Tuesday, May 19, 2015
Guggenheim 101 (Lees-Kubota Lecture Hall) – Guggenheim Aeronautical Laboratory

Science in a Small World - Short Talks

Tuesday, May 19, 2015
Dabney Hall, Garden of the Associates – The Garden of the Associates

Science in a Small World - Poster Session #2

Tuesday, May 19, 2015
Dabney Hall, Garden of the Associates – The Garden of the Associates

Science in a Small World - Poster Session #1

Space-Based Solar Power Project Funded

A sponsored research agreement with Northrop Grumman Corporation will provide Caltech up to $17.5 million over three years for the development of the Space Solar Power Initiative (SSPI). The SSPI will develop the scientific and technological innovations necessary to enable a space-based solar power system—consisting of ultralight, high-efficiency photovoltaics, a phased-array system to produce and distribute power dynamically, and ultralight deployable space structures—that ultimately will be capable of generating electric power at a cost comparable to that from fossil-fuel power plants.

The project was conceived and will be led jointly by three professors in Caltech's Division of Engineering and Applied Science (EAS): Harry A. Atwater, Howard Hughes Professor of Applied Physics and Materials Science and director of the Resnick Sustainability Institute; Ali Hajimiri, Thomas G. Myers Professor of Electrical Engineering; and Sergio Pellegrino, Joyce and Kent Kresa Professor of Aeronautics, professor of civil engineering, and a senior research scientist at Caltech's Jet Propulsion Laboratory.

Atwater's group will design and demonstrate ultralight, high-efficiency photovoltaics optimized for space conditions and compatible with an integrated, modular power conversion/transmission system.

Hajimiri's team will develop the integrated circuits and the antenna design for the system's large-scale phased array, timing control, and conversion of direct current to radio frequency power. "The three groups are working closely to take a holistic approach to the design of the entire system," he says.

Through a modular approach power will be generated, converted, and radiated locally at the same place in space using a distributed power conversion and transmission solution created with modern integrated electronics that eliminates inter- and intramodule power wiring in the system. "This significantly reduces the system mass, and thereby its cost," he adds.

"This space-based, highly adaptive power generator will enable versatile on-demand power anywhere on the planet and will be able to almost instantly distribute the power to different locations," Hajimiri says. "This is enabled through an agile phased-array system that can dynamically direct the power to the desired locations on Earth and simultaneously provide power to multiple destinations on demand. This can substantially reduce the need and the cost associated with the power distribution network across the globe."

Any such system must first be able to collect the solar energy that is then converted and distributed. "One of the key barriers to the realization of cost-competitive space-based solar power systems is the deployment in space of large surface area structures to collect solar power, at low cost," says Pellegrino. "The cost and complexity of launching and deploying conventional deployable structures would be unacceptable for many applications." To circumvent this barrier, his team is developing novel architectures for multifunctional deployable space structures with an overall areal density on the order of 100 grams per square meter, equivalent to one or two sheets of paper. "The concepts that we are investigating build on over 10 years of research on deployable thin-shell structures, which most recently had resulted in the development of low-cost fiber-composite booms and reflectors in which elastic hinges are created simply by making small cuts in the wall of a shell structure," he says.

To achieve all of these goals, Atwater, Hajimiri, and Pellegrino already have assembled a team of students, postdoctoral scholars, and senior researchers that will eventually exceed 50 members. In addition, the EAS division is in the process of building specialized laboratory facilities to support the team. Meanwhile, Northrop Grumman engineers and scientists will collaborate with the Caltech researchers to develop solutions, build prototypes, and obtain experimental and numerical validation of concepts that will allow for the eventual implementation of the system.

"This initiative is a great example of how Caltech engineers are working at the leading edges of fundamental science to invent the technologies of the future," says Ares Rosakis, Otis Booth Leadership Chair of the EAS division and the Theodore von Kármán Professor of Aeronautics and Mechanical Engineering. "The Space Solar Power Initiative brings together electrical engineers, applied physicists, and aerospace engineers in the type of profound interdisciplinary collaboration that is seamlessly enhanced at a small place like Caltech. I believe it also demonstrates the value of industry and academic partnerships. We are working on extremely difficult problems that could eventually provide the world with new, and very cost-competitive technology for sustainable energy."

