Download The Sun - River Ridge CUSD #210

The Sun/ Earth/ Moon Systems
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I. Tools of Astronomy
A. Radiation
1. Light is a common term for
electromagnetic radiation, which are electric
waves.
2. The human eye can only see some
wavelengths these are called visible light.
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3. Electromagnetic radiation (E
radiation) is not just visible light but UV
radiation, radio waves, microwaves, Xrays and gamma rays.
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4. UV light causes sunburns.
5. X-rays help doctors.
6. Electromagnetic radiation is
classified by its wavelengths.
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B. Telescopes
1. A human eye can only see so far.
2. A telescope has the ability to see past
what the average eye can see.
3. Two different types of telescopes are used
to focus visible light.
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4. Refracting telescope or refractors
brings visible light to a focus.
5. Reflecting telescopes bring visible
light to a focus with mirrors.
6. Reflectors are used the majority of
the time.
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C. Telescopes at Other wavelengths
1. Interferometry is the process of linking
separate telescopes together so that they act
as one telescope.
2. Astronomers often have to send their
instruments into space to collect information
they seek.
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3. The hubble space telescope (HST),
which was launched in 1990 and is
expected to operate until 2010.
4. HST was designed to obtain images.
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5. Space exploration was also sending
spacecraft directly to the bodies being
observed.
6. Robot Sojourner part of the
Pathfinder probe to Mars.
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7. Probes are practical only for objects
within our solar system, because the
stars are too far away.
8. Exploring objects in space has been
a top priority for scientists.
9. Most recent program began in 1981.
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10. The space shuttle provides an
environment for scientists to study the effects
of weightlessness on humans, plants and the
growth of crystals and other stuff.
11. The shuttle mission last a MAXIMUM of
17 days, long-term effects must be studied in
space stations.
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12. A new multicountry space
station called the
International Space
Station (ISS) is the
ideal environment to
study the long-term
effect of space.
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II. The Moon
A. Reaching for the moon
1. Astronomers have learned much about
the moon from telescopic observations.
2. Most of our knowledge comes from
the Lunar Prospector and Clementine and
astronauts.
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3. Lunar expeditions began in the late
1950’s.
4. The first step was taken in 1957
with the Sputnik I by the Soviet Union.
5. In 1961 a Soviet man was the first
human in space.
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6. The US’s Project Mercury, Alan B.
Shepard Jr. was the first American’s into
space on May 5, 1961.
7. On July 20, 1969 During the Apollo
11 mission, Neil Armstrong and Buzz
Aldrin were the first to land on the
moon.
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B. Lunar Properties
1. Earth’s moon is unique among all
the moons in the solar system.
2. It is one of the largest moons,
especially compared to the size of the
planet it orbits.
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3. Most moons are much smaller than
the planet they orbit.
4. The orbit of the Moon is also
unusual because the moon is farther
from Earth than most moons are from
the planets they orbit.
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C. The lunar Surface
1. The Lunar surface is dark.
2. The albedo of the moon, the amount of
sunlight that its surface reflects, is very small,
about 7%.
3. Earth has an albedo of 31%.
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4. The physical surface of the Moon is
very different from the earth.
5. There is no erosion on the moon.
6. Regions called highlands are light in
color, mountainous, and heavily covered
with craters.
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7. Regions called maria are dark, smooth
plains.
8. All of the craters on the Moon are impact
craters formed when objects from space
crash into the lunar surface.
9. The material blasted out during these
impacts fell back to the surface as ejecta.
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10. Some craters have long trails of ejecta
called rays, that radiate outward.
11. Rays are visible on the moon as lightcolored streaks.
12. Maria do have a few scattered craters
and rills, which are valleylike structures.
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13. The moon is made up of minerals
similar to earth.
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D. History of the moon
1. The entire lunar surface is very old.
2. Estimates between 3.8-4.6 billion years
old.
3. They think that moon was bombarded
during its first 800 million years.
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4. Which resulted in the breaking and
heating of rocks on the surface of the moon.
5. This formed a layer of loose ground up
rock called regolith.
