Breakthroughs arise when we explore beyond accepted limits. With its legacy in experimental studies of a broad range of extreme environments, the scientists at the Geophysical Laboratory are addressing the following questions at the frontiers of science:
- How can we understand the formation and evolution of planets, from Earth to exoplanets and other celestial bodies in terms of their component materials, under the full range of the environments they experience?
- How can we understand the evolution of the atoms and molecules, minerals and rocks, of those bodies, and how does that knowledge inform our understanding of broader planetary origins and processes?
- What are the roles of extreme environments in the origin and evolution of life? How does that knowledge enlighten our search for life beyond Earth? Is their evidence for that life?
- How far can we extend the limits of materials in extreme environments, as well as make new materials for energy and other societal needs?
- What are the limits of biology in extreme environments, from the molecular to organismic level?
- How does fundamental chemistry change in extreme conditions, in terms of chemical structure, bonding, reactivity, thermodynamics, and kinetics?
- Ultimately, what new physics will appear in extremes, when atoms are brought close together at both the lowest and highest temperatures?
These questions are unified by the common theme of exploring frontiers of materials and processes, from elements to life, in diverse areas of science. Scientists at the Geophysical Laboratory do this by taking advantage of advanced experimental and theoretical techniques on campus, at the facilities it manages at national laboratories, through other programs, and with an extended network of collaborators.
The Laboratory's Second Century
Research at the Geophysical Laboratory (GL) cuts across traditional scientific disciplines, from molecular biology to theoretical physics. Created in 1905, the department was established to investigate the processes that control the composition and structure of Earth as it was known at the time, including developing the underlying physics and chemistry and creating the experimental tools required for the task. Over a century later, this core mission has expanded to include the physics, chemistry, and biology of Earth over the entire range of conditions our planet has experienced since its formation, as well as parallel studies of other planets of this and other solar systems from their surfaces to their cores.
This interdisciplinary research has led to a world-leading program focusing on the physics and chemistry of materials at extreme conditions, and the development of cutting-edge instrumentation and techniques, including those at national x-ray and neutron facilities that GL built and manages. This work addresses major problems in mineralogy, materials science, chemistry, and condensed-matter physics from ambient to millions of atmospheres of pressure and temperatures from millikelvins to those far greater than the surface of the sun. GL scientists examine extraterrestrial materials in meteorites and comets to follow the evolution of chemistry in the solar system from simple to complex molecules. Studies of how chemistry evolved under conditions present on the early Earth are leading to an understanding of how the specific molecules eventually required for life were produced. Unique ancient and modern ecologies are investigated to develop detailed models of their biochemical composition and function. Experimental protocols and instrumentation to be deployed on other planets to search for evidence of past or present life are continuously being developed.
Current research at GL is thus unified by the following overarching questions: What is the nature of matter under extreme conditions, and how can we use that knowledge to understand the cosmos? What are the limits and origin of life as we know it, and is there life beyond Earth? How can we utilize that fundamental knowledge to address major societal challenges (e.g., in energy)? Our studies are opening entirely new dimensions in physics and chemistry, with the prospects for creating novel materials that could have practical applications as well as being crucial to understanding the formation, structure, and evolution of Earth and other planets. There are potentially profound implications for our understanding of life itself. Our research and future plans break down into the following thrust areas that provide a new generation of questions.
Matter in Extreme Environments. Previous work set in motion in part by a century of investment by Carnegie has opened a vast unexplored scientific frontier concerned with the effects of extreme pressures, temperatures, and electromagnetic fields on matter and materials. These extreme conditions drastically alter materials, and the processes in nature that stem from them, at the level of electrons and nuclei. These profound changes force ordinary substances to adopt altogether new states of matter, crossing conventional barriers between insulators and superconductors, amorphous and crystalline solids, ionic and covalent compounds, and vigorously reactive and inert elements. We are on the threshold of studying materials with orders of magnitude larger volume, as well as orders of magnitude higher pressures, where there are many unanswered questions: What is the nature of matter at 1-100 megabars (up to 108 times atmospheric pressure)? What is an atom under these conditions? What new chemistry may emerge when ‘core’ instead of ‘valence’ electrons are responsible for bonding? Are entirely new forms of matter controlled by quantum mechanics, perhaps analogous to Bose-Einstein condensation but in altogether new regimes? These conditions have never been explored and no satisfactory theory exists. We are on the threshold of answering these questions with the development of next-generation high-pressure instruments coupled with new laser and x-ray sources needed to generate extreme conditions.
