Physics and the Universe 1-14-08

Physics and the Universe 1-14-08 - constellation...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Physics and the Universe: Monday January 14, 2008 Cyclic Motions in the Sky Speed of light= C C=3x10^8m/s Distance= Speed x Time = 3x10^8m/s x 1 year = 3x10^8m/s (3x10^7sec/ 1 year) = 9x10^15m = 10^16m 10^16m x 1km/1000m 10^13km = 10 trillion Constellations In ancient times, constellations only referred to the brightest stars that appeared to form groups, representing mythological figures Today, Constellations are well-defined regions of the sky, irrespective of the presence or absence of bright stars in those regions The stars of a constellation appear to be close to one another. The constellation Orion is composed of stars (named how?) (Betelgeuse & Rigel) Stars are named by a Greek letter (α,β,γ,etc.) according to their relative brightness within a given
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: constellation & the possessive form of the name of the constellation The Magnitude Scale First introduced by Hipparchus (160 127B.C.) : Brightest stars: ~1 st magnitude Faintest stars(unaided eye): 6 th magnitude One magnitude difference is quantitatively defined=2.512 1 st magnitude stars are 100 times brighter than 6 th magnitude stars M12=1= 2.512 M13=2=2.512^2=6.3 M14=3=2.512^3=16 M15=4=2.512^4=40 M16=5=2.512^5=100 The Celestial Sphere Zenith= Point on celestial sphere directly overhead Nadir= Point on the c.s directly underneath (not visible!) Celestial equator= projection of Earths equator onto the c.s North Celestial Pole= Projection of Earths north pole on the c.s....
View Full Document

Ask a homework question - tutors are online