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Astronomy 102/104: Our Solar SystemProf. Jean-Luc Margot & Prof. Steve Squyres

Lecture #1: Introduction & Outline• Course Goals--why take Astro 102/104?• Our philosophy, and a promise.• Rules of the Road:

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– Logistics– Expectations– Responsibilities– Communication

• Detailed Syllabus.

Purpose of Astro 102/104• To learn about our origins and our connection to

the universe. To develop an appreciation for Earth as a fragile planetary body in a vast cosmos.

• To understand key principles and processes that

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• To understand key principles and processes that govern the natural world. What is the solar system like today? Why? How did it get that way?

• To become familiar with the scientific process. To acquire tools for further inquiry and learning.

Perfect timing• This is a "Golden Age" of exploration!• Spacecraft are exploring the planets now!

– MESSENGER (’04-now): Mercury.– Magellan (’90-’94): Venus.

Mars Pathfinder (’97) MGS (’97 ’06) Mars Odyssey

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– Mars Pathfinder ( 97), MGS ( 97- 06), Mars Odyssey (’02-now), MER (’04-now), MRO (’06-now): Mars.

– NEAR (’97-’01), Hayabusa (‘05): asteroids.– Deep Impact (’05), Stardust (’04-’06): comets.– Galileo (’95-’03): Jupiter, satellites. – Cassini/Huygens (’04-now): Saturn, satellites.– Voyager (’80s): Jupiter, Saturn, Uranus, Neptune.– AND MORE PAST, PRESENT, AND FUTURE!

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First flyby of Mercury in 30+ years reveals astonishing landforms!

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Lakes and rivers of methane on Titan!

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Astonishing worlds: Iapetus & Hyperion

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New Discoveries Being Made!• Observations of asteroids:

– Many are highly porous. WHY?– Some have satellites! HOW?

• Satellites of Jupiter and Saturn:

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p– Europa may have an ocean!– Titan has hydrocarbon rain and rivers!

• Many objects discovered beyond Neptune.– Hundreds of trans-Neptunian objects.– Pluto demoted! Can they do that?

• Many Sun-like stars have planets!

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Methods• Discover and Explain important patterns and

trends in the data.• GOAL is to UNDERSTAND these patterns, NOT

memorization of facts or numbers

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memorization of facts or numbers.

• Will concentrate on patterns and processes, but some knowledge of facts will be needed.

Will there be math?• At a lower level than

what’s in the get rich book.– some geometry

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– some algebra– smidgen of trigonometry– no calculus– no logarithms– no differential equations

Some Obvious Patterns

Inner Planets

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• WHY?

differ from

Outer Planets.

Some Striking Differences• Example: Our Moon vs. Jupiter’s moon Io.

– Rocky worlds, about the same size.• Io:

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– Volcanic.– Covered with orange sulfur.

• Moon:– Geologically dead.– Covered with gray rock.

• WHY?

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Many Obvious Questions•• Why do outer planets have rings?Why do outer planets have rings?

•• What are rings, anyway?What are rings, anyway?

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What are rings, anyway?What are rings, anyway?

•• Are they permanent or temporary?Are they permanent or temporary?

Timescales•• How and when did the solar system form?How and when did the solar system form?

–– (Answer: ~4,600,000,000 years ago!)(Answer: ~4,600,000,000 years ago!)

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•• How do we know that??How do we know that??

How Has the Solar System Evolved?

•• Everything changes (Why? How? How Fast?)Everything changes (Why? How? How Fast?)•• Examples:Examples:

–– 4 billion years ago the Earth's atmosphere was 4 billion years ago the Earth's atmosphere was very different than it is today (little or no oxygen)very different than it is today (little or no oxygen)

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very different than it is today (little or no oxygen).very different than it is today (little or no oxygen).

–– 4 billion years ago there may have been rivers or 4 billion years ago there may have been rivers or lakes on Mars (today it is a cold, bone dry desert).lakes on Mars (today it is a cold, bone dry desert).

