Question

Explain your reasoning with one or more complete sentences. When Einstein's theory of gravity (general relativity) gained acceptance, it demonstrated that Newton's theory had been (a) wrong. (b) incomplete. (c) really only a guess.

Short answer

Newton's theory was (b) incomplete.

Step-by-step solution

Understanding General Relativity

Einstein's theory of general relativity fundamentally changed our understanding of gravity. Unlike Newton's theory, which described gravity as a force between masses, general relativity describes gravity as the curvature of spacetime caused by mass. This new perspective was needed to explain phenomena like the precession of Mercury's orbit, which Newton's laws couldn't accurately account for.

Analyzing Completeness of Newton's Theory

Despite the revolutionary insights provided by general relativity, Newton's theory was incredibly successful and accurately described a wide range of physical scenarios, especially for objects moving at speeds much less than the speed of light and in weak gravitational fields. General relativity didn't prove Newton's theory to be completely wrong but rather demonstrated its limitations under certain extreme conditions.

Conclusion on Correct Answer

Since general relativity extended and refined our understanding of gravity beyond what Newton's theory could describe, it would be accurate to say that Newton's theory was (b) incomplete. It wasn't entirely "wrong" nor was it "only a guess", but rather a successful approximation within its context of applicability.

Key concepts

Newton's theory of gravity

Sir Isaac Newton developed his theory of gravity in the late 17th century. His theory was groundbreaking for its time and provided a way to understand and predict the movements of planets and objects. Newton's theory is based on the idea that gravity is a force of attraction between two masses. - This force depends on the masses of the objects and the distance between them. - His famous law of universal gravitation is expressed as \( F = G \frac{m_1 m_2}{r^2} \), where \( F \) is the gravitational force between two objects, \( m_1 \) and \( m_2 \) are their masses, \( r \) is the distance between their centers, and \( G \) is the gravitational constant.Newton’s formulation of gravity allowed for the prediction of planetary motion, which was a major scientific achievement. However, it viewed gravity strictly as a force—a perspective that eventually needed expansion.

Incomplete theories

When scientists say a theory is incomplete, they don’t mean it's false or without merit. Instead, an incomplete theory has limitations under certain conditions. Newton's theory of gravity was revolutionary but had its boundaries. - It accurately described gravitational interactions for most situations, such as between Earth and the Moon or moving objects like projectiles. - However, when dealing with extremely massive objects or objects moving at speeds close to the speed of light, Newtonian gravity could not fully explain the outcomes. The introduction of general relativity by Albert Einstein expanded our view of gravity, showing that Newton’s theory was accurate in many scenarios but lacked the scope needed for more extreme conditions, purely because it was developed with the knowledge available at the time.

Curvature of spacetime

One of the most profound changes Einstein introduced with his theory of general relativity was the concept of spacetime curvature. General relativity proposed that gravity is not a force as Newton described it, but rather the effect of mass causing the fabric of spacetime to curve. - Imagine spacetime as a vast, flexible grid. Placing a mass on this grid, such as a planet, causes it to warp or curve. - Objects moving within this curved space are then influenced by this curvature, which we perceive as gravity. This idea beautifully explains why objects follow curves in space, rather than being pulled as by a string. The notion was crucial in understanding celestial phenomena that Newton’s equations couldn’t accurately predict, such as the bending of light around massive objects or the precise orbit of Mercury.

Precession of Mercury's orbit

Mercury's orbit presented a mystery that puzzled scientists for many years. It slightly deviated from the path predicted by Newton’s laws. This phenomenon, known as the precession of Mercury's orbit, could not be explained using Newtonian physics alone. - For decades, small discrepancies in Mercury's orbit around the Sun left astronomers seeking an explanation. Einstein's general relativity provided the solution. - It showed that the factors causing Mercury’s precession were the result of the curvature of spacetime near the Sun’s strong gravitational field. - The accuracy with which general relativity could predict Mercury’s orbit precession was one of its first major triumphs. This marked a critical point where Einstein's theory proved itself indispensable and fundamentally stronger in describing the universe's nuances than the earlier Newtonian views.