Earth Science - 2b

Geocentric

Earth centered model

Heliocentric

Sun centered model

Modern Heliocentric Model

Sun is at the center and the planets revolve around the sun in elliptical orbits

Inertia

Causes planets to move in a straight line

Gravity

causes planets to move towards the Sun

The Greater the mass the ___ of a gravitational pull you will have

more

The less the mass the ___ of a gravitational pull you will have

less

As distance decreases gravitational force

increases

As distance increases gravitational force

decreases

Kelper’s second law

A planet moves faster when it’s closest to the Star it’s revolving

Kelper’s third law

Farther planets have longer orbits and period of revolution while closer planets are the opposite

Perihelion

closest position to the star

Aphelion

farthest position to the star

On earth Perihelion is in….

Early January

On earth Aphelion is..

Early July

Kepler’s first law

all planets orbit in a ellipse with the star at one focus

orbit

the path of a planet

foci

imaginary points of the sun

distance between foci is called

focal distance

length of major axis

distance between two sides of an orbit

eccentricity

Represents how circular/elliptical the shape of an orbit is

closer to 0 means

more circular; less eccentric

closer to 1 means

less circular; more eccentric

Circular orbit

rounder more perfect orbit

elliptical orbit

not circular less of a perfect orbit