Complexity in Earth. It is now recognized that Earth in its entirety is a complex system of processes operating over profound scales of length and time spanning up to 24 orders of magnitude – from atomic to global and from the timescale of electronic excitations to the age of Earth. The newly launched Deep Carbon Observatory addresses this multiscale grand challenge by starting with the element carbon. In fact, we are ignorant of the fundamental physical, chemical, and biological behavior of carbon-bearing systems just a short distance beneath our feet. How much carbon is stored in Earth’s interior, and how much carbon-based fluid and gas is produced at depth? How much carbon moves below, and to and from, the surface? What is the depth and extent of the biosphere? This is just the beginning of a broader set of questions that Carnegie scientists are taking the lead in answering. Moving beyond the view of Earth as perfect crystals, fluids, and gases, the challenge is to look at the full complexity of the entire system in space and time. What is the nature of grain boundaries in the planet? How does rock deform and fluid flow in combination with chemical reactions and phase transformations at depth? What is the fate of biologically derived carbon in the deep subsurface? Our ignorance of the full complexity of the whole Earth as a system has resulted from the severe technical challenges associated with probing processes deep in the planet; the necessary tools for the task are just now coming on line using next-generation x-ray, neutron, laser, and other analytical methods for imaging complex systems in situ as a function of time.
Planets to Stars. Looking beyond Earth, there are vast opportunities to explore new frontiers of matter under extreme environments in the cosmos, including the close to 500 planets now observed outside our solar system. What is the state of matter at the cores of large bodies? What is the nature of the chemistry in their cores and core-mantle boundaries? What interior conditions in massive super Earth’s allow conditions compatible with life? What happens to atoms during impacts of these bodies throughout the cosmos? Answers to these questions require knowledge of materials that make up these bodies – from their potentially unusual atmospheres, oceans, and surface ices and rocks to their dense interiors where the altogether new domains of chemistry and physics, including the intermingling of nuclear processes in dense plasmas, may prevail. Thus ‘Earth-based’ experimental studies of materials over a broad range of conditions now available go hand in hand with observations. Understanding the observations made by Carnegie astronomers will require next generation experiments that could lead to new discoveries about ordinary matter in extreme environments (i.e., not just dark matter and energy). The program requires suites of extreme science instrumentation and facilities onsite at GL and offsite at facilities that we would build and manage.
Origins and Limits of Life. One of the outstanding unanswered scientific questions at present regards the origin of life on Earth, and whether our planet and indeed the Solar System in general is special in the Galaxy. What intersections of chemistry, physics, and geology transform organic chemistry into emergent biochemistry and therefore life? Where did life begin, and what are the limits of life in the cosmos? Is there life within the planet and beyond, as we know it – or as we don’t know it? Looking back to deep time, what is the origin of the Solar System and how did it evolve? How can we distill that information from “reading” the chemical history encoded in the molecular structure of primitive extraterrestrial organic solids found in comets and primitive meteorites? Again, the answers require development and support of powerful analytical instruments located both on campus and at our remote facilities both to examine materials from extraterrestrial environments and to simulate the extreme conditions of their formation and processing in the laboratory.
Advanced Materials. The above research thrusts set the stage for the creation of novel materials, with potentially revolutionary properties and applications. Extreme conditions have played and will continue to play a major role in this pursuit. The Nobel Prize-winning discovery of the high Tc cuprate superconductors was guided in part by a consideration of pressure effects. We have a great tradition in this area that we have never fully embraced. GL laid the foundation for the modern optical glass industry in this country during WWI, and the science that led to Pyrex glass, if not the discovery itself, took place at GL because of our expertise in extreme temperatures, though GL and Carnegie received no credit, either intellectually or financially. It was our expertise in studying complex materials that contributed to the characterization of the cuprate superconductors,1and we still hold the record for the highest temperature superconductivity yet measured (164 K). Can we create room temperature superconductors, one of the ‘holy grails’ of energy science? Can the remarkable materials we continue to discover and whose existence we continue to predict be turned into useful materials? We are on the cusp of a major revolution in the science and technology of carbon – e.g., with diamond ultimately replacing silicon in electronics – a revolution that GL has helped to lead.2 Can we produce materials that are superior to diamond? The challenging problems being addressed in biological systems will likewise lead to new materials discoveries that bridge the living and inorganic worlds. New instrumentation and facilities provide us with not only the ability to probe materials under exotic conditions, but to control and direct matter to create new materials by design.