Scientific American (original English title. Scientific American, abbreviated: Sci Am) is an American popular science magazine, started on August 28, 1845, at first published weekly, then changed to monthly; it is the longest history of the United States, has been published continuously magazine, but also the famous "Science" (Science) sister magazine. To date, 151 Nobel laureates have contributed to the journal, and four of the journal's contributors won Nobel Prizes in '09. As of December 2005, it had a monthly circulation of approximately 555,000 domestic (U.S.) and 90,000 international copies. Although considered a popular, high-level academic journal, the journal does not review manuscripts in a peer-reviewed manner similar to Nature, but rather provides a forum for the presentation of scientific theories and new scientific discoveries.=