Transcript Earth`s Moon

Chapter 6: The Terrestrial Planets and their moons
- Earth and Moon
A closer look reveals a planet
¾ -covered with liquid water
Earth’s Atmosphere is layered. We live in the
troposphere, which has most of the mass and weather.
Convection heats the lower atmosphere,
distributing heat from the ground.
The Greenhouse Effect plays
a major role in heating the Earth’s atmosphere.
Factors include:
Water vapor
Clouds
Snow cover
Carbon dioxide
Methane
CFC gases
Dust and pollution
Desertification
Agriculture
City “heat islands”
Global Warming is definitely occurring,
but this may be due to several reasons.
Global Warming may be due partly to increasing carbon
dioxide levels which increase the Greenhouse effect.
Increasing carbon dioxide levels have been
measured on the Hawaiian volcano, Mauna Loa.
Earth’s interior is revealed by seismology,
the study of earthquakes. Earth is layered.
A layered object:
Inner core
Outer core
Mantle
Crust
Hydrosphere
Atmosphere
Magnetosphere
Observation of Seismic Waves due to earthquakes
reveals the interior structure of the Earth
Global Plates move slowly – plate tectonics
The motion at their boundaries causes earthquakes.
Plate Drift causes many effects: earthquakes, rift valleys,
mountain chains, volcanoes, mid-Atlantic ridge, etc.
Earth’s Magnetosphere varies in size,
depending on the solar wind.
Van Allen Belts,
named after
James Van Allen
of the
Univ. of Iowa,
who sent
instruments up
on early U.S.
spacecraft.
The Aurora Borealis are due to charged particles trapped in
the Earth’s magnetic field, causing air molecules to glow.
There are also aurorae around
Jupiter, Saturn, Uranus, and Neptune.
Earth’s Moon: the interior is not well understood.
Missing from
the Moon are
these features:
Hydrosphere
Atmosphere
Magnetosphere
Full Moon, Near Side
Far side of the Moon.
Moon craters, maria, and highlands.
Meteoroid impacts cause craters and ejecta.
Tides are mostly due to the gravity of the Moon.
Solar and Lunar
effects on Tides
depend on the
relative
orientations
of the Earth,
Moon, and Sun
The tidal bulge is actually offset somewhat
from being directly underneath the Moon.
This produces a torque, a kind of twisting force on the Earth.
The tides cause the Earth to slow down and the
Moon’s orbit to increase in radius (4 cm per century).
Also, the Moon’s rotation is synchronous with its orbit.
The Moon’s
formation is
believed to be
due to a collision
of a massive
(Mars-sized)
object with the
early Earth.
Computer
simulation show
that this could
leave a moonsized satellite in
the correct orbit.
Lunar Evolution: the Moon after the early bombardment
Lunar Evolution:
the formation of the maria by volcanic eruptions
Lunar Evolution:
after 3 billion years of cratering