Circles & GravityCircles & GravityWhat the heck do they have to What the heck do they have to

do with each other?do with each other?AstroAstro

10/15/0810/15/08©2007 Daryl Taylor©2007 Daryl TaylorDT@DTFizzix.com

Intro StuffIntro Stuff(That means “boring stuff..”)(That means “boring stuff..”)

Ancient AstronomyAncient Astronomy– The 1The 1stst REAL Physical Science REAL Physical Science

» Besides “falling over”Besides “falling over”» Some early viewsSome early views

– PtolemyPtolemy– CopernicusCopernicus– GalileoGalileo– Kepler!Kepler!– Newton!Newton!

Intro StuffIntro Stuff(That means “boring stuff..”)(That means “boring stuff..”)

So, where does Tyco Brahe fit in?So, where does Tyco Brahe fit in?– Aristocratic Moron (Autistic)Aristocratic Moron (Autistic)

»Died from a burst bladder!Died from a burst bladder!– Stayed up EVERY night of his lifeStayed up EVERY night of his life

»Mapping the skyMapping the sky»Keeping dataKeeping data

– Volumes & VOLUMES of dataVolumes & VOLUMES of data

Intro StuffIntro Stuff(That means “boring stuff..”)(That means “boring stuff..”)

Kepler?Kepler?– Genius - mathematicsGenius - mathematics– Astronomy - hobbyAstronomy - hobby– Made a living being an Made a living being an astrologerastrologer!!– Was puzzled by some thingsWas puzzled by some things

»But, had no dataBut, had no data

Intro StuffIntro Stuff(That means “boring stuff..”)(That means “boring stuff..”)

Stole Tyco’s stuffStole Tyco’s stuff– Hired a coupla street thugsHired a coupla street thugs

Studied data for Studied data for 19 years19 years.. Published his 3 “Published his 3 “LAWSLAWS””

– NO EXPLANATIONS!NO EXPLANATIONS!– Was NOT a real scientist!Was NOT a real scientist!

Intro StuffIntro Stuff(That means “boring stuff..”)(That means “boring stuff..”)

3 LAWS? 3 LAWS? [Block 4][Block 4]

– EllipsesEllipses– Equal AreasEqual Areas– K = TK = T2 2 / R/ R33

Math or Science?Math or Science? Video Clip!!! YIPPEE!!!Video Clip!!! YIPPEE!!!

Real StuffReal Stuff11stst Law Law (Block 8)(Block 8)

–Planets travel in ELLIPTICAL Planets travel in ELLIPTICAL orbits, not circular.orbits, not circular.

–DefinitionsDefinitions»Circle – ‘r’Circle – ‘r’»Ellipse – ‘a+b’Ellipse – ‘a+b’

–Why?Why?

Circle, duh…

R

ryx 22

Ellipse,

F1

Cby

ax

2

2

2

2

F2

Earth

a b

CONSTANTba

Real StuffReal Stuff22ndnd Law Law

–Planet makes Planet makes ’s with =A’s.’s with =A’s.–Say WHAT?Say WHAT?–Why?Why?

»Gif1&2Gif1&2

Real StuffReal Stuff

Real StuffReal Stuff AristotleAristotle

Real StuffReal Stuff PtolemyPtolemy

Real StuffReal Stuff 33rdrd Law Law

– K=TK=T2 2 // RR33

– DefinitionsDefinitions»RR»TT

– AU?AU?»Taylor’s Constant!Taylor’s Constant!

– Why?Why?

3

2191098.2

msxkK

3

2

1AUyrkT

Real StuffReal Stuff Newton’s Synthesis – Bored Board!Newton’s Synthesis – Bored Board!

221

rmmGFg