James Webb Telescope Reveals Planet-Forming Disks Can Last Longer Than Previously Thought
Researchers at the University of Arizona have discovered that planet-forming disks of gas and dust around tiny stars live much longer than previously thought. The findings provide new insights into planet formation and the habitability of planets outside our solar system.
By Penny Duran, NASA Space Grant Science Writing Intern, University Communications - February 26, 2025
If there were such a thing as a photo album of the universe, it might include snapshots of pancake-like disks of gas and dust, swirling around newly formed stars across the Milky Way. Known as planet-forming disks, they are believed to be a short-lived feature around most, if not all, young stars, providing the raw materials for planets to form.
Most of these planetary nurseries are short-lived, typically lasting only about 10 million years – a fleeting existence by cosmic standards. Now, in a surprising find, researchers at the University of Arizona have discovered that disks can grace their host stars much longer than previously thought, provided the stars are small – one-tenth of the sun's mass or less.
In a paper published in the Astrophysical Letters Journal, a research team led by Feng Long of the U of A Lunar and Planetary Laboratory, in the College of Science, reports a detailed observation of a protoplanetary disk at the ripe old age of 30 million years. Presenting the first detailed chemical analysis of a long-lived disk using NASA's James Webb Space Telescope, the paper provides new insights into planet formation and the habitability of planets outside our solar system.
"In a sense, protoplanetary disks provide us with baby pictures of planetary systems, including a glimpse of what our solar system may have looked like in its infancy," said Long, the paper's lead author and a Sagan Fellow with the Lunar and Planetary Laboratory.
As long as the star has a certain mass, high-energy radiation from the young star blows the gas and dust out of the disk, and it can no longer serve as raw material to build planets, Long explained.
The team observed a star with the official designation WISE J044634.16–262756.1B – more conveniently known as J0446B – located in the constellation Columba (Latin for "dove") about 267 light-years from Earth. The researchers found that its planet-forming disk has lasted about three times longer than expected.
"Although we know that most disks disperse within 10 million to 20 million years, we are finding that for specific types of stars, their disks can last much longer," Long said. "Because materials in the disk provide the raw materials for planets, the disk's lifespan determines how much time the system has to form planets."
Even though tiny stars retain their disks longer, their disk's chemical makeup does not change significantly. The similar chemical composition regardless of age indicates that the chemistry does not change drastically even as a disk reaches an advanced age. Such a long-lived, stable chemical environment could provide planets around low-mass stars with more time to form.
By analyzing the disk's gas content, the researchers ruled out the possibility that the disk around J0446B is a so-called debris disk, a longer-lasting type of disk that consists of second-generation material produced by collisions of asteroid-like bodies.
"We detected gases like hydrogen and neon, which tells us that there is still primordial gas left in the disk around J0446B," said Chengyan Xie, a doctoral student at LPL who also contributed to the study.
The confirmed existence of long-lived disks rich in gases has implications for life outside our solar system, according to the authors. Of particular interest to researchers is the TRAPPIST-1 system, located 40 light-years from Earth, consisting of a red dwarf star and seven planets similar in size to Earth. Three of those planets are located in the "habitable zone," where conditions allow for liquid water to exist and offer the potential for life to form, at least in principle.
Because stars with long-lived planetary disks fall into a similar mass category as the central star in the TRAPPIST-1 system, the existence of long-lived disks is especially interesting for the evolution of planetary systems, say Long and her co-authors.
"To make the specific arrangement of orbits we see with TRAPPIST-1, planets need to migrate inside the disk, a process that requires the presence of gas," said Ilaria Pascucci, a professor of planetary sciences at LPL who co-authored the study. "The long presence of gas we find in those disks might be the reason behind TRAPPIST-1's unique arrangement."
Long-lived disks have not been found for high-mass stars such as the sun, since stars in such systems evolve much more quickly and planets have less time to form. Although our solar system took a different evolutionary route, long-lived disks can tell researchers a lot about the universe, the authors noted, because low-mass stars are believed to vastly outnumber sun-like stars.
"Developing a better understanding of how low-mass star systems evolve and getting snapshots of long-lived disks might help pave the way to filling out the blanks in the photo album of the universe," Long said.
UA News - James Webb Telescope Reveals Planet-Forming Disks Can Last Longer Than Previously Thought
University of Arizona Professors Develop Astronomy Curriculum Materials to Aid Visually Impaired Students
Lunar and Planetary Laboratory's Dr. Steve Kortenkamp and with Dr. Sunggye Hong in the College of Education have made groundbreaking strides to develop astronomy curriculum materials to aid visually impaired students.University of Arizona Professors Develop Astronomy Curriculum Materials to Aid Visually Impaired Students
By Analeise Mayor, College of Science - January 27, 2025
University of Arizona faculty members, headed by professor Dr. Steve Kortenkamp in the Lunar and Planetary Laboratory and Dr. Sunggye Hong in the College of Education, have made groundbreaking strides to develop astronomy curriculum materials to aid visually impaired students.
