Mobile Ad Hoc Networks from Theory to Practice. Fundamental Properties and Services

LeavittБЂ™s genius was to realize that by comparing the relative magnitudes of Cepheids at different points in the sky you could work out where they were in relation to each other. They could be used as БЂњstandard candlesБЂ«-a term she coined and still in universal use. The method provided only relative distances, not absolute distances, but even so it was the first time that anyone had come up with a usable way to measure the large-scale universe. (Just to put these insights into perspective, it is perhaps worth noting that at the time Leavitt and Cannon were inferring fundamental properties of the cosmos from dim smudges on photographic plates, the Harvard astronomer William H. Pickering, who could of course peer into a first-class telescope as often as he wanted, was developing his seminal theory that dark patches on the Moon were caused by swarms of seasonally migrating insects.) Combining LeavittБЂ™s cosmic yardstick with Vesto SlipherБЂ™s handy red shifts, Edwin Hubble now began to measure selected points in space with a fresh eye ...»