Download EarthScience_Topic 3

Topic 3 and 4: Astronomy
Rotation
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- spinning of Earth on its axis
- causes day and night
- 1 day: 23 hours 56 min 4 sec
- apparent motion of the sun around the
earth
• - 15 degrees per hour
Evidence of Rotation
• Coriolis effect
– Causes deflection of winds and ocean currents
– Deflects to the right in the Northern Hemisphere
– Circumpolar stars
– Star trails
Foucault Pendulum
• https://www.youtube.com/watch?v=rdGtcZSF
RLk coriolis
• https://www.youtube.com/watch?v=jbh9_Sjw
9K8 pendulum
• https://www.youtube.com/watch?v=iqpV1236
_Q0 cms
• Questions 1-8
Revolution
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Earth moving in its orbit around the Sun
Takes 1 year (365.25 days)
Moves approximately 1 degree per day
Causes the seasons
Evidence of Revolution
• The location of the constellations in
relationship to Polaris changes from month to
month
Locating objects in the sky
• Celestial sphere: imaginary dome surrounding
Earth
• Celestial objects: objects on the celestial
sphere (sun, stars, moon, planets)
• Zenith: the point located directly overhead of
an observer (altitude of 90 degrees)
Locating objects in the sky
• Altitude: the height above Earth’s surface
– Celestial objects are measured in degrees
– Ex: the altitude of Polaris
• Azimuth: the angular measurement around
Earth’s surface
– Measured in degrees starting with due North
located at 0 degrees Azimuth and moving
clockwise around the horizon.
Direct ray of the sun
• Also known as the Sun’s vertical ray
• Occurs when the sun is directly overhead (at
the zenith)
• NEVER occurs in New York State
Direct ray of the sun
• Question 1-5 page 253
Pg 255
Pg 255 continued…
• Hours of daylight
• Characteristics wkst
Angle of insolation
Angle of Insolation
• Look for the direct ray
– If it is over the equator----eqinox
– If it is over the tropic of caNcer----summer solstice
– If it is over the tropic of capricorn---winter
solstice
Causes for the seasons
• Tilt of Earth’s axis: 23.5 degrees
– The tilt causes different latitudes to have different
amounts of daylight
– More daylight hours means warmer temperatures
in that location
• What happens if we change the tilt? How
does the temperature change with different
tilts?
• Duration of insolation wkst
Causes for the seasons cont.
• Revolution around the sun
– Earths orbit around the sun
Causes for the seasons
• Parallelism of Earth’s axis:
– Earth’s axis does not change direction
– Ex: Summer in the Northern Hemisphere, North
pole is tilted towards the sun
Altitude of the Noon Sun and path
through the sky
• Solar noon:
– When the sun has reached its highest point in the
sky
– NEVER directly overhead in NY
Altitude of the Noon sun and path
through the sky
• Shadow:
– Longer when sun is lower in sky
– Direction at noon depends on your latitude
Where the Sun’s rays are at the
beginning of each season
• When the sun is directly overhead at the
Tropic of CaNcer (23.5 degrees N) it is the
summer solstice
• When the Sun is directly overhead at the
Equator, it is either the Autumnal Equinox or
the Vernal Equinox
• When the Sun is directly overhead at the
Tropic of Capricorn (23.5 degrees S), it is the
Winter Solstice
Noon Sun Angle
• During an equinox:
– The noon sun angle is the complementary angle to
the observers latitude
– Complementary angle = ?
– If the observer is at 45 degrees…
– 50 degrees….
• Is the sun higher in the sky during summer or
lower in the sky?
• By how much?
• During the summer solstice:
– Complementary angle to the observers latitude
+ 23.5 degrees
• Is the sun higher in the sky or lower in the sky
during winter?
• How much?
• During a winter solstice:
– Find the complementary angle to the observer’s
latitude
- 23.5 degrees
Noon Sun angle calculations
• Latitude: 35 degrees North
– Fall equinox:
– Spring equinox:
– Summer Solstice:
– Winter Solstice:
Noon Sun angle calculations
• Latitude: 40 degrees North
– Fall equinox:
– Spring equinox:
– Summer solstice:
– Winter solstice:
• Noon sun angle worksheet
Solar System Models
• Geocentric Model: Earth Centered
• Explained the following:
– Earth was stationary with the sun, moon and
planets revolving around it
– Night and day
– Revolution of the moon
Geocentric model cont.
• Did not easily explain the following:
– Movement of the inner and outer planets
Solar System models cont.