Kortenkamp himself was originally a postdoc at the U of A, where he studied in the Lunar and Planetary Laboratory. His work has largely been in the realm of theoretical astronomy, or “computer simulations of gravitational interactions, asteroids, comets, and dust particles,” as Kortenkamp describes.
Over his career, Kortenkamp has excelled in both research and teaching, and he returned to the University of Arizona first as a part-time instructor, before joining the university full time in 2017.
According to Kortenkamp, he was confronted with the issues of inclusivity in STEM education early on in his teaching career.
“The first opportunity that I had to teach at the university in front of a class, one of my students was blind. And that, for me, was a big challenge.” Kortenkamp said. “There were very few resources available to sort of help in that situation.”
In order to make the course material more accessible for his student, Kortenkamp utilized audio aids and enlarged or simplified graphics with great success. Kortenkamp said the experience ultimately changed his outlook on teaching and his approach to inclusivity in the classroom.
“Each time I taught, I tried to develop some new things that I could use in that situation,” he said.
After joining the University full time, Kortenkamp crossed paths with Dr. Sunggye Hong, who shared his passion for making education accessible for all students. Hong runs the college’s program for the visually impaired and his past work has focused on braille reading, tactile communication, and STEM learning for students with visual impairments.
“I'm totally blind due to a congenital glaucoma, and as I was growing, science was a major that not many of my friends and colleagues with visual impairments could choose,” Hong said.
Hong's work has sought to address the lack of accessibility and barriers for students with disabilities in science, and create opportunities for visually impaired students to become engaged in science fields.
“I think it was 2016 where I received a Request For Proposal talking about STEM learning for students with disabilities, and I began putting the ideas together.” Hong said “That's sort of where the collaboration began.”
In 2019, with grant funding from the National Science Foundation, Kortenkamp and Hong designed a new learning curriculum, which would assist and inspire visually impaired students studying astronomy.
They brought together 33 participating students from middle and high schools across the country, all of whom had an interest in pursuing science education and STEM careers. The hope, Hong said, was to shape their experience with science and get them excited about a future in STEM fields.
According to Hong, there were two main components to the project. The first, of course, was science learning.
“It was kind of like an asynchronous online class,” Kortenkamp said. “We would send them packages in the mail, and then we would meet over zoom.”
To make the course material more accessible for the students, Hong and Kortenkamp compiled various types of tactile tools including braille, printed textile materials, and tactile graphics, as well as assistive technology equipment and audio software.
The materials also included 3D printed kits of spacecraft which had been modified or created to be easily assembled without sight.
“They could – by touching – feel a square peg and a square hole, and assemble them, and they would describe the differences that they're feeling. " Kortenkamp said. “We also had them create a little video for each segment of the curriculum where they had to teach someone else, using their models.”
In addition to the virtual curriculum, the students visited Tucson and the University of Arizona on two different trips to supplement their learning.
“We had different activities every day,” Kortenkamp said. “They were taking tours of different labs on campus and living on campus for a week.”
The second, and perhaps most important, component of the experience was mentorship. Outside of classroom learning, each of the students were also connected with two mentors, a U of A science student, and another mentor who was a professional working in a STEM field, who was also visually impaired.
“We wanted to help them understand that they could work in a field that maybe at first they didn't think they had a chance to.” Kortenkamp said. “So we paired them up with someone working in the field as an engineer, or as a scientist of some type. They would virtually shadow them to learn about what their daily life is like, and how their disability influences how they work in their job.”
According to Hong and Kortenkamp, the program had a profound impact on the students.
“The data clearly showed that the students were indeed much more closely engaged in science. The motivation was there,” Hong said. “We were able to hear from them using their own voices, and from their reactions, we could observe that they were very excited and motivated to participate in science.”
“It’s not a surprise to any of us that many of them are now at a university working their way through,” Kortenkamp echoed.
And it wasn’t just the students who benefited from the program.
“To some degree with our curriculum, we were able to educate scientists as well,” Hong said. “It's not just for visually impaired students to learn about science, it is also an opportunity for the science field to learn about the unique needs of students with visual impairments.”
Kortenkamp shared similar sentiments.
“The takeaway I have, as an astronomer, is that I would have never really thought about this kind of stuff if I hadn't encountered that first student in that first class that I was teaching,” Kortenkamp said. “It was a very eye opening experience for me, and it's interesting the way that these techniques can be used by anybody.”
Kortenkamp said the tactile models and teaching methods developed in the program can be applied in a traditional classroom environment as well, to aid all students, sighted or not. He has found that they encourage his students to engage with the course material in new ways.
“It does at least make everyone in the class aware of how it can be more inclusive,” Kortenkamp said. “I try to emphasize in class that these are also tools that can be used by students who are more tactile learners and visual learners. We could apply it not just to visual impairments, but to other kinds of learning difficulties.”
While Kortenkamp sees these successes as a step in the right direction, towards greater inclusivity in science, he said he wants to push the program even further.
“Going forward, I think it would be really nice to be able to take what we did and turn it into a University of Arizona class,” he said. “There are very few classes in the sciences that are geared towards visually impaired students, so I'd like to take what we have and modify the curriculum to make it fit into the system we have at the university. I would like to create a science class that is available for even non-science students, whether they are visually impaired or not.”
