Only 100 years ago, the universe is assumed to be no larger than the Milky Way; the Earth, Moon, Sun, and planets have their place in the firmament; stars are fixed in the heavens; time is steady, extending from creation to eternity; and atoms -- for those who believe they exist -- obey the rules of classical Newtonian physics. We feel at home in the center of a world we are confident we understand.

Within decades, these certainties are dashed. The edifice of classical thought built over twenty centuries begins to tremble as remarkable new paradigms are forged. "Mysteries of the Universe" (premieres Monday, January 12, 1998, 8pm ET), the second installment of PBS's epic five-part A Science Odyssey, reveals the stories of the men and women who have struggled to make and understand the twentieth century's most astonishing discoveries in physics and astronomy. These breakthroughs are the foundation for the ways we now understand time, space, matter, and energy; they have also led to a continuing reexamination of our place in a universe unimaginably vast and old, composed of tiny and unpredictable subatomic particles.

"Mysteries" launches its intergalactic journey at the turn of the century when George Ellery Hale, obsessed with building the world's largest telescope, devotes almost a decade -- at enormous personal and financial risk -- to the construction of a 100-inch marvel so powerful it can detect the flicker of a candle 5,000 miles away. His aim is to retrieve more precise information about the visible stars. Unexpectedly, his device -- housed in the extraordinary 650-ton dome of the Mount Wilson Observatory in the hills above Pasadena - leads to observations that change the way we understand the universe.

Edwin Hubble, an eccentric and driven young astronomer, uses Hale's telescope to make one of the century's most fundamental discoveries. In plotting the movement of distant galaxies, Hubble realizes that they are zooming away from us at astonishing speeds. And, the farther the galaxy, the faster its flight, as its rate of speed is proportional to its distance away from Earth. The only possible explanation is that the universe is expanding. Hubble's discovery gives rise to an even more profoundly disturbing possibility: if the universe is expanding, it may have had a beginning -- and it may, someday, have an end.

Discoveries in physics are just as unsettling. Albert Einstein finds that time and distance are relative; time slows down and distances contract as a moving object approaches the speed of light. Ernest Rutherford learns that atoms are mostly empty space; our perception of the objects around us as homogeneous solids is an illusion. Niels Bohr must reject classical theory when he surmises that the electrons orbiting around the nucleus of the atom "leap" from one allowed orbit to another; how can matter move from place to place without "existing" in between? Werner Heisenberg's Uncertainty Principle states that we can know either the position or the momentum of an electron, but never both at the same time. Even more surprising is Erwin Schrodinger's vision of matter, composed not of particles, but of waves. And, collectively, these new theories lead to the revolutionary discipline of quantum mechanics -- replete with anti-matter and virtual particles -- perhaps the most powerful and bizarre product of all of twentieth-century science.

Physics and astronomy begin to converge in the second half of the twentieth century as the exploration of the subatomic realm and the exploration of the cosmos make it clear that there is a curious connection between the world of the very small and the vast universe around us.

Not only do the personalities of twentieth-century physicists and astronomers propel the trajectory of discovery, so do the dynamics of heated controversies, competition between very determined individuals -- and chance.

"Mysteries of the Universe" follows the work of astronomer Jocelyn Bell who, tracking the output of an enormous radio telescope in Cambridge, England, notices what she calls "a funny, scruffy, messy, unclassifiable signal from the sky."

The signal is a string of pulses exactly one and a third seconds apart. Never before has a telescope of any kind delivered something like this. Heavenly bodies just don't pulse on and off. Bell's discovery of pulsars is dramatic confirmation of objects that only twentieth-century physics could have imagined.

"Mysteries" also explores the increasing complexity of the portrait of the subatomic world. Murray Gell-Mann, for example, proposes that all atomic particles are made up of something smaller even than a proton; he calls them quarks (a name taken from James Joyce's modernist classic, Finnegans Wake). Although to this day no one has ever seen an individual quark, the weight of indirect evidence is so strong, quarks are now accepted as the building-blocks of atomic particles. Other theorists explore the possibility that matter is composed of even smaller entities -- two-dimensional strings that exist in a ten-dimensional reality, a concept impossible to grasp, but demonstrable with mathematical models. Still others are confronting the possibility that perhaps ninety-nine percent of the universe is made up not of neutrons, protons, and electrons, but of "dark matter," a mysterious substance invisible to even the telescopic eye.

Throughout, "Mysteries of the Universe" demonstrates again and again that the odyssey of science, however unpredictable, is profoundly spellbinding. This is an adventure of discovery for everyone who wonders about the nature of galaxies and atoms, light and time -- a survey of celestial and subatomic wonders that dramatically illustrates the most profound mysteries of creation.

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Major funding is provided by the National Science Foundation.

Corporate sponsorship is provided by IBM. IBM is a registered trademark of IBM Corporation.

Additional funding comes from public television viewres, the Corporation for Public Broadcasting, The Arthur Vining Davis Foundations, Carnegie Corporation of New York, and Becton Dickinson and Company.