Halley's Comet - Amazing Prisoner of the Sun
A paper written for the Fortnightly Club, Redlands, California
March 1, 1979
Frank M. Toothaker
The Hebrew Scriptures assure us: “In the beginning God created the heavens and the earth, and the earth was without form and void, and darkness was on the face of the deep.” That was the writer’s way of saying with the scientist: That was the big boom. The Biblical story pays attention to the land and sea, the sun, moon and stars, but fails to mention the comets. Could it be that the Star of Bethlehem was a comet?
The writer of this paper has no status as a scientist. Nothing but an eager curiosity got him into this adventure. In 1910 he belonged to the senior class of the Dinuba (Calif) High School, and the class was about the business of rehearsing their commencement play. The rehearsal was over, and the fourteen players gathered at the western windows where Halley’s Comet flaunted its tail from the horizon to the zenith. All else must feel the dominance of such an amazing phenomenon. Fourteen pairs of elbows leaned on the window sills; fourteen tongues kept silence for a long moment, then came the questions: “Do you suppose any of us will see this again?” The Armenian dentist is gone, the Transamerica Vice-president is gone, the two beautiful Catholic girls are gone, the friendly Jewess has joined the daughter of the Disciples of Christ preacher. Only one of the fourteen is hanging onto a chance, come 1986 A.D.
Now back to 1910, not in Dinuba but in Redlands, a place often honored by rich visitors and honored Americans. Halley was visiting Redlands but did not rate a full page in the Redlands Daily Facts. Teddy Roosevelt had a page front copy. The University of Redlands merited a spread to celebrate its first Commencement. King Edward’s funeral pushed Halley to one side. Even Julia Ward Howe’s 91st birthday made page one. Even at that Mr. Moore alerted his readers to this streaking visitor from the skies.
What is a comet? It certainly isn’t something you can use to kill the germs in your bathroom, even if you buy two cans. Nobody has yet described it in terms that fit all observations. For example state: “Comets have tails”. Generally so, but some comets have no tail. In trying to say what a comet is one astronomer rather joked: “A comet is a cloud of meteors surrounded at times by a gaseous envelope”. Scientists gather up the hard facts of repeatable observation, observe, test, pursue and classify, and tell us their assumptions. Let us as rank amateurs do the same.
Look, there is the early morning or in the darkling evening is a miraculous streak of light. The tip offers a glowing envelope, called the coma, within which a brighter body of material, often a long arrow of brilliance, is named the nucleus. Streaming off away from the nucleus and coma is the tail, sometimes millions of miles long. The entire apparition never fails to keep its coma aimed in the direction of the sun, and its tail away from the sun. The whole object must be nebulous, having very little solid material in it. On an occasion when the comet came between the sun and the earth it produced no shadow earthward. The tail especially is so insubstantial that even a weak star shines through it.
But material substance does challenge the observer. In the seventeenth century Edmund Halley went to visit Isaac Newton, of falling apple myth, with whom he was collaborating. Had Newton been able to do anything with his problem of gravitation? Well, yes. He had become convinced not only that the earth-mass pulled toward itself all other masses. And further, that other masses exerted a gravitational pull on the earth. All of that proved that the sun never relaxed its gravitational pull upon the comet, and therefore there was material substance in it.
A next question invited the use of mathematics to plot the path of the comet, whence it came and went. Nobody yet conceived the fact of the elliptical orbit of the periodic comets. Halley stuck his neck away out in predicting the reappearance of the comet now bearing his name, and plotting the path by which it would come, and the time sequence.
The mystery of the nucleus of the comet called out various instruments to help the astronomer. First was the telescope. It helped bring into view faint and distant bodies, but did not explain much about their substance. Then came the camera providing records of the amount and direction of movement. Newton has already discovered the nature of light, all colors combined making white light. The prism, breaking up light enabled the comet observer to identify some of the materials involved. Bands of luminous gases in the nucleus told of elements and molecules of material, and proved them to be the same as the materials of the solar system – Cyanogen, Carbon, Methane, Ammonia, Carbon monoxide, Carbon dioxide, Calcium, Iron, Mercury and others. However, from there on the mystery must deepen because the best of scientists cannot agree upon the why of it all. One says the nucleus he is studying is really a frozen ball of gas.
