Gravity and Newton's Law

Definition and History

• Gravitation is a fundamental force of nature that causes objects with mass to attract each other.
• First described by Sir Isaac Newton in his groundbreaking work "Philosophiæ Naturalis Principia Mathematica" (1687).
• Newton's Law of Universal Gravitation states that every point mass attracts every other point mass by a force acting along the line intersecting both points.

Newton's Law of Universal Gravitation

• Mathematical representation: F = G * (m1 * m2) / r^2
• F: gravitational force between two objects
• G: gravitational constant (6.67408e-11 N*m^2/kg^2)
• m1 and m2: masses of the two objects
• r: distance between the centers of the two objects

Key Concepts

• Gravity: the force of attraction between two objects due to their mass.
• Gravitational field: the region around a massive object where the gravitational force can be detected.
• Weight: the force exerted on an object by gravity, dependent on both mass and gravitational field strength.

Gravity in the Universe

• Galactic gravity: holds galaxies together and governs their rotation curves.
• Cosmological gravity: plays a crucial role in the large-scale structure of the universe and the expansion of the cosmos.

Limitations of Newton's Law

• Fails to accurately predict phenomena at very high speeds or in extremely strong gravitational fields.
• Does not account for the bending of light around massive objects.

Modern Understanding of Gravitation

• General Relativity (1915): Albert Einstein's revolutionary theory that gravity is the curvature of spacetime caused by massive objects.
• Gravitational waves: ripples in spacetime predicted by General Relativity, detected directly for the first time in 2015.

Definition and History

• Gravitation is a fundamental force of nature that causes objects with mass to attract each other.
• Sir Isaac Newton first described gravitation in his work "Philosophiæ Naturalis Principia Mathematica" in 1687.

Newton's Law of Universal Gravitation

• States that every point mass attracts every other point mass by a force acting along the line intersecting both points.
• Mathematical representation: F = G * (m1 * m2) / r^2
• G: gravitational constant (6.67408e-11 N*m^2/kg^2)

Key Concepts

• Gravity: the force of attraction between two objects due to their mass.
• Gravitational field: the region around a massive object where the gravitational force can be detected.
• Weight: the force exerted on an object by gravity, dependent on both mass and gravitational field strength.

Gravity in the Universe

• Galactic gravity: holds galaxies together and governs their rotation curves.
• Cosmological gravity: plays a crucial role in the large-scale structure of the universe and the expansion of the cosmos.

Limitations of Newton's Law

• Fails to accurately predict phenomena at very high speeds or in extremely strong gravitational fields.
• Does not account for the bending of light around massive objects.

Modern Understanding of Gravitation

• General Relativity (1915): Albert Einstein's revolutionary theory that gravity is the curvature of spacetime caused by massive objects.
• Gravitational waves: ripples in spacetime predicted by General Relativity, detected directly for the first time in 2015.