Jrod99 said:Does anyone know where I could find (online) a derivation of the deflection angle in gravitational lensing:
alpha = 4GM/Rc^2
Thank you
Gravitational lensing deflection angle is the angle by which light from a distant object is bent as it passes near a massive object, such as a galaxy or black hole, due to the distortion of space-time caused by the object's gravitational field.
Gravitational lensing deflection angle occurs due to the bending of space-time by massive objects, as described by Einstein's theory of general relativity. The mass of the object causes a curvature in space-time, which in turn alters the path of light passing near it.
Gravitational lensing deflection angle is important because it allows us to study and observe objects that may otherwise be too distant or faint to see. It also provides evidence for the presence of massive objects, such as dark matter, in the universe.
There are three types of gravitational lensing deflection angle: strong, weak, and microlensing. Strong lensing is caused by highly massive objects and produces multiple images of the background object. Weak lensing is caused by less massive objects and produces subtle distortions in the shape of the background object. Microlensing occurs when a small object, such as a star, acts as a lens.
Yes, gravitational lensing deflection angle can be used to study the distribution of mass in the universe, including the presence of dark matter. It can also provide information about the expansion of the universe and the nature of dark energy. Additionally, it allows us to study the properties of distant galaxies and gain a better understanding of their formation and evolution.