Dark Matter

The concept of dark matter was first introduced in the 1930s to explain why spinning gallaxies dont just spin apart. The study sumarized in this page was conducted along a concept of "gravitational lensing". Gravitational lensing is a phenomena which occurs when light from distant galaxies is bent around space as it travels toward us. Using this concept the scientists conducted a study using data from the Hubble Space Telescope's Cosmic Evolution Survey (COSMOS) which grouped the observations into 3 shells in order of distance from earth. Using "redshift" measurements the scientist were able to construct a map of the dark matter which distorted the light. "Massey likens this indirect technique, called "gravitational lensing," to peering at a page of text with a magnifying glass."The first thing you notice is that the text is bigger, but also, if you look around the edges of the magnifying glass, the text is slightly distorted," he said. "You can investigate the properties of the magnifying glass by observing these distortions and actually find out what shape the glass lens is." Essentially this is what the scientists did; they were able to construct a model of the dark matter which was distorting the light. Very Excellent. http://www.space.com/scienceastronomy/070108_mm_darkmatter_map.html