"By working together with Caltech, Northrop Grumman extends its long heritage of innovation in space-based technologies and mission solutions," said Joseph Ensor, vice president and general manager, Space Intelligence, Surveillance and Reconnaissance (ISR) Systems, Northrop Grumman, in a press release. "The potential breakthroughs from this research could have extensive applications across a number of related power use challenges."

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Tracking Photosynthesis from Space

Watching plants perform photosynthesis from space sounds like a futuristic proposal, but a new application of data from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite may enable scientists to do just that. The new technique, which allows researchers to analyze plant productivity from far above Earth, will provide a clearer picture of the global carbon cycle and may one day help researchers determine the best regional farming practices and even spot early signs of drought.

When plants are alive and healthy, they engage in photosynthesis, absorbing sunlight and carbon dioxide to produce food for the plant, and generating oxygen as a by-product. But photosynthesis does more than keep plants alive. On a global scale, the process takes up some of the man-made emissions of atmospheric carbon dioxide—a greenhouse gas that traps the sun's heat down on Earth—meaning that plants also have an important role in mitigating climate change.

To perform photosynthesis, the chlorophyll in leaves absorbs sunlight—most of which is used to create food for the plants or is lost as heat. However, a small fraction of that absorbed light is reemitted as near-infrared light. We cannot see in the near-infrared portion of the spectrum with the naked eye, but if we could, this reemitted light would make the plants appear to glow—a property called solar induced fluorescence (SIF). Because this reemitted light is only produced when the chlorophyll in plants is also absorbing sunlight for photosynthesis, SIF can be used as a way to determine a plant's photosynthetic activity and productivity.

"The intensity of the SIF appears to be very correlated with the total productivity of the plant," says JPL scientist Christian Frankenberg, who is lead for the SIF product and will join the Caltech faculty in September as an associate professor of environmental science and engineering in the Division of Geological and Planetary Sciences.

Usually, when researchers try to estimate photosynthetic activity from satellites, they utilize a measure called the greenness index, which uses reflections in the near-infrared spectrum of light to determine the amount of chlorophyll in the plant. However, this is not a direct measurement of plant productivity; a plant that contains chlorophyll is not necessarily undergoing photosynthesis. "For example," Frankenberg says, "evergreen trees are green in the winter even when they are dormant."

He adds, "When a plant starts to undergo stress situations, like in California during a summer day when it's getting very hot and dry, the plants still have chlorophyll"—chlorophyll that would still appear to be active in the greenness index—"but they usually close the tiny pores in their leaves to reduce water loss, and that time of stress is also when SIF is reduced. So photosynthesis is being very strongly reduced at the same time that the fluorescence signal is also getting weaker, albeit at a smaller rate."

The Caltech and JPL team, as well as colleagues from NASA Goddard, discovered that they could measure SIF from orbit using spectrometers—standard instruments that can detect light intensity—that are already on board satellites like Japan's Greenhouse Gases Observing Satellite (GOSAT) and NASA's OCO-2.

In 2014, using this new technique with data from GOSAT and the European Global Ozone Monitoring Experiment–2 satellite, the researchers scoured the globe for the most productive plants and determined that the U.S. "Corn Belt"—the farming region stretching from Ohio to Nebraska—is the most photosynthetically active place on the planet. Although it stands to reason that a cornfield during growing season would be actively undergoing photosynthesis, the high-resolution measurements from a satellite enabled global comparison to other plant-heavy regions—such as tropical rainforests.

"Before, when people used the greenness index to represent active photosynthesis, they had trouble determining the productivity of very dense plant areas, such as forests or cornfields. With enough green plant material in the field of view, these greenness indexes can saturate; they reach a maximum value they can't exceed," Frankenberg says. Because of the sensitivity of the SIF measurements, researchers can now compare the true productivity of fields from different regions without this saturation—information that could potentially be used to compare the efficiency of farming practices around the world.

