A Beam From Arcturus
I
No trees, no hills, no houses. No roads, nor paths, nor glint of running brooks. Simply the Texas prairie, and night closing down to hem the traveler in. The lone cowboy loosens his girths and saddle strings and lets things lie where they fall. He stakes out his pony a few rope lengths away, and comes back to eat a bite and go to bed. With his slicker spread beneath him, he stretches out on his back; and then, with the nape of his neck comfortably settled in the hollow of his saddle, he spends his evening looking straight up. Inevitably he is a stargazer. Thus it was in my day, and so it had been for a long while before. And when you consider that nearly all the stars have Arabian names, it is evident that the herders and horsemen have been stargazers from the first.
I once fell in with a Texas sheep herder who, for lack of anything else to do at night, would go woolgathering among the stars. He was possessed of a mind that could find its way about almost anywhere in the skies. The way he did it was all a mystery to me except that, in passing from constellation to constellation, his mind would use the bigger stars for stepping-stones. And he taught me to find Arcturus, a simple piece of knowledge which I am now able to pass along.
Everyone is supposed to be acquainted with the North Star. Because the North Star is not of the first magnitude, and hardly distinguishes itself from other stars, the Big Dipper is used in finding it. The two stars at the front of the Dipper point directly toward it, some thirty degrees away. Now Arcturus is found by the very same sort of process, conversely. Following along the curve of the handle of the Dipper, the last two stars point out Arcturus about the same distance away as is the North Star from the other end of the Dipper. It is a star of the first magnitude; it is big and beautiful, with a flamelike warmth of color; and once you have set eye on it, you will hardly ever have need of the Dipper to point it out again. This bold and simple step out into the constellations might be the beginning of a lifelong interest, and pleasure in the stars; and if you are young it might cause you to become an astronomer. But, whether it has such effects or not, Arcturus pays.
If someone, in those Texas days, had asked me what good Arcturus was, or what useful purpose it might be made to serve, I should have regarded him with surprise. Arcturus is ‘the shepherd of the stars.’ It is the original diamond in the sky. And though I knew Chicago as the place where all good cattle go, and where they save ‘everything but the squeal,’ I should have been an absolute skeptic if someone had informed me that Chicago was going to put Arcturus to work. But that is what they are now going to do, or something like it!
II
What they are going to do is to start up the big Exposition with the power to be extracted from a star beam. The finger which will set the wheels agoing will not be the finger of a President. That familiar feat of long-distance button pressing is now passée. It was sufficient to excite the wonder of the nineties; but these are different days. The magic touch will now be accomplished by means of a hookup with a star. Instead of earthly force, there will be heavenly light. Instead of President Roosevelt, there will be Arcturus.
There is something very unbiblical about it. ‘ Canst thou bring forth Mazzaroth in his season? or canst thou guide Arcturus with his sons?’ — thus the question is put in the book of Job. And the answer is Yes. There will be direction and guidance of a finger of light extending earthward from this same star of the Bible.
‘Canst thou send lightnings, that they may go, and say unto thee, Here we are?’ — thus continues the voice out of the whirlwind. And again the answer is Yes. The star beam, after it has struck the objective of the big telescope, a lens forty inches in diameter, will be directed down the 63-foot tube into a photo-electric cell. Here it will generate a current of electricity which will pass through a system of amplifiers and out on a telegraph wire. Obeying man’s behest at every crook and turn, the lightnings thus engendered will go eighty-odd miles to Chicago, where they will throw wide the gates, and start up the machinery, and say most effectively, Here we are !
In choosing Arcturus for the work, the planners of the Exposition were guided by reasons and motives largely sentimental. This star is forty lightyears away, a distance that may be computed by remembering that light travels at a speed of 186,300 miles a second. Since the former fair at Chicago was held forty years ago, the oncoming star beam is one that was just starting on its way to Chicago at the time of the World’s Columbian Exposition. Then too — a point not to be neglected when sentiment is to the fore — the materials which make up this star, as shown by the spectroscope, are the same as those which compose our own sun. Stars belonging to the Arcturian classification are made up of protocalcium, iron, calcium, manganese, protostrontium, and hydrogen; and, since our sun belongs to this order, the choice of Arcturus contains, from the astronomical point of view, a pretty touch of local allusion.
