Astronomy

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Transcript Astronomy

Observations:
Sun rises & sets every day
 Sun rises in East & sets in West
 Sun’s path in the sky is an arc
 Sun is at different angular
altitudes in the sky at different
times.
 The sun is never directly above
(at zenith) in NY.
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Astronomy
The Geocentric theory explains all of
these phenomena. Since movement of the
Earth cannot be felt early scientists
thought that the Earth was stationary and
everything else moved around us.
 The geocentric theory says that
the Earth is at the center of the
solar system/ universe.
 Lets draw a little...
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The Geocentric Theory does
not explain this:
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Foucault Pendulum: The first good evidence
of the Earth's rotation was provided by a
swinging pendulum. The pendulum would
continue to swing in the same direction while the Earth
rotated beneath it. A more recent source of evidence of
rotation is the swirling pattern of weather systems seen
by satellites.
The Coriolis Effect makes the Foucault
Pendulum work. The rotation of the Earth puts a
"spin" on the air movement which causes a curve in the
travel direction. In the Northern Hemisphere the turn is
towards the objects right.
Galileo disproved the geocentric theory.
He was the first to turn the telescope to
the sky (he did not invent the telescope)
for the purposes of Scientific observations.
 The moons of Jupiter orbit an
object other than Earth. Galileo
noticed that the four visible moons of
Jupiter appeared to orbit around Jupiter
and therefore did not revolve around the
Earth.
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Jupiter’s Moons
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Galileo also observed the "phases
of Venus" which demonstrated
that Venus orbited around the
sun.
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Let’s draw some more.
The Heliocentric Theory explains
all observations made from
Earth.
 “Heliocentric” makes the sun the center of
attention rather than the earth.
 And more drawing.
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Here's an article written by Benjamin
Franklin about how much sense the
Heliocentric Theory makes:
The Whimsical Cook
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The Columbia
The value of the space program
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Personal Computers
Colorization of black and white movies
Solar powered calculators
Aluminized bags for snack food
Weather satellites
Halogen lights for cars
Sports domes
Microwave Ovens
Pocket calculators
Phone calls by satellite
Laser guided missiles
"Mylar" balloons
"Blue Blocker" sunglasses
Digital watches and thermometers
"DirecTV", "Dish Network", etc
"Kevlar" for bullet proof vests
"Mini Mag" flashlights
Fishing line
Fiber optics for phone calls
"Vortec" engines in GM cars
"Ovation" guitars and helicopter blades
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Medical scanners
Electronic ignition in automobiles
Laser scanners in stores
"Bulb Miser" devices for long life light bulbs
Weather Maps on television
Juice boxes for "Hawaiian Punch", etc
"The Patch" medical device
Breathing systems for Mt. Everest climbers, Scuba
divers and firefighters
“Flexon" eyeglasses and dental braces
Cellular phones and beepers
Cable Television, H B O, Showtime, etc
Pens that write upside down and under water
Anti corrosive paint for bridges, boats & Statue of
Liberty
Scratch resistant coatings on sunglasses
Football helmets for the NFL
Pacemaker batteries that last 20 years and can be
recharged through the skin.
Compact Disks
GPS Navigation Systems
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Rotation - to spin around an axis.
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How long does it take the Earth to spin once?
How many degrees is a full spin?
360°÷24hours= 15°/hr
Earth spins at 15 degrees per hr
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Time zones
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How to figure out what the time difference
is and are you E or W.
The Earth’s Rotation does not have
the same speed all over
At the equator, rotation is
40,074 km/day or 1670 km/hr
At NY
31,200 km/day or 1300 km/hr
At the poles
0 km/day or 0 km/hr
Revolution- to orbit around an
object
 The Earth revolves around the
sun in 365 ¼ days.
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Sidereal Day vs solar day
As the Earth revolves around the sun, different
constellations are visible in the night sky.
As viewed from Earth, the sun is passing through Leo
(even though you can’t see the stars during the day.
The Axis of Rotation is the imaginary line
that the Earth turns about.
 The axis always points to the
North Star. This is called
Parallelism of the Earth's axis.
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The imaginary surface of the Earth's yearly
trip around the sun is the Plane of Earth's
Orbit.
Warning!
The following statement sounds crazy but
you'll understand it if you read it slowly!
"The axis is tilted by 23.5° from
the perpendicular to the plane
of its orbit."
Demonstration
Seasons
Not drawn to scale.
The orbit is not
shaped like this.
Let’s make a chart of the 4 key
dates and what they each mean.
Date
Name
Key points
Summer Solstice
June 21
 N. Pole is tilted towards the sun
 Sun is highest in the sky in NY
 Longest day, shortest night
 Sun is directly over the Tropic of
Cancer.
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Fall (autumnal) Equinox
September 23
 Equal day and night
 Sun is directly over the equator
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Winter Solstice
December 21
 N. Pole is tilted away from the
sun
 Shortest day, longest night
 Sun is directly over the Tropic of
Capricorn
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Spring (vernal) Equinox
March 21
 Sun is directly over the Equator
 Equal day and night
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Zenith
Summer Solstice
June 21
Equinoxen
March 21/Sept 23
Winter Solstice
Dec 21
HW on Seasons
&
Day/Night
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Discussion of a more or less tilted world
An Encarta Animation
OK, Girls & Boys, time for an
activity on seasons and the tilt of
the Earth!
Note:
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The seasons are NOT caused by
the distance from the sun.
