Physics

Aristotle’s (384-322 BCE) model placed the superior planets in right order using their speed on the celestial sphere. He established a geocentric universe in which the…

Principle purpose of this lecture is to present on Examples of Planetary Events. Some events are; Conjunctions: Two objects closest from Earth’s point of view. Stationary: When the ecliptic longitude…

Major purpose of this lecture is to present on cause for Precession of Equinoxes. Precession is caused by the torque applied by the Sun, the Moon, and…

The Sun’s position relative to Vernal Equinox is important for determining the seasons and the calendar. A major function of the calendar was for agriculture. Solar…

The celestial sphere is a device used to represent the direction of celestial objects for observation. For example, someone in Beijing would see the Moon’s…

The term “constellation” is also less formally used to describe a group of star visibly related to each other in a pattern, such as those…

In the heliocentric model, the Earth and other planets orbit the Sun. The prograde and retrograde motions are apparent effects due to relative motions of the…

Prime purpose of this lecture is to present on Geocentric Model of Planetary Motion. Here briefly explains qualitatively the prograde and retrograde motions, and brightness variation. Motion…

Basic purpose of this lecture is to present on Astronomy and Space Science. Here briefly focus on: Astronomy Basics Length, time, angles and Celestial sphere, star maps. Alos…

General purpose of this lecture is to present on Newton’s Law of Motion and Gravity. He invented Calculus as a necessary tool to solve mathematical problems…

Johannes Kepler used the precise observational tables of Tycho Brahe to study planetary motion mathematically. He found a consistent description by abandoning both: Circular motion and Uniform…

Main purpose of this lecture is to present on Ancient History of Astronomy. Astronomy is the oldest of the sciences. When Stoneage humans turned to an agrarian…