Science and reality

Science and reality

Ursa Major • Image by Michal Kryński from Pixabay

Originally published 28 March 1988

For the past cou­ple of months I have had a New York­er cov­er tacked on the wall above my desk. The draw­ing on the cov­er, by Eugène Mihaesco, is sim­ple. A pen lays on a white table, its nib dark with ink. An ink bot­tle stands open. The ink in the bot­tle is a map of con­stel­la­tions of the north­ern sky — Ursa Major, Ursa Minor, and Dra­co — includ­ing the stars Dub­he, Mer­ak, and Mizar.

Sim­ple, yet haunt­ing­ly provoca­tive. Again and again I have paused in my work to look at the draw­ing. It seems to sug­gest that the pos­ses­sor of the pen — a poet? an astronomer? — draws inspi­ra­tion from the ink of night. But the star map, with its con­stel­la­tions and star names, is the work of a cre­ative imag­i­na­tion. So the ink in the bot­tle is both the night and an image of the night. Ambigu­ous? Cer­tain­ly, but that ambi­gu­i­ty is an essen­tial part of both art and science.

Does sci­ence describe real­i­ty, or does sci­ence invent real­i­ty? The ques­tion is as old as Par­menides and shows no sign of res­o­lu­tion. I sus­pect that most sci­en­tists are will­ing to live with the ambi­gu­i­ty. They are con­fi­dent that their the­o­ries describe some­thing that is real in the world, but they also know that the­o­ries are cre­ations of the human mind.

Con­sid­er that lit­tle patch of night in the ink bot­tle — the con­stel­la­tions near the north­ern pole. Few groups of stars have so inspired the human imag­i­na­tion as Ursa Major, the Great Bear. The sev­en bright­est stars of the con­stel­la­tion — the stars we know as the Big Dip­per — are so instant­ly rec­og­niz­able that some­times I won­der if the pat­tern might not be genet­i­cal­ly encod­ed in the human brain, the way some birds are endowed with the abil­i­ty to nav­i­gate by stars.

The Greeks pro­vid­ed a charm­ing leg­end to account for the con­stel­la­tion. The nymph Cal­lis­to was loved by Zeus, who trans­formed her into a bear to pro­tect her from the wrath of Hera, his jeal­ous spouse. One day Cal­lis­to’s son Arcas was out hunt­ing in the for­est and raised his bow to shoot the bear, not rec­og­niz­ing his moth­er in altered form. Zeus observed the impend­ing tragedy from Olym­pus, and speed­i­ly inter­vened. He changed Arcas into a lit­tle bear, and placed moth­er and son into the heav­ens where they remain today, arched poignant­ly toward each oth­er, the eter­nal vic­tims of Zeus’ wan­der­ing eye. But Hera had the last laugh; she moved the two bears into the part of the sky near the celes­tial pole, so they would nev­er set and there­fore nev­er rest.

New experiences, new stories

There was a time when images of bears and the sto­ry of Cal­lis­to and Arcas might have sat­is­fied our curios­i­ty about the sky, but the ten­sion between expe­ri­ence and sto­ry has become too slack for the sto­ry to have any cur­ren­cy as sci­ence. Today we have new sto­ries, sto­ries more close­ly tied to our expe­ri­ence of the stars and more con­sis­tent with our oth­er knowl­edge of the world.

Let me dip my pen into Mihaesco’s ink of night and tell the sto­ry of Dub­he, Mer­ak, and Mizar, the three stars that are named on the map in the bot­tle. Dub­he, the star at the lip of the Dip­per, is a yel­low-orange giant 10 times larg­er than the sun and a hun­dred times more lumi­nous. It lies 100 light years from Earth, a dis­tance so vast that it would take a Voy­ager space­craft, such as the craft we sent to Jupiter, Sat­urn and Uranus, a mil­lion years to get there. Dub­he was once a star very much like the sun, but it has deplet­ed its ener­gy resources and entered its death throes, swelling up to devour its inner plan­ets, and boil­ing away what­ev­er oceans and atmos­pheres those plan­ets might have had. Dub­he’s fate will some­day be the fate of our sun.

Mer­ak and Mizar, at the bot­tom front of the Dip­per’s bowl and at the bend of the han­dle, are sib­ling stars, born at the same time from a great gassy neb­u­la and stream­ing togeth­er through space from the place of their birth. They are stars in the prime of life, many times brighter than the sun, and almost cer­tain­ly accom­pa­nied in their trav­els by fam­i­lies of plan­ets. Mizar is a won­der­ful thing to behold through a tele­scope. It is actu­al­ly a sys­tem of two great suns, bound togeth­er by grav­i­ty, cir­cling about a com­mon cen­ter of attrac­tion once every 10,000 years.

Testing inventions

How is it that astronomers can tell such sto­ries, sto­ries more won­drous than any myth of gods and nymphs, when the ink of night offers to the eye only tiny points of light? The answer is both sim­ple and com­plex. We look, we invent, we look again. We test our inven­tions against what we see, and we insist that our inven­tions be con­sis­tent with one another.

And ten­sion! Always we are test­ing the ten­sion of the instru­ment which is sci­ence, observ­ing that the strings of the­o­ry are taut and res­o­nant. The same the­o­ries — of grav­i­ty and dynam­ics, for exam­ple — describe the fall of an apple from a tree and the stream­ing of stars through space. The sto­ry of the falling apple and the sto­ry of the stars res­onate together.

Night is both the ink of our inven­tion and the inven­tion — an ambi­gu­i­ty we have learned to live with. We are con­fi­dent (or we would­n’t do sci­ence at all) that out there in space, 600 tril­lion miles from Earth, the dying star Dub­he burns with the bril­liance of a hun­dred suns. But we also know that Dub­he is our inven­tion. It is for us as it was for the singer in a famous poem by Wal­lace Stevens: “Even if what she sang was what she heard…there nev­er was a world for her/ Except the one she sang, and singing made.”

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