Search results
Results from the WOW.Com Content Network
The precession of the equinoxes is caused by the gravitational forces of the Sun and the Moon, and to a lesser extent other bodies, on the Earth. It was first explained by Sir Isaac Newton. [31] Axial precession is similar to the precession of a spinning top. In both cases, the applied force is due to gravity.
Axial precession is the trend in the direction of the Earth's axis of rotation relative to the fixed stars, with a period of about 25,700 years. Also known as the precession of the equinoxes, this motion means that eventually Polaris will no longer be the north pole star .
The geographic poles are defined by the points on the surface of Earth that are intersected by the axis of rotation. The pole shift hypothesis describes a change in location of these poles with respect to the underlying surface – a phenomenon distinct from the changes in axial orientation with respect to the plane of the ecliptic that are caused by precession and nutation, and is an ...
Apsidal precession also slowly changes the place in Earth's orbit where the solstices and equinoxes occur. This is a slow change in the orbit of Earth, not the axis of rotation, which is referred to as axial precession. The climatic effects of this change are part of the Milankovitch cycles.
Torque-induced precession (gyroscopic precession) is the phenomenon in which the axis of a spinning object (e.g., a gyroscope) describes a cone in space when an external torque is applied to it. The phenomenon is commonly seen in a spinning toy top , but all rotating objects can undergo precession.
Well, in all honesty, precession makes things complicated. Tropical astrology's foundations came amidst the Babylonian-era need to create things like calendars and clocks, explains Chimenti.
The cycle which Plato describes is one of planetary and astral conjunction, which can be postulated without any awareness of axial precession. Hipparchus (c. 120 BC) is the first Greek credited with discovering axial precession roughly two hundred years after Plato's death (see below).
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!