Celestial mechanics Celestial mechanics Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. As an astronomical field of study, celestial mechanics includes the sub-fields of orbital mechanics, which deals with the launching and orbits artificial satellites, and lunar theory, a specialty which deals with the complications of the orbit of the Moon. Modern celestial mechanics tends to divide between five broad fields of study: All of the above fields overlap, but are sometimes
Abnormal return Abnormal return In finance, an abnormal return is the difference between the actual return of a security and the expected return. Abnormal returns are sometimes triggered by "events." Events can include mergers, dividend announcements, company earning announcements, interest rate increases, lawsuits, etc. all of which can contribute to an abnormal return. Events in finance can typically be classified as information or occurrences that have not already been priced by the market. In stock market trading, abnormal returns are the differences between a single stock or portfolio's performance and the expected return over a set period of time. Usually a broad