Lecture 1 -- Planetary Science
Monday June 3
What we will study:
What the solar system is: A collection of rock and ice around a star
How it's put together
What universal laws make it behave the way it does?
How it formed from the gas and dust of the Universe
Especially: Why it is important for us to understand the planetary perspective
Readings every day
Two homework sets a week, in and out times (40%)
3 exams (15%, 15%, 20%)
Office hours Monday and Thursday 11-12
TA: Ka Chun Yu Office hours Monday 1-2 and Tuesday 11-12 available anytime
Web site: http://macd28.colorado.edu/Astro/ Check out the Cool Image of the Day!
Planetarium shows June 10, June 17 and June 25
Observing sessions: maybe a HW assignment
Is science intrinsically good or bad?
Scientific knowledge has become the Gold Standard for knowledge in our society
We are genetically maladapted to our environment
Our environment is dominated by technology, and thus science
We evolved in forests and grasslands, hunting and gathering
We evolved with the skies overhead to tell time and entertain us
Most of our modern existence involves using technology and science every day that we don't fully understand. For example, the incredibly complex chain of events that result from starting and running our car.
We often decry technology, are afraid in some vague way. For example, we protest the actions of high-tech companies, but are paradoxically utterly dependent upon them
We don't know how to begin to understand our world -- root cause
Let's try to understand HOW science and technology relate to who we are
Study of science is bankrupt if we don't understand what science
means to us as people
To consider carefully the meaning and effects that science has on us
leading up to homo economicus
Greeks invented methodology for truth seeking. Plato 400 BC Timaeus
Had we never seen the stars, the sun, and the heavens, none of the words we have spoken about the universe would have been uttered. But now the sight of day and night, and the revolutions of the years, have created number and given us a concept of time as well as the power of enquiring about the nature of the universe: and from this source we have derived philosophy. No greater good ever was or will be given by the gods to mortal man.
Descartes by 1650 refined and honed science to a sharp edge
Create a model, and a hypothesis observe or test, refine model
By 1800, technology began to radically alter our society
Continued on with an accelerated pace until WWII
WWII Technology triumphs, economic machine grinds into motion
Vannever Bush, The Endless Frontier late 1940s
By the 60's, the dominant image was that science could provide a utopian paradise
Our immersion today--consumer electronics and mutli-media
Homo Economicus in the body of Homo Sapiens
Our innate sense of time
The sky provides a 'perfection' and contains knowledge (planting, etc.)
Time from the sky was the first abstraction -- motion of the stars and planets
Time from the sky was one of the first things we became aware of in our emerging consiousness
Mayans -- heliacal rising of Sirius means plant crops
Polynesians -- used the stars to navigate between Pacific islands
Aristarchus 300 BC: measurement of the distance to the sun (board)
Drew a diagram of a lunar eclipse.
He knew how big the sun was in the sky -- shadow size
He knew how big the moon was -- 3/8 size of Earth's shadow
From this, he could calculate using trigonometry -- 1/3 size of Earth
Sun is 7 times as big, 20 times further than moon
Really 100 times as big and 375 times further away
Eratosthenes: 200 BC measurement of the size of the Earth (board)
Sun shone directly down a well in Aswan
Off 1/50 th of a circle in Alexandria
circumference of the Earth 50 times bigger
What are we to do with this perspective?
Does it have any analog with the sky as it has been bred into us?
How can our technology give us a sense of perspective that we've lost as
Homo Economicus ?
Science and technology are neither good nor evil, but we must pay attention to how they affect our lives.
Planetarium shows (simulate any place on Earth, any date since humans)
Observatory -- We will look at the moon, Jupiter, galaxies, clusters, sun
1:1010 Earth-Moon distance 4 cm
Sizes of planets are also scaled
Pluto: 2,300 km Slightly smaller than moon 40 AU 5 hrs 20 min
Neptune: 50,000 km 4 x larger than Earth 30 AU 4 hrs
Uranus: 50,000 km 4 x larger than Earth 20 AU 2 hrs
Saturn: 120,500 km 9 x larger than Earth 10 AU just over 1 hr
Jupiter: 143,000 km 11 x larger than Earth 5 AU just over half hour
Mars: 6,800 km Just over half as big as Earth 1.5 AU 4 minutes
Earth: 12,756 km 1 AU
Moon: 3,500 km Just over 1/4 size of Earth 400,000 km 1.5 sec
Venus: 12,100 km Just under Earth 0.7 AU 2.5 minutes
Mercury: 5000 km Twice the size of Pluto 0.4 AU 3 minutes
Sun: 1.4 million km 100 times the Earth 8 minutes to Earth
Moon-Earth distance 4 cm. Nearest star 1000 km Santa Fe
We walked at 25 times the speed of light