Transcript: The study of astronomy contains an enormous range in scales of mass. The lightest thing there is is an electron, 10-30 kilograms. The heaviest atom, Uranium atom, is 10-25 kilograms. The tiny living organisms, a bacterium or a virus, about 10-15 kilograms. Somewhere in the middle of the huge range are human beings with a typical mass of 100 or 102 kilograms. The entire Earth is 1025 kilograms. The sun, 1030 kilograms. And the entire mass of the observable universe, containing some 60 billion galaxies, amounts to 1052 kilograms. The entire range from the largest to the smallest is 82 orders of magnitude or powers of 10.