Light, Very Distant and Very Close.

On Tuesday we went to Puerto Mosquito on Vieques to see the bio-luminescent display there. So far on the visit to Puerto Rico, it had been mostly cloudy and I was hoping for this to continue since the Moon was slightly more than half full. As it turned-out, the skies were totally clear, but the Moon didn't rise until sometime after we left.

Our guide was an expert on astronomy--at least that part of it involving the names of principle stars and constellations. He had a bright green laser-pointer with which he could point out features in the sky. My red laser pointer only creates a bright dot where the light hits something solid. The guide's would create a beam that seemed to go-off into infinity. I suspect that the higher frequency of his light (green v. red) caused it to have an higher incidence of scatter, also it was most likely more powerful than a usual pointer. In any case it allowed for a planetarium-like experience, which was helped by the very dark skies.

The only light seen from the water was from when a fish would dart about and from where the water was disturbed by the electric pontoon boat we were on. Even as the mechanism of this light is known--dinoflagellates, it was nonetheless quite magical. It got better though; we were able to get out of the boat and swim around in the bay. It was a chilly evening and the water too was cool, but the discomfort was well-worth it. Any movement however small, would cause a glow in the wake of the movement. The guides forced us to wear life-belts, which is totally understandable, but somewhat disappointing from an aesthetic stand-point. It turned-out to be beneficial in a couple of ways: The best bio-luminescent effects were from slow movements and this would be difficult given the need to remain floating. Rapid movements create a kind of milky cloud of blue-green light, slow movements create a much clearer light--sort of like champagne, where the tiny bubbles are illuminated from within and light-up the rest of the fluid. The best technique was to knife your fingers forward, just under the surface of the water. Light and bubbles would form at the tips of each finger and spread in a wake behind each one.

The best effect was from lying still, just floating. What would happen is that one would see small dots of light on your skin. If I recall correctly, these would occur both in and out of the water--so it might be droplets of water on the skin and air bubbles on the skin under water. Possibly, what I saw were individual Noctilucales, which can be 1-2 mm in diameter. Either way, they had the same brightness and apparent size as the stars above. It was odd, contemplating one dot of light coming from an incomprehensibly violent and large object which emitted the light I just saw many centuries before I was born and another dot, much the same in appearance but coming from a little single-celled organism on my arm.

All three of the girls were similarly entranced by the swim and were reluctant to get out when called.