We drop anchor in a cove on the windward side of Hayman Island. No one else is around. We put on masks and plunge in. The reef is like Sydney’s light show, except in living color — orange and white clownfish, triggers, surgeons, the coveted coral trout. The corals themselves pile atop one another, antlers, lattices and squiggly brains. A dome-shaped bommie is bigger than our boat. Here, finally, I get a sense of the reef’s range of scales. Take this mesmerizing detail, the wild biodiversity right in front of us, and multiply that a million times. The reef network is built of microscopic organisms, and it’s visible from the moon.