A late comer in the quest for knowledge is a pair of orbiting observatories, developed by NASA. Now for the first time these observations are not filtered through earth’s atmosphere. When a space probe is enabled to fly close to a passing comet it will surprise human observers. Numbers of intercepts fill the drawing boards, waiting for a first trial. To date the Orbital Astronomical Observatory has found a vast envelope of hydrogen around Comet Tago-Sato-Kosaka measured to a diameter of a million miles, and Comet Bennett in a cloud of hydrogen calculated to be eight million miles in diameter. The Tago-Sato-Kosaka comet was examined by ultra-violet light. With this procee at hand we can expect the astronomer to come up with some answers to today’s unknowns.
We have not touched the question: “Where does a comet come from?” We are back in the field of guessing. Did some power gather up cosmic dust left over from the “big boom” and motivate it as we observe its motion? Are these emissions erupted from the planets, or their satellites? Are they captured bits of space dust? Solid knowledge appears to be primitive and inconclusive. Evidence exists that the emissions carry electric charges, some negative, some positive.
We can ask the plaguing question: “Why is a comet?” Why did some of the solar stuff organize itself into a mobile unit which streaks toward the sun, swings around it, but never plunges into it, and then speeds away? And, where does it go? Why, as we now know, do some comets follow a parabolic course and are never seen again? A general consensus now holds to the conviction that no material escapes from the solar system, and that no comet goes too far from its sun that it never returns. The time factor might be millions of years which is a bit difficult to work with. Nevertheless, comets which have appeared in recent years are being tentatively dated for return. Comet Ikeya-Seki (1968 I) is scheduled to reappear after 89,000 years and Comet Tago-Sato-Kosaka (1969 IX) may be expected here after 419,000 years. Many short period comets pass perihelion. Perhaps most well know is Encke which passes the sun every 3.3 years. Strangely, it completes its orbit in less time each successive pass, about two and one half hours less. Encke held a theory to explain this speedup: That a certain resistance to the comet’s pass at perihelion accounted for the increase of its velocity. Since I cannot understand the argument I shall spare you.
Halley’s Comet incited this paper. As of today the world has some seven years to prepare for its reappearance. The time space between appearances has been varied because of interferences of the great planets, varying as much as five years.
Edmund Halley was the first person for whom a comet was named. He was born into a family having financial means whose parents took care to see that he received a first class education in classics and mathematics. First it was St. Paul’s school, then at Queen’s College, Oxford. His keen mind caught the attention of Joseph Moxon, a globe maker employed by King Charles II. Halley read the globe so sharply that Moxon remarked, “If a star were misplaced he would presently find it”.
Halley had at his disposal a £300 annual allowance from his father. Thus as he advanced in Queen’s College he acquired the use of a 24” telescope with which he observed a lunar
eclipse. In 1676 he discovered sun spots, a phenomenon previously unknown. At the age of 20 he began communicating with the Royal Society. About that time King Charles II began to take an active practical interest in astronomy. He sought to map the skies of the northern hemisphere with greater accuracy. To that end he employed Robert Hook and Sir Christopher Wren to design and build an Observatory on Greenwich Hill. At this juncture the British East India Company offered Halley an expense paid trip to the island of St. Helena. In spite of leaving his college before graduation he took the trip. He now looked at the skies of the southern hemisphere. Imagine his thrill at the opportunity that enabled him to plot over 300 stars in that sky and to find a new constellation. He honored his king by naming the constellation Robur Carolinum. In response the King, knowing that Halley had been denied his degree by Oxford, ordered that the Master of Arts be conferred on him. It was done. By the age of twenty two he was made a member of the Royal Society. As a scientist he gained stature by devising a system for measuring distances between objects in the solar system. In 1687, working with Isaac Newton he began plotting the orbits of comets. He uncovered the records of the passage of thirty comets between the years 1300 and 1600 A.D. Before 1704, using European sources he had calculated the orbits of 24 comets. He found that Chinese sources provided more and better records of appearances as far in the past as 240 B.C. Biblical inferences pointed back to 840 B.C. but the records could not support much scientific weight.
