To
discriminate the planet among stars everywhere in the sky would be
almost impossible. If, however, some method could be devised for
localizing that precise region in which the planet's existence might
be presumed, then the search could be undertaken with some prospect
of success.
To a certain extent the problem of localizing the region on the sky
in which the planet might be expected admitted of an immediate
limitation. It is known that all the planets, or perhaps I ought
rather to say, all the great planets, confine their movements to a
certain zone around the heavens. This zone extends some way on
either side of that line called the ecliptic in which the earth
pursues its journey around the sun. It was therefore to be inferred
that the new planet need not be sought for outside this zone. It is
obvious that this consideration at once reduces the area to be
scrutinized to a small fraction of the entire heavens. But even
within the zone thus defined there are many thousands of stars. It
would seem a hopeless task to detect the new planet unless some
further limitation to its position could be assigned.
It was accordingly suggested to Le Verrier that he should endeavour
to discover in what particular part of the strip of the celestial
sphere which we have indicated the search for the unknown planet
should be instituted.
Pages:
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381