It has always been taught that Sir Isaac Newton was born in the same year that Galileo died, 1642. However, certain documents and diaries recently unearthed in Pisa have revealed not only that the two scientists were contemporaries, but that they actually met. This occurred during a summer vacation that Newton spent touring Italy. The find also shows how Newton's universal law of gravitation was derived from Galileo's studies of falling bodies, and explains the legend of the apple. As far as can be reconstructed, it all went something like this.
A warm sunny day in Pisa. The Leaning Tower stands midstage, surrounded by the town plaza. The door at the base faces the audience. As the CURTAIN rises, Galileo, dressed in the traditional manner of the medieval Italian professional class, is sitting in the top gallery of the tower, eating his lunch. Beside him on the balustrade is a flagon of Chianti. On his other side is a wooden lunch box and next to it, a bag of apples. Near him on the top story of the tower, is a pile of bricks and rubble left by construction workers. The moon is visible in the sky near the top of the tower. Galileo selects one of the apples, but as he is about to take a bite, he stops and examines it.
GALILEO Oh-oh. Eesa not so good, this one. (He pulls a face and tosses the apple nonchalantly over his shoulder, but in the same movement inadvertently knocks the lunch box off the balustrade so that both objects fall together out of sight to the rear. A moment later an indignant shout comes from backstage.)
NEWTON Gadzooks!
GALILEO (turning and peering down) Santa Maria! Was accidente. Scusate!
Newton enters from behind the tower. He is wearing an English gentleman's outfit of blue velvet coat with lace ruffs, white breeches, and silk stockings, and he is carrying a cane. He appears, smoothing a dent from his three-cornered hat.
NEWTON (muttering) That travel agent shall hear of this. 'Tis not safe to walk abroad by day in these parts. (He puts his hat back on his head, looks up, and shouts toward the top of the tower.) And what, sir, is the meaning of this outrage? Thou art a menace to decent, God-fearing citizens. What hast thou to say for thyself?
GALILEO (shouting back) I already said, was accidente. Ees not expected for people to be out there in midday sun. You Engleesh?
NEWTON I do have that distinct honor.
GALILEO You okay?
NEWTON It's hardly any thanks to you if I am. Had the luncheon box not fallen a matter of mere seconds after the apple was despatchedas was evidently the caseme brains would have been done in as well as me feather. A negligence suit would have been incontestable, and I can assure you that the sum involved would not have been a trifling one.
GALILEO (curiously) Why you so sure that box falla after apple, eh?
NEWTON A matter of observation and simple logic, my good man. Both objects arrived at the same instant. It is common knowledge, is it not, that in falling, a heavier body will acquire a greater velocity than a lighter one. The box was clearly heavier than the apple. Therefore one is obliged to conclude that it commenced its descent later.
GALILEO Well, ees not so, see. Both falla from 'ere at same time. I am up 'ere. I see.
NEWTON (sighs) That's quite absurd. I have no doubt whatsoever that the two trajectories terminated simultaneously, which contradicts your assertion. Obviously your recollection has been distorted by preconceived notions or a subjective error.
GALILEO Ees no so, Engleesh. I know what I see. Maybe itsa your observations that not so wonderful.
NEWTON (to himself) Hrrmph! What an extraordinary suggestion. (He resumes shouting.) Very well. We'll see about that. Kindly repeat the experiment, and this time watch closely.
GALILEO No, you watch. (He takes another apple and picks a brick from the pile of rubble, then leans out over the parapet.) You ready?
NEWTON (backing to a safe distance) Proceed.
Galileo releases the brick and the apple together. They fall and land at the same time. Newton stares in amazement.
NEWTON 'Pon me soul, the fellow's right! This is indeed a more intriguing business than I had given mind to pondering before. (He looks up.) Perforce I must retract my words. It seems I owe you an apology, sir.
GALILEO Grazie.
NEWTON Do it again.
GALILEO Certamente.
Galileo continues dropping pairs of apples and bricks from the top of the tower. While this is going on, various people enter from left and right. Some exit again, shaking their heads, while others stay to watch. Eventually the stage around the foot of the tower is littered with apples and bricks, and a crowd of curious bystanders has gathered behind Newton. Oblivious to them, Newton looks up once more, and as he does so, he sees the moon above the tower. He straightens up slowly, staring at it.
GALILEO Whatsa matter now down there?
