Download Review Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015

Review
Astronomy 1 — Elementary Astronomy
LA Mission College
Spring F2015
Quotes & Cartoon of the Day
“One may wonder, What came before? If
space-time did not exist then, how could
everything appear from nothing? . . .
Explaining this initial singularity—where
and when it all began—still remains the
most intractable problem of modern
cosmology.
— Andrei Linde
“But who shall dwell in these worlds if they
be inhabited? ... Are we or they Lords of
the World? ... And how are all things made
for man?”
— Johannes Kepler
“Our sun is one of 100 billion stars in our
galaxy. Our galaxy is one of billions of
galaxies populating the universe. It would
be the height of presumption to think that
we are the only living things in that
enormous immensity.”
— Wernher von Braun
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Announcements
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Observing Project &
Extra Credit Due
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Midterm graded &
gradebook updated to
drop lowest
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remainder of grading
(hopefully) updated this
weekend
Final 12/15 at 10-12
AM!
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Last Class
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Debrief Midterm
Debrief LT
Cosmology & Fate of the Universe
Exoplanets (time permitting)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
This Class
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Review/Debrief Midterm
Exoplanets (time permitting)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
About the Final
Astronomy 1 — Elementary Astronomy
LA Mission College
Spring F2015
About the Final
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Similar format to Midterms
Similar length
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Little new material, mostly cumulative
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a little longer, some choice of questions
Study the stuff on the midterms!
But don’t memorize the questions themselves, you probably
won’t see many that are identical
You may bring a full sheet of notes
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both sides
handwritten
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
About the Final
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Don’t leave stuff blank!
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Can you remember ANYTHING about the topic?
Apply logic!
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Comprehension before Computation -- Big Picture
before Details
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State units with numbers (except magnitude)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Topics
Astronomy 1 — Elementary Astronomy
LA Mission College
Spring F2015
TOUR OF UNIVERSE
Our “Cosmic Address”
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LAMC
Sylmar
Los Angeles County
CA
US
Earth
Solar System
Milky Way Galaxy
Local Group
Virgo Supercluster
The Universe
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
SCIENCE
Science
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Definition
Method
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KEY: Hypothesis, Test, Revision
Nomenclature -- Hypothesis, Theory
Characteristics of Science & Belief System
Be able to recognize science and not-science
Be able to recognize a scientific hypothesis
Be able to describe the scientific method
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
THE NIGHT SKY
Diurnal Motion
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Daily
Everything Rises in East, sets in West
Moves in circles around the NCP (and SCP)
Earth is rotating
Be able to answer questions using diagrams from the
Position LT
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Lunar Phases
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Cause of phases
ID of phases
Timing of rise/set/transit
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Eclipses
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Solar and Lunar
Cause
Geometry
Timing
Why not every full/new
moon
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Zodiac & Apparent Solar Motion
Name:____________________!
ICE 2!
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Ecliptic
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Takes a year to cycle
through
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ASTRO 110/120!
Date:__________
Levine Spring 2013
Zodiac
Meaning of “The Sun is
in Taurus etc.”
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Seasons
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It’s the axial tilt
It’s about energy transfer
Be able to discuss observable consequences
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when is the Sun high in the sky, day length etc.
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
OLD DEAD GUYS
Greeks to Kepler
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Greek ideas
Copernican Revolution
Tycho Brahe
Kepler the dude
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Kepler’s 3 laws of Planetary Motion
1. The orbits of the planets are ellipses, with the Sun at one focus.
2. A line from a planet to the Sun sweeps out equal areas in
equal periods of time
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Planets move fastest when physically closest to the Sun, and slowest
when farthest.
3. A planet’s orbital period squared, is proportional to it’s farthest
distance from the Sun cubed:
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P2 = a3
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Be able to recognize these
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Possible calculation with 3rd law
Work with ellipses and eccentricity
Recognize examples of 2nd and 3rd law (faster/slower longer period/
shorter period)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Kepler to Sir Issac
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Galileo
Sir Issac
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Contributions and fields of study
Law of Universal Gravity
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Law of Universal Gravity
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Be able to explain how the force varies (larger or
smaller) with mass of either object, both objects and
distance
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Be able to work the inverse square relationship -- how
does force change if distance doubles....
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
LIGHT, OPTICS, TELESCOPES
Nature of Light
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Why this is important for Astronomy
electromagnetic radiation
waves, particles, duality
all light, from radio to gamma ray is same thing
all light travels at the same speed in vacuum
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c=3x108 m/s
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Properties of Light
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Waves
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λ = c/f
Interference
Particles
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Relationship of wavelength and frequency
Photoelectric effect
E = h f = hc/λ
h = 6.6 x 10-34 Js = 6.6 x 10-34 J/Hz
Know what these relationships mean
Know how the ranking task worked
Possibility of seeing a a simple calculation
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Electromagnetic Spectrum
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difference between red and blue light
Basic bands of EMR (e.g. radio, visible, IR etc.)
Relationship between band, wavelength & Energy
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Telescopes and Observatories
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Refractors and Reflectors
Size (of primary) matters
Atmospheric Transmission & Seeing
Multiwavelength Astronomy
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What are IR and Radio good for?
