The Planets (9 page)

There will be time enough, after Darwin returns to England, for him to marry and put the concerns of his children ahead of his own, to wander in circles for years of private thought as the souvenir birdskins and other mementos from the Galápagos help him divine the secret of life’s diversity.

For now, hunting fossils, “geologizing,” climbing the Andes, he ponders the forces that can uplift such massive mountains over ages, or grind them to gravel, or make them tremble.

“February 20
^th
[1835]—The day has been memorable [here] in…Valdivia, for the most severe earthquake experienced by the oldest inhabitant. I happened to be on shore, and was lying down in the wood to rest myself. It came on suddenly, and lasted two minutes; but the time appeared much longer. The rocking of the ground was most sensible. The undulations appeared to my companion
and myself to come from due east; whilst others thought they proceeded from south-west; which shows how difficult it is in all cases to perceive the direction of these vibrations. There was no difficulty in standing upright, but the motion made me almost giddy. It was something like the movement of a vessel in a little cross ripple….”

Indeed, the continents themselves are voyaging. They ride as passengers aboard great slabs of the earth’s crust in constant motion. In 1912, German geologist Alfred Wegener explains that the east coast of South America complements the western edge of Africa because the two continents are pieces of the same jigsaw puzzle. Once in a prehistoric era they lay cheek by jowl, part of a single land mass Wegener calls “Pangaea” (“All-earth”), surrounded by the waters of “Panthalassa” (“All-sea”), before geological forces pulled them apart.

Today the Old World and the New continue to recede from each other along a still-widening rift in the mid-Atlantic, where molten material wells up from inside the Earth and lays down new ocean floor. As the Atlantic spreads, the Pacific shrinks. Under the restless coasts of Peru, Chile, Japan, and the Philippines, old, cold ocean floor is plunging back into Earth’s infernal interior, to the
accompaniment of earthquakes and volcanoes, and sometimes catastrophic tsunamis.

The ocean bottom undergoes constant recycling, and no part of it is older than two hundred million years. The continents, in contrast, stay topside through the ages, eroded but still intact after four billion years. Instead of sinking under each other, the continents wrinkle when the stress of contact deforms their crust: The Appalachian Mountains testify to an ancient collision between Africa and North America, while the ongoing pressure on the Himalayas continues, even now, to increase their altitude.

Modern explorations conducted by submarine and spacecraft reveal the true, apolitical network of Earth’s borderlines, hidden underwater. Mid-ocean ridges and complementary coastal trenches divide the surface of the globe into a mosaic of some thirty plates, each one carrying a piece of a continent, a part of a sea floor. The mosaic pattern changes as plates separate, collide, or grind sidewise past one another, impelled by the pent-up residual heat of the Earth’s violent birth and ongoing radioactive decay.

The seismic shocks that pierce the Earth during earthquakes permit the deepest possible
introspection. They suggest the continents and ocean floors cast only a thin skin, or crust, around the planet. This crust slims to a slender mile under some ocean areas, while the continental crust averages a thickness of twenty miles plus, yet the crust in its entirety accounts for only one-half of one percent of Earth’s mass. The great bulk of the planet (about two-thirds of its mass) consists of the rocky yet fluid mantle roiling between the crust and the core. At the center of the Earth, part of the iron-nickel core has already cooled to a solid ball. Seismologists can hear it rotating independently inside the still-molten outer core, turning almost one second a day faster than the rest of the world.

Like the hidden levels of the inner Earth, the invisible layers of Earth’s atmosphere have also been charted, from low in the troposphere, up through the stratosphere and mesosphere to the top of the thermosphere. The magnetic field and radiation belts surrounding Earth can be mapped from space. Also from space, a network of global positioning satellites can pinpoint locations—even individuals—on the planet with centimeter accuracy, while laser beam reflectors planted on the Moon by Apollo astronauts gauge the exact Earth-Moon distance.

Earth’s place in space is now known to such confident extremes of accuracy that the most recent transit of Venus, on June 8, 2004, was relegated to the status of a tourist attraction—a chance to see an anomaly unknown to any living soul, given the date of the previous transit, on December 6, 1882. In the interim between that transit and this, the extent of the known world had expanded to include additional planets of the Solar System, extrasolar planets in the Galaxy, and the configuration of the Milky Way itself, twirling through space with billions of stars in its spiral arms. A longer view into the infinite takes in the other galaxies of our Local Group, and the clusters and superclusters of galaxies stretching out in space and back in time to the birth of the universe. But even this sophisticated sense of our surroundings, like Ptolemy’s map, captures only the present moment’s self-awareness.

