What is gravitational lensing? Why don't we notice the gravitational lensing of light by ordinary objects on Earth?

Gravitational lensing is a phenomenon that occurs when a massive object, like a star or galaxy, bends the path of light coming from a distant light source due to its gravitational force. This bending of light causes the light to follow a curved path around the massive object, resulting in the formation of multiple images or distorted images of the light source when observed from a certain position.

Gravitational lensing is based on the principles of general relativity, which states that the presence of a massive object causes spacetime to curve. As light travels through spacetime, it follows this curvature. Therefore, when there is a massive object between a light source and an observer, the light from the source will be bent around the object, causing its apparent position to change. The amount of bending depends on the mass of the object and the distance between the object, the light source, and the observer.

There are several reasons why we do not notice the gravitational lensing of light by ordinary objects on Earth: 1. The mass of objects on Earth: Gravitational lensing is more noticeable around massive objects like stars and galaxies. The objects we encounter on Earth have relatively small masses, so their gravitational force is not powerful enough to cause noticeable bending of light. 2. The distance between objects: Gravitational lensing is more easily observed when the massive object, the light source, and the observer are at significant distances from each other, such as in the case of galaxy clusters. On Earth, objects are typically much closer together, reducing the visible effects of gravitational lensing. 3. The angle of viewing: Gravitational lensing is more noticeable when the light source, the massive object, and the observer are aligned. In everyday life, it is highly unlikely for this perfect alignment to happen with objects on Earth.

Gravitational lensing is a phenomenon in which light is bent by the gravity of massive objects, causing the light to follow curved paths and resulting in the formation of multiple or distorted images of the light source. This phenomenon is based on the principles of general relativity and depends on factors like the mass of the object and the distance between the object, the light source, and the observer. On Earth, we don't notice the gravitational lensing of light by ordinary objects because they have relatively small masses, they are too close together, and the perfect alignment required for noticeable lensing is rare.