Earth operates as a system of interconnected spheres

Earth Spheres:

• Biosphere: all living things

• Hydrosphere: all forms of water

• Geosphere: the solid earth and loose debris on top

• Atmosphere: all gasses

Earth’s energy sources:

• The sun is the external source

• Earth’s core is the internal source

Earth’s external source:

• The sun provides the majority of the energy that runs processes on the surface

• The sun provides 340 watts/meter² at the edge of the atmosphere of incoming solar radiation

• Incoming solar radiation at the surface of the earth is 240 watts/meter²

Earth’s internal source:

• Heat flow from the Earth’s core is measured in microwatts/meter²

• Heat flows out of the Earth at places like volcanos and other warm spots

• This heat flow is unevenly distributed around the Earth

• The Earth’s internal source comes from 2 sources: the cooling of this original molten earth, and radioactive decay.

• The effects of this source are that it runs all plate tectonic movements, including volcanos, earthquakes, mountain building, and basin formation

• Lord Kelvin tried to apply science in discovering the age of the Earth by trying to determine the cooling of a molten ball the size of Earth to current temperatures

• Radioactive decay provides heat in an ongoing way throughout the Earth and keeps the Earth much warmer than it would have been had it simply been cooling over time

Earth’s systems

• Earth’s processes are the result of energy flowing and mass cycling within and between Earth’s systems

• Carbon in large amounts constantly cycles within Earth’s systems

Earth exchanges mass and energy with the rest of the solar system

• Earth gains and loses energy through incoming radiation from the sun, heat loss into space, and gravitational forces from the sun, moon, and planets

• Earth gains mass from impacts of meteorites and comets

• Earth loses mass through the escape of gasses into space

Ecosystems

• Ecosystems are regions where organisms actively interact with each other and their environments

• Ecosystems supply food, fuel, oxygen, and nutrients needed to sustain life

• Ecosystems provide services such as climate regulation, the cycling and purification of water, and the development and maintenance of soil all needed to maintain the biosphere

Feedbacks

• A change in part of one system can cause new changes to that system or to other systems

• Feedbacks are changes that can increase or decrease the original change and be unpredictable and/or irreversible

• Feedback loops are a system where some portion or all of the produced by the system returns as output