Great article!

I just wanted add one note about hidden life - it's that we have known about bacteria for 350 years, but only realized the existence of archaea in the late 1970s.

Worse yet, unlike bacteria, we still don't have any effective generally technologies for identifying and classifying different species within the archaea, or really for understanding how they live and live together, because most of our evidence is indirect in the form of DNA fragments.

We know rather a lot about a few archaea, we know a little about many more, but nearly all of the species we know nothing about at all. (A biologist friend explained to me that the issue is the seeming impossibility of culturing most species of archaea individually, possibly because a large number of species are always interdependent.)

It's really exciting and a tiny bit scary. I was going to say that at least archaea haven't been suggested as pathogens, but I would have been wrong.