*
Since the Sun appears to circle the sphere of the earth, 360 degrees around, once every 24 hours, Ptolemy calculates each hour’s time difference as 360 divided by 24, or 15 degrees of longitude.

*
Kepler’s third law of planetary motion, published in 1609, expressed only the relative distances among the planets, based on the revolutionary period of each. No actual distances had yet been calculated.

D
uring the glory days of the Apollo project, a young astronomer who analyzed Moon rocks at a university laboratory fell in love with my friend Carolyn, and risked his job and the national security to give her a quantum of Moon dust.

“Where is it? Let me see!” I demanded at this news. But she answered quietly, “I ate it.” After a pause she added, “There was so little.” As though that explained everything.

I was furious. In an instant I had dropped from the giddy height of discovering the Moon right there in Carolyn’s apartment to realizing she had eaten it all without leaving a crumb for me.

In a reverie I saw the Moon dust caress
Carolyn’s lips like a lover’s kiss. As it entered her mouth, it ignited on contact with her saliva to shoot sparks that lodged in her every cell. Crystalline and alien, it illuminated her body’s dark recesses like pixie powder, thrumming the senseless tune of a wind chime through her veins. By its sacred presence it changed her very nature: Carolyn, the Moon Goddess. She had mated herself to the Moon somehow via this act of incorporation, and that was what made me so jealous.

Of course I had heard the old wives’ tales advising women to open their bedroom curtains and sleep in the Moonlight for heightened fertility or a more regular menstrual cycle, but no folklore described powers to be won from the Moon by eating its dust. Carolyn’s deed conjured Space Age magic, undreamed of when her mother and mine were new wives.

I still envy Carolyn her taste of the Moon. In reality I know she is married now to a veterinarian in upstate New York and has three grown children. She doesn’t glow in the dark or walk on air. She has long since lost all traces of that Moon morsel, which no doubt passed through her body in the usual way. What could it have contained, anyway, to preoccupy me all these years?

A few grains of titanium and aluminum?

Some helium atoms borne from the Sun on the solar wind?

The shining essence of all that is unattainable?

All of the above, probably, all rendered the more extraordinary for having traveled to her across 240,000 miles of interplanetary space, in the belly of a rocket ship, and hand-delivered as the love token of a handsome man. Lucky, lucky Carolyn.

The Apollo astronauts themselves did not intentionally swallow any Moon dust, though it clung to them, covered their white boots and space suits with grime, and so climbed with them back into their lunar modules. The moment they removed their bubble helmets, a smell of spent gunpowder, or of wet ashes in a fireplace assailed them. It was the Moon dust, tamely burning in the oxygen atmosphere the men had carried from home. Outside on the airless lunar surface, did the trodden dust give off any odor of its own? Does a tree falling in a forest make a sound if no one hears?

The astronauts judged the dusty surface of the Moon a shade of tan, like beach sand, when they looked at it facing Sunward, but said it turned gray when they turned the other way—and black when they scooped dust samples into plastic bags. The
unearthly glare of unfiltered Sunlight bedeviled their color and depth perception, and that of their photographic film as well. Similarly attuned to the light of Earth’s atmosphere, the film formed its own interpretation of the new landscape’s subtle hues and stark relief, so that in the end the men’s pictures betrayed their color memories of walking on the Moon.

The view of the Moon from Earth is no less fooled by tricks of light. How else could the Moon derive its silvery gleam from dust and rocks dark as soot? The dusky markings that draw the face of the Man in the Moon reflect only 5 to 10 percent of the Sunlight that falls on them, and the brighter lunar highlands no more than 12 to 18 percent, making the Moon overall about as shiny as an asphalt roadway. But the rough-hewn lunar surface, sprinkled with ragged particles of Moon dust, multiplies the myriad planes where light may strike and ricochet. Thus the tan, gray, black dust clothes the Moon in white radiance. And seen against the somber backdrop of the night sky, the Moon appears whiter still.

Whiteness defines our image of the Moon, except for those occasions when it hangs golden on the horizon, burnished by added thicknesses of air,
or dips into Earth’s shadow and glows red in total lunar eclipse. No one ever seriously believed the Moon looked green in color, only that it resembled a green cheese—a whitish, splotchy wheel of new-made curds, not yet ripe for eating. True, the Moon may turn blue after a volcano sullies Earth’s atmosphere, or be called blue when it becomes full more than once per calendar month, but the reliable whiteness of the ordinary Moon is what grants the idiomatic Blue Moon its air of rarity.

