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Chapter 7 Earth in Space. Section 1 Earth’s Motion and the Seasons. Earth’s Shape. It’s a sphere (Almost!) A 3D shape with all surface points the same distance from the center. Gravity is centered at the core of the earth Pulls all objects on earth toward the center.
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Chapter 7 Earth in Space. Section 1 Earth’s Motion and the Seasons
Earth’s Shape • It’s a sphere (Almost!) • A 3D shape with all surface points the same distance from the center. • Gravity is centered at the core of the earth • Pulls all objects on earth toward the center. • It bulges somewhat at the equator and is flattened a little near the poles. • Due to the rotation of Earth on its axis.
Motions of Earth • Earth….. • Rotates on its axis. • The imaginary line between the North and South Pole. • Tilted 23.5 ° away from vertical. • Causes day and night. • Revolves around the sun. • Along with the tilt, causes parts of Earth to experience seasonal change. • Takes 365 ¼ days to complete one revolution.
Earth is actually closer to the sun.. • in January. • and furthest from the sun in July.
Solstices • Summer and Winter • Summer Solstice • June 21 or 22 • The sun is at its highest in the sky and the longest day of the year. • Sun rays directly hitting the Tropic of Cancer. • Winter Solstice • December 21 or 22 • The sun is at its lowest in the South sky and the shortest day of the year. • Sun rays directly hitting the Tropic of Capricorn.
Equinoxes • Spring (Vernal) • March 21 or 22 • Earth’s tilt is neither to nor away from the sun. • Sun rays hit equator. • Autumnal • September 21 or 22 • Same as above.
Section 2 Earth’s Moon • The Moon • Aka. Luna • Moon Features • Dark colored low land areas • Maria- (Galileo) Latin word for seas. • Light colored highland areas. • Craters • Depressions formed from meteorite collisions.
The Moon’s Interior. • Apollo missions left seismographs, earthquake measuring devices, on the moon to measure moonquakes! • A model of the interior of the moon was formed. • The Moon has: • Crust • 60 km thick facing the earth • 100 km thick away from the earth • Solid Mantle • Iron Rich Solid Core
Moon Motion! • 27.3 • The number of days it takes the moon to revolve around the earth. • Also, the number of days it takes the moon to rotate one turn on it’s axis. • Therefore, we only ever see one side of the moon from Earth.
Moon Phases. • Why do we see different phases of the moon? • THE SUN! • As the moon revolves around the Earth, the sun always lights one half of it. • We don’t always see the entire lighted part. • The part that we do see is the phase or position of the moon.
New Moon • Moon is between Earth and Sun • We don’t see any of the moon • Seen during the day. • Full Moon • Earth is between Moon and Sun • We see the entire lighted half • Waxing Moon • The lighted side of moon is increasing each night. • Period between a new moon and a full moon. • Waning Moon • The lighted side of moon is decreasing each night. • Period between a full moon and a new moon. • Crescent • A phase in the waxing and waning stages that looks like a crescent roll. Shows 1/8 of the Moon’s lit surface. • Gibbous • A phase in the waxing and waning stages that shows ¾ of the moon’s lighted surface.
Eclipses! • Occur only when the Sun, the Moon, and the Earth are lined up perfectly. • A few times per year. • Most of the time the Moon’s shadow misses the Earth. • And the Earth’s shadow misses the moon.
Solar Eclipse • Occurs during the new moon phase. • Earth moves into the shadow of the Moon. • The Moon blocks the sunlight from reaching certain points on Earth. • During a total solar eclipse the stars can be seen and the earth is dark. • Lasts a few minutes. Why?
Small dark region = umbra, total solar eclipseShaded region = penumbra, partial solar eclipse
Lunar Eclipse • Occurs during a Full Moon. • The Moon moves into the Earth’s shadow. • Moon usually appears to be dark red • Can see the edge of the Earth’s shadow moving through the moon.
Lunar EclipseNotice how the Sun’s Rays bend around the Earth.Dark Area = UmbraShaded Area = Penumbra
Section 3: Our Solar System • Found in which Galaxy?
The Inner Planets • Mercury • Closest to the sun. • Has no atmosphere. • Daytime temps. can reach 880 ° F. • Nighttime temps. with no atmosphere to hold in heat can reach – 275 ° F.
Venus • 2nd planet from the sun. • Earth’s twin in size, shape, and mass. • Thick atmosphere made of Carbon Dioxide. • Greenhouse effect causes temps. to reach 880° F.
Earth • Water can exist as solid, liquid, and gas. • Atmosphere is made of Ozone (O3). • Perfections that enable life. • Ozone layer/atmosphere. • Orbit/distance from the sun. • Temperatures. • Presence of water. • All this by chance? You decide.
Mars • The Red Planet. • The 4th planet from the sun. • Iron Oxide/ Rust causes the red color. • Olympus Mons – largest volcano in solar system. • Polar ice caps. • 2 moons. • Phobos • Deimos
The Outer Planets • Jupiter • Number 5 • Largest planet. • The Great Red Spot. • A giant storm that has raged for over 300 years. • 61 moons. • Why? • 4 largest - Galilean Satelites • Io • Europa • Ganymede • Callisto
Saturn • Number 6 • Ring system that circles the planet • Rings made of ice and rock. • At least 31 moons. • Largest = Titan
Uranus • Number 7 • Methane in atmosphere makes planet bluish green! • At least 27 moons. • Axis points to sun. • Faint rings.
Neptune • Number 8 • The rocky core is as big as Earth. • Fast winds in the gaseous atmosphere. • At least 11 satellites. • Triton has nitrogen geysers
Pluto • Number 9. (Maybe?) • Only traveled 20% of orbit since discovery in 1930. • 3 moons. • Charon = largest • Dwarf planet. • Member of Kuiper belt. • 134340 Pluto • New name.
Other Objects in Solar System. • Asteroids • Small rocky objects that mostly lie in a belt located between Mars and Jupiter. • Divide the inner and outer planets.
Comets • Made of rocky particles and ice. • Form tails when parts of the comet vaporize. • Found in: • Kuiper belt – beyond Neptune (Pluto) • Oort Cloud – far beyond Pluto • Haley’s Comet • Comes by Earth every 76 years. • 1986
It’s a bird, it’s a plane, it’s a meteor. I think? • Meteoroid • Small objects from comets and asteroids in the solar system • Meteor • When the meteoroid enters the atmosphere of Earth. • Meteorite • When they fall to earth.
Meteoroid Meteor Meteorite