Frontispiece: Woman in the morning sun This portrayal of the glowing sunrise by the German artist Caspar David Friedrich conveys wonder and mystery. It also has a transcendental, mystical quality. The painter once compared the “radiating beams of light” in one of his paintings to “the image of the eternal life-giving Father.” (Courtesy of Museum Folkwang, Essen.)
From the distant past to the modern era, astronomers have always had an insatiable curiosity about the Universe, and an overwhelming desire to find out what it contains, how it is put together, and how it functions. They have used new telescopes and novel instruments to extend our vision to places that cannot be seen with the unaided eye, discovered a host of unanticipated objects, found out how various parts of the night sky are related, and discovered that the Universe is larger, more complex, and older than has been previously thought. A Brief History of Astronomy and Astrophysics traces out the unfolding history of these discoveries, and anchors our present understanding of the Universe within the findings and personalities of accomplished astronomers.
This ongoing search of the unknown began more than four hundred years ago, when Galileo Galilei turned his spyglass to the skies and discovered Jupiter’s four large moons. As larger visible-light telescopes were constructed, innumerable unseen stars were found, their motions were deciphered, and the expanding Universe of galaxies was discovered. Only the nearest few of these galaxies can be seen without a telescope to collect their light.
Telescopes that operate at radio wavelengths were next used to discover remote radio galaxies, which can be viewed back to the early stages of our Universe. Observations of those radio galaxies that pass near the Sun led to the accidental sighting of radio pulsars, and the subsequent detection of the binary neutron star that was used to demonstrate the existence of gravitational radiation. Just recently, the sound and waveforms of these rippling gravitational waves have been detected, and attributed to the merger of two black holes into a bigger one on several occasions. And in the meantime, the three-degree cosmic microwave background radiation was unexpectedly discovered while observing radio galaxies during one of the first tests of ground links to a communication satellite.
A Brief History of Astronomy and Astrophysics discusses pervasive movement and relentless change throughout the Cosmos, from its birth to its ultimate fate, and everything in between. These ever-widening horizons of astronomy and our changing perceptions of the Universe were often entirely unanticipated and subjected to controversy, doubt, and even ridicule. They illustrate that the known Universe, which can be observed at any given time, is just a modest part of a much vaster one that remains to be found, often in the least expected ways.
As each day ends, we might watch the Sun set, or notice the Moon move across the sky. Satellites are now employed to glance down at the spinning Earth and up to watch the moving stars or look out at the Universe flying apart. Every planet, star, and galaxy has to remain in movement just to stay suspended in space.
Stars are slowly transforming themselves into new forms as they burn their substance away, and entire galaxies evolve over cosmic time intervals. Nothing stays the same anywhere in the Universe. As we watch everything change, we see how one part affects another and naturally wonder how it all began and the way it might end.
This book includes fascinating biographical details that bring human interest to our emerging understanding of the Universe. Important discoveries have been made by astronomers who came from all walks of life and grew up in diverse regions of the globe, from rural farms to big cities. Some were born into poverty and did not go beyond the early grades in formal education. Others had a privileged youth and studied at the world’s most prestigious universities. They have all helped part a cosmic veil to reveal fantastic, previously unknown and wonderfully beautiful aspects of the world.
Accomplished astronomers also partook in the hopes, fears, loves, friendships, mistakes, and enlightenments that the rest of us share. Some of them were driven by ambition and a few were careless about crediting the work of others. Several were humble, quiet, and self-effacing.
Spiritual yearning played an important role in the inquiry, persistence, and discoveries of men who provided the foundation for our celestial science. Many great astronomers, like Johannes Kepler, Galileo Galilei, Isaac Newton, Arthur Stanley Eddington, Henry Norris Russell, and Albert Einstein, participated in a search for an underlying order and pattern to the observable Universe, which they believed had been put in place by its Creator.
Other accomplished astronomers or astrophysicists were either atheists or agnostics, and thought that faith in God was not important to scientific inquiry. Nonetheless, some of them, such as Subrahmanyan Chandrasekhar, believed that their religion provides a rational, tolerant way to live life.
Moreover, most contemporary astronomers and astrophysicists, from Einstein to the present day, have retained belief in an order within the known and vast unknown Cosmos, however it may have originated. This pattern often includes a well-defined predictive behavior that they are now spending their lives trying to find and test.
Our book also helps convey the sense of awe and wonder that we can all experience when looking out at the stars at night. It is as if we are observing, and participating in, something grander and more inclusive than ourselves. On these occasions, Nature becomes a source of joy, even with a sacred depth, and we can marvel at the splendor of the Universe that surrounds us. It can fire our curiosity, help propel us through life, and keep a sparkle in our eyes. We can all regard it with awe, mystery, wonder, and gratitude.
Kenneth R. Lang
Professor Emeritus
Tufts University