Download Unit 5 -

The Solar System
Unit 4
Unit 4 Vocabulary
1.
2.
3.
4.
5.
6.
7.
8.
9.
Rotation
Revolution
Axis of rotation
Summer solstice
Winter solstice
Autumn equinox
Vernal equinox
Oblate sphere
Geodesy
Solar eclipse
11. Lunar eclipse
12. Ecliptic plane
13. Specific heat
14. Spring tide
15. Neap tide
16. Foucault’s pendulum
17. Coriolis effect
18. Latitude
10.
Unit 4 vocabulary
19. Longitude
20. Conduction
21. Convection
22. Radiation
23. Big bang theory
24. Steady-state
theory
25. Inflationary
universe model
26. Doppler effect
27. Precession
28.
29.
30.
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Barycenter
Nutation
Eccentricity
Chapters:
◦ 11.1
◦ 28-31
The Sun-Earth-Moon System
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The relationships between the Sun, Moon, and
Earth are important to us in many ways.
– The Sun provides light and warmth and an energy source.
– The Moon raises tides in our oceans and illuminates our
sky with its monthly cycle of phases.
– Both are used for the calendar and timekeeping systems.
The Sun-Earth-Moon System
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Seasons, moon phases, tides and eclipses.
•
Our view of the Sun’s position changes throughout the
year as Earth moves in its orbit about the Sun. Seasons
occur on Earth because Earth’s axis is tilted.
•
The Moon goes through a cycle of phases each lunar
month that correspond to our changing view from
Earth of the sunlit side of the Moon.
The Sun-Earth-Moon System
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Seasons, moon phases, tides and eclipses.
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Tides are caused by the gravitational attraction of the
Moon, and to a lesser extent, the gravitational attraction
of the Sun.
A solar eclipse occurs when the Moon lies directly
between Earth and the Sun. A lunar eclipse occurs when
the Moon passes through Earth’s shadow.
Moon Phases
- Half the Moon is always lit by Sun
- As the Moon orbits the Earth, we see
different parts of the lighted half.
http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html
 Revolution
of Moon around Earth makes us
have different angles of Moon
 Looks like it’s changing shape
 These are "phases" of the Moon
http://btc.montana.edu/ceres/html/birthdayphases.htm
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“Waxing:” increasing, growing larger
"Waning“: decreasing, growing smaller
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Waxing: increase illuminated
portion
Waning: decrease illuminated
portion
Eight phases
Daily Motions
Earth’s Rotation
– There are two relatively simple ways to demonstrate that
Earth is rotating.
1. A Foucault pendulum, which has a long wire, a heavy
weight, and will swing in a constant direction, appears from
our point of view to shift its orientation.
2. Flowing air and water on Earth are diverted from a northsouth direction to an east-west direction as a result of
Earth’s rotation in what is known as the Coriolis effect.
Daily changes to Earth

Due to rotation◦ Rotation – Earth spinning around its axis.
◦ Earth rotates towards the east (counter-clockwise
from the north star)
◦ Causes the sun to rise, set and rise again in a 24
hour period.
Daily changes to Earth

Seasonal changes due to tilt
and revolution
◦ Caused because Earth is tilted
on its axis and moves around
the sun
◦ Summer = the hemisphere tilted
toward the sun
◦ Winter = the hemisphere
tilted away from the sun
Daily changes to Earth

Tidal impact due to the moon
and sun.
◦ High tide and low tides are
caused by gravitational
attraction with the moon
(mostly) and the sun.
Solar Eclipse
The moon passes directly between the
sun and Earth.
 Umbra area = total eclipse
 Penumbra area = partial eclipse

Lunar Eclipse
When the moon passes through Earth’s
shadow.
 Can happen only at the time of a full
moon and the moon is the opposite
direction from the sun.

Shape of the Earth
Because Earth rotates, the sphere is distorted
by the centrifugal force. This is the force that
causes objects to move outward away from
the center of gravity.
 Earth's circumference and diameter differ
because its shape is classified as an oblate
spheroid or ellipsoid, instead of a true sphere.

