the earth, the moon, and the sun physical science 2011-2012
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The Earth in SpaceSection 7-1
Gravity from the Earth-Moon-Sun system directly affects the conditions for life here on
Earth.
The Physical Characteristics of the Earth
• Diameter (12,714 km/7,926 mi.)• Circumference (40,075 km/24,901 mi)• Mass (5.98 x1024
kg/1,130,000,000,000,000,000,000,000 lbs.)• Average distance from the Sun (149,000,000
km/92,384,987 mi.)• Average distance from the Moon (384,400
km/238,855 mi.)
The Earth’s Magnetic Field
The Earth’s magnetic field helps protect the Earth from harmful radiation/energy
from the Sun.
The Magnetosphere
Areas of charged particles (protons and electrons) that circle the Earth above the
atmosphere. The particles are held in place by gravity and are called the “Van Allen belts”.
The AuroraA stream of particles called the “solar
wind” flow through space from the Sun toward the Earth and collide with the
magnetic field that causes them to flow down toward the north and south poles.
The AuroraThe “solar wind” particles then collide with atoms in the atmosphere at the
poles and cause the solar wind particles to give off light.
The Earth and Venus• Same size• Venus has an atmosphere of 96% CO2
creating an average temp of 460 Celsius (860 F)
• Earth has an atmosphere of 0.04% CO2 creating an average temp of 15 Celsius (60 F).
The Earth and Mars• Earth is twice as large• The Earth’s gravity is strong enough to
hold our atmosphere in place, Mars cannot hold one sufficient for life as we understand it
• Average temperature on Mars is -63 Celsius (-85 F)
Time and SeasonsSection 7-2
People have used the movements of the Earth, Moon, and Sun to measure time for thousands
of years.
Time Zones
• The Earth spins one complete turn in 24 hours, so 360 degrees of motion in 24hrs give you 15 degrees of movement an hour.
• 360/24 = 15• This motion creates 24 time zones of 15
degrees of longitude each.
Longitude
Lines running east to west that when used with lines of latitude help us calculate position on the Earth. GPS
Years and Days
• Rotation measures days (1 rotation 24hrs)• Revolution measures years (1 revolution 365
days)
The Tilted AngleThe 23.5 degree tilt causes the angle that
the sun hits the Earth to change throughout the year.
Equinox vs. Solstice
• Equinox (Spring and Fall, equal day and night hours)
• Solstice (Summer and Winter, most hours of daylight and least number of hours of daylight)
The surface of the Moon is barren rock, this is how the Earth would look
with no water or plant life
Origin of the Moon(Disproven Ideas)
• The Capture Theory• The Binary Accretion Theory• The Fission Theory
The Capture TheoryThis theory stated that the moon
formed somewhere else in the solar system and was pulled in by the gravitational pull of the Earth.
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