Earth and Moon

Rotation and Revolution

Seasons on EarthTwo reasons the Earth has seasons:

1. 23.5 degree tilt

2. Revolution around sun

Third Rock from the Sun

• 70% water• Water in all three

states (solid, liquid, and gas)

• Life

The Surface of Earth• Geologically Active with a surface that is

constantly changing– Weathering and erosion– Plate tectonics

Atmosphere of Earth• Oxygen rich

• Blocks out most of the sun’s damaging rays

• The atmosphere deflects millions of tiny and not so tiny meteors every day that otherwise would have hit the earth and us.

Our Moon

Surface of the Moon

Craters

Highlands

Maria

Characteristics of our Moon• Gravity is only one-sixth as strong as Earth’s

• Temperatures can range from 100oC to -170oC

• No air or liquid water

Phases of the Moon

• Caused by its position relative to the Earth and the sun.

Phases of the moon

Apollo Moon Missions

• 1963-1972• Apollo 11, 12, 14, 16, 17 landed humans on the

surface of the moon• The six missions that landed on the moon returned

a wealth of data and 400 kg of lunar samples.• Experiments included soil mechanics, meteoroids,

seismic, heat flow, lunar ranging, magnetic fields, and solar wind experiments.

Apollo Moon Landings

moon landing.asx

The Sun

• Average size yellow star

• 110 times the diameter of the Earth

• Approximely 4.6 billion years old

The Surface of the Sun• The photosphere

• 5,000-8,000 oC

• The sunlight that reaches Earth comes from the photosphere

Features of the SunProminence

Loops of gases that link different parts of sunspot regions

Features of the SunSunspots

Areas of gas on the sun that are cooler than thegases around them

Sunspot cycle of 10-11 years

Features of the SunSolar Flares

An explosion ofHydrogen gas from The sun’s surfaceThat occurs when Loops in sunspot Regions connect

Increases solar wind Causes magnetic storms

Life Cycle of the Sun

Historical Contributions in Earth-moon-sun

Aristotle (384-322 BC)

-Greek philosopher and scientist

-Believed in an earth-centered universe

-Thought the heavens moved naturally and endlessly in a complex circular motion

Earth-Centered Models

Ptolemy (100-170 AD)• Astronomer and mathematician

• Believed the earth was stationary and was the center of the universe

• Tried to solve the problem of retrograde movement of Mars

marsmovie.gif

Sun-Centered Models

• Copernicus (1473-1543)– Believed in a sun-centered

universe (Heliocentric)– Earth orbits the sun in a circular motion– Did not publish his theory until his

death because of the Catholic Church

Galileo (1546-1642)

• Discovered Jupiter’s moon (4 largest)

• Upheld Copernicus’s sun-centered theory

• Place under house arrest for life by the Catholic Church due to his beliefs

•Built a telescope and discovered mountains and craters on the moon•Observed the phases of Venus•Observed Sun Spots