Pioneers of Astronomy
The pioneers of astronomy laid down a solid foundation for modern day space exploration.
Nicholas Copernicus once said “The massive bulk of the earth does indeed shrink to insignificance in comparison with the size of the heavens." While we may attribute our knowledge of the solar system and astronomy to modern day telescopes, space shuttles, and space probes, it is important to remember that the size of the heavens would not even be discovered without the pioneers of astronomy. From Nicholas Copernicus and Albert Einstein to astronauts and space organizations like NASA, the pioneers of astronomy have laid down an important foundation for which exploration of the stars today is firmly rooted.
The Earth is the center of the universe. All other heavenly bodies, including the Sun, revolve around it. Each moon, and planet, and star is set in a crystal sphere which turns forever. As the spheres turn, they make beautiful music. Ptolemy, the Prince of Astronomers, said it was so in the second century A.D. The Church taught it for more than 1,000 years.
“Rubbish!” thought Nicholas Copernicus. “The Sun itself occupies the center of the universe.” He echoed the belief of an ancient Greek philosopher named Pythagoras. He was sure that any motion he saw in the sky was due to the movement of Earth.
Copernicus could not prove his theory mathematically. Neither could he draw a satisfactory diagram of the paths of the planets. Nevertheless, he believed what his eyes told him to be true.
Nicholas Copernicus was born in Thorn, Poland, on February 19, 1473. He was a serious, hard working student who graduated in arts from the University of Cracow in Poland, in law from the University of Ferrara, and in medicine from the University of Padua in Italy.
At twenty-four, he became canon of the cathedral of Frauenberg, thanks to a powerful uncle who was bishop of Ermland. Copernicus did not take up his post at the cathedral until he was thirty. He called Frauenberg “the remotest corner of the Earth.”
He spent his days there in religious duties, in the practice of medicine, and in the study of the stars. The telescope had not yet been invented so Copernicus scanned the heavens with his naked eye.
He made careful tables recording the movements of the planets. He studied the changing brightness of the planet Mars. It was his observations of Mars which led him to believe that the Sun was the center of the universe and that the Earth moved in an orbit between Venus and Mars.
Copernicus knew he would be laughed at if he published his views. He might even be tried by the Church for heresy, or false teaching. Martin Luther, the religious reformer, was particularly scornful of him. “This fool,” he said, “seeks to overturn the whole art of astronomy. But as the Holy Scriptures show, Jehovah ordered the Sun, not the Earth, to stand still.”
Copernicus made several neatly handwritten copies of his theory in a paper he called the Commentary and gave them to his friends. However, because he did not publish his ideas, few people outside of Poland heard of them at first.
By 1533, Copernicus had written a book called The Revolution of Celestial Orbs. It set out his arguments for the theory of a rotating and moving Earth. It also dismissed many false ideas. For instance, Copernicus explained that the Earth takes its atmosphere with it as it spins around, so we do not have a constant howling gale as Ptolemy suggested we should.
Ten years passed before The Revolution was published. By then, its author was a frail old man of seventy, paralyzed by a stroke. He did not live to see his book in print.
Nicholas Copernicus, a quiet scholar who had no heart to quarrel with man or Church, left a gift of knowledge which turned his world upside down.
Tycho Brahe was a big, brawny, hot-tempered Dane with a bright red beard, sharp eyes, and a nose for trouble.
Born on December 14, 1546, the son of a nobleman, he was kidnapped and later raised by his uncle, Jorgen Brahe. Tycho's father agreed to his adoption after a second son was born in the family.
At thirteen, Tycho was sent to the University of Copenhagen to study rhetoric, philosophy, and law. A young man named Anders Vedel went with him, to make sure Tycho kept to his books. Uncle Jorgen wanted his nephew to become a great statesman.
In 1559, something happened to change Jorgen Brahe's dream. Tycho saw a partial eclipse of the Sun. He was amazed when the eclipse took place exactly as scientists said it would. Tycho began to buy books on astronomy and mathematics and read them in secret. Finally, he made a pact with Vedel: He would study law by day and the stars by night.
Tycho was a wanderer and went to several universities. When he was at the University of Rostock in Germany, his temper got him into trouble. He quarreled with another young nobleman at a party. The two fought a duel and Tycho lost a piece of his nose. He made a false nose of gold, silver, wax, and probably copper, which he wore for the rest of his life.
The dashing Dane became interested in astronomical instruments. He designed a sextant, which measured the angle between two stars, without reference to the horizon.