NEWTON (after a pause) I have a conundrum to exercise your wits, sir. Consider as an hypothesis that the tower were constructed as high as the moon itself. That condition satisfied, and given the apple and brick were released without imparted momentum, would they plunge to the ground in the manner we have been observing, or would they remain suspended as does the moon? If the former, then why, pray, does the moon itself fail to obey that same compulsion? And if the latter, what form of agency would preserve them in seeming in defiance of the nature of all objects to fall to the earth? Well, sir, answer me that.
GALILEO You losta me somewhere. Say again.
NEWTON (muttering) Oh, God help us. (In a louder voice) Would they stay up? If so, why? If not, what keeps the moon up?
Galileo looks up at the sky and scratches his head. After a moment or two he looks down again.
GALILEO I gotta one for you. Ask question other way round. Moon goes around Earth like stone on string, yes? So, where ees string? Why Moon not go off on straight line?not, why doesn't eet fall down?
NEWTON (to himself) Egad, a conundrum for a conundrum. Would not the apple and the brick participate also in the tendency to be propelled tangentially? Methinks we have the elements of a contradiction.
GALILEO One force up, one force down. Both forces same, so notheeng movesjust like moon. Ees okay, no?
NEWTON (thinks, then shakes his head and shouts back) The outward force on the apple and the brick would differ by virtue of their different masses. How, then, assuming equality of angular velocity, could equilibrium be preserved for both?
GALILEO Ees okay eef downward forces different too. Brick ees 'eavy, apple not so 'eavy.
NEWTON Hmm, were that true, then the masses would tend to cancel. All objects would describe similar trajectories . . . Aha! And that would imply that all bodies would experience equal acceleration towards the ground.
GALILEO Which ees what I 'ave been saying. Everytheeng 'its ground at same time. Makesa no difference. What you theenk we just been looking at?
Newton stands thinking to himself. For the first time, the sound of the wind becomes audible in the background.
NEWTON This could be a matter of some considerable import unless I'm mistaken. Does there exist, I wonder, some method of formulation whereby these astounding truths might be reduced to some lawful mathematick? (He calls up again toward the top of the tower.) I say, how view you the possibility that these principles might be committed to some system of orderly symbolic brevity? (aside) I'm damned if I can understand anything written in this wretched olde worlde English meself.
GALILEO Ees getting windy up 'ere. What you say?
NEWTON (cupping a hand to his mouth) I said, perhaps we should essay the construction of a precise formulation of these discoveries. Might I suggest that we repair forthwith to an alehouseprovided such establishments be not unknown in these latitudesin search of more congenial surroundings, suitably conducive to discussion. What sayest thou to that?
GALILEO (as the sound of the wind rises) Eh?
NEWTON Oh damnation! (He draws a deep breath and cups both hands to his mouth.) How can we put this into numbers? Are there any pubs near here? . . . Pubsvino, or whatever? . . . Sit down and talk.
GALILEO (nodding vigorously) Ah, si. (He gestures toward the far side of the plaza) There am one or two over de square. One meenute. I come down. (He disappears from sight.)
Newton stands frowning to himself while he waits.
NEWTON What did that fellow say? It sounded like m-one m-two over d squared . . . (He gazes down at the objects strewn around the foot of the tower and rolls one of the apples absently with his foot. Suddenly he gasps.) Good grief, that's it! Why, the man must truly be a genius!
Galileo appears from the tower door. He points offstage and begins walking to the right. Newton remains transfixed. After a few paces Galileo stops and looks back.
GALILEO Why you standa like that, Engleesh? I thought you wanna talk somewhere.
NEWTON (disbelievingly) My dear fellow . . . An insight of sheer brilliance! I am overcome with respect, and I must confess, not a little humbled.
GALILEO What you talkeeng about?
NEWTON You mean . . . (His expression changes at once.) What exactly did you say up there?
GALILEO I said there are a couple of pubs over de square. Ees what you ask, no? (He waits impatiently as Newton produces a notebook and begins scribbling furiously.) What you doeeing now?"
NEWTON (breezily) Oh, merely a few purchases that I was reminded of, which I would not wish to escape my mind. (He stuffs the notebook back in his pocket, straightens his hat, and takes a tighter grip on his cane.) There, that should suffice. Now, where were we? Ah yes, to a tavern. Very good. Lead on, my dear fellow. Lead on.
Black-out. They exit right.