Prepare for a super long review. There’s a lot to talk about.
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Everywhere you look, there’s life. Even when there’s no light. Even when there’s no oxygen. Even when you think the environment is too toxic. This becomes even more interesting when you consider life on other planets and other solar systems. Despite Earth being the only place we’ve ever found evidence of it, one could think life should be everywhere—not only because of its inherent stubbornness, but also because the building blocks for it are common in the universe.
But life also has huge hurdles to overcome. While we can find life even in the most unlikely places—places you would never think are possible—it exists in a perpetual dichotomy between how adaptable it can be and how vulnerable it is anyway.
You need the right type of star, but that star must also be calm enough for long enough to not kill you. Also, your planet must be just far enough to not burn, but not so far away that it freezes. Said planet may also need a slight, stable tilt and possibly even be pulled between its satellite and its star in a cosmic tug-of-war to maintain long-term stability. Or not. Jury’s still out.
If you get such a star and such a planet, it might turn out that life itself creates conditions that put it in danger (See: the Great Oxidation Event, a.k.a. the “Oxygen Holocaust” in colloquial circles). Or maybe said planet’s geology will play a trump card from time to time, pushing that life to its very limits. We can’t forget the Ordovician extinction that occurred thanks to the plate tectonics.
Some asteroids and comets might reset the clock. Turns out, there’s a debated hypothesis suggesting a peak of impacts roughly every 27.5 million years that aligns with mass extinctions. See: the poor non-avian dinosaurs. Oh, and in case you thought that wasn’t enough, there’s also the matter of supernovas. It’s a good thing we’re not close to one, because the mass extinction of invertebrates might have been because of one. Whoops.
So, not easy. But you know what? Life is still kicking, and some exoplanets resemble the habitats of extremophiles here on Earth. So we now think life could have had a chance in more places than we used to. Right now, it’s easy to think about Mars or Venus as candidates. But I bet you never thought about Mercury, or some of Jupiter’s and Saturn’s moons, such as Enceladus, Europa, or Titan. I bet you never thought about Pluto.
It turns out the possibilities are endless. Some of these places may have pockets capable of protecting the emergence of life; others may hide oceans under a thick coat of ice; and others can obtain energy from within the planet or moon itself rather than the sun. There are so many possibilities you can’t help but feel excited, as well as completely sure there mustbe life out there, we just haven’t been able to find it with our rather recent technology.
I think the author did an amazing job presenting all the options within and outside the solar system, as well as explaining the whys and the hows behind them. Mercury and Pluto were particularly shocking for me; they truly never crossed my mind.
She also explores the multiple technologies that have been developed over the years to search for life and then moves on to what lies ahead in the field, from planned missions to future telescopes. She succeeds in making one point very clear: we’re just starting this journey. There’s a lot we still don’t know, let alone understand. I finished the book feeling oddly hopeful about our chances, even if they will take a while to bear fruit.
My only criticism is the epilogue. Cabrol’s expertise in astrobiology is undeniable, and I learned a lot from her, but some of her views about Earth’s future felt overly pessimistic and based on broad generalizations. In doing so, she ignores real evidence of progress or repeats beliefs I’m not entirely sure still hold true.
For example: “The Earth is overcrowded”. Right, today it might be. But much of the developed world is going through a birth crisis because, surprise, people are not having children. That means, in the not-so-distant future, we will have real issues maintaining our way of life because the population will be too aged. We’re already seeing this in many countries.
She also argues that individual lifestyle changes will collectively be enough to protect Earth and ourselves from contamination. See, I’m not saying “don’t recycle”, but the scientific consensus emphasizes policy and corporate responsibility as critical steps to actual large-scale change. Individual action is simply not enough. We would be far more useful demanding that governments start paying attention to that so it can be regulated, make it a serious cause. By that I mean through peaceful means, of course: The goal is to convince people, not to frighten them into opposition.
She further claims we were more “connected” with the physical world before and that we lost touch with it through technology. Again, another half-truth. I don’t think we were more “connected”; if anything, we were far less conscious of our impact. We simply weren’t that many to cause the kind of damage we do today, and the Industrial Revolution hadn’t yet taken place. It’s hard to make that claim when we know humans hunted plenty of species to extinction, and we only started caring about conservation fairly recently.
Another half-truth is the sixth mass extinction. We simply haven’t reached those numbers, but the author doesn’t clarify this. Long story short, yes, we’ve caused the extinction of multiple species, that much is true, but to start talking about a mass extinction, a whole lot more will need to disappear to make such a claim. We should absolutely check ourselves and do our best to tone things down, learn to live in the ecosystem we’re a part of, but her statement is careless at best.
Truth be told, the epilogue soured my opinion about the book a bit. I don’t doubt her knowledge in astrobiology, but her assessment of what’s happening here on Earth feels biased and incomplete. There are a lot of things we do need to worry about, but we’re not at this world-ending scenario. And while a lot more could and should be done, the world has been moving towards a more sustainable future.
I hope you leave this review feeling a bit more hopeful about the future than pessimistic. Humans tend to see only the bad and dark, but I swear there’s a lot of light hiding in plain sight if only you’re willing to open your eyes.