Now that OCO-2 is online and producing data, Frankenberg says that it is capable of achieving higher resolution than the preliminary experiments with GOSAT. Therefore, OCO-2 will be able to provide an even clearer picture of plant productivity worldwide. However, to get more specific information about how plants influence the global carbon cycle, an evenly distributed ground-based network of spectrometers will be needed. Such a network—located down among the plants rather than miles above—will provide more information about regional uptake of carbon dioxide via photosynthesis and the mechanistic link between SIF and actual carbon exchange.

One existing network, called FLUXNET, uses ground-based towers to measure the exchange of carbon dioxide, or carbon flux, between the land and the atmosphere from towers at more than 600 locations worldwide. However, the towers only measure the exchange of carbon dioxide and are unable to directly observe the activities of the biosphere that drive this exchange.

The new ground-based measurements will ideally take place at existing FLUXNET sites, but they will be performed with a small set of high-resolution spectrometers—similar to the kind that OCO-2 uses—to allow the researchers to use the same measurement principles they developed for space. The revamped ground network was initially proposed in a 2012 workshop at the Keck Institute for Space Studies and is expected to go online sometime in the next two years.

In the future, a clear picture of global plant productivity could influence a range of decisions relevant to farmers, commodity traders, and policymakers. "Right now, the SIF data we can gather from space is too coarse of a picture to be really helpful for these conversations, but, in principle, with the satellite and ground-based measurements you could track the fluorescence in fields at different times of day," he says. This hourly tracking would not only allow researchers to detect the productivity of the plants, but it could also spot the first signs of plant stress—a factor that impacts crop prices and food security around the world.

"The measurements of SIF from OCO-2 greatly extend the science of this mission", says Paul Wennberg, R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering, director of the Ronald and Maxine Linde Center for Global Environmental Science, and a member of the OCO-2 science team. "OCO-2 was designed to map carbon dioxide, and scientists plan to use these measurements to determine the underlying sources and sinks of this important gas. The new SIF measurements will allow us to diagnose the efficiency of the plants—a key component of the sinks of carbon dioxide."

By using OCO-2 to diagnose plant activity around the globe, this new research could also contribute to understanding the variability in crop primary productivity and also, eventually, the development of technologies that can improve crop efficiency—a goal that could greatly benefit humankind, Frankenberg says.

This project is funded by the Keck Institute for Space Studies and JPL. Wennberg is also an executive officer for the Environmental Science and Engineering (ESE) program. ESE is a joint program of the Division of Engineering and Applied Science, the division of Chemistry and Chemical Engineering, and the Division of Geological and Planetary Sciences.

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Weighing—and Imaging—Molecules One at a Time

Building on their creation of the first-ever mechanical device that can measure the mass of individual molecules, one at a time, a team of Caltech scientists and their colleagues have created nanodevices that can also reveal their shape. Such information is crucial when trying to identify large protein molecules or complex assemblies of protein molecules.

"You can imagine that with large protein complexes made from many different, smaller subunits there are many ways for them to be assembled. These can end up having quite similar masses while actually being different species with different biological functions. This is especially true with enzymes, proteins that mediate chemical reactions in the body, and membrane proteins that control a cell's interactions with its environment," explains Michael Roukes, the Robert M. Abbey Professor of Physics, Applied Physics, and Bioengineering at Caltech and the co-corresponding author of a paper describing the technology that appeared March 30 in the online issue of the journal Nature Nanotechnology.

One foundation of the genomics revolution has been the ability to replicate DNA or RNA molecules en masse using the polymerase chain reaction to create the many millions of copies necessary for typical sequencing and analysis. However, the same mass-production technology does not work for copying proteins. Right now, if you want to properly identify a particular protein, you need a lot of it—typically millions of copies of just the protein of interest, with very few other extraneous proteins as contaminants. The average mass of this molecular population is then evaluated with a technique called mass spectrometry, in which the molecules are ionized—so that they attain an electrical charge—and then allowed to interact with an electromagnetic field. By analyzing this interaction, scientists can deduce the molecular mass-to-charge ratio.

