earth and space science origin of modern astronomy chapter 22
TRANSCRIPT
Earth and Space Science
Origin of Modern Astronomy
Chapter 22
22.2 The Earth-Moon-Sun System• I. Motions of Earth
– A. ___________________ – the turning, or spinning, of a body an its axis.
• Gives us day and night• Each rotation takes _________________• _______________________ – time interval
from one noon to the next – nearly 24 hours• _____________________ – the time it takes
for Earth to make one complete rotation with respect to a star other then the sun
– 23 hours, 56 minutes, 4 seconds
22.2 The Earth-Moon-Sun System
– B. _________________ – the motion of a body, along its orbit around some point in space.
• Earth moves 107,000 km/hr• Average distant from sun is 150 million km• The orbit is an ellipse, which means it is closer at
some times than at others.• ________________ – Earth is closest to sun
– Occurs on January 3 each year
• _________________– Earth is farthest from sun– Occurs on July 4 each year
22.2 The Earth-Moon-Sun System
– The Seasons – • The imaginary line that connects Earth’s orbit
with the celestial sphere is the plane of the ecliptic
• The celestial equator is the projection of the Earth’s equator on the sky.
• The Earth’s tilt on its axis is __________• When the sun’s apparent position is plotted
on the celestial sphere over a period of a year’s time, its path intersects the celestial equator at two points: the spring equinox and the autumn equinox.
22.2 The Earth-Moon-Sun System
– At two other times of the year the sun appears 23.5ô north and south of the equator
• Summer and winter solstice
– C. ____________________________ – the slight movement of Earth’s axis
• Over a period of 26,000 years.
22.2 The Earth-Moon-Sun System• II. Earth-Sun motions
– A. The entire solar system moves in the direction of the star Nova
– B. The Milky Way Galaxy is also in motion – towards to Andromeda Galaxy
– C. These speeds are very great.
22.2 The Earth-Moon-Sun System• III. Earth-Moon motions
– A. The Earth has one natural satellite – the moon.
– B. The Moon orbits the Earth in a period of about one month.
– C. It’s motion is counterclockwise around the Earth.
– It’s orbit is also elliptical• Perigee – _____________________• Apogee- ____________________
22.2 The Earth-Moon-Sun System• IV. Phases of the Moon
– A. The changes in the amount of the moon that appears lit.
• _____________– when the moon is between the Earth and the sun – we cannot see the lit portion
– It appears like there is no moon at all in the sky
• ________________– small sliver that approaches the first quarter.
• ______________– half circle – right side lit
22.2 The Earth-Moon-Sun System
• ____________– from first quarter to full moon.
• _____________– when the Earth is between the moon and the sun.
– we see the whole lit portion of the sun
• ______________– moving from full moon the third quarter.
• ______________– half circle – left side lit• ___________________– from third quarter to
new moon.
22.2 The Earth-Moon-Sun System• The moon’s period of rotation and its
revolution around the Earth are the same– That is why we see the same side of the
moon all the time.
– 271/3 sidereal month– 291/2 synodic month
22.2 The Earth-Moon-Sun System• V. Eclipses – shadow effects
– A.__________________– when the moon is between the Earth and the sun the moon casts a shadow on the earth.
– B. __________________ – when the Earth is between the sun and the moon
– C. For an eclipse to take place the moon’s orbit must cross the plane of the ecliptic when in the new or full moon phase.
22.3 Earth’s Moon
• VI. Moon facts– A. The only natural satellite of the Earth– B. Diameter is ____________________– C. Diameter is ______that of the Earth– D. Our information comes from the
______________________ missions between 1969 and 1972
– E. On moon the force of gravity is only _________ that of Earth’s.
22.3 Earth’s Moon
• VII. The Lunar Surface– A. ________________ – mostly from
rapidly moving debris or meteorites• It is heavily cratered• Pg. 631, figure 19• Rays – the material ejected from a crater
– Surrounds the crater
– B. ______________________ – densely pitted, light colored areas
• Mountain ranges
22.3 Earth’s Moon
– C. _______________ – beds of basaltic lava
• Dark, relatively smooth areas• Occurred when asteroids punctured lunar
surface allowing lava to “bleed” out.– Rilles – long channels
» Ancient lava flows
– D. ____________________ – soil-like layer covering the lunar surface
22.3 Earth’s Moon
• VIII. Lunar History– A. Believed to have been formed when a
Mars-sized object struck the Earth, ejecting a huge amount of crust and mantle rock, which eventually formed the moon.
• Known as the _______________________
________________________________.