Though he said such a course might still be years in the making, Kortenkamp intends to continue using the methods and materials he developed, in his current classes, and his hope is to one day expand the work he’s done into a program that can sustain itself, “whether it's just in the state of Arizona or maybe even broader.”
College of Science News - University of Arizona Professors Develop Astronomy Curriculum Materials to Aid Visually Impaired Students
Asteroid Bennu Comes From a Long-lost Salty World With Ingredients For Life
Two research publications by the OSIRIS-REx sample analysis team suggest that conditions for the emergence of life were widespread across the early solar system.
By NASA and Daniel Stolte/University Communications - January 29, 2025
Nature had the conditions to "cook up" the chemical precursor ingredients for life before Earth formed, according to two studies published by the sample analysis team of NASA's OSIRIS-REx mission, which is led by Dante Lauretta at the University of Arizona.
The OSIRIS-REx spacecraft returned a sample from asteroid Bennu in 2023, and following a year of in-depth analyses in labs across the globe, researchers conclude that these conditions and ingredients may have been common across the solar system, increasing the odds of life forming on other planets and moons.
"These samples from Bennu are an incredible discovery, showing that the building blocks of life were widespread across the early solar system," said Lauretta, Regents Professor of Planetary Science and Cosmochemistry at the U of A Lunar and Planetary Laboratory and a co-author on both papers. "By studying how these ingredients interacted in environments like those on Bennu and in places inferred for the early Earth – such as salty ponds similar to those Darwin once imagined – we can better understand how life might emerge and where to search for it beyond our planet."
Zoe Zeszut, lab manager and research scientist at the University of Arizona Kuiper-Arizona Laboratory for Astromaterials Analysis, prepares a vial containing extraterrestrial sample material for analysis.
Bennu coalesced from a small portion of the leftover rubble resulting from a giant collision of asteroids. Preserved in the vacuum of space since the solar system's formation about 4.5 billion years ago, the samples have provided scientists with unparalleled insights into the conditions of that era.
Based on their findings, presented in two publications in Nature and Nature Astronomy on Jan. 29, the researchers share several theories about the history of Bennu and the solar system.
Bennu’s molecular composition suggests the ice and organic compounds in its parent body originated in the extremely cold outermost disk of gas and dust that gave rise to the solar system.
Temperatures in the outer disk could dip to minus 400 degrees Fahrenheit, allowing volatile gases that easily evaporate in warmer conditions to accumulate and freeze – among them water vapor, carbon dioxide, methane and ammonia, which was detected in "exceptionally high" abundances in the Bennu samples, according to the Nature Astronomy paper.
Up-close image of a combined focused ion beam and secondary electron microscope in the Kuiper-Arizona Laboratory for Astromaterials Analysis. This instrument allows scientists to first scan a sample to find an interesting target, then cut it into cross sections.
Given the right environment, ammonia can react with formaldehyde, which was also detected in the samples, to form complex molecules such as amino acids – the building blocks of proteins. Fourteen of the 20 amino acids that life on Earth uses to make proteins are found in the Bennu sample. The research team also found all five nucleobases that life on Earth uses to encode structural information in more complex biomolecules like DNA and RNA.
"Besides pointing to the outer solar system origin of abundant ammonia in Bennu's ancestor, our work also supports the idea that objects that formed far from the sun could have been an important source of the raw ingredients for life throughout the solar system," said Danny Glavin, a senior sample scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Glavin, together with colleague Jason Dworkin, led the paper in Nature Astronomy.
With life's ingredients found in Bennu samples, the big question is: How did these building blocks turn into the chains of molecules needed to activate biology?
"You can have all the ingredients for whatever you want to make, but you have to have the environment to make them do something," said Tim McCoy, curator of meteorites at the Smithsonian's National Museum of Natural History in Washington, D.C.
Along with Sara Russell of the Natural History Museum in London, McCoy co-led 66 scientists from four continents in a study of minerals in the Bennu samples. In the Nature paper, they describe evidence of an ancient environment well-suited to kickstart the chemistry of life.
Ranging from calcite to halite and sylvite, scientists identified 11 minerals that comprise a complete set of "evaporites" from a brine, or salt-saturated water. These evaporites form as water containing dissolved salts evaporates over long periods of time, leaving behind the salts as solid crystals.
"We're seeing minerals in Bennu samples that we have never seen before in a meteorite or any extraterrestrial sample," McCoy said.
Finding evaporites indicates that the interior of Bennu's ancestor was warm enough to support liquid water for a substantial amount of time. Liquid water is necessary for life, as it facilitates its essential chemical reactions, while salts can prevent water from freezing. Salts also help concentrate simple molecules, making it easier for them to combine into the complex compounds life depends on.
While several evaporites have been reported from meteorite samples, the Bennu sample represents the first time researchers have seen a complete set preserving an evaporation process that could have lasted thousands of years or more. This process happens in basins of water on Earth, including drying lakes and shallow seas. The researchers deem it possible that on Bennu's ancestor, water could have existed in underground pockets or veins, but not on the surface, as it would have quickly boiled away due to lack of atmospheric pressure.
