Chapter 29 Flashcards
Sphere
A round three dimensional object where the surface is an equal distance from the center in all directions.
Ellipse
An elongated, closed curve with two foci (Focuses).
Is the Earth a perfect sphere?
No. The diameter is longer than pole to pole.
What are some ancient observations that prove Earth is a sphere?
Any object that falls, falls straight down. The shadow on the moon during a lunar eclipse is round. If the Earth were flat, everyone on Earth would see the same stars.
What are two factors that affect gravitational strength?
The mass of an object and the distance between them.
Which diameter is longer than the other?
The diameter from pole to pole is longer than the diameter of the equator.
What does the magnetic field protect Earth from?
Harmful radiation from the sun.
What does the magnetic field protect Earth from?
Harmful radiation from the sun.
Which hemisphere is the south magnetic pole located in?
Northern hemisphere.
Which hemisphere is the north magnetic pole located in?
Southern hemisphere.
What degrees does the Earth tilt at?
11.7 degrees
Can the magnetic poles change?
Yes, they can.
What is the name of the large scale movements when the magnetic poles switch?
Magnetic reversals.
When do the magnetic reversals occcur?
Every 200,000 years.
When was the last time the poles flipped?
80,000 years ago.
Which part of the Earth’s magnetic field deflects harmful radiation from the sun?
Earth’s magnetic field.
What are the two scientific names for the Northern and Southern lights.
Aurora Borealis and Aurora Australis.
How are the Aurora’s created?
Electrically charged particles from the sun and atoms collide in the atmosphere causing lights.
When is Earth closet to the sun?
Early January and it is about 147 million kilometers away.
When is Earth farthest away from the sun?
Early July and it is about 152 million kilometers away.
Time Zone
An area 15 degrees wide where time is the same.
Rotation
The spinning of Earth on it’s axis an imaginary line running from North to South pole.
Revolution
The motion of Earth in an elliptical orbit around the sun.
Ecliptic
The plane of Earth’s orbit around the sun.
Solstice
When Earth’s rotational axis is tilted directly toward the sun or away from the sun.
Equinox
Earth’s rotational axis is perpendicular from the center of Earth to the center of the sun.
Ẃho devised a method of timekeeping around 3000 B.C.?
The Babylonians.
What was the symbol for degree taken from?
The sun.
How many degrees does the earth spin in one day?
360 degrees.
How many hours does it take the earth to make one full rotation?
24 hours generally but specifically 23 hours, 56 minutes, and 4 minutes.
How many degrees does the earth spin in one hour?
15 degrees.
What direction does the sun rise?
The East.
What direction does the sun set?
The West.
True or false. All time zones are the exact same size.
False, they are modified to fit around cities, states, and country borders as well as other key sites.
How many time zones are there in the world?
Twenty four time zones.
Which direction do you move to add hours to the time?
East.
Which direction would you move to subtract hours from the time?
West.
How many time zones are there in the United states?
Six time zones.
What are the names of the time zones?
Atlantic/Alaskan time, Pacific time, Mountain time, Eastern time, and Hawaiian time.
What is a solar day?
The movement of the sun from noon one day to noon the next day.
What is a sidereal day?
The time from one star to the next day it appears.
What are the two main reasons for seasons?
The tilt of the axis and the revolution around the sun.
What two seasons have equinoxes?
Summer and Winter.
Which month is the summer solstice?
June 21.
Which month is the winter solstice?
December 21.
Which two seasons are equinoxes?
Spring and Fall.
Which month is the spring equinox?
March 20th or 21st.
Which month is the fall equinox?
September 22nd or 23rd
When is the longest day of the year?
Summer solstice, June 21.
When is the shortest day of the year?
Winter solstice, December 21.
When are the days almost 12 hours of day and 12 hours of night?
The summer and winter equinoxes.
Tide
A rise or fall in the ocean surface.
Moon Phase
Something that reflects the change of the moon as seen from Earth,
Solar Eclipse
When the moon moves directly between the Earth and Sun and casts a shadow on Earth.
Lunar Eclipse
When the Earth passes between the Sun and Moon and casts a shadow on the moon.
Maria
The dark colored, flat, lava filled regions of the moons surface.
Regolith
A layer of dusty lunar material produced by collisions between asteroids, comets, and the moon.
How many days does it take for the moon to revolve around the moon?
27.3 days.
A complete lunar phase cycle takes 29.5 days, what is this called?
A synodic month.
Do we ever see the back side of the moon?
No we cannot.
What causes a tide to rise or fall?
The gravitational pull by the sun and moon.
What is the rise of sea level called?
High tide.
After the sea level rises how long does it take the sea level to drop?
About 6 hours.
Is the sun or moon farther from the Earth?
The sun.
Does the sun or moon have a greater effect on Earth’s tides?
The moon.
How are the Earth, sun and moon aligned for a spring tide?
The Sun, Earth, and moon are parallel in that order.
How are the Earth, sun and moon aligned for a neap tide?
The sun and Earth are parallel horizontally and the Earth and Moon are linear vertically w/ the moon on top.
What does the phase of the moon you see depend on?
The position of the relative location between the Sun, Earth, and Moon.
When does a new moon occur?
When the moon is between the Earth and sun. A new moon will be fully covered in darkness.
How many phases of the moon are there?
There are eight phases.
What is the definition of waxing phases?
Waxing- The illuminated portion that we see appears larger each night.
What is the definition of waning phases?
Waning- The illuminated portion that we see appears smaller each night.
What are the moon phase names?
New Moon, waxing crescent, 1st quarter, waxing gibbous, full moon, waning gibbous, 3rd quarter, and waning crescent. (IN THAT ORDER.)
Where is the word month derived from?
Month is derived from the same root word as moon.
How are the Earth, moon, and Sun aligned during a solar eclipse?
The moon moves directly between the sun and Earth during a solar eclipse.
What is an umbra?
The darkest portion of the moon’s shadow.
What is a penumbra?
The lightest portion of the moon’s shadow.
How are the Earth, moon, and Sun aligned during a lunar eclipse?
The Earth is located between the Sun and the Moon.
How are the depressions on the moon formed?
When asteroids, comets, and meteorites collide with the moons surface
Are there mountains on the moon?
Yes.
Which side of the moon is thicker?
The far side/the dark side/the side not facing the Earth.
Is the mantle of the moon a solid or liquid?
The mantle of the moon is a solid.
What did the Clementine spacecraft do? (Two things.)
Confirmed the thickness of the moon’s crust and provided information on the mineral content of the moon rocks.
What did the lunar prospector do? (Three things.)
Took photographs of the surface, confirmed the core is solid and iron rich, and collected evidence that supported the presence of water-ice on the moon.
What is the giant impact theory?
Where it was thought to be that a mars size object collided with Earth. Then debri was went out into orbit and condensed forming a large mass (the moon).