Back home in Denmark, on the evening of December 11, 1572, Tycho saw a startling sight. It was a nova, or “new star,” in the constellation Cassiopeia. “Since I had, almost from boyhood, known all the stars of the heavens perfectly,” he wrote, “it was quite evident to me that there had never before been any star in that place in the sky, even the smallest...”
He asked his servants and some passers-by if they, too, saw the star. If a new star had appeared in the sky, then Aristotle and the ancient teachers were wrong. The heavens were not changeless as they said. (Of course, today we know Tycho didn't really find a new star at all. It had just been too dim to see—until it exploded).
The Danish people were slow to recognize Tycho's work in astronomy. He was ready to move to Germany when King Frederick II of Denmark gave him the small island of Hven and the money to build a home and observatory.
There, in November, 1577, Tycho observed a comet in the sky. He studied it for the next two months, compared his findings with those of other scientists, and concluded that a comet was farther out in space than the Moon.
Tycho did not believe the Copernican theory that the Sun was the center of the universe and he thought our planet was too bulky to move in space. He decided, therefore, that Earth was the stationary center of the universe, the Moon and the Sun orbited the Earth, and the rest of the planets orbited the Sun.
Tycho's greatest contribution to astronomy was his observation of the Moon and the planets. His most ambitious work was a catalog which listed 777 stars and their locations. He did all of this before the telescope was invented.
Tycho Brahe had a nose for trouble, but his keen eyes and methodical mind brought him fame.
Recommended Reading:The Martyrs of Science by Sir David Brewster
Galileo Galilei was bored. The cathedral service droned on and on. He raised his eyes and lazily watched the sway of a chandelier. There was a beat to it, a rhythm. Galileo put his fingers to his pulse and timed the swings. He noticed something. Even though the arc of the swing grew smaller, the tempo remained the same.
At his home in Pisa, he experimented with two balls of different weight which he hung from threads of equal length. He discovered the law of equal times for objects swinging through equal arcs. Galileo might be called the first modern physicist because of his work in mechanics and motion. Yet, we remember him best as an astronomer.
It was Galileo who turned the telescope to the sky and shattered the beliefs of his time. He looked at the "Man in the Moon" and discovered the face was formed by mountains and valleys, much like the Earth's. Planets were “perfectly round and definitely bounded, looking like little moons, spherical and flooded with light.” The shining band of the Milky Way was really a “vast crowd of stars.”
In January 1610, Galileo discovered “four PLANETS never before seen from the creation of the world up to our own time.” You can imagine his excitement. He had spied the four brightest moons of Jupiter. Moreover, their movement around the planet was another proof that Copernicus was right about the Solar System. Galileo's telescope revealed other wonders of the universe: the disc of Saturn; possibly even the planet Neptune. He was the first to discover the movement of sunspots.
Clearly, the heavens were not unchanging as the Church taught. Neither was the Earth the stationary center of our planetary system. Galileo wrote his views in a book called The Starry Messenger. It caused an uproar. His friend, Cardinal Barberini, told Galileo to believe what he pleased, but to keep it quiet in public. He was officially warned by the Church not to hold or defend the Copernicus.
When Barberini became Pope Urban VIII, Galileo was sure that things would change for the better. Although it was still against Church law to defend the Copernican theory, Galileo got around the rules by writing a dialogue, or conversation, among three friends. One supported the theories of Aristotle. Another argued for Copernicus. The third repeated the teachings of the Church. Pope Urban was enraged.
In September 1632, Galileo was called to Rome to be tried for heresy. After three interrogations by the dreaded Inquisition, the aged astronomer knelt and confessed his wrongdoing. He vowed never again to hold, defend, or teach the false doctrine that the Sun was the immovable center of the universe.
Galileo's Dialogue Concerning the Two Chief World Systems was placed on the Index of Prohibited Books. He was banished to his villa at Arcetri to live out his life in loneliness. He died on the night of January 8, 1642. The embittered Pope would not permit a monument to be placed over his tomb.
William Herschel, German immigrant to England, turned a hobby into one of the most astronomically productive lives in history. His work on double stars, deep sky objects, planetary observations, and even telescope making, won the respect and admiration of the professional astronomers of his day.
Friedrich Wilhelm Herschel was born on November 15, 1738, in Hanover, Germany. His father was an oboist in the regimental band of the Foot Guards of Hanover. Early in his life, Wilhelm dabbled in his father's musical and military occupations, but ended up devoting himself to his father's passing interest, astronomy.
During the Seven Years War with France, Herschel and a brother were posted to England with the Guards and then to the German battlefields. They left the front lines to live in England, where Herschel changed his name to Frederick William.
He was a popular young man and a good musician. Eventually, he became the organist at the Octagon Chapel in Bath. He also taught music and had many private pupils.