U of A co-authors on the two publications include Jessica Barnes, Harold Connolly, Dani DellaGiustina, Pierre Haenecour, Dolores Hill, Tom Zega and Zoe Zeszut, all of whom helped with sample analysis taking advantage of the advanced technological resources of U of A's Kuiper-Arizona Laboratory for Astromaterials Analysis. The following graduate students also were part of this work: Maizey Benner, Kana Ishimaru, Nicole Kerrison, Iunn Ong, Beau Prince, Lucas Smith.
UA News - Asteroid Bennu Comes From a Long-lost Salty World With Ingredients For Life
Snow4Flow: Studying Glaciers From Arizona
Snow4Flow is a new University of Arizona-led NASA mission to study arctic glaciers using advanced radar mounted on low-flying aircraft. Captained by Jack Holt, a professor at the University of Arizona’s Lunar & Planetary Lab, the mission’s goal is to improve climate modeling and to better understand glacial loss and its impact on sea level rise.
NASA's Pandora Mission One Step Closer to Probing Alien Atmospheres, With Mission Operations Based at U of A
Pandora, a small satellite mission poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres cleared an important milestone by completing the spacecraft bus, which acts as the spacecraft's "brains."NASA's Pandora Mission One Step Closer to Probing Alien Atmospheres, With Mission Operations Based at U of A
By Francis Reddy/NASA Goddard Space Flight Center and Daniel Stolte/University Communications - January 16, 2025.
Pandora, NASA's newest exoplanet mission, is one step closer to launch with the completion of the spacecraft bus, which provides the structure, power and other systems that will allow the mission to carry out its work. Pandora's exoplanet science working group is led by the University of Arizona, and Pandora will be the first mission to have its operations center at the U of A Space Institute.
The completion of the bus was announced Thursday during a press briefing at the 245th Meeting of the American Astronomical Society in National Harbor, Maryland.
"This is a huge milestone for us and keeps us on track for a launch in the fall," said Elisa Quintana, Pandora's principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The bus holds our instruments and handles navigation, data acquisition and communication with Earth – it's the brains of the spacecraft."
Pandora is a small satellite poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres – especially the presence of hazes, clouds and water. The data will establish a firm foundation for interpreting measurements by NASA's James Webb Space Telescope and future missions aimed at searching for habitable worlds.
"Although smaller and less sensitive than Webb, Pandora will be able to stare longer at the host stars of extrasolar planets, allowing for deeper study," said Pandora co-investigator Daniel Apai, professor of astronomy and planetary sciences at the U of A Steward Observatory and Lunar and Planetary Laboratory who leads the mission's Exoplanets Science Working Group. "Better understanding of the stars will help Pandora and its 'big brother,' the James Webb Space Telescope, disentangle signals from stars and their planets."
Astronomers can sample an exoplanet's atmosphere when it passes in front of its star as seen from Earth's perspective, during an event known as a transit. Part of the star's light skims the planet's atmosphere before making its way to the observer. This interaction allows the light to interact with atmospheric substances, and their chemical fingerprints – dips in brightness at characteristic wavelengths – become imprinted in the light.
The concept of Pandora was born out of necessity to overcome a snag in observing starlight passing through the atmospheres of exoplanets, Apai said.
"In 2018, a doctoral student in my group, Benjamin Rackham – now an MIT research scientist – described an astrophysical effect by which light coming directly from the star muddies the signal of the light passing through the exoplanet's atmosphere," Apai explained. "We predicted that this effect would limit Webb's ability to study habitable planets."
Telescopes see light from the entire star, not just the small amount grazing the planet. Stellar surfaces aren't uniform. They sport hotter, unusually bright regions called faculae and cooler, darker regions similar to the spots on our sun, both of which grow, shrink and change position as the star rotates. As a result, these "mixed signals" in the observed light can make it difficult to distinguish between light that has passed through an exoplanet's atmosphere and light that varies based on a star's changing appearance. For example, variations in light from the host star can mask or mimic the signal of water, a likely key ingredient researchers look for when evaluating an exoplanet's potential for harboring life.
Using a novel all-aluminum, 45-centimeter-wide telescope, jointly developed by Lawrence Livermore National Laboratory and Corning Specialty Materials in Keene, New Hampshire, Pandora's detectors will capture each star's visible brightness and near-infrared spectrum at the same time, while also obtaining the transiting planet's near-infrared spectrum. This combined data will enable the science team to determine the properties of stellar surfaces and cleanly separate star and planetary signals.
The observing strategy takes advantage of the mission's ability to continuously observe its targets for extended periods, something flagship observatories like Webb, which offer limited observing time due to high demand, cannot regularly do.
Over the course of a yearlong mission, Pandora will observe at least 20 exoplanets 10 times, with each stare lasting a total of 24 hours. Each observation will include a transit, which is when the mission will capture the planet's spectrum.
