Solar System Organization Chapters 3 4 Forming the

Solar System Organization Chapters 3 & 4

Forming the Solar System • Accretion- the process of building something up gradually by the gathering together of small pieces • Explain how this would build a star? • The solar system?

Gravity • Newton’s Law of Gravity- stated that every object in the universe attracts every other object • The strength of the force of gravity between the two objects depends on two factors: the masses of the objects and the distance between them.

What Determines Gravity? • Earth revolves around the sun in a nearly circular orbit • Orbit- path of an object as it revolves around another object in space • What keeps the Earth and the moon from flying off into space?

Inertia • Inertia- the tendency of an object to resist change in motion • You feel the effects of inertia everyday when riding in a car and it brakes suddenly. The car stops, but you fly forward (that’s why they invented the seatbelt!) • The more mass an object has, the more inertia • The more mass and inertia the harder it is for the object to stop (give an example)

Inertia • Isaac Newton created a law about inertia • Newton’s First Law of Motion- that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted upon by a force

Models of the Solar System 4. 6 • There are two models of the solar system

What is the Geocentric Model? • Geocentric- Earth is at the center of the revolving planets and stars • Ptolemy took the geocentric model a little further by saying that moved in circles carried along by larger circles • This helped to explain what we see in the sky

Geocentric Model

How did the Heliocentric model develop? • Heliocentric model- sun centered • All planets revolve around the sun • Aristarchus first developed this idea • Many scientists further developed the heliocentric idea

Heliocentric Model

Heliocentric Model • Copernicus was able to work out the arrangement of the known planets and how they moved around the sun • Brahe and Kepler furthered the idea after years of detailed calculations, Kepler found that the obit of each planet is an ellipse ( oval shape) • Galileo evidence gradually convinced other that the heliocentric model was correct