The Sun-Earth-Moon System

Folder:All notes pertaining to Earth and Environmental will

be kept here

Planet Earth

Earth’s ShapeEarth is sphere shaped

Aristotle reasoned this because round shadows were being cast on the moon during eclipses.

Other evidence came through sailors that would see the tops of the sail masts as they came over the horizon.

Today we have satellite imagery to give us real shape. It is spherical shaped as it bulges out around the equator area and the poles are somewhat flattened.

Physical Properties of Earth

Diameter (pole to pole) 12,714 kmDiameter (equator) 12,756 kmCircumference (poles)40,008 kmCirumference (equator) 40,075 kmMass5.98 X 10 27 gDensity 5.52 g/cm3

Average distance to sun 149,600,000kmPeriod of rotation (1 day) 23 hr, 56 minPeriod of Revolution (1 year) 365 day, 6 hr, 9 min

Poles~ Earth has poles, northern and southern.~ They fall along the imaginary line called the axis.~ The spinning of Earth on its axis, called rotation, causes day and night to occur.

Earth RotationAs Earth rotates the sum comes into view at day break.Earth continues to move, giving illusion that sun is moving until sun setEarth Continues to move even through the sun is not visible

Again: Day/Night Effect