The ethics of encountering non-sentient alien life in our solar systems boils down to a core dilemma, says Waller. ‘Is it about conservation and preservation? Or is it about our needs, wants, and desires?’ On Earth, natural-resource grabs have a history of bringing out the worst in us as a species. Consider the example of gold. Conquistadores exterminated entire societies in their hunt for gold, when they weren’t enslaving people to mine it. Prospectors in California blasted away mountains with water canons to access it, permanently altering the geology of the state. Today, small-scale gold miners in South America rip apart rainforests and pollute rivers with mercury, trying to sop up the last specks of gold to sell to a market still in upswing.

There’s plenty of reason to believe other planets will be chock-full of resources we’d like to exploit, even if the life forms are microbial – perhaps especially if they’re microbial.

Think of everything we use Earth microbes for: creating and preserving food, treating disease, and processing waste, to name a few. All of that could be enhanced by exploiting a whole new tree of life. Imagine new antibiotics to which Earth bacteria could never evolve resistance, or microbes that excreted a renewable fuel that burns hotter than oil. Or just all the weird cheeses we could make! Synthetic biologists would see their toolkit multiply exponentially the more trees of alien life we discover.

Perhaps the scariest lesson of resource grabs is that we rarely label our actions as evil or even problematic while we’re engaged in them.