Karl Harshman, who leads the Mission Operations Team at the U of A Space Institute that will support the spacecraft's operation, said: "We have a very excited team that has been working hard to have our Mission Operations Center running at full speed at the time of launch and look forward to receiving science data. Just this week, we performed a communications test with our antenna system that will transmit commands to Pandora and receive the telemetry from the spacecraft."
Pandora is led by NASA's Goddard Space Flight Center. Lawrence Livermore National Laboratory provides the mission's project management and engineering. Pandora's telescope was manufactured by Corning and developed collaboratively with Livermore, which also developed the imaging detector assemblies, the mission's control electronics, and all supporting thermal and mechanical subsystems. The infrared sensor was provided by NASA Goddard. Blue Canyon Technologies provided the bus and is performing spacecraft assembly, integration and environmental testing. NASA's Ames Research Center in California's Silicon Valley will perform the mission's data processing. Pandora's mission operations center is located at the U of A, and a host of additional universities support the science team.
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Newly Discovered 'Kiss and Capture' Mechanism Explains the Formation of Pluto and Its Largest Moon
By Niranjana
By Niranjana Rajalakshmi, University Communications - January 6, 2025
Billions of years ago, in the frigid outer reaches of our solar system, two icy worlds collided. Rather than destroying each other in a cosmic catastrophe, they spun together like a celestial snowman, finally separating while remaining forever linked in orbit. This is how Pluto and its largest moon, Charon, originated, according to a new University of Arizona study that challenges decades of scientific assumptions.
A study led by Adeene Denton, a NASA postdoctoral fellow who conducted the research at the U of A Lunar and Planetary Laboratory, has revealed this unexpected "kiss and capture" mechanism, which could help scientists better understand how planetary bodies form and evolve. By considering something planetary scientists had overlooked over decades – the structural strength of cold, icy worlds – researchers have discovered an entirely new type of cosmic collision.
The findings were published in the journal Nature Geoscience.
For decades, scientists have theorized that Pluto's unusually large moon Charon formed through a process similar to Earth's moon – a massive collision followed by the stretching and deformation of fluid-like bodies, Denton said. This model worked well for the Earth-moon system, where the intense heat and larger masses involved meant the colliding bodies behaved more like fluids. However, when applied to the smaller, colder Pluto-Charon system, this approach overlooked a crucial factor: the structural integrity of rock and ice.
"Pluto and Charon are different – they're smaller, colder and made primarily of rock and ice. When we accounted for the actual strength of these materials, we discovered something completely unexpected," Denton said.
Using advanced impact simulations on the U of A's high-performance computing cluster, the research team found that instead of stretching like silly putty during the collision, Pluto and the proto-Charon actually became temporarily stuck together, rotating as a single snowman-shaped object before separating into the binary system we observe today. A binary system occurs when two celestial bodies orbit around a common center of mass, much like two figure skaters spinning while holding hands.
"Most planetary collision scenarios are classified as 'hit and run' or 'graze and merge.' What we've discovered is something entirely different – a 'kiss and capture' scenario where the bodies collide, stick together briefly and then separate while remaining gravitationally bound," said Denton.
"The compelling thing about this study, is that the model parameters that work to capture Charon, end up putting it in the right orbit. You get two things right for the price of one," said senior study author Erik Asphaug, a professor in the Lunar and Planetary Laboratory.
The study also suggests that both Pluto and Charon remained largely intact during their collision, with much of their original composition preserved. This challenges previous models that suggested extensive deformation and mixing during the impact, Denton said. Additionally, the collision process, including tidal friction as the bodies separated, deposited considerable internal heat into both bodies, which may provide a mechanism for Pluto to develop a subsurface ocean without requiring formation in the more radioactive very early solar system – a timing constraint that has troubled planetary scientists.
The research team is already planning follow-up studies to explore several key areas. The team wants to investigate how tidal forces influenced Pluto and Charon's early evolution when they were much closer together, analyze how this formation scenario aligns with Pluto's current geological features, and examine whether similar processes could explain the formation of other binary systems.
"We're particularly interested in understanding how this initial configuration affects Pluto's geological evolution," Denton said. "The heat from the impact and subsequent tidal forces could have played a crucial role in shaping the features we see on Pluto's surface today."
UA News - Newly Discovered 'Kiss and Capture' Mechanism Explains the Formation of Pluto and Its Largest Moon
Study Sheds Light on Origin of Genetic Code
Nearly all living organisms use the same genetic code, the building blocks of life. A new study suggests conventional wisdom about how the code evolved is likely flawed.
By Daniel Stolte, University Communications - December 12, 2024
Despite awe-inspiring diversity, nearly every lifeform – from bacteria to blue whales – shares the same genetic code. How and when this code came about has been the subject of much scientific controversy.
Taking a fresh approach at an old problem, Sawsan Wehbi, a doctoral student in the Genetics Graduate Interdisciplinary Program at the University of Arizona, discovered strong evidence that the textbook version of how the universal genetic code evolved needs revision. Wehbi is the first author of a study published in the journal PNAS suggesting the order with which amino acids – the code's building blocks – were recruited is at odds with what is widely considered the "consensus" of genetic code evolution.
