User talk:Dileep Sathe

Retrograde exoplanets revive an old challenge Recently discovered retrograde exoplanets challenge existing planetary theories - as some astronomers feel (http://www.eso.org/public/news/eso1016/) - no doubt - but any student of introductory mechanics can also pose a below.conceptual problem, discussed below. Consider moons of planets. Jupiter has many moons, mostly orbiting in the forward direction. But some of them are retrograde moons – that is backward-orbiting. The first such moon of Jupiter, discovered in 1908, is Pasiphae. This situation poses a problem in the equation of orbital velocity of moon. According to our age-old assumption, the gravitational force provides the centripetal force for the planetary motion or motion of a moon around the mother planet. But as moons are of two types, prograde and retrograde our age-old assumption is not useful as there is no consideration of direction. This is a great inability of our knowledge (not being able to decide the direction of motion – anticlockwise / clockwise) which I call as the A/C paradox. Above discussion can be better understood with my poster on http://photos.aip.org/quickSearch.jsp?qsearch=dileep&group=10&submit=GO Jupiter is in the center, green orbit is that of a prograde moon and red orbit is that of a retrograde moon. The poster is more clearly seen between Prof. Martin Perl (Nobel Laureate, Physics, 1995) and myself. In a sense, our solar system is a troubling one, as I have said in a letter in CHANGE, May-June 2008, 5, http://changemag.org/Archives/... Feel free to write me for more information, using – dvsathe[at]gmail.com