Nor is this view as far-fetched as might appear. Owing to the increased power of telescopes, our idea of creation is constantly enlarging. The astronomer aims his instrument more deeply into some nook of the sky, and discovers whole universes holding sway in spaces heretofore unsuspected. At present writing, there are estimated to be 30,000 million suns in our own sidereal system; and there are more than two million such systems or galaxies. And this is not counting the dark stars, which betray their presence by interfering with the light of others. There are fixed stars or suns millions of light-years away, a distance which makes Arcturus, with its forty lightyears, seem rather near. The light of our own sun, on the other hand, is but a few minutes in reaching us. So we may easily understand that an astronomer who has just been on one of those longer journeys into space might feel, as he turned his thoughts to the sun, that he was getting quite near home. And when he is choosing a star to press the button of an exposition here on earth, he may be excused for taking into account its resemblance to our own sun, and, indeed, regarding his choice with a certain feeling of local patriotism and sectional pride. As a matter of mere utilitarian fact, any other star could have been made to do the work about as well as Arcturus.
From the point of view of the backyard astronomer, there could hardly have been a better choice. Arcturus is a spring and summer star — one which does not, like Aldebaran or Betelgeuse, require you to stand outdoors and admire it when the thermometer is below zero. Since the cold nights are the clearest, astronomers have to be faithful winter workers; they must pursue their task in even the coldest weather without benefit of fire. Any artificial heat in the observatory would escape through the opening at the top and cause tremors in the atmosphere which would distort the image. A professor of the University of Chicago, getting ready to go to work upon the winter stars, dons a big, shaggy overcoat such as might cause him to be mistaken for a visiting cattle drover. During the unusual cold weather of last fall and early winter, they put on their airplane outfits and brought forth foot warmers reminiscent of horse-and-buggy days. This is a point to be kept in mind when one is deciding whether he will become a real astronomer or only an admirer of the summer skies. Arcturus, culminating in June, is decidedly a pleasant star to look at.
III
The predestined beam will come to earth near the shore of a beautiful lake in southern Wisconsin, this being the site of the largest refracting telescope in the world. The Yerkes Observatory is a long, low, Romanesque building of brown brick and terra cotta; and the big dome which dominates its 326 feet of length and two minor towers gives it a tremendously intellectual look.
Upon entering this dome, 90 feet in diameter, one finds himself on a great expanse of wooden floor — a space sufficient to accommodate a metropolitan grand ball or the four rings of an ordinary circus. Your friend the astronomer touches a button and the floor begins to rise with you; but, since the chairs and stepladders and other furniture all go along, you are not aware of the motion until you perceive that the cast-iron pediment of the telescope is sinking through and growing shorter. You are surprised to learn that the movable parts of the telescope, comprising a total weight of 20 tons, of which the tube alone weighs 6 tons, can be easily swung into position by hand; and that this floor, itself weighing 37 1/2 tons, will rise and fall through a distance of 23 feet, and accommodate itself to any position of the eyepiece. Various attachments for photography, spectrography, and photometry are used to take the place of the eyepiece, the new photometer alone weighing 55 pounds, and being bolted on by means of a ring 19 inches in diameter.
It is not till you look at the great size of these small details, and consider the clock which keeps the tube traveling in time with the machinery of the universe, that you begin to have a true appreciation of this noble instrument. Because clear nights are none too numerous, and because the refracting type of telescope is the only kind that can be used to work upon the sun, its every moment is occupied. The observatory has a large staff of workers, notable among them being Edwin Frost, the blind astronomer who recently retired from the directorship, and George Van Biesbroeck, a new citizen of ours who was formerly astronomer of the Royal Observatory in Belgium. The new director is Dr. Otto Struve.
The first question that the visitor asks upon viewing such a large telescope is, naturally enough, ‘How much does it magnify?’ Meaning thereby, ‘How much bigger does it make a star look?’ And the answer is, ‘Not at all.’ A star viewed with the naked eye is just a point of light. Viewed with the telescope it is still just a point of light. It remains a shining thing without a visible body. The most powerful telescope is unable to make a ‘disc’ out of a star. Any feeling that one is going to get behind the brilliancy and pry into details is bound to be disappointed.
This does not hold true, of course, when the astronomer is looking at the planets. The Yerkes telescope will show Mars about the size of a man’s thumb nail. This small company of dead worlds, accompanying the earth on its travels around the sun and shining by reflected light, belongs to our own home acre of space. The moon, that planet-of-a-planet, shows up with a most blistery and volcanic surface. But when the telescope is aimed at anything beyond the planets, any magnification may not be looked for. The distances are too inconceivably great. While there must be magnification, scientifically considered, it is of no avail in making the object larger to the camera or the eye.
If the Yerkes telescope were placed at the distance of a star and pointed at our own solar system, the earth and its companion planets would not be visible. Only the sun, greater in size and shining by its own fires, would make itself known. Conversely, when the Wisconsin telescope is centred upon one of these luminaries of the night, all of them suns shining by their own fire, we have no means of knowing whether they have their own planets or not. Such bodies would be too small and too pale for any telescope to distinguish. Outside of our five visible planets and the moon, all that we see at night are suns. Of these suns, Arcturus is a thousand times the size of our own.
