The Earth, the Moon, and
the Sun
Physical Science
2011-2012
The Earth in Space
Section 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 Aurora
A 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 Aurora
The “solar wind” particles then collide
with atoms in the atmosphere at the
poles and cause the solar wind particles
to give off light.
Aurora Borealis
(Northern Lights)
Aurora Australis
(Southern Lights)
The Earth’s Orbit around the Sun
The Earth’s Orbit around the Sun
• Elliptical shaped orbit
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)
Size Comparisons
Size
Comparisons
Time and Seasons
Section 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
Time Zones
Years and Days
• Rotation measures days (1 rotation 24hrs)
• Revolution measures years (1 revolution 365
days)
The Reason for the Seasons
The Earth is tilted 23.5 degrees
The Tilted Angle
The 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 Earth’s Moon
Section 7-3
Rotation and Revolution
The moon revolves once
around the Earth every 27
days.
How does the Moon
affect the Earth?
The Tides
The Pull of the Moon and the Sun
The Surface of the Moon
The surface of the Moon is barren
rock, this is how the Earth would look
with no water or plant life
Craters, Maria, and Mountains
Maria (Dark Spots) Regolith (Light Spots)
Asteroid Impact
Origin of the Moon
(Disproven Ideas)
• The Capture Theory
• The Binary Accretion Theory
• The Fission Theory
The Capture Theory
This theory stated that the moon
formed somewhere else in the solar
system and was pulled in by the
gravitational pull of the Earth.
The Binary Accretion Theory
The Moon condensed from the same
loose space material as the Earth did.
The Fission Theory
A portion of molten material was
ejected from the Earth as it cooled.
Origin of the Moon
(Modern Theory)
The Giant Impact Theory