Shape of the Earth
The equatorial bulge at Earth's equator is
measured at 26.5 miles (42.72 km) and is
caused by the planet's rotation and gravity
 This means that instead of being of equal
circumference in all areas, the poles are
squished and a larger circumference and
diameter at the equator.
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Shape of the Earth

The Earth's gravitational pull is slightly weaker
at the Equator due to its equatorial bulge.

The slightly weaker gravitational pull and
momentum of the spinning Earth makes
equatorial regions ideal places for space
launches. It takes an enormous amount of
energy to launch a satellite or other
spacecraft out of the Earth's atmosphere.

Did you know that the Sun blasts more than a
billion tons of matter out into space at millions of
kilometers per hour?
oUltimately, energy from the Sun is the driving force behind
weather and climate, and life on earth.
How does energy flow from the sun
to the Earth?
The transfer of energy from the Sun occurs
primarily by radiation.
 Once the Sun’s energy reaches Earth, it is
intercepted first by the atmosphere. A small
part of the Sun’s energy is directly absorbed,
particularly by certain gases such as ozone and
water vapor.
 Some of the Sun’s energy is reflected back to
space by clouds and Earth’s surface.

How does energy flow from the sun
to Earth?
The Sun warms the planet, drives the
hydrologic cycle, and makes life on Earth
possible.
 The amount of sunlight received on Earth’s
surface is affected by the reflectivity of the
surface, the angle of the Sun, the output of the
Sun, and the cyclic variations of the Earth’s
orbit around the Sun.

Specific Heat
Why, on the same day, are the temperatures
of water, sand, and asphalt so
different? Specific heat is the key.
 Specific heat is how much heat energy is
needed ro raise the temperature of a
substance.
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Specific Heat
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Water has a very high specific heat. That
means it needs to absorb a lot of energy
before its temperature changes. Sand and
asphalt, on the other hand, have lower
specific heats. This means that their
temperatures change more quickly. When
the summer sun shines down on them, they
quickly become hot.
Transferring Heat Energy

Here are three easy things to know about
the way heat flows:
1) There has to be a temperature difference.
Energy only flows as heat if there is a
temperature difference.
2) Energy as heat flows from a higher
temperature to a lower temperature.
3) The greater or larger the difference in
temperature, the faster the energy flows.
Radiation

A type of energy that can travel through
space. It doesn't need matter to conduct
it from place to place. It can travel
through air or through a vacuum.
◦ Ex: When you stand near hot molten lava, the
heat you feel on your skin is mostly radiant
heat. This type of heat doesn't need air to
travel through. Even if you were standing in a
vacuum (no air) you would feel the heat.
Conduction
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A type of heat flow that results when things
are actually touching. Energy traveling as heat
by conduction needs matter to flow through.
Conduction cannot travel through a vacuum
because in a vacuum there are no atoms or
molecules…something made of atoms or
molecules has to touch something else made
of atoms or molecules in order for there to
be conduction.
◦ Ex: If you touch a hot object the heat is
conducted by physical contact with your skin.
Convection
A type of heat transfer in which the
motion is not generated by an external
source but only by density differences.
 Can occur in fluid or air

◦ Ex: Ocean currents and winds
Combustion and nuclear reactions
Combustion: a chemical reaction (sharing,
transfer, loss, gain of electrons; burning with
the presence of oxygen.
 Nuclear reactions:
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◦ Fission: Process in which heavy atomic nuclei split
into smaller, lighter nuclei.
◦ Fusion: Process in which light hydrogen nuclei
combine into heavier helium nuclei.
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The Sun emits many forms of electromagnetic
radiation in varying quantities.
As shown in the diagram:
◦
◦
◦
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about 43% is in the visible parts of the spectrum
about 49% in the near-infrared
7% ultraviolet
less than 1 percent of solar radiation is emitted as xrays, gamma waves, and radio waves.
Earth’s Magnetic Field
The Earth has a substantial magnetic field.
It protects us from harmful solar wind
from the sun.
 Charged particles given off by the Sun are
deflected by the Earth’s magnetic field.
 These particles interact with our atmosphere
and create the auroras.
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Earth’s Magnetic Field
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The origin of the Earth's magnetic
field is not completely understood,
but is thought to be associated with
electrical currents produced by the
coupling of convective effects and
rotation in the spinning liquid
metallic outer core of iron and
nickel.
Earth’s Magnetic Field