"The genetic code is this amazing thing in which a string of DNA or RNA containing sequences of four nucleotides is translated into protein sequences using 20 different amino acids," said Joanna Masel, the paper's senior author and aprofessor of ecology and evolutionary biology at the U of A. "It's a mind-bogglingly complicated process, and our code is surprisingly good. It's nearly optimal for a whole bunch of things, and it must have evolved in stages."
The study revealed that early life preferred smaller amino acid molecules over larger and more complex ones, which were added later, while amino acids that bind to metals joined in much earlier than previously thought. Finally, the team discovered that today's genetic code likely came after other codes that have since gone extinct.
The authors argue that the current understanding of how the code evolved is flawed because it relies on misleading laboratory experiments rather than evolutionary evidence. For example, one of the cornerstones of conventional views of genetic code evolution rests on the famous Urey-Miller experiment of 1952, which attempted to simulate the conditions on early Earth that likely witnessed the origin of life.
While valuable in demonstrating that nonliving matter could give rise to life's building blocks, including amino acids, through simple chemical reactions, the experiment's implications have been called into question. For example, it did not yield any amino acids containing sulfur, despite the element being abundant on early Earth. As a result, sulfuric amino acids are believed to have joined the code much later. However, the result is hardly surprising, considering that sulfur was omitted from the experiment's ingredients.
According to co-author Dante Lauretta, Regents Professor of Planetary Science and Cosmochemistry at the U of A Lunar and Planetary Laboratory, early life's sulfur-rich nature offers insights for astrobiology, particularly in understanding the potential habitability and biosignatures of extraterrestrial environments.
"On worlds like Mars, Enceladus and Europa, where sulfur compounds are prevalent, this could inform our search for life by highlighting analogous biogeochemical cycles or microbial metabolisms," he said. "Such insights might refine what we look for in biosignatures, aiding the detection of lifeforms that thrive in sulfur-rich or analogous chemistries beyond Earth."
The team used a new method to analyze sequences of amino across the tree of life, all the way back to the last universal common ancestor, or LUCA, a hypothesized population of organisms that lived around 4 billion years ago and represents the shared ancestor of all life on Earth today. Unlike previous studies, which used full-length protein sequences, Wehbi and her group focused on protein domains, shorter stretches of amino acids.
"If you think about the protein being a car, a domain is like a wheel," Wehbi said. "It's a part that can be used in many different cars, and wheels have been around much longer than cars."
To get a handle on when a specific amino acid likely was recruited into the genetic code, the researchers used statistical data analysis tools to compare the enrichment of each individual amino acid in protein sequences dating back to LUCA, and even farther back in time. An amino acid that shows up preferentially in ancient sequences was likely incorporated early on. Conversely, LUCA's sequences are depleted for amino acids that were recruited later but became available by the time less ancient protein sequences emerged.
The team identified more than 400 families of sequences dating back to LUCA. More than 100 of them originated even earlier and had already diversified prior to LUCA. These turned out to contain more amino acids with aromatic ring structures, like tryptophan and tyrosine, despite these amino acids being late additions to our code.
"This gives hints about other genetic codes that came before ours, and which have since disappeared in the abyss of geologic time," Masel said. "Early life seems to have liked rings."
UA News - Study Sheds Light on Origin of Genetic Code
U of A Projects Research Expenditures Surpassed $1B for FY 2024, Joining a Select Group of US Research Institutions
UniversityU of A Projects Research Expenditures Surpassed $1B for FY 2024, Joining a Select Group of US Research Institutions
University Communications and Research, Innovation and Impact - December 17, 2024
Retrieving the largest asteroid sample ever brought to Earth, advancing a vaccine for Valley fever to human clinical trial – the world's first against fungal infection to reach this stage – and mitigating the effects of extreme heat are examples of the power of the University of Arizona faculty, staff and student research and innovation. University officials project research activity has exceeded $1 billion in fiscal year 2024, which ended on June 30, 2024, and are submitting this data to the National Science Foundation for review. The official number will be confirmed in the fall.
"Our faculty members tackle urgent global challenges, from energy and environmental issues to national security, human health and the societal impact of technological change," said University of Arizona President Suresh Garimella. "The scale of our research enterprise provides the capacity to lead multi-institution and interdisciplinary successes like the OSIRIS-REx mission and to pursue revolutionary advancements that will benefit people everywhere, such as personalized medical treatments with the Center for Advanced Molecular and Immunological Therapies. Research advances human knowledge and is a core part of our mission: It provides the hands-on learning experience that prepares our students to pursue their goals and contributes to the cutting-edge workforce Arizona needs while also strengthening communities and creating opportunity throughout the state."
Reaching this milestone places the U of A among a select group of top research institutions, including Stanford University, Duke University, Harvard University, the University of California, Los Angeles, the University of Florida, the University of Michigan, and the University of North Carolina.
