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POPS Earth Science Unit 1: Astronomy – Teacher Notes

Cosmic Survey: Our Universe and Solar System
o How Big?
 See table
o How Far?
 See table
o How Old?
 See table
o Test Your Knowledge
 What planet has the shortest orbit?
 Earth
 Mercury
 Venus
 Neptune
 What was the first living creature to orbit the Earth?
 Laika (a dog)
 Albert (a rhesus monkey)
 Ham (a chimpanzee)
 Felix (a cat)
 Which planet in the solar system has rings?
 Saturn
 Uranus
 Neptune
 All of the above
 What is a shooting star?
 Comet
 Dying Star
 Meteor
 Space Junk
 What is the largest moon in our solar system?
 Ganymede (Jupiter)
 Moon (Earth)
 Titan (Saturn)
 Phobos (Mars)
 What is a Light Year?
 The time it takes for light become stable.
 The distance between photons in a light molecule.
 A year in which the mass of anti-matter is temporarily greater than matter.
 The distance light travels in a year.
 Which is the best explanation for the movements of planets and stars?
 The earth is the center of the solar system. The sun and other planets revolve around the
earth.
 The sun and the moon orbit Earth. All other planets orbit the sun.

The Sun is the center of the solar system. The earth and planets revolve around the sun.
How do we Quantify the Size and Scale of Our Universe and Solar System?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our universe and solar system?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
Objects in the world we live in range in size from the unimaginably large…
galaxy
1019 km in diameter
…to the incredibly small
nickel atoms
50 million would stretch across width of little finger.
Which Is Greater?
The Number Of Sand Grains On Earth…
…or Stars In The Sky?
Sand or Stars?
Sand
Calculate grains in a teaspoon
Multiply by all the beaches and deserts in the world
Earth has roughly 7.5 x 1018 grains of sand
or seven quintillion, five hundred quadrillion grains
Stars
Even on clear and starry night, you won't see very many stars.
The number is a low, low "several thousand"
Victory for Sand!
But…
With a Hubble telescope, count:
distant galaxies
faint stars
red dwarfs
everything we've ever recorded in the sky.
722 (70 sextillion) stars in the observable universe
(a 2003 estimate)
Multiple stars for every grain of sand.
Stars win.
And yet…
…you will find the same number of molecules in just ten drops of water.
Managing Numbers
metric prefixes
ratios
Metric Prefixes
Kilo = 1,000 = 10 x 10 x 10 = 103
1
1
Centi = 100 = 10 𝑥 10 = 10-2
Other Metric Prefixes
Nano = one billionth = 10-9
Micro = one millionth = 10-6
Milli = one thousandth = 10-3
Centi = one hundredth = 10-2
Kilo = one thousand = 103
Mega = one million = 106
Giga = one billion = 109
Ratios
A comparison which describes the relationship between numbers.
The ratio of the length of the larger fish to the smaller fish is 2:1
Ratios
The diameter of an apple compared to the diameter of the earth
Check Your Understanding
A pancake recipe feeds 9 people and calls for 600 milliliters of water.
How many mL of water would you use if you wanted to feed 14 people?
Check Your Understanding - Solution
Set it up as a proportion
A proportion is two ratios set equal to each other
600 𝑚𝐿
9 𝑝𝑒𝑜𝑝𝑙𝑒
=
𝑥 𝑚𝐿
14 𝑝𝑒𝑜𝑝𝑙𝑒
X = 933.33 mL
Check Your Understanding
Takes 25 minutes to read 14 pages of a book.
How long will it take to read 61 pages?
Tying it all together
Tying it all together
Tying it all together
Tying it all together
Tying it all together
Tying it all together
What matter is contained in our universe and solar system?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our universe and solar system?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
Star
A large, glowing ball of gas that generates heat and light through nuclear fusion
Planet
A moderately large object which orbits a star; it shines by reflected light. Planets may be rocky, icy, or gaseous in
composition.
Moon
An object which orbits a planet.
Asteroid
A relatively small and rocky object which orbits a star.
Comet
A relatively small and icy object which orbits a star.
Solar (Star) System
A star and all the material which orbits it, including its planets and their moons
Nebula
An interstellar cloud
of gas and/or dust
Galaxy
A great island of stars in space, all held together by gravity and orbiting a common center
Universe
The sum total of all matter and energy; that is, everything within and between all galaxies
What matter is contained in our universe and solar system?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our solar system and universe?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
Inner and Outer Planets
Eight planets of Solar System divided into two groups.
Inner planets
Outer planets
Separated by asteroid belt.
A region of space containing many asteroids
About half the mass of belt is contained in four largest asteroids.
Ceres, Vesta, Pallas, and Hygiea
Inner Planets
The first four planets closest to the Sun:
Mercury
Venus
Earth
Mars
Inner Planets
“Terrestrial Planets”
solid surface and are similar to Earth
composed of heavy metal, such as iron and nickel
few or no moons
Mercury – no moons
Venus – no moons
Earth – 1 moon
Mars – 2 moons
Outer Planets
The last four planets, not including dwarf planets
Jupiter
Saturn
Uranus
Neptune
Outer Planets
“Jovian planets” or “gas giants”
Gaseous/no solid surfaces
Composed mostly of hydrogen and helium
All have rings
Larger than inner planets
comprise 99% of the mass of the celestial objects orbiting our Sun
Many moons
Jupiter – 50 moons
Saturn – 53 moons
Uranus – 27 moons
Neptune – 13 moons
International Space Station
Departing Space Station Commander Provides Tour of Orbital Laboratory (25:05)
How Do Celestial Bodies Move? What causes them to Move That Way?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our solar system and universe?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
An Important Distinction…
Revolve
To orbit around another object.