The apparition never fails to get human attention, amazement and often fear. Common people greet it with all kinds of interpretations, many of them as harbingers of evil. A comet in 71 A.D. prefigured the destruction of Jerusalem by Rome. Many believed that the death of Mahomet or Charlemagne or Attila or Philip Augustus had been portended by comets. When Julius Caesar met his Brutus the Latin Suetonius pronounced “It was a celestial chariot to convey his soul heavenly”. In 79 A.D. a comet supposedly foretold the death of Vespasian, but the emperor cut that notion to size, saying, “Be not so set up. The hairy one does not portend the end of me. The king of the Parthians is a hairy one, and I am bald”. When Halley’s Comet recurred in 1066 A.D. common gossip said it foretold the success of the Norman Conquest. The weavers of the Bayeux tapestry incorporated it where visitors may view it today. Shakspere gathered all the superstitions into one verse:
“Threatening the world with famine, plague and war,
To princes, death; kingdoms and many curses
To all estates, inevitable losses;
To herdsmen, rot; to ploughmen, hapless seasons;
To sailors, storms; to cities, treasons”.
We should suppose that such senseless anxieties were a thing of the past. Hear this: In 1910 Stephen Gardener of Pasadena dug and furnished a cave for himself in which he took refuge. A writer, George Cutler joked about it. He asked, “How can you be safe from the comet?” Pay up your subscription to the newspaper, and be good”. In Albuquerque a rich rancher died from taking poison. He told his neighbors he didn’t care to live in a beautiful world after Halley’s Comet had destroyed it. Fortunately most people rejected panic. Actually the earth passed through the tail of the comet and no one felt any sort of shock. At an earlier date youthful Harry Emerson Fosdick viewed a comet, then begged his father’s permission to run out and bring it home.
1979 sees us looking ahead the seven years for the reappearance of Halley’s Comet. Large telescopes will identify its appearance as early as 1984, and it may come into eye vision by 1985. The best view is projected for Nov. 18th 1985 at night and early morning in the skies nearest the Pleiades. The next best viewing is expected for the evening of April 15, 1986. At this point we must restrain our eagerness. We are not likely to see the brilliant apparition we saw in 1910. The comet will be three times as far from earth as it was previously. Again, we the people have in seventy six years sent up vast clouds of smog. Third our cities have turned on millions of kilowatts that turn the night sky over such wide expanses that we have created a permanent twilight. Even an observatory fifty miles distant finds this quite unacceptable. For this pass we must look to the less developed Southern Hemisphere for best viewing.
In spite of these hindrances the astronomer refuses to surrender. A few million dollars funding must be multiplied many times to take better equipment and better knowledge. The close study opportunity comes only once in 76 years and scientists believe it worth the price and the preparation.
Dr. Donald K. Yeomans of Jet Propulsion Laboratories in Pasadena has calculated with the greatest of accuracy the orbit of Halley, taking into fullest account the perturbations caused by the comet’s passage near the nine planets. We may also be amazed that his tracing of Halley’s orbit may set up the possibility of the existence of a previously undreamed planet. If so the orbit of that planet would provide a day of 464 earth years.
From the Lawrence Radiation Laboratory at the University of California, from NASA, from Harvard and the Smithsonian Center scientists are busy with preparation. Two instrumental probes are considered. One, urged by NASA plans an instrumental space craft propelled by derivatives of mercury. Active work on this project is to be centered in Kitt Peak, west of Tucson, Arizona. The second research proposal will call for the creation and launching of a solar sail or kite with a sweep of several miles. The kite, if built as planned, will be unfolded and serviced with power of solar radiation. The goal is to maneuver the kite to within two kilometers above the coma of the comet, from which close proximity many different readings can be made and transmitted to earth.
During the reading of this paper Halley has covered about 60,000 miles of space. On Feb. 9, 1986 it will still require three and one half hours to whip around the sun and start off on another orbit of about thirty four billion miles. Halley invites you to search the skies and receive your reward. If you are determined to enjoy the best possible view you may wangle an invitation to join Editor for the Redlands Daily Facts, Frank Moore for the flight to South America “where every prospect pleases” and smog is not as vile.
Encyclopedia Britannica. Volume 6. 1965.
Dictionary of National Biography. Volume VII. Oxford. p. 988.
Current Literature. Nov. 1909.
Heward, Dr. E. Vincent and Moore. The Nineteenth Century.
The Redlands Daily Facts. May 1910.
Scientific American. Many references. 1906-1910.
Sky and Telescope. Nov. 1972, June 1975, Nov. 1977.
Richardson, Robert S. “Getting Acquainted with Comets”.
Brown, Peter L. “Comets, Meteors and Men”.
Moore, Patrick. “Comets”.