Our Earth & Moon

(Chapter 16)

Student Learning Objectives

• Compare and contrast interior structures of the Earth & Moon

• Describe surface features for our Earth & Moon

• State the theory for the origin of our moon.

What do we know about the Earth?

Earth is a relatively small planet.

Oblate spheroid71% liquid water surface

The Earth is an active terrestrial planet.

7 main tectonic plates

Question: What is Pangea?

Fun Earth Facts• Travels through space at 660,000 miles per hour

• Weighs 6,588,000,000,000,000,000,000,000 tons

• Rotates more slowly in March than in September

• Rotates at an average speed of 283 mph

If the oceans were evenly distributed over the entire surface of the Earth, the water would be approximately 2 miles deep at every point

Earth reflects an average of 30% of the sunlight that is incident upon the surface.

Earth Albedo= 0.306

Venus Albedo = 0.750

Planet Albedo

Practice: What does it mean for a planet to be in the habitable zone?

Planet Earth is composed primarily of metals.

Fe, O, Si, Mg

Earth is in the “Habitable Zone” (–60º F to +120º F)

Atmosphere

The greenhouse effect traps heat near the surface of Earth.

Global warming is the general increase in planet temperatures.

76% Nitrogen (N2)22% Oxygen (O2)2% Trace Gasses

Question: Is the greenhouse effect “bad”?

Practice

1) What contributes most to our greenhouse effect?

2) What common molecule increases albedo?

3) What is ozone and why is it important?

Earth’s Magnetic Field

The Earth is surrounded by a magnetic field, and the poles switch!

http://www.nasa.gov/topics/earth/features/2012-poleReversal.html

The motion of ionized particles inside Earth's liquid core coupled with Earth’s rotation induces the magnetic field.

Solar particles interact with Earth's magnetic field.

What causes the Aurora?

Solar particles hitair molecules

Molecules give off light(return to Ground state)

Air moleculesare “excited”

How do we know the interior structure of the Earth?

Earthquake waves allow mapping of interior.

P waves travel through both solid and liquid matter

S waves travel through only solid matter

P waves are compression waves. (Pressure Wave)

Longitudinal wave

S waves begin as a quick vibration. (Shear Wave)

Transverse wave

Earth’s 5 LayersSolid inner core

(iron and nickel)

Liquid Outer Core(convection currents)

Molten Mantle(solid rock flows)

&

Constantly changing surface

Earth’s Changing Outer Layers

Crust(plates floating on mantle)

Surface(shifting plates & weather result in continual change)

The Moon is about 25,000 miles more distant at apogee than at perigee.

Harvest Moon

It would take an average of 135 days to drive to the moon at a speed of 70 mph

What are the characteristics of the Moon?

Image Credit: APOD

Fun Moon Facts• Earth-Moon distance is

an average of 239,000 miles or 0.00257 AU

• More than 100 spacecraft have been launched to explore the moon

• If the Sun were as tall as a typical front door

– Earth would be the size of

a nickel

– The Moon would be the size of a pea

The moon is a satellite of the Earth.

49 Moons would fit across the diameter of the Earth

About Our Moon

Cool and Solid

3 Surface features

1/4 size of Earth-387 to 253 °F

Regolith

Highlands

Maria (craters filled with basalt)

The moon is egg shaped with the large end pointed towards earth.

Practice

1) Why is the temperature range larger on the Moon than it is on Earth?

2) Compare the interior layers of the Earth and Moon. Are they relatively similar or very different?

The Apollo Missions were 1963 – 1972.

July 20, 1969Neil Armstrong steps on Moon

Followed by Edwin Aldrin

Apollo 11 Mission

Giant Impact Theory

Earth was impacted by a Mars-size object after Earth had differentiated.

Earth tilt

Moon composition