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Our Cosmic History
Saturday Symposia
Lecture #2:
“Our Cosmic Context - A Brief Tour of the Universe”
Dr. Todd Duncan
Center for Science Education, Portland State University
October 18, 2008, 10 a.m.
Goals of the series…
1.
Big picture view of science to give the details a meaningful
context. (In this case, the story of our own origins, relevant to
our perspective on who we are and where we are headed.)
2.
Help weaving big picture motivation provided by the series
into the details of science curricula (complement broad-brush
view with nitty-gritty details)
3.
Building a community of people curious about the universe
and our place within it (regardless of professional role:
teacher, student, researcher, or other member of the public)
After the lecture:
Roundtable discussion for teachers
11:30 am - 12:30 pm
in the entryway of Hoffman
Wiki Site for resources & continuing discussion:
http://oregonteacherscholars.pbwiki.com/Our-Cosmic-History
(or link from www.scienceintegration.org)
Upcoming…
l
Lecture #3:
“The Early Universe big bang to stars & galaxies”
Dr. Aparna Venkatesan
Dept. of Physics & Astronomy, University of San Francisco
Oct. 25, 2008
10 a.m.
Hoffman Hall, PSU
Warm-up Questions
1. The radius of Earth is about…
a. 64 km
b. 640 km
c. 6,400 km
d. 64,000 km
2. About how far away from us is the closest star
other than our Sun?
a. About the same distance as the Sun.
b. Ten times farther than the Sun.
c. One hundred times farther.
d. One thousand times farther.
e. More than a thousand times farther.
3. Which answer shows the most accurate
arrangement of the three objects in order from
closest object to Earth to farthest from Earth?
a. center of Milky Way --> Andromeda galaxy --> North Star
b. center of Milky Way --> North Star --> Andromeda galaxy
c. Andromeda galaxy --> North Star --> center of Milky Way
d. North Star --> Andromeda galaxy --> center of Milky Way
e. North Star --> center of Milky Way --> Andromeda galaxy
Today – A quick tour of the universe…
The series overall presents the history of the universe
as a framework for how that history made our existence
possible. So first we need to know something of the
structure and arrangement of this universe whose
history we want to describe.
Theme - Gaining perspective on how we connect to the
universe: we are products of the whole universe, not
just our immediate surroundings
“In human affairs an idea is a greater moving
force than any physical influence... So the shape
of our future will depend to a large extent on our
understanding of our role in the cosmic process.”
– Louise B. Young (The Unfinished Universe)
Your Self-image
within the Universe
• I am one cog in a giant machine.
• I am the “eyes of the Milky Way” – a way for the
universe to notice and appreciate itself.
• I am a cosmic artist – a contributor to a universal
creative process.
• I am a participant in a definite cosmic plan or
purpose, with some assigned role to play in carrying
out that purpose.
• I am a random speck in a vast uncaring universe.
“On the maps provided by science, we find
everything except ourselves.”
– Bryan Appleyard (Understanding the Present: Science and the Soul
of Modern Man)
“Small as we are, minute as is the point by which
the cosmos impinges upon each one of us, each
one desires to feel that his reaction at that point is
congruous with the demands of the vast whole…”
– William James (The Sentiment of Rationality)
A healthy consciousness is like a spider’s web, and you are the
spider in the centre. The centre of the web is the present moment.
But the meaning of your life depends on those fine threads which
stretch away to other times, other places, and the vibrations that
come to you along the web…Normally, your consciousness is like a
very small spider’s web; its threads don’t stretch very far. Other
times, other places, are not very real to you…And our lives are
turbulent, like living in a strong wind, so the web gets broken pretty
frequently. But sometimes the wind drops, and you manage to create
an enormous web. And suddenly, distant times and distant places
become realities, as real as the present moment, sending their
vibrations down into your mind.
— Colin Wilson (The Philosopher’s Stone)
Cassini-Saturn-Earth
Sun From Earth
About 109 Earths fit across
the face of the Sun
Distance from Earth to Sun (1 Astronomical Unit)
is about 150 million km
Astronomical Distances
•
To make the numbers somewhat manageable, take the fastest thing we
know of (light: 300,000 km/s), and express distances in terms of how
far light would get in a certain amount of time.
