globalgeography3

EARTH’S MAGNETIC FIELD
A. TEMPERATURE
Ranges between -50 to +50 degree C. Range is 100 This stable temperature is maintained by 1.Carbon dioxide and water vapour which causes Greenhouse Effect 2.Plant cover on the earth
UNIT 2
CHAPTER 3
PHYSICAL CONNECTIONS
HOW UNIQUE IS THE EARTH IN OUR SOLAR SYSTEM?
UNIQUE FEATURES OF EARTH
Constant and relatively mild temperature Abundance of water Sufficient quantity of gases such as Oxygen, Nitrogen, Carbon dioxide for life Atmosphere to protect living beings from ultraviolet radiations
1. Earth’s distance from the sun
Earth’s distance is balanced from the sun and only a relatively small portion of sun’s energy actually reaches the Earth. If the Earth was closer, the temperature would probably be too high and if it was too far away, the planet would be too cold.
LAYERS OF ATMOSPHERE
Five distinct layers have been identified using • thermal characteristics (temperature changes) • chemical composition • density.
GREENHOUSE EFFECT
Importance of green house gases
Without the greenhouse effect, the Earth’s average temperature would drop to about -73 degree Celsius
As a dissolving agent, water helps distribute the nutrients needed for plants and other organisms. Water provides the necessary hydrogen during photosynthesis
METEOR CRATER
/meteor-impact-craters.shtml /featured/10-greatest-major-impact-craters-onearth/1403
Atmosphere helps to maintain an even and stable surface temperature on Earth. Atmosphere protects living beings from ultraviolet radiations
• Note: Meteor Crater
EARTH IS REFERRED AS A FRAGILE MIRACLE,WHY?
The four important conditions exist in a perfect balanced combination.
The life sustaining conditions depends on the planetary position of the EARTH and other characteristics. 1.Earth’s distance from the sun 2.Its rotation on its axis and its revolution 3.Its gravitational force 4.Its magnetic fields
2. The rotation and revolution of the Earth The rotation of the earth and its revolution help distribute solar energy more evenly around the planet.
EARTH’S RErams/at mosphere/index.html
TROPOSPHERE STRATOSPHERE MESOSPHERE THERMOSPHERE EXOSPHERE
1. TROPOSHERE
The troposphere begins at the Earth's surface and extends from 6 to 20 km high. As the density of the gases in this layer decrease with height, the air becomes thinner. Therefore, the temperature in the troposphere also decreases with height in response. Almost all weather occurs in this region. The transition boundary between the troposphere and the Stratosphere is called the Tropopause.
LIFE ON EARTH
ATMOSPHERE TEMPERATURE
WATER
GASES
PLANETARY POSITION
EARTH’S STATISTICS
Surface Gravity: 9.78 m/s^2 Rotation Period with respect to Sun: 24 hrs Revolution Period about the Sun- 365 days 5 hrs Minimum Distance from Sun: 146 million km Maximum Distance from Sun: 152 million km Satellites: 1 (the Moon)
C. IMPORTANCE OF GASES
Earth has an atmosphere which composed of Nitrogen – 78 Oxygen – 21 Carbon dioxide – 0.03 Essential for life
IMPORTANCE OF ATMOSPHERE
4. The Magnetic Field
It helps protect Earth from Cosmic radiation and particles.
Note: Earth is largely protected from the solar wind, a stream of energetic charged particles emanating from the Sun.
Note: Energy Balance /earthguide/diagrams/energybalance/index.html
B. Importance of Water
Ocean water helps to distribute heat around the world because of its ability to absorb heat Ocean currents largely controls the planets weather pattern and climate Oceans acts as great reservoir for evaporation of water into the atmosphere
2. ROLE OF PLANT COVER
a. Through photosynthesis and respiration plants help to control the water vapour and carbon dioxide in the atmosphere b. Areas of plant cover decreases the albedo (reflectivity effect) and thereby maintain the temperature.
OZONE LAYER
The Ozone Layer: The stratosphere contains a thin layer of ozone which absorbs most of the harmful ultraviolet radiation from the Sun. The ozone layer is being depleted, and is getting thinner over Europe, Asia, North American and Antarctica --"holes" are appearing in the ozone layer.
3. Earth’s gravitational force
It holds the atmosphere in place. Its gravity is strong enough to keep the gases like Oxygen, Nitrogen and carbon dioxide from escaping into the space