6. The Maria slightly younger than the
highlands are between 3.1-3.8 billion years
old.
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E. Tectonics on the moon?
1. Mountain ranges around maria were not
formed tectonically.
2. Some think that the moon has layered
structures like the crust, upper mantle, lower
mantle and core.
3. Seismometers measure moonquake
strength and frequency.
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4. It is thought that the moon is not
tectonically active.
5. The fact that the moon has no active
volcanoes supports this theory
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F. Formation theories
1. Capture theory- as the solar system
was forming, a large object ventured
too near to the forming earth,
becoming trapped in its gravitation pull
and this is our moon.
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2. Problem with this theory- something
would have had to slow down the passing
object to become trapped.
3. Another problem- the moon and earth are
composed of very similar elements. If the
moon had been captured you would think
they would have DIFFERENT elements.
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4. Simultaneous formation theory- the moon
and earth formed at the same time and in the
same general area.
5. Problem- different amounts of iron on
Earth and on the moon. The moon is iron
poor and the earth has tons of it.
6. The most commonly accepted theory- the
impact theory.
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7. Impact- the moon formed as a result of a
gigantic collision between earth and mars
about 4.5 billion years ago.
8. As a result of the collision, materials from
the incoming body and from Earth’s outer
layers were ejected into space, where they
then merged together to form the moon.
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9. Heat produced by the impact would
have evaporated any water present on
the moon.
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III. The sun-earth-moon system
A. Daily Motions
1. The most obvious pattern is rising
and setting of the sun.
2. The sun rises in the east and sets in
the west as do the moon, planets and
stars.
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3. The sun, moon, planets and stars do
not orbit around the earth every day.
4. It only appears that way to us
because we observe the sky from a
planet that rotates once every day.
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B. Earth’s rotation
1. The length of a day as we
observe it is a little longer than the time
it takes Earth to rotate once on its axis.
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C. Annual motions
1. Annual changes are the result of Earth’s
orbital motion around the Sun.
2. The plane in which earth orbits about the
sun is called the ecliptic.
3. At one point the earth’s axis is tilted
toward the sun while the other is tipped away42
from the sun.
4. Our seasons are created by this tilt and by
the Earth’s orbital motion around the sun.
5. Summer solstice the Sun is directly
overhead at the tropic of cancer around June
21st.
6. The winter solstice the sun is directly
overhead at the tropic of Capricorn this is
around December 21st each year.
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7. There is also autumnal equinox and
vernal equinox.
8. Equinox means equal nights.
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D. Phases of the moon
1. The moon does not emit visible
light, instead we see the moon’s
reflection of the sun’s light.
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2. Scientists theorize that Earth’s
gravity slowed the moon’s original spin
until the moon reached synchronous
rotation the state at which its orbital
and rotational periods are equal.
3. One of the moons effects on earths
the formation of tides.
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4. The moon’s gravity pulls on earth
along an imaginary line connecting
earth and the moon, and this creates
bulges of ocean water on both the near
and far sides of earth.
5. Earth’s rotation also contributes to
the formation of tides.
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E. Solar eclipses
1. A solar eclipse occurs when the moon
passes directly between the sun and earth
and blocks our view of the sun.
2. The sun is much larger than the moon, it
is much farther away also which causes the
sun and moon to be the same size.
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3. Solar eclipse does not happen every
month.
4. The closet point in the moon’s orbit to
earth is called perigee, and the farthest point
is called apogee.
5. When the moon is near apogee, it appears
smaller as seen from earth.
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6. This is called an annular eclipse because
from earth, a ring of the sun called an
annulus is visible around the moon.
7. A lunar eclipse occurs when the moon
passes through the Earth’s shadow.
8. This can happen only at the time of a full
moon, when the moon is in the opposite
direction from the sun.
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9. During a total lunar eclipse, the
moon is faintly visible, because sunlight
that has passed near earth has been
refracted by earth’s atmosphere.
10. The maximum number of eclipses,
solar and lunar combines that can be in
a year is seven.
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11. The last time this occurred was in
1982 and it won’t happen again until
2038. (How old will you be in 33
years?)
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The End
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