What is Rotation ?
 |
| A sphererotating about an axis |
A rotation is a circular movement of an object around a center (or point) of rotation. A three-dimensional object always rotates around an imaginary line called a rotation axis. If the axis passes through the body's center of mass, the body is said to rotate upon itself, or spin. A rotation about an external point, e.g. the Earth about the Sun, is called a revolution or orbital revolution, typically when it is produced by gravity.
Rotation and revolution
While revolution is often used as a synonym for rotation, in many fields, particularly astronomy and related fields, revolution, often referred to as orbital revolution for clarity, is used when one body moves around another while rotation is used to mean the movement around an axis. Moons revolve around their planet, planets revolve about their star (such as the Earth around the Sun); and stars slowly revolve about their galaxial center. The motion of the components of galaxies is complex, but it usually includes a rotation component.
Latitude and Longitude:
Earth is a vast planet and finding the location of one place precisely among the other places is almost impossible if not for the longitude and latitude co-ordinates of that place.
The parallels of latitude and meridians of longitude forms an invisible grid over the surface of the earth.
Latitude are the parallel horizontal lines also called ‘parallels’. These lines are equidistant and spread from east to west. Each degree is 69 miles and is further divided into minutes and seconds. Halfway from east and west is the equator at 0 degrees.
Longitude are the vertical lines also called meridians. These are not equidistant rather they intercept in North pole and South pole. The line 0 degree passes through Greenwich(England) and is called prime meridians.
Minutes and Seconds:
Minutes and Seconds:
For precision purposes, degrees of longitude and latitude have been divided into minutes (') and seconds ("). There are 60 minutes in each degree. Each minute is divided into 60 seconds. Seconds can be further divided into tenths, hundredths, or even thousandths dot
For example:
Our office on Galveston Island, Texas, USA, is located at 29 degrees, 16 minutes, and 22 seconds north of the equator, and 94 degrees, 49 minutes and 46 seconds west of the Prime Meridian.
Refrences
- http://en.wikipedia.org/wiki/Rotation
- http://maryamberlas.blogspot.com/2015/04/latitudes-and-longitudes.html
