I have never felt closer to the sky than when I was 170 feet under the ocean here at Tuffy Canyons, Belize. It happened on Easter morning.

A half-dozen of us slipped out of a boat on the barrier reef here and followed our dive master, Michael, into a canyon, dropping through jagged openings past profusions of coral waving like wheat in the wind. There were clouds of fish, turtles and the occasional shark.Then the ocean floor suddenly fell away. We were hovering like unharnessed window washers on a vast wall of rock and coral, the outermost edge of the second-longest barrier reef in the world, the boundary of the big deep.

We were looking for a pod of dolphins that had graced these parts the day before. But I wasnít prepared for infinity.The color down there was the mother of all blues. I found it oddly comforting. Maybe it was just narcosis of the deep, but Iíve never felt so connected to the cosmos.Iíve been diving on and off for about 11 years. I got my certificate the day the space shuttle Columbia burned up over Texas with seven astronauts aboard, effectively ending the shuttle era.

I climbed out of the water that day and went to my cottage on the island of Dominica and stared up at Orion, recalling my boyhood dreams of space travel and saying goodbye to them. The stars would never be my destination. Iím no marine biologist. I dive for the childish joy of flying, zooming up and down like Superman, and for the Zen joy of being surrounded by colorful fish you canít catch, like errant thoughts you canít follow.

Inextricable link

But the cosmos has a way of catching me. All the aspirations of the sky are concentrated down below. Inner space and outer space, yinning and yanging together. The sea is its own cosmos, but it is inextricably linked to the vast invisible ocean around us. The hydrogen in its water molecules was made in the Big Bang, the oxygen in them was made in a star ó a marriage made literally in heaven. The electrons that glue those molecules together attained their masses and glueyness during a subtle shift in the properties of the vacuum, when the Higgs field and its famous particle, the Higgs boson, kicked in a trillionth of a second after the universe was born.

Whatever meaning we can ascribe to the universe arose in these depths and those mysterious processes. All the logic of outer space, its vistas and apocalypses concentrated in this blue caldron of creativity and possibility, the restless sifting of chance, adaptation, survival and extinction. Life began percolating somewhere hereabout 3.5 billion years ago, crawling out into a new oxygenated atmosphere three billion years after that.

Indeed the seas are a gene soup, according to the biologist J. Craig Venter, who has spent the last few years trawling for microbes in his yacht Sorcerer II and has discovered at least six million new genes. What they do is anyoneís guess.Inevitably as you hang in the blue void, you wonder if this magic has occurred anywhere else. Iíve spent my share of time gazing up at the Milky Way from campfires or my old backyard on summer evenings in the Catskills, wondering if anyone is, was or will be out there, or how we would ever know or meet them in the confounding depths of space and time. It always makes me feel lonely.

And last month NASA requested ideas for a robot mission to Jupiterís most enigmatic moon, Europa, whose sheath of ice is thought to encase an ocean with more water than is contained on the oceans of Earth. John M. Grunsfeld, the former astronaut who heads NASAís space science directorate, said, ďEuropa is one of the most interesting sites in our solar system in the search for life beyond Earth.Ē

In the meantime there is life down there, and itís hard not to feel connected when you are in the womb, so to speak. Itís one place Iím never lonely.

There is a certain pose you associate with dive masters, swimming backward, legs akimbo as if in a Barcalounger, encouraging you onward. After a few minutes on the wall, Michael beckoned, thumbs upward, and we began the long slow ascent, keeping our eyes out for those dolphins, which did not appear again. Back to the sunny surface. Back to cosmic loneliness.