But mass spectrometry often cannot discriminate subtle but crucial differences in molecules having similar mass-to-charge ratios. "With mass spectrometry today," explains Roukes, "large molecules and molecular complexes are first chopped up into many smaller pieces, that is, into smaller molecule fragments that existing instruments can handle. These different fragments are separately analyzed, and then bioinformatics—involving computer simulations—are used to piece the puzzle back together. But this reassembly process can be thwarted if pieces of different complexes are mixed up together."

With their devices, Roukes and his colleagues can measure the mass of an individual intact molecule. Each device—which is only a couple millionths of a meter in size or smaller—consists of a vibrating structure called a nanoelectromechanical system (NEMS) resonator. When a particle or molecule lands on the nanodevice, the added mass changes the frequency at which the structure vibrates, much like putting drops of solder on a guitar string would change the frequency of its vibration and resultant tone. The induced shifts in frequency provide information about the mass of the particle. But they also, as described in the new paper, can be used to determine the three-dimensional spatial distribution of the mass: i.e., the particle's shape.

"A guitar string doesn't just vibrate at one frequency," Roukes says. "There are harmonics of its fundamental tone, or so-called vibrational modes. What distinguishes a violin string from a guitar string is really the different admixtures of these different harmonics of the fundamental tone. The same applies here. We have a whole bunch of different tones that can be excited simultaneously on each of our nanodevices, and we track many different tones in real time. It turns out that when the molecule lands in different orientations, those harmonics are shifted differently. We can then use the inertial imaging theory that we have developed to reconstruct an image in space of the shape of the molecule."

"The new technique uncovers a previously unrealized capability of mechanical sensors," says Professor Mehmet Selim Hanay of Bilkent University in Ankara, Turkey, a former postdoctoral researcher in the Roukes lab and co-first author of the paper. "Previously we've identified molecules, such as the antibody IgM, based solely on their molecular weights. Now, by enabling both the molecular weight and shape information to be deduced for the same molecule simultaneously, the new technique can greatly enhance the identification process, and this is of significance both for basic research and the pharmaceutical industry." 

Currently, molecular structures are deciphered using X-ray crystallography, an often laborious technique that involves isolating, purifying, and then crystallizing molecules, and then evaluating their shape based on the diffraction patterns produced when x-rays interact with the atoms that together form the crystals. However, many complex biological molecules are difficult if not impossible to crystallize. And, even when they can be crystallized, the molecular structure obtained represents the molecule in the crystalline state, which can be very different from the structure of the molecule in its biologically active form.

"You can imagine situations where you don't know exactly what you are looking for—where you are in discovery mode, and you are trying to figure out the body's immune response to a particular pathogen, for example," Roukes says. In these cases, the ability to carry out single-molecule detection and to get as many separate bits of information as possible about that individual molecule greatly improves the odds of making a unique identification.

"We say that cancer begins often with a single aberrant cell, and what that means is that even though it might be one of a multiplicity of similar cells, there is something unique about the molecular composition of that one cell. With this technique, we potentially have a new tool to figure out what is unique about it," he adds.

So far, the new technique has been validated using particles of known sizes and shapes, such as polymer nanodroplets. Roukes and colleagues show that with today's state-of-the-art nanodevices, the approach can provide molecular-scale resolution—that is, provide the ability to see the molecular subcomponents of individual, intact protein assemblies. The group's current efforts are now focused on such explorations.

Scott Kelber, a former graduate student in the Roukes lab, is the other co-first author of the paper, titled "Inertial imaging with nanoelectromechanical systems." Professor John Sader of the University of Melbourne, Australia, and a visiting associate in physics at Caltech, is the co-corresponding author. Additional coauthors are Cathal D. O'Connell and Paul Mulvaney of the University of Melbourne. The work was funded by a National Institutes of Health Director's Pioneer award, a Caltech Kavli Nanoscience Institute Distinguished Visiting Professorship, the Fondation pour la Recherche et l'Enseignement Superieur in Paris, and the Australian Research Council grants scheme.