• Heliocentric model: sun centered
• Explained the following:
– Places the sun in the center of the solar system
– Day and night
– Seasons
– Motion of all celestial objects
Solar System Models
Solar System models
Solar System Models
Solar System Models
Direction of Rotation and Revolution
• Earth rotates from west to east
• Earth revolves in a counter clockwise direction
Retrograde Motion
Apparent Diameter Change
Star trails
• https://www.youtube.com/watch?v=tp6UkqI
wVfk
Constellations
• Random patterns of stars in the night sky
• Difference constellations are visible at
different times of the year
• The big dipper is always visible in the
northern sky of NY
• Evidence of revolution
Shape of Orbit
• Shape of Earth’s orbit: slightly elliptical with
the sun at one foci
• Eccentricity: how oval an orbit is. How out of
round it is
Eccentricity Calculations
The Force of Gravity
• Gravity: invisible of attraction
• Gravity depends on mass and distance
• The larger the mass, the greater the
gravitational attraction
• The closer the objects are together, the
greater the attraction
Planet Velocities and Area
• Equal area Equal time animation
• Fabric of cosmos clip
Distance of planets with respect to the
Sun
• Perihelion: closest to the sun
• Aphelion: farthest point from the sun
Kepler’s 3 laws
• 1st law: the path of the planets around the sun
is elliptical in shape with the sun being located
at one focus
Kepler’s three laws
• 2nd law: equal areas in equal intervals of time
Equal areas Equal Time
Kepler’s 3 laws
• 3rd law: the farther a planet is from the sun,
the longer it takes to complete its orbit
around the sun
Satellites
• Satellite: any object moving in an orbit around
another object
Phases of the Moon
• The apparent shape of the moon depends on
the changing positions of the sun, earth, and
moon
• One complete orbit of the moon around earth
takes 27 1/3 days.
• One complete cycle of the moon’s phases
takes 29.5 days.
Half of the Moon is always lit up by the sun. As
the Moon orbits the Earth, we see different
parts of the lighted area.
http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html
The revolution of the Moon around the
Earth makes the Moon look as if it is
changing shape in the sky.
http://btc.montana.edu/ceres/html/birthdayphases.htm
This is caused by the
different angles
from which we see
the lighted part of
the Moon's
surface. These are
called "phases" of
the Moon.
http://btc.montana.edu/ceres/html/birthdayphases.htm
http://www.niehs.nih.gov/kids/l
unar/why_phases.gif
The Moon passes through four major shapes
during a cycle that repeats itself every 29.5
days. The phases always follow one
another in the same order:
New moon
First quarter
Third quarter
Full moon
New Moon
The lighted side of the Moon faces away from
the Earth. This means that the Sun, Earth, and
Moon are almost in a straight line, with the
Moon in between the Sun and the Earth. The
Moon that we see looks very dark
New Moon
Waxing Crescent Moon
This Moon can be seen after the New Moon, but
before the First Quarter Moon. The crescent
will grow larger and larger every day, until the
Moon looks like the First Quarter Moon.
("Waxing" means increasing, or growing larger.)
http://btc.montana.edu/ceres/html/birthdayphases.html
Waxing Crescent Moon
http://btc.montana.edu/ceres/html/birthdayphases.html
First Quarter Moon
The right half of the Moon appears lighted and
the left side of the Moon appears
dark. During the time between the New
Moon and the First Quarter Moon, the part of
the Moon that appears lighted gets larger and
larger every day, and will continue to grow
until the Full Moon.
First Quarter Moon
Waxing Gibbous Moon
This Moon can be seen after the First Quarter
Moon, but before the Full Moon. The amount
of the Moon that we can see will grow larger
and larger every day. ("Waxing" means
increasing, or growing larger.)
http://btc.montana.edu/ceres/html/birthdayphases.html
Waxing Gibbous Moon
http://btc.montana.edu/ceres/html/birthdayphases.html
Full Moon
The lighted side of the Moon faces the
Earth. This means that the Earth, Sun, and
Moon are nearly in a straight line, with the
Earth in the middle. The Moon that we see is
very bright from the sunlight reflecting off it.
