Chapter 23 The Sun Earth Moon System

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Terms in this set (...)

Sphere
a round three-dimensional object.
Axis
imaginary vertical line around which Earth spins.
Rotation
spinning of Earth on its axis.
Earths axis is an imaginary vertical line around which Earth spins.
Earths axis is tilted 23.5 degrees.
spinning of Earth on its axis causes day and night.
Revolution
Earth's yearly orbit around the Sun.
the movement of an object around another object.
Orbit- path the object moves around another object.
ellipse- an elongated closed curve
Earth makes one complete revolution around the Sun every 365 1/4 days.
Ellipse
Earths orbit which is an elongated closed curve.
Solstice
day when the Sun reaches its greatest distance north or south of the equator.
*we experience this when the Sun is the greatest distance north or south of the equator.
*Earth experiences two of them each year.
Equinox
occurs when Sun is directly above Earth's equator.
* When the Sun is directly above the equator
* the number of daylight and nightime hours are equal.
*occirs twice a year.
*march 20 or 21 and september 22 or 23
Characteristics of Earth
Spherical
has an imaginary vertical line around it called axis.
core generates a magnetic field
Earth's rotation causes day and night.
Earths orbit is an ellipse.
Rotates on tilted axis.
Its tilted axis and its revolution around Sun causes seasons.
Day and night
The side of Earth that faces the Sun will experience day and the side of the Earth that faces away from the sun is night.
Moon phases
different forms that the moon takes appearence.
Waxing
means that more of the illuminated half of the Moon can be seen each night.
Full Moon
Occurs when all of the Moons surface facing Earth reflects light.
Waning
illuminated half each night.
Solar eclipse
occurs when the Moon moves directly between the Sun and Earth and casts its shadow over part of Earth, the darkest part of moons shadow is called umbra, surrounding the umbra is a lighter shadow on Earths surface called penumbra.
Lunar eclipse
Occurs when Earth's shadow falls on the Moon, Earths shadow falls on the moon a lunar eclipse occurs, begins when the moon moves into Earths penumbra.
Maria
Dark, flat regions.
Impact basin
depression left behind by an object striking the Moon also known as impact crater.
Hemisphere
Earth is divided into 2 hemispheres
Northern and the southern
anything above the equator is in the Northern hemisphere
anything below the equator is the Southern hemisphere.
We live in Northern hemisphere.
What causes season?
Earths seasons are caused by the tilt of Earth on its axis
As Earth revolves around the Sun different parts of the Earth recieve more direct or indirect Sun rays causing different seasons
Seasons in hemisphere
Northern hemisphere experience summer when the hemisphere is tilted towards the Sun.
Northern hemisphere experiences winter when the hemisphere is tilted away from the Sun
Seasons in the Southern hemisphere are opposite seasons in the Northern hemisphere.
Summer solstice
on this day the length of the daylight is the longest year.
Winter solstice
on this length of day is the shortest day of the year.
Which area represents sunlight at the equator? Why?
The angle because the heats not all together.
Which receives more energy the smaller area or the larger area? Why?
The smaller area has more heat together.
If this were Earths surface why would the larger area be colder?
Its spread out not all together.
If this were Earths surface why would the smaller area be warmer?
All of the heat is together.
When the light is at an angle what season is our area experiencing? When the light is more direct what season is our area experiencing?
Area is experiencing cold. The area is now experiencing summer.
Moon
It has maria
It orbits Earth
It is smaller than Earth
It has large craters
Its pull affects the tides in the ocean on Earth
Moons surface
Moons surface shows striking contrast of light and dark
Dark zones were partly flooded by lava when the volcanoes erupted billions of years ago
When meteors hit the moon, cracks may have formed allowing lava to reach surface and fill up large craters
Resulting dark flat regions are called Maria
Moons mass
moon is less massive than Earth due to gravity at the lunar surface is only about 1/6 of that on Earth
Motions of Moon
Moon does not experience seasons.