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Monday, June 1, 2015

Charles C. Gates Jr.–Franklin Thomas Laboratory - Dedication and Celebration

Two Caltech Seniors Win Watson Fellowships

Janani Mandayam Comar and Aaron Krupp join the 47th class of Watson fellows

Caltech seniors Janani Mandayam Comar and Aaron Krupp have been named 2015 Thomas J. Watson Fellowship winners. Each fellowship is a grant of $30,000 awarded to seniors graduating from a selected group of colleges. According to the Watson Foundation's website, "Fellows conceive original projects, execute them outside of the United States for one year and embrace the ensuing journey. They decide where to go, who to meet and when to change course." Fifty fellows were selected from a pool of nearly 700 candidates.

 

Janani Mandayam Comar is a biology major from Downers Grove, Illinois. During her Watson year abroad, she will be using Bharatanatyam, a classic dance form from the Indian state of Tamil Nadu, to reflect the experiences of various "outsider" communities. "Bharatanatyam was originally an exclusively female way of connecting with God," Comar says. "It was revived in the early 1900s as a way to tell stories through movement, and it is now danced by both men and women, and is no longer confined to Indian communities."

In Australia, Comar will be working with the transgender community, whose situation is in some ways mirrored by traditional Indian culture. "Hindu mythology has a lot of transgender elements although the subject is taboo in modern Indian society," she explains. In South Africa, home of the oldest expatriate Indian community in the world, Comar will investigate the role that Indian women played during apartheid, and in Malaysia, a country where human trafficking is still common, she will work with nongovernmental organizations that assist trafficked women in order to tell their stories. Finally, in Buenos Aires, she plans to join a studio teaching Bharatanatyam. "They're working in a foreign culture where it had not previously been appreciated," she says. "The situation has parallels to women's efforts to break into STEM [science, technology, engineering, and mathematics] fields, especially in male-dominated societies like Argentina."

Comar will be entering an MD/PhD program on her return to the United States and plans to become a physician-scientist, eventually as a professor at a medical school. 

 

Aaron Krupp of Needham, Massachusetts, is a mechanical engineering major. Over the next year, he will be working on low-tech projects to improve the quality of life on the most basic level at sites in India, Southeast Asia, and Nepal. In India, he plans to help manufacture durable roofing tiles out of recycled cardboard. He also will be working near refugee camps along the Thai-Myanmar border to help develop charcoal-based drinking-water filtration systems, and in Nepal, he will be assembling used bicycle parts into lever-driven, variable-torque all-terrain wheelchairs.

"I am getting involved in small components of projects that are already underway," says Krupp, who currently has no post-Watson plans. For example, the water filters are the product of a lab at North Carolina State University in Raleigh, where Krupp worked last summer, and the off-roading wheelchairs are an MIT project that he first encountered in 2013 while working at a hospital in rural Haiti after the magnitude-7.0 earthquake. 

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Five from Caltech Elected to American Academy of Arts and Sciences

The American Academy of Arts and Sciences has elected five Caltech community members as academy fellows. They are faculty members Michael B. Elowitz, professor of biology and bioengineering and an investigator with the Howard Hughes Medical Institute; Mory Gharib (PhD '83), Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering, director of the Ronald and Maxine Linde Institute of Economic and Management Sciences, and vice provost; and Linda C. Hsieh-Wilson, professor of chemistry; and Caltech trustees James Rothenberg and Maria Hummer-Tuttle. The American Academy is one of the nation's oldest honorary societies. Members are accomplished scholars and leaders representing diverse fields including academia, business, public affairs, the humanities, and the arts.

