ocr: 9 or MARS AND EARTH: A COMPARATIVE HISTORY Formation HHE SEARCH EUR Earth, Mars, and the other planets of our: solar system came into being about 4.6 billion years ago within the primitive nebula. In the disk surrounding the young Sun, stellar dust collected, spinning around small central bodies. The colliding particles formed larger and larger particles, and eventually aggregated. As their mass increased, they attracted even more particles. We can assume that Earth and Mars, like Venus, Mercury, the Moon, and the other bodies in the solar system, all had as similar composition at this time. A ...