See what the Earth
looks like RIGHT NOW
Let’s see how the sun’s
position changes
throughout the year
Time for a lab
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Take out lab 8-3: Ellipses
Lets see some ellipses
Perihelion Jan 3
93,000,000 miles
Aphelion July 4
95,000,000 miles
Not drawn to scale! The
shape is more like a circle
Kepler’s Laws
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1) All planets travel in elliptical
orbits with the sun at one focus.
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Note: The Earth's orbit is so close to a
perfect circle that it can't be
distinguished with the human eye.
See for yourself
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2) Each planet travels in such a
way that a line joining the
planet and the sun sweeps equal
areas in equal times.
Keppler’s Second Law
April
March
February
May
June
January
July
August
September
December
October
November
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3) Relationship between distance
and period:
P2 = D3
Where P is the Period in Earth Years
And D is the distance in “AU’s”
An “AU” is an astronomical unit, which
is the average distance from the sun
to the Earth.
Two videos
The Powers of Ten
 Bill Nye: The Moon
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The Moon
The moon revolves around the
Earth once a month (moonth).
 Moon rises 50 minutes later every
day.
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It can be seen during the day just about as
much as the night.
Phases of the moon handout
Sun: way
the heck to
the left
L
R
Full
L
New
Waning
Gibbous
R
Waning
Crescent
Last Half/
Last Quarter
Waxing
Crescent
Waxing
Gibbous
First Half/
First Quarter
Notice the changing diameter of
the Moon during the 'moonth'. As
the Moon's orbit brings it closer to
earth (perigee) at the New Moon,
it appears larger to us. Also notice
how the Moon 'rocks' up and
down and back and forth. That
happens because the Moon's
orbit takes it above the Earth's
equator (allowing us to see more
of the south polar region) and
below the equator revealing more
of the north polar region of the
Moon. The back and forth (eastwest) rocking is due to the
changing orbital velocity of the
moon.
The Names of the Full Moons
Here are the traditional names given to each month's full moon from the "Old
Farmer's Almanac":
January
February
March
April
May
June
Wolf Moon
Snow Moon
Worm Moon
Pink Moon
Flower Moon
Strawberry Moon
July
August
September
October
November
December
Buck Moon
Sturgeon Moon
Harvest Moon
Hunter's Moon
Beaver Moon
Cold Moon
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A lunar eclipse
occurs when the
Earth blocks out
the Moon's
sunlight. The
moon goes into
the Earth's
shadow.
Lunar eclipses
happen during a
Full Moon.
Earth
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penumbra
umbra
moon
Eclipses
sun
Earth
sun
umbra
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penumbra
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A solar eclipse is when the moon blocks
sunlight from reaching the Earth.
Solar Eclipses happen during a New Moon.
Eclipses do not occur every time there is a full or new
moon because the moon's orbit around the Earth is
inclined.
moon
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A view of a Solar Eclipse as Seen
from Space
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http://www.stormcenter.com/media/06033
1/
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Angular size of the moon activity
Tides
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The strength of gravity depends on
how close two objects are and their
masses.
m1m2
F 2
d
m1 and m2 are
masses of the
objects
d is the distance
Let’s draw a diagram of how the moon
causes tides!
Lets draw a diagram of what the tides look
like.
A Spring Tide is caused by a full
moon and a new moon. The
water “springs” from its highest
level to its lowest for the month.
 A Neap Tide is caused by the half
moon phases. The high tide is
not so high and the low is not so
low.
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The Planets
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Take out Lab 8-5: The Planets
The Solar System
Time for a sing-a-long
Comets
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Chunk of ice and dirt following an
elongated elliptical orbit.
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DVD Weather- Wind Chp 9 (Solar Wind)
Has a tail only when it comes close to the sun.
The heat melts it and the solar wind sweeps the
tail away.
The tail always points away from the
sun.
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Encarta Solar System:
Great Comets!
Meteors
Meteor Showers result mainly from debris
from the orbit of the comet.
 If the Earth crosses the path, the debris
will fall to Earth as a visible meteor or
“shooting star.”
 If the rock is big enough it will survive the
fiery entry into the atmosphere and hit the
surface as a meteorite.
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Video on what
causes a meteor
shower
Stars
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Circumpolar and star trails
Circumpolar
Constallations
Stellar Fusion
Hydrogen nucleus
(Proton)
Helium
2.016
Mass=1.008
Mass=4.0026
Mass=1.008
1.008 x 4 = 4.032
4.032 – 4.0026 = .0294
E=mc2
E = energy
m = mass
c2 = speed of light squared
.0294 x 186,000 x 186,000 = a lot from a little
Lab: Stellar Classification
Short video on the formation of the Earth
The Life of a Star
Cloud of gas
Contracts
Heats up
Fusion
If the star is 7x the
sun or smaller:
Swell up to a red
giant
Shrink to a white
dwarf
Slowly cool and die
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
If the star is 7x the
sun or larger:
Swell up to a red
giant
Shrink collapse and
explode as a
supernova
Dies as a rapidly
spinning core…
Or better yet!
A black hole!
Time for a sing-a-long
DVD:
The Right Stuff
The Doppler Shift
Lab: Spectral Analysis
Deep Space
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If asked- Travel @ speed of light: Encarta
animation (mind warping!)
Spring
March 21
Summer
June 21
Winter
Dec 21
Fall
Sept. 23
North Pole
NP 24hr
LI 16hr
Summer June 21
Eq 12hr
SP 0hr
South Pole
North Pole
NP 12hr
LI 12hr
Equinoxes
Eq 12hr
March 21/
SP 12hr
Sept23
South Pole
North Pole
NP 0hr
LI 8hr
Winter Solstice
Eq 12hr
Dec 21
SP 24hr
South Pole