Cassini at Saturn

Cassini at Saturn

Artist's conception of the Cassini spacecraft arriving at Saturn • NASA/JPL (Public Domain)

Originally published 27 June 2004

Each of us is born at the cen­ter of the world.

For nine months our phys­i­cal selves are assem­bled mol­e­cule by mol­e­cule, cell by cell, in the dark­ness of our moth­er’s womb. A sin­gle fer­til­ized egg cell splits into two. Then four. Eight. Six­teen. Thir­ty-two. Ulti­mate­ly, 50 tril­lion cells or so.

At first, our future self is a mere blob of pro­to­plasm. But slow­ly the blob begins to dif­fer­en­ti­ate under the direc­tion of genes. A sym­me­try axis devel­ops. A head, a tail, a spine. At this point, the embryo might be that of a human, or a chick­en, or a mar­moset. Limbs form. Dig­its, with tiny translu­cent nails. Eyes, with papery lids. Ears pressed like flow­ers against the head. Clear­ly now a human. A nose, nos­trils. Downy hair. Genitals.

As the phys­i­cal self devel­ops, so too a men­tal self takes shape, not yet con­scious, not yet self-aware, knit­ted togeth­er as webs of neu­rons in the brain, encap­su­lat­ing in some respects the evo­lu­tion­ary his­to­ry of our species, instincts impressed by the genes. The instinct to suck, for exam­ple. Already, in the womb, the fetus press­es its tiny fist against its mouth in antic­i­pa­tion of the moment when the mouth will be offered the moth­er’s breast.

What, if any­thing, goes on in the mind of the devel­op­ing fetus we may nev­er know. But this much seems cer­tain: To the extent that the emerg­ing self has any aware­ness of its sur­round­ings, its world is coter­mi­nous with itself. We are not born with knowl­edge of the antipodes, the rings of Sat­urn, or the far flung realm of the galax­ies. We are born into a world that is scarce­ly old­er than our­selves and scarce­ly larg­er than ourselves.

And we are at its center.

As I write, the Cassi­ni space­craft, named for the sev­en­teenth-cen­tu­ry astronomer who dis­cov­ered a dark gap in Sat­urn’s rings, is clos­ing in on the giant plan­et. If all goes well, it will be the first space­craft to go into orbit around Saturn.

The craft will dash through the rings, drop a pod onto the sur­face of Sat­urn’s largest moon, Titan, and spend four years study­ing the plan­et and its moons, con­tin­u­ing an inves­ti­ga­tion that began in the sum­mer of 1610 when Galileo Galileo first spied Sat­urn’s rings through a telescope.

Galileo had no idea what he was look­ing at. We see what we expect to see, and who could have expect­ed rings? He guessed that Sat­urn had two big moons, one to either side of the plan­et, moons that inex­plic­a­bly soon disappeared.

Dur­ing suc­ceed­ing decades, oth­er astronomers peered at Sat­urn through their instru­ments, try­ing to unrav­el the rid­dle. The Dutch­man Chris­t­ian Huy­gens was the first to guess the truth — thin, flat rings that are some­times tilt­ed to our view and some­times seen (or not seen) edge-on. Nature has a way of con­found­ing our expec­ta­tions, turn­ing out always to be big­ger, old­er and odd­er than we have supposed.

The Cassi­ni voy­age to Sat­urn is a cul­mi­na­tion of this extra­or­di­nary intel­lec­tu­al adven­ture, a thrust­ing of our species into great­ness, into grandeur, away from the ompha­los — world cen­ter — of our birth.

We are adept at find­ing ways to ignore the world as it presents itself to inquir­ing minds — the world of the light-years and the eons revealed by the sci­en­tif­ic quest. The womb always beck­ons, with its com­fort and secu­ri­ty, its total enclo­sure by a lov­ing, atten­tive par­ent. Per­haps we are genet­i­cal­ly pre­dis­posed to favor ideas of the world in which we are cen­tral. We find a thou­sand rea­sons to affirm the cos­mic impor­tance of self, mis­tak­ing coin­ci­dence for causal­i­ty, acci­dent for neces­si­ty. None of us is immune to the siren call of the omphalos.

Anoth­er uni­verse awaits us. A uni­verse in which the whole of a human life is but a tick of the cos­mic clock. A uni­verse that may con­tain more galax­ies than there are cells in the human body.

The jour­ney into that uni­verse requires courage — for each indi­vid­ual, and for our species. Unique­ly of all ani­mals, humans have the capac­i­ty to let our minds expand into the space and time of the galax­ies. No oth­er crea­tures can num­ber the cells in their bod­ies, as we can, or count the stars. No oth­er crea­tures can imag­ine the explo­sive birth of the uni­verse 13 bil­lion years ago from an infi­nite­ly hot, infi­nite­ly small seed of energy.

That we choose to make this jour­ney — from the pre­sumed cen­ter of the world into the ver­tig­i­nous spaces and abyss of time — is the glo­ry of our species and our most daunt­ing challenge.

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