Class_2

# Class_2 - What's so special about 360 Why not use 435 Is...

This preview shows pages 1–6. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: What's so special about 360? Why not use 435? Is there a natural choice? Ratio of arc length to radius: Angle = A1/R1 = A2/R2 A circle makes an angle of 2 at the center radians = 180 1 = /180 radians Trigonometry is much easier (next slide...) ' !"# !"# \$ \$ * * + # # \$ ) ' ' % ( # ) ') % & ")" # & %& ' ' At any quarter, the sun, earth and moon form a right-angled triangle 3 hypotenuse is 19 times perpendicular (3 = 0.052 radians = 1/19.1) Sun-Earth = 19 x Sun-Moon Modern figure is 390 (89.85 ) (0.15 = 1/390 rad) DS:Dm = RS:Rm (similar triangles) Hence RS = 19 Rm (acc. to Aristarchus) What should be the modern value? RS = 400 Rm , . & 12 / 0 12 12 12 - 1 2 2 12 2 )" & 3 ") & !+! & " ))! & )'#4# & Nearer stars move w.r.t. farther stars sin(p) = 1 A.U. / d sin(p) \$ p (small p) / * - 4 / 6' ") ' ") %+% 0 & & 8 9 " ) 6) #') "& + !"% " % +& ) 5-/ # % & 7 # % & 6) " + / 6- / 6) 6- ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 6

Class_2 - What's so special about 360 Why not use 435 Is...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online