ASTR-1010ASTR-1010Planetary AstronomyPlanetary Astronomy

Day-3Day-3

3 X 5 Card Time3 X 5 Card Time

• Name (legibly)!!

• What is the language of Science?

Course AnnouncementsCourse AnnouncementsLabs are posted on-line. It is your responsibility to

print it our prior to coming to the laboratory.

Clarksville Astronomy Club meeting Tuesday Jan. 26 @ 7:30pm in the Sears Planetarium

Begin moon observations ASAP … you’ll need them in 2 weeks.

1st Quarter Observing – Monday Jan. 25 – 7:00pm

HOMEWORK (already)HOMEWORK (already)Homework Chapter 1: Due Monday

EveryoneEveryone should have tried SmartWorks site by now

Homework Chapter 2: Due Wednesday Jan. 27

Beginning with chapter 2, you better read the text and THINK before you blindly answer questions.

Homework Chapter 3: Due Monday Feb. 8

Rotating Sky Simulation – Due Wednesday Jan. 27

*** Warning – this will take some time to do, so don’t wait until Tuesday night to start it ***

Heliocentric UniverseHeliocentric Universe• Anti-intellectual fervor of 5th Century

– Libraries destroyed, The Church came to power– Islamic scholars saved and translated much of the Greek

philosophic work– Contact with Hindu scholars, interaction with Chinese

culture and science• Nicholas Copernicus (1473-1543)

– Aware of Aristarchus's work– Advocated the heliocentric view

• Tycho Brahe (1546-1601)– Observational data– All done with naked eye

Heliocentric UniverseHeliocentric UniverseJohannes Kepler (1571-1630)

– 3 Laws of Planetary Motion• 1. Elliptical orbits, Sun at one focus• 2. Equal area in equal time• 3. P2 = ka3 (P in years, A in Astronomical Units)

Heliocentric UniverseHeliocentric Universe• Galileo Galilei (1564-1642)

– Laid foundations of modern physics• Inertia (later explained by Newton's 1st law)• Gravity

– First to use a telescope for astronomical purposes• 1. Sunspots – Sun was not a perfect surface.• 2. Craters on Moon – Moon was not a perfect surface.• 3. Observations of thousands of stars not visible by eye.

– So stars more numerous than Tycho thought.

• 4. Geocentric Universe death– Four moons orbiting Jupiter– Phases of Venus

Modern ScienceModern Science

• Isaac Newton (1642-1727)– 1687 – Principia – precise math descriptions – 3 Laws of Motion– Universal Law of Gravitation– Invented Calculus (to prove Kepler's Laws)– Developed new type of telescope

GravityGravity• 1666 – Newton

– Apple & tree ==> Moon & Earth

• Universal Law of Gravitation– Every mass attracts every other mass through

a force called gravity.– Directly proportional to product of masses.– Inversely proportional to square of distance

between them.

Hallmarks of Modern ScienceHallmarks of Modern Science

1. Modern science seeks explanations for observed phenomena that rely solely on natural causes.

2. Science progresses through the creation and testing of models of nature that explain the observations as simply as possible.

3. A scientific model must make testable predictions about natural phenomena that would force us to revise or abandon the model if the predictions do not agree with observations.

Modern ScienceModern Science

• The Scientific Method.– Observations– Question– Hypothesis– Prediction– Test– Revise/More

Predictions

Modern ScienceModern Science

• OR The Eureka Moment.– Look at Nature in a “general way”

• not looking for anything in specific

– Galileo– Voyager 1, 2 - Europa

• Must overcome “personal experience”– Gravity doesn't “work” because of drag.

Modern ScienceModern Science

• Occam's Razor– William of Occam (1285 - 1349)– K.I.S.S.

• Verifiable Observations– UFOs vs. Einstein Theory of Relativity

• Science, Nonscience, Pseudoscience

• Objectivity

• Scientific Theory– Newton, Darwin, Einstein

Concept Quiz – World ViewConcept Quiz – World View

Which of the following would be a scientific way of viewing nature?

A. All ideas are equally valuable and should be equally respected.

B. Well established ideas should never be checked or tested.

C. Nature informs us about the usefulness of our ideas.

Science Is a ProcessScience Is a Process• Science is a method for learning about

nature.

• The scientific method works like this:– Ideas are tested against nature.– Tests come from observation or calculation.– The tests falsify some ideas and support others.

• All scientific knowledge is provisional.

A Scientific Result: A Scientific Result: We Are StardustWe Are Stardust

• Our bodies contain many types of atoms.

• Except for the hydrogen in water (H2O), all the atoms were made in stars.

• Stars generate energy by making heavier elements out of light ones.

• They eject the material into space.

• New stars and planets (and humans) form out of the ejected material.

Astronomy and mathematics are closely linked

Pythagoras569 – 475BC“The underlyingStructure of theUniverse isMathematical”

Science and MathematicsScience and Mathematics

• Science discovers patterns and rhythms in nature.

• Most phenomena work regularly and predictably.

• Mathematics is the language of patterns.

• Mathematics works when used to describe nature and its patterns.

Concept Quiz – Astrology as Concept Quiz – Astrology as ScienceScience

Astrology sounds scientific, because it uses charts and graphs and mathematics. Which of these would lead you to conclude that it is not a science?

A. Astrologers cannot agree on ways of rejecting ideas.B. Astrological “energies” are not predictable.C. The Earth is viewed as having a special and unique

place in the universe.D. All the above.