 

Michael B. Elowitz was noted for his work that "helped to initiate synthetic biology." Elowitz studies genetic circuits—interacting genes and proteins that enable cells to sense environmental conditions and to communicate. He and his group build simplified synthetic genetic circuits and study their effects in bacteria, yeast, and mammalian cells. He has received numerous honors in recognition of his work, including a MacArthur Fellowship in 2007.
 

Mory Gharib and his group use nature's own design principles—apparent in fins, wings, blood vessels, and more—as inspiration for a myriad of inventions. They have studied fluid flows inside the zebrafish heart to develop efficient micropumps and more efficient artificial heart valves, and cactus spine to develop arrays of nanoneedles, based on carbon nanotubes, for painless drug delivery. Gharib holds nearly 100 patents, and was elected to the National Academy of Engineering in 2015.

Linda C. Hsieh-Wilson was noted for her pioneering work in the new fields of chemical glycobiology and chemical neurobiology. Her work combines organic chemistry and neurobiology in order to understand how carbohydrates contribute to fundamental brain processes such as cell growth and neuronal communication, neural development, and memory at the molecular level. She and her group discovered a means for suppressing tumor-cell growth by blocking the attachment of certain sugars to proteins, restricting delivery of certain carbohydrates to proteins within the tumor.

Maria Hummer-Tuttle, a lawyer, was a partner and chair of the management committee and co–managing partner of Manatt, Phelps and Phillips in Los Angeles. She currently serves on the boards of Caltech, the J. Paul Getty Trust, the W. M. Keck Foundation, the Suu Foundation, and the Foundation for Art and Preservation in Embassies. Hummer-Tuttle is president of the Hummer Tuttle Foundation, serves on the advisory board of the USC Center on Public Diplomacy at the Annenberg School as well as on the program advisory committee of the Annenberg Retreat at Sunnylands, and is a member of the Pacific Council on International Policy, the Council on Foreign Relations, and the Getty Conservation Institute Council.

Jim Rothenberg is chairman of the Capital Group Companies, Inc. In addition to his service on the Caltech board, he serves on the boards of Capital Research and Management Company, the Capital Group Companies, Inc., and American Funds Distributors, Inc. In addition, he is a portfolio counselor for the Growth Fund of America, as well as vice chairman of the Growth Fund of America and Fundamental Investors. A chartered financial analyst, he was named to the Harvard Corporation as the treasurer of Harvard University in 2004. He also serves as a director of Huntington Memorial Hospital in Pasadena.

Elowitz, Gharib, and Hsieh-Wilson join 83 current Caltech faculty as members of the American Academy. Also included in this year's list are five alumni: Robert Cohen (MS '70, PhD '72), St. Laurent Professor of Chemical Engineering at MIT and codirector of the DuPont-MIT Alliance; Alexei Filippenko (PhD '84), professor of astronomy at UC Berkeley; Katherine Hayles (MS '69), professor of literature at Duke University; Michael Snyder (PhD'83), professor and chair of genetics at Stanford University; and Donald Truhlar (PhD '70), professor of chemistry at the University of Minnesota.

Founded in 1780 by John Adams, James Bowdoin, John Hancock, and other scholar-patriots, the academy aims to serve the nation by cultivating "every art and science which may tend to advance the interest, honor, dignity, and happiness of a free, independent, and virtuous people." The academy has elected as fellows and foreign honorary members "leading thinkers and doers" from each generation, including George Washington and Ben Franklin in the 18th century, Daniel Webster and Ralph Waldo Emerson in the 19th, and Albert Einstein and Woodrow Wilson in the 20th.

A full list of new members is available on the academy website at https://www.amacad.org/content/members/members.aspx.

The new class will be inducted at a ceremony on October 10, 2015, in Cambridge, Massachusetts.

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Understanding the Earth at Caltech

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Credit: Courtesy J. Andrade/Caltech

The ground beneath our feet may seem unexceptional, but it has a profound impact on the mechanics of landslides, earthquakes, and even Mars rovers. That is why civil and mechanical engineer Jose Andrade studies soils as well as other granular materials. Andrade creates computational models that capture the behavior of these materials—simulating a landslide or the interaction of a rover wheel and Martian soil, for instance. Though modeling a few grains of sand may be simple, predicting their action as a bulk material is very complex. "This dichotomy…leads to some really cool work," says Andrade. "The challenge is to capture the essence of the physics without the complexity of applying it to each grain in order to devise models that work at the landslide level."

