AST-A 105 Lecture Notes - Lecture 2: Logarithmic Scale, Significant Figures, Linear Scale
Document Summary
Rule: multiplier is the decimal number between 1 and 10. it is followed by 10 n , where n is the number of digits minus 1. Thousand = 1,000 = 10x10x10 = 10 3. Logarithmic scale: increase some number of times. 1, 2, 3, 4, 5 (increase: 1) 2, 4, 8, 16, 32 (increase: 2x) Astronomical scales: space is big, space is empty, no direct experience of astronomical scales, most diagrams are . To scale: size doesn"t match separation. Sun is 400x more distant than the moon. They look the same size in the sky (solar eclipses) Voyager 1: 140 au (probe launched in 1977) Voyager 1 (speed 38,000 mph = 17 km/s) Most of the stars we see in the sky are within 250 light years. The sun lies along one of our galaxy"s spiral arms, known as the . The sun is about 26,000 light years from the center. Andromeda visible with a naked eye. others are not.
