explain thorey of genral relativity
Answers
Albert Einstein's general theory of relativity is one of the towering achievements of 20th-century physics. Published in 1916, it explains that what we perceive as the force of gravity in fact arises from the curvature of space and time. Einstein proposed that objects such as the sun and the Earth change this geometry.
The general theory of relativity describes the force of gravity. Einstein wasn't the first to come up with such a theory — back in 1686 Isaac Newton formulated his famous inverse square law of gravitation. Newton's law works perfectly well on small-ish scales: we can use it to calculate how fast an object dropped off a tall building will hurtle to the ground and even to send people to the Moon. But when distances and speeds are very large, or very massive objects are involved, Newton's law becomes inaccurate. It's a good place to start though, as it's easier to describe than Einstein's theory.
Suppose you have two objects, say the Sun and the Earth, with masses $m_1$ and $m_2$ respectively. Write $r$ for the distance between the two objects. Then Newton’s law says that the gravitational force $F$ between them is
\[ F=G_ N\frac{m_1 m_2}{r^2}, \]
where $G_ N$ is a fixed number, known as Newton's constant.
The formula makes intuitive sense: it tells us that gravity gets weaker over long distances (the larger $r$ the smaller $F$) and that the gravitational force is stronger between more massive objects (the larger either of $m_1$ and $m_2$ the larger $F$).