Teach Astronomy - Incidence of Microlensing скачать в хорошем качестве

Teach Astronomy - Incidence of Microlensing

http://www.teachastronomy.com/ Stars are very small, and space is very empty. So the probability of a microlensing event is small because it depends on the occasional instance where a dark, small object passes in front of a more distant star. The probability is about ten to the minus six in the halo of the Milky Way which means that millions of stars have to be followed every night to see the occasional microlensing event. This technique was only made possible in the last decade with the advent of the large format CCD detectors which allow millions of stars to be monitored every night. Several hundred microlensing events have now been seen, and this science is rapidly maturing as one of the best ways to detect substellar objects and planets.