1 light year = the distance light travels in 1 year
= about 10 trillion km (1013 km)
To convince yourself that this really is a distance, think of looking at a
car speedometer. If you ride in a car at 50 miles/hour, for 1 hour, you
will go 50 miles. If you travel at that speed for 2 hours, you go 100
miles. Most people would just call that 100 miles, but you could also
call it “2 car hours.” A light year is the same sort of unit.
Solar system scale
40 AU (about 5 light hours) to Pluto
How far away are the stars?
The closest star, Proxima Centauri, is 4.2 light
years away
That’s almost 7,000 times the Sun – Pluto distance!!
We reside in a galaxy of ~ 300 billion stars. On this
image of our Milky Way Galaxy, diameter of green circle
is 1000 times bigger than the distance from our solar
system to Proxima Centauri !!!
Red dot is still 100 times too big!
Andromeda Galaxy (M31)
Whirlpool Galaxy (M51)
Image Credit: S. Beckwith (STScI), Hubble Heritage Team
http://astro.uchicago.edu/cosmus/projects/sloangalaxies/animations.html
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Summary of Distance Scale
• Portland to Eugene -------------- about 150 km
• Earth (circumference) ------------ ~40,000 km
• Distance to Moon ----------- ~384,000 km (~ 1 light second)
• Distance to Sun --------------------- ~ 8 light-minutes
• Distance to nearest star (beyond sun) --- ~ 4 light years
• Milky Way Galaxy (diameter) ---- ~ 100,000 light years
• Distance to nearby galaxy ------ ~ 2 million light years
• Most distant visible galaxies ----- ~ billions of light years
Cassini-Saturn-Earth
“Precisely when we grasp the vastness of the universe we
also grasp an equally vast interior, the enormous
geography of the soul, so to speak. Words may fail
afterward, forcing us to rely on hackneyed descriptions that
emphasize our insignificance, but what we actually sense,
if only for an instant, is largeness of spirit.”
– Edwin Dobb (Harpers, Feb. 1995, p.40)
“The most beautiful experience we can have is a sense of the
mysterious.…A knowledge of the existence of something we
cannot penetrate…I am satisfied with the mystery of life's eternity
and with a knowledge, a sense, of the marvelous structure of
existence – as well as the humble attempt to understand even a
tiny portion of the Reason that manifests itself in nature.”
– Albert Einstein
“What is demanded…is not…to endure the meaninglessness, of
life, but rather to bear [our] incapacity to grasp its…meangfulness.”
– Viktor Frankl
Composition of the Universe
• The stuff we’re made of (baryonic matter, e.g.
protons and neutrons) only comprises ~ 4% of
the energy content of the universe
• ~4% of energy is baryonic matter, ~23% exotic
dark matter, and ~73% dark energy
Bullet Cluster
Dark Matter Survey
Large Hadron Collider
• Search for dark matter “WIMP” particles
• LHC rap -
http://www.youtube.com/watch?v=j50ZssEojtM
Sun From Earth
“The Sun, with all the planets
revolving around it, and depending on
it, can still ripen a bunch of grapes as
though it had nothing else in the
Universe to do.” –Galileo Galilei
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
“There are more things in heaven and Earth…than are
dreamt of in your philosophy.” –Shakespeare (Hamlet)
Seal
Cosmic History in a Nutshell
Adapted from Girl Meets Boy: A Comedy about the
Universe, by Melinda Lopez
(http://cfa-www.harvard.edu/seuforum/exhibit/resources/GMB_CUESCRIPT.pdf)
Thanks to…
• Oregon Dept. of Education Math/Science Partners Grant
(primary funding for this lecture series)
• Portland State University Center for Science Education
• Beaverton and Hillsboro School Districts
• Pacific University
• Science Integration Institute
References
• Duncan & Tyler, Your Cosmic Context: An Introduction to
Modern Cosmology (Addison-Wesley, 2009)
• Poitier, The Measure of a Man: A spiritual autobiography
(HarperCollins, 2000)
• Cosmus education web site (tour of the universe, etc.):
http://astro.uchicago.edu/cosmus/
• Sloan Digital Sky Survey: http://www.sdss.org/
• Science Integration Institute
http://www.scienceintegration.org