Full Moon
Waning Gibbous Moon
This Moon can be seen after the Full Moon, but
before the Last Quarter Moon. The amount of
the Moon that we can see will grow smaller
and smaller every day. ("Waning" means
decreasing, or growing smaller.)
http://btc.montana.edu/ceres/html/birthdayphases.html
Waning Gibbous Moon
http://btc.montana.edu/ceres/html/birthdayphases.html
Third (Last) Quarter Moon
Sometimes called Third Quarter. The left half of
the Moon appears lighted, and the right side
of the Moon appears dark. During the time
between the Full Moon and the Last Quarter
Moon, the part of the Moon that appears
lighted gets smaller and smaller every day. It
will continue to shrink until the New Moon,
when the cycle starts all over again.
Third Quarter Moon
Waning Crescent Moon
This Moon can be seen after the Last Quarter
Moon and before the New Moon. The
crescent will grow smaller and smaller every
day, until the Moon looks like the New Moon.
("Waning" means decreasing, or growing
smaller.)
http://btc.montana.edu/ceres/html/birthdayphases.html
Waning Crescent Moon
http://btc.montana.edu/ceres/html/birthdayphases.html
http://www.opencourse.info/astronomy/introduction/04.motion_moon/moon_phases.gif
Waxing & Waning
http://www.nasm.si.edu/apollo30th/moontheater/phasepage4.html
http://www.nasm.si.edu/apollo30th/moontheater/phasepage4.html
http://www.calvin.edu/~lmolnar/moon/images/phases.gif
Eclipses of the Moon and Sun
• Penumbra: the lighter part of a shadow
“partial shadow”
• Umbra: the darkest part of a shadow
Lunar eclipse
• Occurs when the moon is in the full moon
phase
• The moon moves into earth’s shadow
• Earth’s shadow is so large it may last for an
hour or more (until the moon moves out of
Earth’s shadow)
Solar Eclipse
• Occurs when the moon is in the new moon
phase
• The moons shadow moves over Earth’s
surface
• The eclipse occurs where the point of the
shadow hits Earth’s surface
Path of Totality
Tides
• The rising and falling of the ocean surface
• Change in tide is result of the changing
positions of the moon and sun relative to
earth
• 2 high tides and 2 low tides per day
Spring Tide
• Occurs when the moon and Earth are aligned
in a straight line with sun
• Occur twice a month
• It is the highest of the high tide and lowest of
the low tide
• Greatest change from high to low tide
Neap Tide
• Occurs when the moon and Earth are at a
right angle with the sun
• Occur twice a month
• It is the lowest of the high tides and the
highest of the low tide
• Smallest change between high and low tide
Our solar system
• Terrestrial planets: rocky planets- primarily
composed of silicate rocks
– Examples: mercury, venus, earth, mars
• Jovian Planets: gas giants, very low density
-Examples: jupiter, saturn, uranus, neptune
• Size comparison video
• Asteroid belt: located between mars and
jupiter
– Is composed of thousands of asteroids
– Meteor: a streak of light in the sky that occurs
when a meteoroid enters Earth’s atmosphere
“shooting star”
• Meteorite: meteor that reaches Earth’s
surface
• Comets: a dirty ice ball that revolves around
the sun
– When close enough to the sun, exhibits a tail
How a comet really travels through
space…
Galaxy
• Galaxy: a huge system that includes billions of
stars, planets, moons and all other space
matter that is held together by gravitational
attraction
• Our galaxy: Milky Way
• Type: Spiral
The universe
• The universe: includes everything that exists
from the smallest object to the largest galaxy
• Big bang theory: about 15 billion years ago an
massive explosion took place and started the
formation of the universe
– Evidence: the universe is still expanding in every
direction.
• Radioactive aftermath of the initial explosion
(background radiation)
• Red shift galaxies
Spectral Lines
• The separation of different colors based on
wavelengths
Doppler Effect
• Red Shift: objects moving away
– Caused by the expansion of space
– The farther away an object moves the more the
wavelength is stretched out
Doppler Effect
• Blue shift: objects moving towards another
object
– The closer object moves the more the wavelength
is decreased.
• Doppler shift
A star is born
• Nebula- cloud of dust hydrogen and plasma
ProtostarMassive star (high mass)super
red giantsuper nova blackhole or neutron
star
• NebulaProtostarMain Sequence star(low
mass)  Red giantplanetary nebulawhite
dwarf
A star is born
• Star formation: stars start out in a nebula
which is a massive cloud of dust, hydrogen,
and plasma. Due to gravitational attraction
the cloud collapses and the temperature
increases significantly Nuclear fusion starts
with hydrogen becoming helium
• A protostar forms and depending on mass the
star will either become a massive star or a
main sequence star
• Star formation video
HR diagram