Cameras & Spectroscopes
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
SOLAR SYSTEM
Solar System Properties
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Overall “bulk” properties
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Disk shape
two types of planets
Space “debris”
common age
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Solar System Properties
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“Anatomy” What and Where
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Sun
Inner SS & terrestrial planets
Asteroid Belt
Outer SS & Jovian planets
Kuiper Belt
Heliopause
Oort cloud
Size/Distance Scales
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Solar System Formation
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Raw materials -- big bang, role of supernovae
Theories of Formation
Solar Nebula Theory
Differentiation
Frost line
Planet formation -- both types
Disk clearing
Cratering & Craters
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Solar System Bodies
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Terrestrial Planets
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dynamo effect
What went wrong for Venus and Mars
Greenhouse effect
Jovian Planets
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common properties
common properties
Why are Titan and Enceladus interesting
Why isn’t Pluto a “planet” and what it is
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
STARS & GALAXIES
Stellar Properties
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Luminosity
Magnitude system
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Apparent vs. Absolute magnitude
review the ranking tasks
Distance ladder & difficulty of distances
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Stellar parallax
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know how angle & distance relate
Standard Candle
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how does a standard candle work
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Color and Temperature & Size
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stars are (mostly)
like blackbodies
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temperature and
peak wavelength
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temperature and
size & luminosity
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Spectral Type
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Color ~ temperature ~ spectral class
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Harvard computers & Harvard classification scheme
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be able to answer questions based on the blackbody LT
OBAFGKM
Brightness and temperature and size (Giants)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
HR Diagram
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What is it?
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Main sequence
What can be plotted on
it?
Red giants
Supergiants
White Dwarfs
Evolution
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Stellar Lifecycles
© NASA
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Star formation
Main Sequence lifetime
End states and what determines them
Mass is everything!!!!!
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More mass means shorter life
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Main Sequence & Red Giant phase
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Main Sequence
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Hydrostatic Equilibrium
H to He nuclear fusion
Most of a star’s life
Sun is on MS
Red Giant
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New hydrostatic equilibrium
H to He fusion in shell
He fusion in core
1/10th the duration of MS lifetime
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Endgame Scenarios
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Giant stars
Planetary nebulae
White dwarfs
Type II supernovae
neutron stars & pulsars
black holes
type Ia supernovae
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
The Milky Way
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Barred Spiral
General structure
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disk, bulge, halo
General Content
Where are we?
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Galaxy Classification
NASA/ESA
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Characteristics of types
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Describe spirals, barred spirals, ellipticals, irregulars
Which are most common?
What are their overall properties?
Which tend to have older or younger stars
Which tend to have black holes (all)
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
COSMOLOGY
Telescopes are Time machines
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Lookback time
Concept of the Observable Universe
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Expanding Universe
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Space is expanding, not stuff
Raisin bread & balloons
Role of gravity in holding structures together
Cosmological principle
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Big Bang
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NOT an explosion
Universe was infinite immediately
How long ago was it?
The whole universe was in a hot, dense state
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energy became matter became stars and galaxies
Evidence for Big Bang
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Expansion
H,He,Li abundance in early universe
Cosmic Microwave Background
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Cosmic Microwave Background
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Penzias & Wilson
2.7 K
Very smooth but somewhat bumpy
Not the very beginning, 380,000 years after BB
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Fate of Universe
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3 fates: Open, Closed, Critical or Big Crunch, Big Chill/
Big Rip
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Dark Matter & Dark Energy
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Most of universe is dark
Dark Matter
Dark energy dominates universe
Dark energy is unknown cause of local expansion
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
EXOPLANETS
Exoplanets
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If we get to them today…
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
IN SUMMARY…
The Galaxy Song
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
So Long and Thanks for All the Fish!
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Other Worlds
Extrasolar planets and systems
Astronomy 1 — Elementary Astronomy
LA Mission College
Spring F2015
There are a lot of planets out there!
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1879-1935 extrasolar
planets around 1225
stars
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471-484 multiple planet
systems
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http://exoplanet.eu/
catalog/
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Simple flat-table list
4696 Kepler
candidates!
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
There are a lot of planets out there!
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298 are very large
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Radius larger than 6x Earth
150 are small
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Radius less than 1.25 x Earth
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
DETECTION METHODS
How do we find them?
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Direct imaging
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Radial Velocity (RV)
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Planet blocks light from parent star
Gravitational microlensing
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Planet induces doppler shift in parent star
Transit photometry
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Rare
Planet causes background object to brighten
Astrometry
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Planet causes parent star to shift position periodically
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Exoplanet Image
Beta Pictoris b (bright spot) orbiting its star (center)
Credit: Bruce Macintosh et al.
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Beta Pictoris about
63.5 light years from
Earth
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Beta Pic b (planet)
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dist from Beta Pic about
9x dist Earth from Sun
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VERY large, ~ 1.6x
radius of Jupiter
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
RV Animation
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Transit Method Animation
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
KEPLER
Kepler
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Capable of finding
earth-sized planets in
the habitable zone of
nearby stars
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Transit method
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Now in modified
extended mission K2
(has lost 2 reaction
wheels)
962 confirmed planets
to date
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Kepler Overview
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
MOST EARTHLIKE PLANET “EARTH 2.0”
KEPLER 452B
Transit Graph
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Artist’s Concept
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Kepler 452b
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Kepler 186-f came first
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Kepler 186f discovered April 2014 was first Earth-size
planet in Habitable zone.
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Composition not as clearly confirmed as rocky
Orbits very close to a dim M-type Star
about 500 ly distant
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015
“Earth 2.0” Kepler 452b
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Discovered July 2015 (press con 7/23)
Orbits G-type Star
about 1400 ly distant
Astronomy 1 - Elementary Astronomy
LA Mission College
Levine F2015