Scale: 1015 meters = 1 Pm = 1 petameter


The entire solar system we know as home now lies within the dot representing the Sun. A beam of sunlight requires a bit more than a month to cross this image. We are in the midst of the Oort cloud, the vast sphere of rock and ice from which comets come. The largest of these chunks would be no more than a few kilometers in diameter. If all the matter in the Oort cloud were condensed into a single body, it is thought that it might be about 1/10 to 1/100 as massive as Earth. The Oort cloud is left over from the primordial ball of gas and dust that condensed 4 1/2 thousand million years ago to give birth to the Sun and its family of planets and moons.

Copyright © 2016 by Bruce Bryson