Unit E – Space Exploration Lesson 4-7 (sec 3.3) Using Technology to Interpret Space

A. Triangulation is based on the geometry of a triangle triangulation uses to determine the 2 angles and a baseline distance to an object baseline slide 1 of 6

B. Parallax is the apparent shift in position of an object (eg. star) when viewed from two different places parallax parallax is used to determine the angles for triangulation the is used as the and the measurements are taken diameter of the Earth’s orbit baseline 6 months apart slide 2 of 6

C. Star Composition separate colours in prisms visible light separate the called a spectroscopes light from stars into colours and bands spectrum each creates its own unique spectrum element the is compared to the to determine the spectrum of a star spectra of known elements star’s composition slide 3 of 6

Absorption Spectrum of Hydrogen slide 4 of 6

D. Star Motion the is an apparent change in frequency of waves (sound, light) due to the movement of the source Doppler effect changes in can be used to determine light waves how fast and in what direction a star or galaxy is moving slide 5 of 6

when a star is moving from earth, the spectrum is as wavelengths away red-shifted stretch out when a star is moving the earth, the spectrum is as wavelengths towards blue-shifted compress distant galaxies show a red-shift ….means universe is expanding slide 6 of 6

Assignment Worksheet 8