Chapter Summary

This narrative of the history of the universe has been necessarily brief, but it does point out three themes that are important to remember as we continue.

First, it could be said—by virtue of human numbers (over 6 billion) and our impact on the planet—that we are the dominant species on earth today. But our evolutionary history makes up a small fraction of the whole history of the universe and even of the earth. We are the new kids on the evolutionary block, and we have not as of yet even proved ourselves successful by the criterion of longevity. Cockroaches have been around hundreds of times longer than we have; bacteria have been around since the beginning of the fossil record. By these standards, our species is in its infancy.

Second, as the Bible says, “there is no new thing under the sun.” Indeed, although we often speak of the “origin of the earth” or the “ origin of life,” the only real origin is that of the universe itself. All the events listed above have been rearrangements of what already existed: matter condensing from energy as it cools; large atomic particles forming from smaller ones; stars coming together from cosmic dust; heavy elements being created from lighter ones in the nuclear furnaces of those stars; the elements of inorganic molecules being rearranged to form the molecules of life; and the shuffling of the genetic code, producing the extraordinary multitude of living things that have inhabited this planet.

Third, and perhaps most humbling, the specific history of the universe, including the earth and its life, could have happened in countless other ways. Each event in our story is contingent upon preceding events. Even our evolution is dependent upon the specific sequence of events that came before it. If those events had been different, we might be different—or we might not be here at all. Imagine if that asteroid had not hit the earth 65 million years ago. In other words, the evolution of humans—or anything else for that matter—was not inevitable. We’re lucky we’re here.

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