One time around the other object is one revolution.
Rotate
To spin around an axis that runs through the object.
One spin is one rotation.
So, which way does the world rotate?
Hold right fist with thumb extended and pointing straight up
Thumb points north
Fingers curl in direction of Earth's rotation
Earth rotates in right-handed manner
Your right hand as a model
Counter clockwise
Kepler’s Laws of Planetary Motion
Kepler’s 1st Law
All planets move in elliptical orbits
sun at one focus
Kepler’s 2nd Law
A line that connects a planet to the sun, sweeps out equal areas in equal times.
(Planets move faster when they’re close to the sun.)
Kepler’s 3rd Law
The square of the period of any planet is equal to the cube of its average distance from the sun.
If you know an object’s average distance from the sun, you can calculate how long it takes to orbit the sun.
A helpful video (6:54)
How Do Celestial Bodies Move? What causes them to Move That Way?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our solar system and universe?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
What forces affect our planets?
Due to the size and scale of space, gravity is the most influential of the four fundamental forces on our planets.
Any two objects exert an attractive force on each other
The Law of Gravitation
So, what affects the gravity between objects?
Mass
The attractive force of gravity increases if the mass of the objects increases.
Distance
The attractive force of gravity increases if the distance between the objects decreases.
Newton’s Law of Universal Gravitation
Mass Versus Weight
Mass
The amount of matter in an object
Does not change due to location and/or gravity
May change if something is taken away or added to it.
Weight
Gravitational force exerted on matter
Changes depend on location and/or gravity
The farther out from earth, the less you weigh.
Mass Versus Weight
Your weight would be 0.2% less on the top of Mt. Everest.
Why do you weigh less?
Predict what happens to your mass.
Predict Your weight on Different Planets of Or Solar System.
What does this weight change depend upon?
Calculate your Weight on Other Planets
Weight =
(mass)(gravity factor)
1 kg = 2.2 lbs
Analyze your data
Where do you weigh the most?
I weigh the most on _______ with a weight of __________kilograms.
Where do you weigh the least?
I weigh the least on _______with a weight of _________ kilograms.
Use what you have learned
Predict how much would you weigh on some far away stars
Andromeda
gravity factor of 1.725
Ursa Major
gravity factor of 6.063
What does this tell you about the force of gravity on these stars (compared to Earth)?
What does it tell you about their size?
How Do We Know About Other Stars and Planets? What Does That Information Tell Us about the Origins of the
Universe?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our solar system and universe?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
Electromagnetic Spectrum
First, a review of the electromagnetic spectrum. (5:03)
White light is all the wavelengths of visible light shown at the same time.
Photon Model of Light
“Wave/Particle Duality”
Light is both a particle and a wave.
Photon
A particle of light
The relationship between energy and wavelength is inverse
Photon Model of Light – part 2
Photon strikes electron in atom
electron (e-) absorbs energy.
e- changes location to higher energy level.
Photon Model of Light
e- at higher energy level is unstable
energy emitted as photon of same energy.
e- returns to “ground state.”
We see light at wavelength corresponding to photon’s energy!
Can we use this?
Spectroscopy
Using prisms or diffraction gratings to separate light into individual wavelengths.
From the word "spectrum," with the suffix “-scopy” meaning, “to see.”
Diffraction gratings separate wavelengths of light into much finer detail than prisms.
How we use the spectrum to get information about distant objects? (5:56)
White light Through a Diffraction Grating
Different Elements Through a Diffraction Grating
The spectra of:
Argon
Helium
Hydrogen
Mercury
Spectrum plural is spectra
Sunlight Through a Diffraction Grating
The spectrum of sunlight, as viewed from space
view is clear
Image wrapped (like text on a page) to save room.
Gaps in spectrum tell what gases are present in outer layers of the sun.
The Hubble Telescope
One of NASA's most successful and long-lasting science missions.
The Hubble Telescope
Orbits Earth above atmosphere
less distortion
Helped determine the age of universe, identity of quasars, and existence of dark energy.
Want more?
Go to http://hubblesite.org/gallery/
How Do We Know About Other Stars and Planets? What Does That Information Tell Us about the Origins of the
Universe?
Cosmic Survey : Our Universe and Solar System
How do we quantify the size and scale of our universe and solar system?
What matter is contained in our solar system and universe?
How do celestial bodies move?
What causes them to move that way?
How do we know about other stars and planets?
What does that information tell us about the origins of the universe?
The Doppler Effect
The Big Bang
Edwin Hubble - 1929
Universe is expanding.
Distance between galaxies and speed at which they move apart is a direct relationship.
2 galaxies in visible universe may be far enough apart that they are expanding faster than speed of light!
Entire Universe was contained in a single point in space.
about 14 billion years ago
Single violent explosion came to be known as the "Big Bang."
Stephen Hawking Explains the Big Bang (5:40)
If time,
http://www.youtube.com/watch?v=MCPBbjea1-g (12:03)
http://www.youtube.com/watch?v=xkfyoF6Gbj0 (11:57)
http://www.youtube.com/watch?v=H_CZCmJ2om0 (3:13)
Corresponds to abd article and questions