The telescope on the shore of Lake Geneva, Wisconsin, increases the brilliancy, the light-strength, of any luminary 40,000 times. But that is different from what we ordinarily understand by magnification. This light-gathering power reaches out into space and brings to view galaxies that no eye could ever see, especially when used in connection with the photographic plate. By means of the spectroscope and the photo-electric photometer the astronomer may determine the distance, speed, and composition of stars in a way quite incomprehensible to the layman. It is this greatly condensed light-strength from Arcturus that will hit the interior of the photo-electric cell and knock loose electrons from the atoms composing the inner coating of hydride of potassium. The power coming from the star will thus be transformed into electric current; and this, when amplified, will serve to set machinery in motion.
IV
If I have rather emphasized the inability of the big tube to give contour and body to a star, it is with the idea of lending encouragement to the honorable company of back-yard astronomers. Many of them this spring and summer will be pointing out Arcturus. Let not the humble shepherd nor the desert-dwelling horseman forget for one moment the great achievements of the naked-eye astronomers. Ptolemy was one; Tycho Brahe was one; Copernicus was one. These men had no optical helps at all, only such lensless straightedges as could be aimed like a gun.
It is also worth remembering, and reflecting upon, that, the calendar as we have it to-day, which remains unsusceptible of any real mathematical improvement, came to us straight from astronomers who worked with the eye alone. Originally known as the Julian calendar, it was devised before the birth of Christ. And so far as it became the Gregorian calendar by virtue of an added calculation, that final perfection also came before the invention of the telescope. Let the back-yard astronomer, inheriting his craft from the shepherds of Chaldea, think upon this and be comforted. Let him not say, as he gazes this spring upon Arcturus, ‘O that I had a little telescope, or even a good field glass.’ Let him remember that he is dealing with the stars, the thousands of far-distant suns, and not a few mere planets. And if he goes to the World’s Fair, let him look aloft and remember that the managers had the shrewdness to include Arcturus among its most powerful attractions.
There is no more democratic body of scientists than those who work in our big observatories. They are not forgetful of what has been achieved by the amateur in the line of pure discovery. They cannot themselves do it all. That field with trillions of suns is too large a flock for any mortal shepherd to take care of. There are variable stars that need a regular checking-up, and these are systematically parceled out among amateur observers. There are even temporary stars, such as the star of Bethlehem is said to have been, and these have need of the opportune discoverer. The mere amateur, boasting nothing more than a pocket telescope, has been known to capture a comet or bring to attention some other heavenly novelty. When this happens he lets an observatory know about it, and then the big guns of astronomy set to work and wrest from it the ultimate secrets of its being.
V
The Yerkes Observatory is in the next county but one from where I live, and I have repeatedly had the idea of going down there and asking certain questions. I wanted to find out something about the new photometer with the hydride of potassium cell at the heart of it. More especially I wanted to look in at the little clear space or window on top of the quartz bulb through which the beam from Arcturus would pass. Finally, on a drear November day such as will prompt a man to do anything by way of a change, I got into the car with my wife and headed south.
Having arrived at the observatory, I got into a wrong entrance; and then I walked along the 326 feet of front looking for the right button to press. A lucky touch at a promising doorway brought forth a young lady who, without asking any questions, ushered me at once into the office of Dr. Clifford C. Crump. Dr. Crump, in addition to being an astrophysicist, is secretary and librarian to the largest lens in the world.
Now ensued a quite unexpected outcome. Early in my visit I happened to make mention of Shakespeare. From that time on we spoke of nothing else. Dr. Crump, who has recently gone back to his first love in literature, responded with all the warmth of a new convert to Shakespeare. He proposed a solemn compact which I agreed to. At an opportune time I was to read a Shakespeare play through with him, and he in turn would allow me to see the universe through the forty-inch lens. It was a bargain such as a man would be foolish to refuse in these dollarless days.
I seized upon it with the reflection that a man can sometimes get the most valuable goods in the world for practically nothing.
More than two hours passed before we could bring our visit to an end; and then it was so late in the evening that only a few minutes remained for us to go and have a look at the photo-electric cell, upon which Professor Elvey had just been doing some work.
When I awoke the next day it dawned upon me that I had asked hardly any of the questions I intended to ask, although I had seen all that I wanted to see. I had to make another trip to Williams Bay with this original purpose in view.
I cannot but regard this as a great victory for Shakespeare. It was a triumph for poetry and the drama in the very inner courts of modern science. Shakespeare was indeed one of the ‘earth-treading stars.’ Like Sirius or Vega or Betelgeuse, he was made, not for an age, but for all time.