enteenth century, science played an important role in motivating explorations. The British and French science academies were important driving forces behind the largest of the eighteenth-century expeditions. In the nineteenth century, scientific exploration was becoming the principal goal of exploration, with the voyages of Beagle and Challenger as prime examples. The last of the primarily geographic explorers were pressing toward the North and South poles, the last of the earth’s uncharted territories, as the twentieth century began. In the twentieth century, we moved beyond our own planet and went to the moon. On the way, we saw the earth from space for the first time, blue and inviting, alone in the black immensity of space. In the decades that followed, we flew in and above the earth’s atmosphere, photographed the entire land surface, probed the deepest ocean trenches, charted the ocean’s currents, mapped the entire ocean floor by satellite, and studied the movements of the earth’s core. Everywhere we looked we found life, even in and below hydrothermal vents at the bottom of the ocean. Our spacecraft went to all the planets in the solar system but one. With the help of modern technology, we can visit any point on the earth. Nowhere on the earth’s surface is there a virgin place, unvisited, uninspected. As the twenty-first century begins, the very nature of exploration is being transformed. We are now more closely, deeply observing our world and the changes being wrought in our midst. Humans have always modified their environment to better suit their needs. But over the last half century, such alterations have assumed global proportions. As a result, our advanced civilization is spending more and more of its time and treasure coping with the unintended by-products of its activities—air and water pollution, ecosystem decline, biological invasions, chemical contamination, and radiation. Humans now appropriate more than half the fresh water circulating in the hydrological cycle and fix more nitrogen than nature itself does. Air pollution has gone global and is changing the climate. The escape of chlorine and bromine compounds into the stratosphere created an Antarctic ozone hole. Industrial activity brought Scripps Institution of Oceanography shares its centennial year with innovators who changed the twentieth century and our ability to navigate it; the founding of the Ford Motor Company and the first flight of the Wright brothers in Kitty Hawk, North Carolina, also occurred in 1903. Automobiles and airplanes have dramatically evolved over 100 years, and Scripps science is much different today than it was in the summer of 1903, when William E. Ritter and a handful of his students began studying marine life in San Diego Bay. Scripps quickly became a multidisciplinary institution, researching and teaching all of the subjects pertinent to the oceans—physics, chemistry, biology, and geology. Scripps had few formal curricular—or geographical—constraints inhibiting research initiatives, and studies soon extended to such areas as volcanology, seismology, atmospheric science, and climate science. Today, Scripps is more like an earth science research center than a traditional ocean institution. Its foundation of twentieth-century achievements has positioned Scripps to meet the even more profound interdisciplinary challenges of the twenty-first century. Indeed, Scripps, at 100, is at a turning point. Our established competence in ocean and earth science is the principal asset we can invest in the future—though this principal asset is at risk, as Scripps faces its worst financial crisis since the Great Depression. That alone will force change, but there is a more profound reason for change. The earth itself changed profoundly in the last century, and ocean and earth science are changing in response. So to ask where Scripps is going, we must ask where science has been and where it is going.