–– Mars has 2 moons today, but in 1 billion years it Mars has 2 moons today, but in 1 billion years it will have only 1 moon.will have only 1 moon.

• Extrapolation in time predictions about the future.– How will Earth's atmosphere change?– How will our climate change?– Will objects strike the Earth? When?

Why Understand the Past?

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Will objects strike the Earth? When?• Extrapolation in space inferences about other places.

– Many other stars have planets.– Could some of them be Earthlike?– Could there be life??

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Major Course Topics

(1) General Solar System Concepts.

(2) The Inner Solar System.

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(3) Small Bodies and the Outer Solar System.

(4) Origins.

Some Philosophy• Our goal is to help you learn how to distinguish

solid science from nonsense. • For example:

– Planets around other stars.

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Planets around other stars.– Repeated massive mass extinctions due to impacts.– Evidence of ancient life on Mars.– Ice at the poles of the Moon and Mercury.

• Which of these are TRUE, POSSIBLY TRUE, EXAGGERATIONS, OR EVEN NONSENSE?

• Use Carl Sagan’s baloney detection kit.

A Promise from us...• We will work hard to help you learn.• Our Responsibilities:

– Clearly present the information.

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– Provide opportunities for questions, discussion.– Be prepared for lectures, sections, labs.– Provide fair and consistent grading.– Make astronomy matter!

And from you...• But you must work hard too!

– Come to Lecture:• Be here on time: prompt 11:15 start.• Class will end at 12:05 (not 12:00…)

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Class will end at 12:05 (not 12:00…)– Go to Section.– Do the reading.– Turn in assignments on time.– Ask Questions!

• Absolute academic integrity expected at all times.

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Lecture Style• Follows the textbook, but not verbatim.• More information provided only in lecture.• Other lecture features:

" h i i " hi hli h d f h l

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– "The Main Point" highlighted for each class.– Active learning.– Group activities.– Demonstrations.– Discussions: Astronomy in the News, etc.– Mars rover mission updates.

Handouts:Syllabus

and

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andGround Rules

Your Weekly Section Meeting• Your chance for more personal contact.• Weekly quizzes or problem sets assigned.• Detailed discussion of reading, lectures.

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• Detailed discussion of homework.• Critical preparation for prelims & final.• You will get a better grade if you attend lectures

and sections.

Lab: Astro 104• Astro 104 has an additional lab component.• Four classroom lab activities (in Clark 132):

– Radioactive Dating.

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– Planetary Orbits.– Impact Cratering.– Rotation of Saturn and its Rings.

• One on-campus observatory activity (at Fuertes Observatory, weather permitting).

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Observing the Sky• On clear Friday evenings, the Cornell

Astronomical Society holds open-house observing at Fuertes Observatory on north campus, from 8:00 pm to midnight

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8:00 pm to midnight.– Check http://astro.cornell.edu/facilities/fuertes

• You are strongly encouraged to go out and see the planets with your own eyes! Dress warmly.

• Planetarium program (SkyGazer) comes with your textbook.

Additional Resources• Course website:

http://www.astro.cornell.edu/courses/a102– Lecture notes, homeworks, links, etc.

• Textbook publisher website:

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Textbook publisher website: http://www.masteringastronomy.com– Animated figures, tutorials, quizzes, etc.

• Numerous planetary data archives:– Header graphic based on images from

http://www.solarviews.com © Calvin J. Hamilton

For Additional Help• Office Hours:

– Prof. Margot: MF 3:00-4:30 (but call ahead).– Prof. Squyres by appointment only (due to

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continuing Mars rover operations).• Each TA has his/her own office hours:

– Consult the handout or web site for details.• Any of us are available at other times by

appointment, with advance notice.

Next Lecture...• The Sky.• Historical Overview of Planetary Science.

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• Reading this week:– Preface and Chapter 1.– Chapter 2.1, 2.4.– Chapters 3, 4.