Solar wind is first deflected by the bow
shock. The corresponding region of space
sitting behind the bow shock and
surrounding the Earth is termed the
magnetosphere; it represents a region of
space dominated by the Earth's magnetic
field in the sense that it largely prevents
the solar wind from entering.
How our universe began

There are three theories we will discuss about
the origin of the universe:
◦ The steady state theory – says that new matter is
created as the universe expands so that the overall
density of the universe stays the same.
◦ The inflation theory –says that a period of extremely
rapid expansion of the universe happened prior to the
Big Bang and was dominated by a type of vacuum
energy that later produced the matter that fills the
universe today.
◦ The big bang theory – says that the universe began
about 13.7 billions years ago as a single point and has
been expanding ever since.
Steady-state Theory
Inflation Theory
Big Bang Theory
Organization of the universe
Universe
Galaxies
Solar systems
(planetary
systems)
 Stars
 Satellite
planets around
a star – ex:
Earth is a
satellite planet
to our sun
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The universe is expanding
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Astronomers in the early 20th Century got the shocks
of their lives when they discovered that galaxies
appeared to be rushing away from us. They did this by
taking spectra of the galaxies, and then measuring the
shift in their spectrum due to their motion.
This phenomenon is called the Doppler Shift . With light,
an object approaching you has its light waves
compressed, or shortened. This is called a blue shift
(since in visible light the shorter wavelengths are blue). If
the object is moving away, the wavelengths are stretched,
resulting in a red shift of the spectrum.
The universe is expanding

As objects move they emit a light
◦ Red shift- objects are moving away
◦ Blue shift- objects are moving closer
◦ All planets and galaxies are showing a red shift
 What does this mean?
Movement through space
Movement of our
solar system
through the Milky
Way Galaxy.
 It takes the sun
over 200 million
years to revolve
around the galaxy.
 The last time we
were in the same
place dinosaurs
were just starting
to appear.

Motion of the Earth

How does the Earth move within our solar
system?
◦ Orbital motion – The Earth orbits (revolves) around
the sun once per year.
 Change in seasons dependent on the tilt of the Earth
◦ Rotation around the axis – Earth rotates around the
axis once per day.
 Causes day and night

How does the solar system move in the galaxy?
◦ Our solar system follows the path of the sun around
the galaxy center.
 Takes over 200 million years for our solar system to orbit the
center of the Milky Way galaxy
Motion of the Earth
1. Precession - A slight movement in the direction of the
earth’s axis, but without any change in tilt.
◦ This changes the stars near (or not near) the Pole but does
not affect the seasons as long as the angle stays the same.
◦ Happens over a period of 26,000 years. Right now our axis
points at Polaris. In the year 14,000 it will point at Vega.
Motion of the Earth
2. Nutation - a wobbling, or swaying motion around the
axis
◦ Causes a change in the angle ½ degree over an 18 year
period due to the moon exclusively
◦ Will slightly increase or decrease the amount of seasonal
effects
Motion of the Earth
3. Barycenter – the point between 2 objects where they
balance each other.
◦ Our sun actually orbits the barycenter of the solar system
as it moves through the galaxy because of the tug from the
planets.
Models of the solar system

2000 years ago, many philosophers developed
ideas about the universe based on what they
saw.

One of these was Aristotle , a Greek
philosopher who lived from 385 to 322 B.C.

He promoted an Earth-centered (Geocentric)
universe model.
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Heliocentric Model

Copernicus came up with the model we use today –
the sun-centered or Heliocentric model.
 When Copernicus first developed his model it was quite
controversial and was not accepted until after his death
in 1543.
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Each planet revolved around the sun in the same
direction but at different speeds.
Both the geocentric and heliocentric models first
had the planets orbits as perfect circles.
Heliocentric Model
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Sun-centered model
Heliocentric Model
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A Danish astronomer named Tycho Brache
devoted his life to making detailed observations
of the positions of the stars and planets.

He hired a German assistant name Johannes
Kepler.

Kepler was able to explain Brache’s observation in
mathematical terms.

