From Mica
Nature's Telescope, Nature's Scale: Gravitational Lensing
The presence of mass creates gravity. If something else is flying by a massive object, its gravity will bend the path of that object. This is why planets orbit the Sun; their path is continually bent around the Sun into a circle. It turns out that even the path of light is bent as it goes near a massive object; this effect is known as gravitational lensing. We can see examples in astronomy where background galaxies are magnified, distoried, and even given multiple images by the gravitational lensing of intervening galaxies. Even very mild gravitational lensing can be used to measure the mass of the intervening galaxies. Finally, gravitational lensing has been used to determine that the dark matter in our galaxy cannot be made up entirely of small massive objects, such as very dim stars or brown dwarfs.
Media
Slides (PDF format)
There is no audio recording of this talk because Troy was away for Christmas