Celestial Objects

Vocabulary

Celestial Object Celestial Sphere Revolution Rotation Gravity Geocentric Heliocentric

What are celestial objects?Everything in outer space

Stars Planets Comets Asteroids & Meteors

Solar System vs Galaxy vs Universe What’s the difference? SIZE?!

Celestial Sphere Imaginary sphere

around the earth that all objects appear to be on.

Motions in space

Everything moves in space.Why? Because of gravity.

Yes there is gravity everywhere.

Motions in spaceOrbits

Movement of planets around a central body that is elliptical

Rotation Planetary movement on its axis

Revolution Planets moving around on its orbit

Rotation

Earth rotates 15 o per hour

Stars path

GravityThis is the force that pulls

on other objects.

What causes it? Mass of an object causes an

attraction between them. So if you have mass there is

gravity.

NewtonGravity has three laws

1st law ▪ Object at rest will stay at rest until acted

upon by another force.

2nd law ▪ An object will move if the force is greater

then the mass.

3rd law ▪ When an object applies a force on a surface

the surface pushes back with equal force.http://www.youtube.com/watch?feature=player_detailpage&v=lMtXfwk7PXg

Models of our Solar System Geocentric

Earth Centered. Circular orbits Ptolemy Retrograde

motions

Heliocentric Sun Centered Circular orbits–

elliptical (now) Copernicus, Kepler and

Galileo Daily movements

Proof of Heliocentric models

Pendulum As the earth rotates it

allows the pendulum to swing.

Because the pendulum swings and moves that means the Earth rotates.

Famous dead guys

Newton – Laws of gravity

Ptolemy – Geocentric model

Copernicus – Heliocentric model