For many years, William regarded astronomy as a hobby, as his father had. By 1774, however, he was spending more and more time and money on astronomy books, object glasses, telescope rentals, and "stargazing."
William's success in Bath allowed him to send for his sister Caroline. Caroline was supposed to take singing lessons, but she soon found herself cooking, cleaning, and recording star sightings for her brother. When he began to build his own reflecting telescopes, Caroline wrote that she was "as useful a member of the workshop as a boy might be to his master in the first year of his apprenticeship." Like many beginners, William made mistakes, but he eventually built large and excellent telescopes. He even sold telescopes to eager customers.
The second of Herschel's telescopes had a mirror with a focal length of 2 meters. On March 13, 1781, he aimed it at the foot of Castor in Gemini. Caroline sat just inside the door, taking notes.
"In the quartile near Zeta Tauri," he called from the garden. "The lowest of two is a curious either nebulous star, or perhaps a comet." Four nights later, the object had moved. Word was sent to the Greenwich and Oxford observatories, whose astronomers tracked it in an oval orbit.
His “comet” turned out to be a planet, making Herschel the first person in recorded history to discover a new planet. He called it Georgius Sidus, "George's Star," to honor King George III of England. It was later renamed Uranus. Herschel later discovered two of Uranus' moons, Titania and Oberon.
The King became Herschel's patron. He made him his royal astronomer, paid him a pension, and later gave him a grant to build a giant telescope.
In the first month after the new telescope was completed, Herschel discovered two new moons of Saturn, Enceladus and Mimas. In the years that followed, he studied many things: double stars, which he found moved in orbit around each other, supporting Newton's Law of Gravitation; nebulae in the Milky Way, some of which he decided were actually clouds of gas; the shape of the Milky Way galaxy, the Sun and sunspots.
As he studied the Sun, he had an idea. "Suppose... we are driving along a road, then the lights ahead appear to move outwards, to our left and right. Those behind us, seem to close in." If the Sun were moving, might not the stars mimic the motion of the lights along the road? He looked for a point in the heavens where the stars seemed to move in opposite directions in equal numbers. His calculations showed that the Sun was moving through space toward the constellation Hercules, taking our Solar System with it.
Frederick William Herschel, a far-seeing man of many interests, died on August 25, 1822. His sister Caroline, returned to Hanover. During her work with her brother, she had made considerable achievements herself. She discovered six comets, and revised and corrected the great star catalogue of John Flamsteed. After her brother's death, she found herself "a person with nothing more to do in this world." She died, much honored, in January, 1848.
Recommended Reading:Discoverers of the Universe: William and Caroline Herschel by Michael Hoskin
School, thought young Albert Einstein, was a bore. He disliked the German schools with their strict rules and dull classes. He thought of his elementary teachers as "sergeants" and his high school teachers as "lieutenants." Because of his lack of interest he was dismissed from high school before he graduated. But he learned to satisfy his love of knowledge outside the classroom.
Einstein was born on March 14, 1879, in Ulm, Germany. He had a sense of wonder and a feel for the inner workings of nature. When he was five his father showed him a compass. He pondered the way the needle always pointed north. He thought the "empty" space between the North Pole and the compass must contain something which made the needle move!
At age twelve he was given a book on geometry by a family friend. It helped him stretch his mind to grasp the broad puzzles of nature, and sharpen it to cut to the depths of a problem.
At sixteen, Einstein was already probing the ideas of modern physics. For example, he wondered what would happen if he could follow a beam of light. The science of his day couldn't answer his questions. But he wanted to know anyway.
His poor performance in the German schools made it difficult for him to enter the Swiss Federal Institute of Technology—he flunked the entrance exam. He entered another school to catch up on what he'd missed. There he found "responsible and happy work such as cannot be achieved by regimentation." He later passed the entrance exam to the Swiss Institute, but found it almost as unpleasant as his German schools. It was a long four years, but he graduated.
Einstein's first steady job was with the Swiss Patent Office. He had to pick out the main ideas in inventions and rewrite them simply and clearly. It was easy enough for him, and the work left him enough energy to think about physics in his spare time. Between 1901 and 1904 he published five papers which aimed at proving the existence of atoms, which some scientists still doubted. In 1905 he published four papers. One was the dissertation for his Ph.D; The rest would turn the world of physics on its ear.
