational forces are balanced, often associated with stable celestial bodies.

Black Hole Formation

Black holes can form from the remnants of massive stars that have undergone gravitational collapse.

Gravity's Effects on Light

Gravity can bend light pathways, leading to phenomena such as gravitational lensing.

Hyperbolic Orbits

Trajectories of objects that pass close to a massive body and escape its gravitational influence.

Rotational Gravity Effects

How rotation can influence perceived gravitational forces, such as in spinning spacecraft.