Yak period 7/8 earth science honors check out cayleys presentation: http://docs.google.com/Presentation?id=dgtjph37_1254g77nd3

### Big Bang Theory

States that all matter and energy started out concentrated in a small area and, after a gigantic explosion, matter began to organize into subtonic particles and atoms

### Eccentricity

The degree of ovalness of an ellipse, or how far an ellipse is from being a circle; computed using a formula

### Ellipse

A closed curve around two fixed points called foci, in which the sum of the distances between any point of the curve and the foci is a constant

### Focus

In an ellipse, either of two fixed points located so that the sum of their distances to any point on the ellipse is constant

### Gravitation

The attractive force that exist between any two objects in the universe; proportional to the product of the masses of the objects and inversely proportional to the square of the distance between their centers; also called gravitational force

### Inertia

The concept that an object at rest will tend to remain at rest and that an object in motion with maintain the direction and speed of that motion unless an opposing force affects it

### Luminosity (of a star)

Measures how bright the star will be in relation to the sun if all stars were the same distance from the observer

### Nuclear fusion

The combining of the nuclei of smaller elements to form the nuclei of larger elements with some of the mass being converted into energy

### Red shift

When earth and other celestial objects are moving apart and the electromagnetic waves are spread out

### Revolution

A planets movement around the sun in a path called an orbit; the movement of one body around another in a path called an orbit

### Rotation

The spinning of an object, such as a planet, moon, or star, on an imaginary axis- like a top

### Solar system

Any star or small group of orbiting stars and all the other objects that revolve around the star

### Star

Usually a large ball of gas held together by gravity that produces tremendous amounts of energy and shines