The Day We Found the Universe - Marcia Bartusiak [4]
The story of our universe's discovery centers mightily on Shapley and Hubble, scientific knights who jousted with each other for years over the universe's true structure. These archrivals shared similar backgrounds and yet couldn't have been more different in temperament and tactics. Both were born in rural Missouri and both came to astronomy through unusual routes: Hubble as a discontented high school teacher, Shapley as a crime reporter. And each, after obtaining his doctoral degree, was selected by the visionary George Ellery Hale to work at the Mount Wilson Observatory, the greatest astronomical venue in its day. Each pursued a question that few others were asking. For Shapley, it was our precise location within the Milky Way; for Hubble, our place in the universe at large.
Their work took place during a crucial moment of transition. While European astronomers were diverted by World War I and its resulting turmoil, American astronomers were free to push forward on the question of the spiral nebulae. Figuring out the universe's exact configuration became an American obsession, its participants drawn from the Lick, Mount Wilson, and Lowell observatories, newly built in the western United States. The world's older observatories had no chance at all, for at the Lick and Mount Wilson observatories, in particular, astronomers had access to advanced telescopes situated on prime high-elevation sites, a combination essential to cracking the mystery.
Hubble gets deserved credit for providing the last, painstaking turn of the lock. “Hubble's drive, scientific ability, and communication skills enabled him to seize the problem of the whole universe, make it peculiarly his own, contribute more to it than anyone before or since, and become the recognized world expert of the field,” wrote astronomer Donald Osterbrock, archivist Ronald Brashear, and physicist Joel Gwinn for a centennial celebration of Hubble's birth.
By 1929, just five years after his initial finding on the galaxies, Hubble made an even more astounding discovery. He and his colleague Milton Humason gathered the key evidence that opened the door to proving that the universe was expanding, with the galaxies continually riding the wave outward. Space-time was in motion! Half the work to reach this startling conclusion was actually performed on an Arizona mountaintop a decade earlier by Vesto Slipher, a Lowell Observatory astronomer whose vital role in arriving at this finding is now largely forgotten outside the halls of academia. Such is the power of Hubble's legend. It pushed the contributions of others into the shadows as the years progressed. This book intends to shine the spotlight once again on the entire cast of characters who contributed to revealing the true nature of the universe and laid the groundwork for Hubble's success.
Knowledge of the cosmic expansion was a transforming event. It allowed astronomers to escape the confines of their home galaxy, letting them explore a far larger cosmological vista. The Milky Way was now fleeing outward, giving theorists free rein to contemplate the universe's very origin. They mentally put the cosmic expansion into reverse and imagined the galaxies drawing closer and closer to one another, until they ultimately combined and formed a compact fireball of dazzling brilliance. In this way, they realized that the universe had emerged in the distant past from an enormous eruption—the Big Bang. No longer was our cosmic birth a matter of metaphysical speculation or a biased whim; it had become a scientific principle that could be tested and probed.
This new cosmic outlook came about through a unique convergence—the perfect storm—of sweeping developments. Not only did a burgeoning economy provide the money—and new technologies the instruments—to make these discoveries, but newly introduced ideas in theoretical physics supplied some answers.