Newly released data from the NSF's Higher Education Research and Development Survey confirmed that the university delivered $955 million in total research activity in FY23 (including more than $356 million in health sciences); this year's submission for the survey exceeds that mark. The survey ranks institutions based on research expenditures, providing a comprehensive measure of research vitality, and for the sixth consecutive year, the U of A ranks among the nation’s top 20 public research institutions and the top 4% of over 900 universities and colleges that invested in research and development.
The U of A also maintained its No. 1 ranking in astronomy and astrophysics – a distinction held annually since 1987. Additional key rankings include:
- No. 4: High Hispanic enrollment
- No. 6: NASA-funded activity
- No. 7: Physical sciences
- No. 20: Public universities overall
- No. 36: All universities
"Research is the cornerstone of the University of Arizona's standing as a world-class institution, and our latest rankings reaffirm this excellence," said Tomás Díaz de la Rubia, senior vice president of research and innovation. "Our extraordinary research community – faculty, postdocs, students and staff – continues to tackle the world's most pressing challenges while forging transformative partnerships with government, industry and nonprofit organizations. This work is guided by our land-grant mission, driving innovation and discovery, enriching student learning, and strengthening Arizona's economy, workforce and communities."
Read more about U of A Research, Innovation & Impact.
"The University of Arizona offers a unique environment to pursue groundbreaking research across diverse fields, including my work on Alzheimer's disease and related dementias at the U of A Health Sciences Center for Innovation in Brain Science," said Coco Tirambulo, an M.D./Ph.D. student at the U of A College of Medicine – Tucson. "Growing up in my parents' adult care home, I witnessed the challenges faced by patients and caregivers, which fuels my commitment to advancing precision medicine therapies. I hope our research leads to transformative solutions for families navigating neurodegenerative diseases."
UA News - U of A projects research expenditures surpassed $1B for FY 2024, joining a select group of US research institutions
New 'Spectral Fingerprint' Atlas of Satellites Aims to Improve Space Security
LPL researchers have created the first astronomical equivalent of a fingerprint database for satellites, a critical first step toward easily identifying human-made objects in the increasingly crowded geostationary orbit.
By Stephanie Doster, Space 4 Center - November 12, 2024
University of Arizona researchers have created the first astronomical equivalent of a fingerprint database for satellites, a critical first step toward easily identifying human-made objects in the increasingly crowded geostationary orbit.
This database, or spectral atlas, includes 96 satellites in the geostationary orbit, or GEO – home to satellites used for communications, imaging, navigation and other purposes – that are visible from Tucson.
Adam Battle, a Ph.D. candidate in the U of A Lunar and Planetary Laboratory supported by the Space4 Center, led the research, which was published Tuesday in The Planetary Science Journal.
"Satellites look like tiny dots in the sky, even through most telescopes. For decades, humans have launched tens of thousands of objects into space with no mechanism for
identifying them easily," Battle said. "This is the first time this sort of systematic, big atlas of spectral data has been collected for these objects. It gives us a baseline for differentiating space objects, for knowing where everything is and what has changed and keeping that space safe."
The United States Space Surveillance Network, part of the U.S. Space Command, tracks more than 45,000 artificial objects in Earth's orbit, including about 350 active payloads in GEO.
The GEO belt is a unique orbit about 22,000 miles above Earth's equator. Satellites in GEO orbit at the same rate and direction as Earth; from the ground, they appear to stand still. Only so many orbital slots are available in GEO, making them valuable to companies and nations looking to put satellites there. The average lifespan of a satellite in GEO is about 15 to 20 years, after which they are maneuvered into a higher, "graveyard" orbit where they remain as space junk.
"The orbital space around the Earth is getting congested, and we unfortunately do not have license places for satellites to identify them easily. This work is the first step towards making space safe, secure and sustainable," said Vishnu Reddy, director of the university's Space4 Center and a planetary science professor who co-authored the paper. Reddy, Battle's Ph.D. advisor, initiated the project when he started at the U of A nearly a decade ago.
Other co-authors of the research include Roberto Furfaro, professor of systems and industrial engineering and Space4 deputy director, and Space4 Center software engineer Tanner Campbell.
The U of A team used the power of spectroscopy to create the atlas. With spectroscopy, the team can measure how the sun's light interacts with materials on the satellites like metals, paint and solar panels, and how these interactions change with illumination conditions. The results are a detailed pattern of colors for those unique conditions – a color fingerprint – that can be used to identify that specific object.
Using a telescope built by U of A students and housed on campus, Battle observed objects in GEO for 192 nights during every season between January 2020 and June 2022, except for the cloudy summer months. A typical night's worth of observing involved imaging one object every 45 seconds for the entire night. This generated 284 separate datasets and about 190,000 spectra.
As part of his study, Battle focused on repeated observations of five satellite bus types – the central structure to which communications arrays, thrusters and solar panels are mounted – to determine how their spectra varied over nights and seasons and how they differed from the spectra of natural objects.
The resulting atlas contains the unique detailed patterns of colors for 96 individual satellites observed in GEO from Tucson.
"Historically, scientists have used brightness measurements, as the phase angle changes.
