1 minute read
Isaac Newton expands on Kepler
further determined that this ratio holds even if the rotating object is not a planet but some other orbiting celestial body or satellite.
ISAAC NEWTON EXPANDS ON KEPLER
Advertisement
Isaac Newton lived in the late 1600s and was most interested in how mathematics could be applied to the physical sciences, such as astronomy. At the time, there was a lot of interest in planetary motion so this is what he studied from a mathematical perspective. He published his law of universal gravitation in 1687.
Kepler’s ideas on planetary motion were prevalent in Newton’s time and were accurate representations of how the planets move. Newton expanded on these by having three of his own laws, mainly related to motion and forces related to motion. He argued that these three laws applied also to astronomic or celestial bodies. These were Newton’s three laws explained:
• First Law of Motion—this indicates that a body in motion stays in motion unless acted on by an outside force of some kind. Stationary objects also remain that way unless a force is applied and direction of movement will always be straight unless a force sidelines this straight motion in some way.
• Second Law of Motion—this indicates that an object’s ability to accelerate is in proportion to the amount of force applied to it. If there is no force, the velocity will stay the same. There is constant acceleration in planetary motion which affects the direction of the planet’s movement. The gravity of the sun will force the planet in a path around it.
• Third Law of Motion—this indicates that any force applied on another object will have an equal and opposite force applied back to the first object. When you sit on a chair, you exert a force that is directly opposed by the chair itself on your bottom. The sun in the sky feels the force of each planet but does not change much because of the large size differential between the two objects.
From all of these laws came Newton’s law of universal gravity. It considers both the mass of two objects as well as the distance between them. As the masses of the objects
