In the solar system most of the rotational and orbital motions are in the eastward direction. This is referred to as direct motion. Those in the opposite direction are called retrograde. There are three types of retrograde motion in astronomy. Planets, as scientists have noted move relative to the stars, moving from west to east in the sky. When we look at the sky, at the same time on two different nights, we will generally notice that the planets have [...]
Tidal force is a secondary effect of gravitational force and its most common manifestation, at least on the planet Earth, are tides. Tidal force, by technical definition is the differential force of gravity which arises because the force exerted on one body by another is not constant across the diameter in that the side which is the nearest to the second body is subject to more gravitational force compared to the side farther away.
Anything we throw up in the air will fall back to the ground. This is because of the downward pull of gravity, which is causes the downward acceleration of 9.81 meters per second squared. For an object to leave the surface of the earth, without falling back due to gravity, it must possess a speed of at least 25,000 miles per hour. This is the escape velocity from the planet.
People are very conscious of their weight. When they see that they exceed the normal weight they should have, they worry and go on a diet and perform regular exercise. But if they go to the moon or where there is no gravity pulling them down, they become weightless. The earth has a gravitational force that pulls anything down towards the surface when it enters its atmosphere. Weight is equal to the force applied on a person or any object [...]
Photo by: Mbz1 Creative Commons Tides are the periodic fluctuations of large bodies of water. They are caused by the gravitational interaction between the Earth and the Moon in what is generally called tidal forces. Although tidal changes may occur as a result of other factors like the Moon’s altitude and distance, the positions of the sun and the Earth and the depth of ocean floors and coastal topography.