Teach Astronomy - Gravitational Microlensing скачать в хорошем качестве

Teach Astronomy - Gravitational Microlensing

http://www.teachastronomy.com/ One of the fundamental predictions of the theory of general relativity is the fact that mass can bend light. The gravitational bending of light is called lensing. There are several forms of lensing. In the most extreme form of lensing, multiple images are formed when a dark object lies between us and the more distant object. There are two effects in lensing. One is the splitting of the images, and the second is the amplification of the light. In the situation where a low mass dark object lies between us and a more distant star, microlensing occurs. It's called microlensing because the amplitude of image bending is very small, tiny fractions of an arcsecond, a thousandth or maybe even millionths of an arcsecond. However, image amplification and light amplification occurs, and so microlensing manifests itself in terms of a momentary brightening of a distant star caused by an intervening dark object.