The document discusses key characteristics of Earth that support life. It describes Earth's location in the solar system, its atmosphere composed primarily of nitrogen, its size and mass that maintain gravity and the atmosphere. It also discusses Earth's magnetic field, generated by electric currents in the molten iron core, which shields the planet from solar winds. Finally, it notes the crucial presence of water, which exists in all three states and has a cooling effect through the hydrologic cycle.

1. Earth and Life Science
HUMSS and GAS

2. Earth sciences
are the fields of study concerned with the
solid Earth, its waters, and the air that envelops
it. They include the geologic, hydrologic, and
atmospheric sciences with the broad aim of
understanding Earth's present features and past
evolution and using this knowledge to benefit
humankind

3. Characteristics of Earth
1. Earth’s location
2. Earth’s atmosphere
3. Earth’s size and mass
4. Earth’s Magnetic Field
5. Presence of water

4. Earth’s location
 It is considered to be one of the inner planets next to
Venus.
 Its distance from the sun is about 93 million miles
and it takes about 500 seconds for sunlight to reach
the earth’s surface.
 Earth’s tactical location also prevents it from
planetary collisions.
 is the third planet in the solar system

5. Earth’s atmosphere
 is the gaseous layer that envelops the earth
 It regulates the planet’s surface temperature.
 Most of the element that makes up the atmosphere is
nitrogen (about 78%).
 Photodissociation is the process by which ozone molecules
(O3) in the stratosphere is broken down (decomposition
reaction) into elemental oxygen (O) and diatomic oxygen (O2)
as it absorbs high energy solar radiation and then convert it
into low energy radiation. This way, harmful high-energy
radiation will not go directly into the earth’s surface.

6. Earth’s size and mass
 The size of the earth also plays a vital role in keeping
its life support system afloat.
 The size of a planet is directly related to its
gravitational pull.
 The acceleration due to gravity helps the planet
maintain its atmosphere.

7. Earth’s Magnetic Field
 Our planet is a big ball of magnet.
 Its geographic north serves as its magnetic south and its geographic south
serves as its magnetic north. The region around earth that is dominated by
magnetic field is called magnetosphere which extends to about 65, 000 km
in space.
 Its magnetic properties are the result of its internal activities involving
electric current flowing in the molten core made possible by its rotation.
 The inner core is the solid layer of the earth and is made predominantly of
iron. Since it is compressed by pressure due to earth’s gravity, it is solid in
form. The outer core on the other hand, is liquid in form and is made up
predominantly of iron and nickel.

8. Earth’s Magnetic Field
 As the earth spins, the flow of liquid iron and nickel in the
outer core produces electric current, thereby producing
magnetic field. The invisible magnetic field then passes
through the earth’s layer and into the space. This magnetic
field shields earth from the harmful surge of charged particles
from the sun called solar winds and other space weather.
 Most of the particles of solar winds cannot cross the earth
because it gets deflected by the magnetic field. Without the
magnetic field, earth would have been as hot and lifeless as
Mars.

9. Presence of water
 is impossible without a biologically essential compound called water
(H2O).
 Three fourths of the Earth’s surface are covered with water.
 Scientists have found out that there are other planets of the
universe that contain water. However, this compound may exist as
ice or vapor alone. On earth however, water exists as gas forming
clouds, as liquid in the form of oceans and lakes and as solid in the
form ice caps. This is due to hydrologic cycle.
 Water has a cooling effect due to its heat capacity. It has the
capacity to absorb heat without raising its own temperature. As a
result, life on earth will be benefited by the cooling effect of water.