The most famous had a simple title: “On the Electrodynamics of Moving Bodies." It answered the question he had asked himself when he was sixteen. One of the main ideas was simple: The velocity of light is the “speed limit of the universe.” But this idea revolutionized two basic concepts of physics. Newton had said that space and time were absolute; Einstein's paper showed this wasn't so. Even mass was not absolute, he said, but depended on the speed of matter. One of the other papers again argued for the existence of atoms and molecules. The third tackled the old problem of whether a light beam was made up of waves or particles. Einstein said light was made up of small bundles of waves which he called photons. In a sense, light was both waves and particles—“wavicles."
But Einstein was far from finished. Ten years later he presented his General Theory of Relativity. This theory tackled the problem of gravity and the “shape" of space. Einstein found that gravity slows down time, and “bends" light by curving the space through which light travels. This meant that the old geometry didn't describe the universe exactly. And, Einstein maintained, there are not three dimensions but four length, width, depth—and time! The two separate concepts of space and time were joined into one—space-time.
Einstein spent the rest of his life trying to find one set of equations that would work for all four of the basic forces of the universe. He could not solve that problem, and today physicists are wondering if it is even possible. He died on April 18, 1955, leaving the question for the next "Einstein" to solve.
By 1955, the troublesome student and unknown patent clerk was one of the most famous and respected persons in the world. He once received a letter from a schoolgirl in British Columbia who was "writing to you to find out if you really exist." Albert Einstein existed all right. He devoted his life to thought, to wonder. What people should know about Albert Einstein, he once wrote, is not what he did or suffered, but "how he thinks, and what he thinks." His thinking changed and deepened our understanding of the universe.
Edwin Powell Hubble
Edwin Powell Hubble had the build of a boxer and the punch to go with it. He might have been World Heavyweight Champion. Instead, he chose to become an astronomer.
Hubble was born in Marshfield, Missouri, on November 20, 1889. He was a star student and a first class athlete. After high school, he went to Oxford University as a Rhodes scholar. When he returned from England, he opened a law practice in Louisville, Kentucky.
To Hubble, astronomy was something special, like the ministry. He thought you should have a calling for it. In 1914, he heard the "call." He left Louisville to work at Yerkes Observatory in Wisconsin. He fought in France in World War I, then went off to Mount Wilson Observatory near Pasadena, California.
At the time, a great controversy raged over the possibility of galaxies beyond our own. Telescopes of the late 19th century were powerful enough to pick out many fuzzy patches among the stars, but not powerful enough to show what those patches were. As a result, they were a classified as "nebulae," or clouds. Most astronomers believed that all nebulae lay within our own galaxy.
The new 100" telescope at Mount Wilson was the most powerful in the world. In 1924, Hubble used it to study the Andromeda Galaxy (it was then called the Andromeda Nebula). He found many Cepheid variable stars in the outer regions of the nebula.
Cepheids have very characteristic ways of changing brightness and are easy to recognize. In 1912, Harvard astronomers Henrietta Leavitt and Harlow Shapley had worked out a formula for determining the distance of a Cepheid by measuring its brightness. Hubble used this formula to find the distance of the Cepheids in Andromeda. He was able to prove that the Andromeda Nebula was far outside our galaxy—that it was, in fact, a separate galaxy altogether.
Hubble identified many other galaxies among the stars. He worked out a system for grouping galaxies by their forms, such as ellipses, spirals, and barred spirals. His system is still in use today.
To measure the movement of a star, astronomers use an instrument called a spectroscope. A prism breaks the starlight into a band of colors, like a rainbow, which is then photographed. If a star is moving toward Earth, its light appears bluer than normal. If it is traveling away from us, the light appears redder. A star's speed is called its radial velocity.
Hubble's helper, Milton Humason, was a spectroscope expert. Together, they studied the photographs of far-off galaxies. Then, they made tables of their calculations.
Hubble found that most galaxies were moving away from us at fantastic speeds. He said that the increase in their speed was related to the increase in their distance. He called this the "Distance Velocity Ratio." It is now known as Hubble's Law.
Hubble believed the universe was expanding, with the galaxies growing farther and farther apart. It was, he said, like a balloon covered with small dots. As the balloon is inflated, each dot moves farther away from every other dot.
Today, a great controversy rages over Hubble's idea of an expanding universe. Some scientists think the light from galaxies started out as violet, millions of years ago, and then became weaker and redder as it traveled through space. Most astronomers agree, however, that "redshifts" are a sign of radial velocity.
Hubble's Law gave birth to modern cosmology the science of the universe, its parts, and its laws. Nicholas Copernicus told us that the Sun, not Earth, was the center of the Solar System. Hubble showed us that our galaxy, the Milky Way, is just one of millions of islands in the vast sea of space.
The renowned Hubble Space Telescope gets its name from the great astronomer. The telescope went into orbit in 1990, and is still in operation in our solar system.