Gravity plays an essential role in the formation of celestial bodies, functioning almost like a divine force in the universe. Initially, the cosmos was an empty expanse, filled only with gas clouds. As these gases cooled, small particles began to merge together, influenced heavily by gravitational attraction. Without gravity, these particles would have drifted aimlessly through space without forming the suns and planets that populate the universe.

The concept of gravitation can be viewed as the universe's desire to bring elements together, creating order from chaos. It is this fundamental force that prompts the aggregation of matter, transforming it into the intricate structures we observe today. Mary Roach's insights in "Packing for Mars" highlight the profound impact gravity has on cosmic evolution and existence itself.