Rotation of Moon
Moons rotates on its axis once ever 27.3 days
Moons revolution
Moon revolves around the Earth every 27.3 days. Since the moon revolves and the rotates about the same amount of time we always see the same side of the Moon (phase locked)
Phases of the Moon
The changing shape of the bright part of the Moon is called its phase. The phase of the Moon depends on its position in relation to Sun and Earth. As the Moon makes its way around Earth we see bright parts of Moons surface at different angles causing the Moons appearance to change.
Moon phase cycle
(8 phases in cycle) new moon, waxing crescent, 1st quarter, waxing gibbous, full moon, waning gibbous, 3rd quarter, waning crescent.
New moon (phase 1)
New moon is day 1 of moon phase cycle
Waxing crescent (phase 2)
A few days after the new moon you begin to see a small silver moon. This is called a waxing crescent moon.
First quarter moon phase
When moon has completed about a quarter of its turn around the Earth we can see half of the illuminated part.
Waxing gibbous moon phase
during next several days we keep seeing more of illuminated part of moon.
Full moon phase
occurs when the Earth is between the Sun and the Moon. The full moon is the only moon phase where half of the side of the moon that faces Earth is lit up.
Waning phase
Moons phases are waning you see less of its illuminated half each night
Waning gibbous moon
Phase after the full moon is called waning gibbous
Last quarter (3rd quarter)
Opposite side of the moon is lit up compared to the first quarter moon
Explain how the Sun, Moon, and Earth are positioned relative to each other during a new moon and how this alignment changes to produce a full moon?
A New Moon occurs when Moon is between Earth and Sun. During a new moon the lighted half of the moon is facing the Sun and the dark side is faces Earth.
Describe what phase the Moon must be in to have a lunar eclipse and a solar eclipse?
The moon must be in umbra to have a lunar eclipse. Also the moon must be in penumbra to have a solar eclipse.
Define the terms umbra and penumbra and explain how they relate to eclipses.
Umbra is the darkest portion of the moons shadow. Penumbra is the surrounding umbra that is lighter shadow on Earths surface.
Explain why lunar eclipses are more common than solar eclipses and why so few people ever have a chance to view a total solar eclipse.
Lunar eclipses are more common because it can be seen by anyone on the nighttime side of Earth. Solar eclipses are less common because only a few lucky people get to witness a total solar eclipse because the region where the Moons umbra strikes Earth can witness one.
Eclipses
-occurs when Earth or Moon temporarily blocks the sunlight from reaching the other
-during a new moon the moons shadow may fall on Earth and cause a solar eclipse the suns light is blocked by the moon
-during a full moon the Earths shadow can be cast on the moon resulting on a lunar eclipse the sunlight on the moon is blocked by the Earth
-an eclipse can occur only when the sun, moon and the Earth are lined up perfectly.
Umbra
the darkest portion of the moons shadow, a person standing within the umbra experiences a total eclipse.
Penumbra
Surrounding the umbra is a lighter shadow on Earth's surface called the penumbra.
Phase
A particular appearance or state in a regularly recurring cycle of changes.
Why do we always see the same side of the Moon?
The rotation and the revolution of the Moon around Earth takes 27.3 days. Since it is the same amount of time. The same side of the Moon always faces Earth.
Explain what causes the phases of the Moon?
Moon phases are the different forms that the Moon takes in appearance from Earth. The Moon seems to shine because its surface reflects sunlight.
Why dont we see a solar and lunar eclipse ever month?
You dont see solar and lunar eclipses each month because the Sun, Moon and Earth need to be lined up. The Moons orbit is not on the same plane.
Explain why the phases of the Moon are not shadows but solar and lunar eclipses are.
The phases of the Moon are not shadows but solar and lunar eclipses are because a solar eclipse occurs when the Moon moves directly between the Sun and Earth casts a shadow over part of Earth. The lunar eclipse occurs when Earth's shadow falls on the Moon.