Credit: Kelly Lance ©2013 MBARI

Geobiologist Victoria Orphan looks deep into the ocean to learn how microbes influence carbon, nitrogen, and sulfur cycling. For more than 20 years, her lab has been studying methane-breathing marine microorganisms that inhabit rocky mounds on the ocean floor. "Methane is a much more powerful greenhouse gas than carbon dioxide, so tracing its flow through the environment is really a priority for climate models and for understanding the carbon cycle," says Orphan. Her team recently discovered a significantly wider habitat for these microbes than was previously known. The microbes, she thinks, could be preventing large volumes of the potent greenhouse gas from entering the oceans and reaching the atmosphere.

Credit: NASA/JPL-Caltech

Researchers know that aerosols—tiny particles in the atmosphere—scatter and absorb incoming sunlight, affecting the formation and properties of clouds. But it is not well understood how these effects might influence climate change. Enter chemical engineer John Seinfeld. His team conducted a global survey of the impact of changing aerosol levels on low-level marine clouds—clouds with the largest impact on the amount of incoming sunlight Earth reflects back into space—and found that varying aerosol levels altered both the quantity of atmospheric clouds and the clouds' internal properties. These results offer climatologists "unique guidance on how warm cloud processes should be incorporated in climate models with changing aerosol levels," Seinfeld says.

Credit: Yan Hu/Aroian Lab/UC San Diego

Tiny parasitic worms infect nearly half a billion people worldwide, causing gastrointestinal issues, cognitive impairment, and other health problems. Biologist Paul Sternberg is on the case. His lab recently analyzed the entire 313-million-nucleotide genome of the hookworm Ancylostoma ceylanicum to determine which genes turn on when the worm infects its host. A new family of proteins unique to parasitic worms and related to the early infection process was identified; the discovery could lead to new treatments targeting those genes. "A parasitic infection is a balance between the parasites trying to suppress the immune system and the host trying to attack the parasite," Sternberg observes, "and by analyzing the genome, we can uncover clues that might help us alter that balance in favor of the host."

Credit: K.Batygin/Caltech

Earth is special, not least because our solar system has a unique (as far as we know) orbital architecture: its rocky planets have relatively low masses compared to those around other sun-like stars. Planetary scientist Konstantin Batygin has an explanation. Using computer simulations to describe the solar system's early evolution, he and his colleagues showed that Jupiter's primordial wandering initiated a collisional cascade that ultimately destroyed the first generation population of more massive planets once residing in Earth's current orbital neighborhood. This process wiped the inner solar system's slate clean and set the stage for the formation of the planets that exist today. "Ultimately, what this means," says Batygin, "is that planets truly like Earth are intrinsically not very common."

Credit: Nicolás Wey-Gόmez/Caltech

Human understanding of the world has evolved over centuries, anchored to scientific and technological advancements and our ability to map uncharted territories. Historian Nicolás Wey-Gόmez traces this evolution and how the age of discovery helped shape culture and politics in the modern era. Using primary sources such as letters and diaries, he examines the assumptions behind Europe's encounter with the Americas, focusing on early portrayals of native peoples by Europeans. "The science and technology that early modern Europeans recovered from antiquity by way of the Arab world enabled them to imagine lands far beyond their own," says Wey-Gómez. "This knowledge provided them with an essential framework to begin to comprehend the peoples they encountered around the globe."

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At Caltech, researchers study the Earth from many angles—from investigating its origins and evolution to exploring its geology and inner workings to examining its biological systems. Taken together, their findings enable a more nuanced understanding of our planet in all its complexity, helping to ensure that it—and we—endure. This slideshow highlights just a few of the Earth-centered projects happening right now at Caltech.

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