Sunday, June 29, 2008

Tasting the universe

Anne's illumination today quotes Roy Gould: "Our gaze fill the universe." A lovely thought. Although it is perhaps rather more accurate to say: The universe fills our gaze.

But I'm just being a stickler. Let's replace "gaze" by "thoughts" and reconsider the statement.

There is a sense, I suppose, in which human thoughts are percolating into the universe. Since the first radio transmissions a century ago, some measure of intelligently modulated electromagnetic energy has leaked into space. At most, it will have traveled a hundred light-years (or so) from Earth, which means it will have filled a space containing, by my rough calculation, something like 7000 star systems -- a tiny corner of our Milky Way Galaxy. Still, no matter how imperceptibly weak, our thoughts are out there. Our little bubble of thought-filled space grows year by year.

But the universe filling our thoughts -- now that's another matter. We can see the core of the Andromeda Galaxy with the naked-eye (maybe the Triangulum Galaxy, too), which means that even our most ancient conscious ancestors might have caught photons from stars 2 million light-years away (whether such a faint blur registered as a conscious thought we have no way of knowing). Today we have contrived a huge number of instruments, on the surface of the Earth and in space, to catch photons from distant objects, some from galaxies and quasars more than 10 billion light-years away, some from the immediate aftermath of the big bang itself. Out of these celestial messengers we have constructed a mental image of the universe we live in.

In the last chapter of Honey From Stone I wrote of the way we construct the star Vega, bending it to our thoughts:

At Ireland's latitude Vega dominates the summer night, by virtue of its brilliance and its commanding position near the apex of the sky. The light of the star does not make its way to my eye as a directed ray, as it might be easy to suppose. The energy produced in Vega's thermonuclear core moves away from the surface of the star in every direction, out past the glowing ring of interplanetary dust, into the great emptiness of interstellar space, becoming as it expands ever more dilute. You can think of the energy that leaves Vega at a particular instant as being carried away from that star on the surface of an imaginary sphere. The radius of the sphere increases at 186,000 miles per second, the speed of light, distending the star's light over an ever-increasing area, stretching the energy density of the light always thinner. At our distance from Vega -- twenty-seven light-years -- the star's light is dispersed over a spherical surface with an area of 320 septillion square miles (an unimaginably large number -- 320 followed by twenty-eight zeros). When we see Vega, it is with the infinitesimally small fraction of Vega's light that just happens to be intercepted by the pupils of our eyes. How can I suggest how little of Vega's light our eyes actually gather up? Compare the area of the pupils of our eyes (twice the area of this letter O) with the area of the surface of a sphere with a radius of twenty-seven light years. Or here is another analogy: If the light radiated by Vega at a particular instant is compared with all of the sand on all of the beaches of the world, then the fraction of the light that will eventually enter my eye is a single grain. No, the analogy is not yet mathematically correct. Let the light radiated by Vega be compared with the entire material bulk of the planet Earth; then the fraction of the energy that will enter my eye is still far less than a grain of sand. It is out of that pinch of starlight that I construct the star.
Lordy, I love to do these silly calculations. And so the universe fills my thoughts. On a typical dark, uncloudy night the light of ten thousand distinctly visible stars might enter my eyes, ten thousand wavelets of energy arriving at slightly different angles from out of the depths of space, colonizing my consciousness. The universe filling my thoughts to overflowing.

We open our eyes and the universe rushes in. Up there several hundred miles above the surface of the Earth is another great eye, one I helped pay for, the Hubble Space Telescope, with a mirror 5 million times bigger than this letter O and no atmosphere to absorb and blur the light of stars and galaxies, keeping its electronic vision fixed on tiny patches of the celestial dome, soaking up photons, soaking, soaking, then beaming the information down to Earth, where you and I try as best we can to assimilate it, to grasp the depth and scale, until our brains feel like they will explode from all that universe, all that depth and scale, all those myriad stars and galaxies, packed into a softball-sized wad of conscious meat. Honey From Stone again:

Starlight blows through my body like wind through the hedge. My atoms ebb and flow in a cosmic tide of radiation. Vega surges into luminescence and electrons do handsprings in the cortex of my brain. Planets are gathered in Vega's dusty brim; I am warmed by their gentle heat. If you sip the sea but once, said the Zen master, you will know the taste of all the oceans of the world. Tonight I have sipped 10,000 stars. I have tasted the universe.

Further Reading

It is more than twenty years since I wrote Honey From Stone, with its wonderful linocuts by my Irish friend Bob O'Cathail (click to enlarge). The book is still in print, in its fourth incarnation.

Discuss this essay and more over on the Science Musings Blog.