What is gravitational lensing?

Gravitational lensing refers to the phenomenon where light from a distant source, such as a galaxy or a star, is bent as it passes near a massive object, like another galaxy or a black hole. This occurs because massive objects create a gravitational field that can influence the path of light, much like an optical lens bends light.

The effect can magnify and distort the appearance of background objects, making them appear brighter or even creating multiple images of the same object. This effect is a crucial tool in astrophysics, allowing astronomers to observe objects that would otherwise be too faint to detect, and even providing insights into the distribution of dark matter in the universe.

Other options do not accurately depict the nature of gravitational lensing. While gravity does play a role in forming black holes, that process is distinct from the bending of light. The process of star formation involves the accumulation of gas and dust in space, unrelated to lensing effects. The refraction of light in Earth's atmosphere refers to a different optical phenomenon caused by the atmospheric layers and does not involve gravity in the same manner as gravitational lensing.