While white light bouncing off the Moon contains every color, Moonshine perceived on Earth mischievously bleeds familiar sights of any color. The full wattage of the full Moon dims in comparison to direct Sunlight, by a factor of 450,000, and so falls just below the retina’s threshold for color vision. Even the brightest Moonlight induces pallor in each face it illuminates, and creates shadows like oubliettes, where all who enter disappear.

The wan colors of Moonbeams bloom in Moon gardens planted with lilies, angel’s trumpet, sweet rocket, and the like, all of them white or nearly so, or prized for their nocturnal habits. The giant Moon flower, evening’s answer to the morning glory, opens its white petals at day’s end, as do its companions the four-o’clocks, the vesper iris, and
the night gladiolus. Evening primrose also finds welcome in Moon gardens, despite pink blossoms, because the primrose wafts its perfume after dark.

The Moon itself refuses to be confined to the night. It spends half its time in the daylight sky, where many people take no notice of it at all, or mistake it for a cloud. Only for a few days each month does the Moon truly vanish, rendered invisible in the vicinity of the Sun. The rest of the time the inescapable Moon changes shape by the hour, waxing and waning and whining for attention.

The first sight of the young Moon arrives as a smile at twilight. Though only the slimmest sliver of silver crescent shines on us this early in the Moon’s monthly cycle, the rest of the Moon reveals itself in just-discernible form, as though the old Moon were lying in the young Moon’s arms. Leonardo da Vinci, sketching the Moon at such a time, recognized the faint light cupped inside the bright crescent as Earthshine. The phantom Moon, Leonardo explained in the crabbed, left-handed mirror writing of his notebooks, catches the Earth’s reflection of the Sun, and beams back an attenuated echo.

By the time the Moon moves one quarter of its
way around the Earth, the Sun’s light covers half the Moon’s face, like the icing on a cookie with precise hemispheres of chocolate and vanilla. Soon the terminator—the day-night line—arches like a bow, and still more of the lunar surface lights up as the Moon gains its gibbous phase. These stages of lunar expansion, unfolding from the dark of the Moon through crescent, quarter, gibbous, and full, promise growth. Herbals and farmers’ almanacs commend the waxing phases as proper times for sowing peas, harvesting root crops, and pruning trees to assure abundant fruit. Timber, however, by the same token, must never be taken in a waxing Moon, because wood wet with rising sap will resist the saw, requiring harder work, and after cutting it will warp.

The full Moon rising at Sunset raises an illusion of grandeur that doubles or triples its apparent size. The splendor of this sight derives from the mind’s own sense of the horizon as a faraway place where anything that looms large must be huge indeed. Later on in the night, once the Moon has ascended the sky, where a different distance scale applies, the Moon resumes its normal dimensions, though the world below be mad. Dogs bay, coyotes howl,
lycanthropic men morph into werewolves, and vampires prowl under a full Moon. More crimes are committed, more babies are born, more lunatics run amok. Or so some claim, since the full Moon’s startling light, almost bright enough to read by, sustains a prevailing expectation of mayhem.

Every full Moon of the year has earned at least one name tying it to lost seasons of tradition—Wolf Moon, Snow Moon, Sap Moon, Crow Moon, Flower Moon, Rose Moon, Thunder Moon, Sturgeon Moon, Harvest Moon, Hunter’s Moon, Beaver Moon, Cold Moon—though no such tributes apply to any of the Moon’s other phases.

The state of technical fullness, when the Moon stands opposite the Sun in Earth’s sky, lasts only a minute in the monthly life of the Moon. A moment later, as the Moon yields to decline, darkness encroaches from the right, retracing the path of the previous light. One by one the features drop from the face of the Man in the Moon—or the rabbit in the Moon, or the toad—in the same order they showed themselves before. First to come or go is high, round Mare Crisium (the Sea of Crises), followed, as in some fantastic Latin incantation, by Lacus Timoris (the Lake of Fear), Mare
Tranquillitatis (the Sea of Calm), Sinus Iridum (the Bay of Rainbows), Oceanus Procellarum (the Ocean of Storms), Palus Somni (the Marsh of Sleep).