In Improbable Planet: How Earth Became Humanity’s Home, Hugh Ross tells the story of Earth’s four-billion-year history (as scientists currently understand it) from initial chaos to present wonders. But whereas secular scientists often narrate this story as one of random, unplanned chance that just happened to lead to intelligent lifeforms, Ross narrates it as overflowing with intentional purpose through the mind-bogglingly complex cascading of unlikely events, each in their proper place and order, as if someone was thoughtfully preparing a planet to eventually house humans created in his image.
The book’s scope starts with our sun’s favorably formed position in the galaxy, describes the order that emerged from the early solar system’s chaos and the precise formation of the moon, and carries on through the history of Earth from its remarkably early appearance of life on up to the present day. Key themes include:
- The challenge of the sun’s gradually increasing brightness over billions of years, and how continual shiftings of components in the Earth’s atmosphere and the types of life on Earth just happened to maintain a habitable temperature window for liquid water, from the early methanogens to a later cycle dominated by carbon dioxide, whose levels gradually decreased with the appearances of more efficient oxygen-producing life
- How life and the planet interacted to change and maintain both – such as life and plate tectonics being necessary to sustain each other, and the role that different life forms played at different points in history to change the atmosphere or influence the development and erosion of continents
- How successive appearances of creatures affected the planet in ways that not only maintained the temperature zone but also prepared things for future appearances of creatures – such as early bacteria that produced the oxygen which allowed for more efficient aerobic energy processes, or the sulfate-reducing bacteria (SRBs) that transformed minerals from toxic to benign states that proved crucial to future human civilization
Unfortunately, Ross pushes too hard on his claims of specific purpose. For example, surely we are woefully too ignorant at this point to confidently claim that our galaxy’s position in the universe is the only setup that could lead to a habitable environment for intelligent life! And many of his claims would be dismissed by opponents as unimaginatively reversing the cause and effect – if some conditions had turned out differently a couple billion years prior, they say life would simply have adapted to it in a different direction.
While that may be true for some cases, there are also clear physical limits on life’s flexibility, and Ross is right to marvel at life’s remarkable persistence, teetering on the edge of darkness through multiple extinction events and near-snowball events, but never fully snuffing out, and always leading to further progression. And even while trying to restrain my bias with as much skepticism as possible, in my mind many of the unlikely events Ross points out truly do carry whiffs of intention, due to the ordering and timings required to keep the chain of events going.
The moon-forming collision, the Grand Tack, the Late Heavy Bombardment, the late veneer accretion, the “boring billion”, the slushball events – Ross’s narrative of purpose also makes all of this history more memorable and interesting. Why is Earth the only planet to buck the naturally decreasing density of planets from the sun? Why have our orbits just barely avoided destructive resonances and maintained stability for billions of years? How did life arrive so quickly to start the adjustments that completed just in time for intelligent creatures to appear and flourish in the blink of geologic time before the sun gets too bright for decreasing carbon dioxide to maintain the habitable window and the moon gets too far away for those beautiful perfect solar eclipses? Is there Someone watching and even orchestrating all of this?
In some ways the book is an updated and explicitly Christian version of Rare Earth. Ross is an old-earth creationist, and while he sprinkles some critique of evolution, especially around initial abiogenesis and the sudden appearances of new life forms in key places (the Cambrian explosion, of course, but also less familiar junctures), much of the content overlaps peaceably with evolutionary creationist ideas. What young-earth creationists should take away from this book is an appreciation that the old-earth view, whatever their opinions on its doctrinal merits, can hold a much greater – not lesser – wonder and admiration for the perfect plans of an almighty Creator.
Many are familiar with the Earth’s “perfect distance from the Sun,” and maybe some other anthropic characteristics. But if it’s impressive for a God to think up and instantly create a beautiful universe out of nothing, with Mars over there and the Earth and moon over here with all of the useful elements that they have today, perhaps it’s exponentially more impressive for a God to plan and masterfully piece together that same configuration over billions of years, with the laws of physics and distributions of elements interacting in just the right ways for the right supernova to seed the right proportions of iron and aluminum and copper and silver and gold and the right collision to create the right size moon and all the other things that had to happen when and where they did for everything to end up the way that it did.
One of Ross’s interesting theological contributions highlights that Earth’s habitability will not last forever, and in fact has a relatively short amount of time left. I don’t know if all of Ross’s thought-provoking claims are correct – did the perfectly-timed lake-and-fjord-inducing Ice Ages really make the present era the most aesthetically beautiful in all of Earth’s history, just in time for us? – but together they make a strong case for the argument that we are here for a reason. That case will remain relevant and be tested in fascinating ways as we exhilaratingly discover more about exoplanets – and thus also more about the relative uniqueness of our own – in the coming months and years.