In the early 1600’s Kepler developed 3 laws that explained
most aspects to planetary motion.
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Kepler’s Laws
Kepler’s 1st Law - law of ellipses
 Kepler’s 2nd Law - law of equal areas
 Kepler’s 3rd Law - law of periods
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Kepler’s 1st Law, the law of ellipses

Each planet orbits the sun
in a path called an ellipse.
◦ An ellipse is an oval whose
shape is determined by 2
points with the figure.
◦ Each of these points are
called a foci.
◦ The sun is one foci point for
our planets.
◦ Some ellipses look like
circles - This happens when
there 55is only one foci point.
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Kepler’s 1st Law, the law of ellipses

Because the planets do not travel in a perfect circle,
they are not always the same distance from the sun.
◦ The point where the orbit is the closest is called
perihelion.
◦ The point furthest away from the sun is called aphelion.
Properties of Ellipses

Eccentricity - how flattened the ellipse is, more flattened,
the more eccentric (measurements always between 0
and 1 with 1 equaling a flat line and 0 equaling a perfect
circle)
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Kepler’s 2nd Law - law of Equal
Areas
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Describes the speed at which any given planet
will move while orbiting the sun.
The speed at which any planet moves through
space is constantly changing.
A planet moves fastest when it is closest to
the sun and slowest when it is furthest from
the sun.
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Kepler’s



rd
3
Law - Law of periods
Kepler found a mathematical relationship
between the size of a planet’s ellipse and its
orbital period. He found that the ratio of a
planets ellipse to its orbital period is nearly the
same for all of the planets
The orbital period (p) in Earth years and distance
from the sun (a) in A.U.’s gives the ratio of
p²/a³=1
Mercury, the closest planet to the sun, takes 88
days to orbit the sun. While the dwarf planet
Pluto requires 248 years to do the same.
Fundamentals
Sunlight reaching the Earth can heat the land, ocean,
and atmosphere. Some of that sunlight is reflected
back to space by the surface, clouds, or ice. Much of
the sunlight that reaches Earth is absorbed and warms
the planet.
2. When Earth emits the same amount of energy as it
absorbs, its energy budget is in balance, and its
average temperature remains stable.
3. The tilt of Earth’s axis relative to its orbit around the
Sun results in predictable changes in the duration of
daylight and the amount of sunlight received at any
latitude throughout a year. These changes cause the
annual cycle of seasons and associated temperature
changes
1.
Gradual changes in Earth’s rotation and orbit around
the Sun change the intensity of sunlight received in
our planet’s polar and equatorial regions. For at least
the last 1 million years, these changes occurred in
100,000-year cycles that produced ice ages and the
shorter warm periods between them.
5. A significant increase or decrease in the Sun’s energy
output would cause Earth to warm or cool. Satellite
measurements taken over the past 30 years show that
the Sun’s energy output has changed only slightly and
in both directions. These changes in the Sun’s energy
are thought to be too small to be the cause of the
recent warming observed on Earth
4.
Test Review
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Draw and label the different moon phases
What causes our seasons?
Draw a lunar eclipse.
Draw a solar eclipse.
What is the penumbra? Umbra?
Identify each season and which latitude the sun is directly over?
What is the Foucault pendulum prove? And how does it prove it?
What is rotation? How long does it take?
What is revolution? How long does it take?
What are 2 pieces of evidence that our Earth is rotating? Explain
each.
How many degrees is the Earth tilted?
What causes the bulge around the equator?
What is the shape of Earth? And why?
Name, describe and give an example of the 3 ways heat is
transferred on Earth.
Explain differential heating of our Earth. (water vs. land)
Why is Earth’s magnetic field important?
Test Review
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Who came up with the Geocentric universe model?
Who came up with the Heliocentric universe model?
What do each of them mean?
Know what all of Kepler’s laws state.
What is Earth’s focus point?
How is eccentricity measured?
Do planets closer to the sun or further from the sun
have faster revolutions?
Know the organization of the universe.
What is the evidence for the universe expanding?
Know the definitions of precession, nutation and
barycenter
Be able to label – foci, major axis, semi-major axis,
perihelion, aphelion