But using spectroscopy allows you to add another layer of information, and the ultimate goal is to be able to uniquely identify different satellites with machine learning algorithms trained on these 'fingerprints,'" Battle said. "We can also compare these spectra to samples in the lab to begin estimating what materials are used on the spacecraft."
David Cantillo, another Lunar and Planetary Laboratory graduate student working with Reddy, is building a telescope in Australia, where he plans to expand the atlas by studying space objects in GEO that aren't visible from the United States.
"The next step is to combine the power of machine learning with this incredible dataset for fast and credible identification of satellites," Furfaro said. "We are working towards the goal where we can operationally deploy this tool for a wide range of space applications."
UA News - New 'Spectral Fingerprint' Atlas of Satellites Aims to Improve Space Security
U of A Scientists Have Their Eyes on Europa, Jupiter's Mysterious, Icy Moon
The largest spacecraft to ever explore the solar system, NASA's Europa Clipper, will orbit Jupiter and make 49 planned flybys of its moon Europa to study the moon's icy shell and help researchers better understand what lies beneath.
By Daniel Stolte, University Communications - October 28, 2024
The largest spacecraft to ever explore the solar system blasted into the sky above NASA's Kennedy Space Center in Cape Canaveral, Florida, on Oct. 14. NASA's Europa Clipper will orbit Jupiter and make 49 planned flybys of its moon Europa to study the moon's icy shell and help researchers better understand what lies beneath.
Scientists at the University of Arizona Lunar and Planetary Lab, which has longstanding expertise imaging other worlds in unprecedented detail, will participate in many aspects of the mission, with emphasis on developing the data processing methods to produce beautiful images, mosaics and topographic data.
Europa Clipper carries nine scientific instruments to provide a comprehensive study of the moon Europa, which is covered by a thick, icy crust, under which scientists believe lies a vast ocean of liquid water. This makes Europa one of the prime destinations in the solar system to search for extraterrestrial life, as scientific evidence suggests that the ingredients for life may exist on Europa right now. If the mission determines Europa is habitable, it may mean there are more habitable worlds in our solar system and beyond than previously imagined.
At the heart of the science instrument suite on board the orbiter is the Europa Imaging System, or EIS (pronounced "ice"), which will capture Europa's valleys, ridges, dark bands and other features in detail. Developed at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, EIS consists of a wide-angle camera and a narrow-angle camera, each with an 8-megapixel sensor, that will map Europa with high-resolution color and stereoscopic images.
"I look forward to seeing the surface of Europa at a level of detail we have never seen before," said Sarah Sutton, a research and development engineer and scientist in the U of A Lunar and Planetary Laboratory who will work on Europa image processing and planning.
Sutton, who has researched Mars for most of her career, is part of a group at the university led by Regents Professor Alfred McEwen, who is also principal investigator of NASA's HiRISE camera on the agency's Mars Reconnaissance Orbiter, which has been photographing the surface of Mars for over a decade and a half.
"It will be exciting to test our ideas about Europa's surface evolution and to discover new things about this intriguing ocean world," Sutton said. "I hope we get to observe active changes happening on the surface, or even actively erupting plumes of gas and dust."
McEwen, who serves as deputy principal investigator on the EIS instrument, wants to answer key questions, including: How deep is Europa's ocean, and how thick is the ice shell? Is Europa currently active? Are there eruptions or plumes that can carry subsurface materials to the surface? Are there complex organic molecules on Europa's surface?
"EIS will be essential or helpful to all of these objectives," he said. "At closest approach, about 50 kilometers (30 miles) from the moon's surface, we'll be able to image small patches of the surface down to about 50 centimeters (20 inches). Together, our cameras will provide essential information needed for a future landing mission to Europa."
Another instrument, REASON, short for Radar for Europa Assessment and Sounding: Ocean to Near-surface, is an ice-penetrating radar designed to look inside Europa's icy crust and study the nature of the interior. Reaching as deep as 30 kilometers (nearly 20 miles) into Europa's icy crust, the observations will allow scientists to build a picture of how the crust of Europa evolved to its present state and how it functions today, according to Lynn Carter, associate professor of planetary sciences and University Distinguished Scholar who serves a co-investigator on the REASON team.
"Our observations will place real constraints on the nature of the icy crust and how it changes through time and interacts with the subsurface ocean," she said. "This is a really critical part of the puzzle for determining if Europa could be habitable. I'm excited that we could see something new and unexpected."
Europa Clipper is the first mission designed to conduct a detailed study of Jupiter's moon Europa. During its journey, the spacecraft will travel 1.8 billion miles (2.9 billion kilometers) to reach Jupiter in April 2030. To power its extensive instrument suite in the faint sunlight that reaches Jupiter, Europa Clipper carries the largest solar arrays NASA has ever used for an interplanetary mission. With arrays extended, the spacecraft spans 100 feet from end to end. With propellant loaded, its launch weight registered at a whopping 13,000 pounds.
Elizabeth Turtle of APL, who serves as the principal investigator on the EIS camera, obtained her doctorate at the U of A's Lunar and Planetary Laboratory and later held a faculty position there. All in all, at least 20 other LPL alumni work on the Europa Clipper mission in one form or another.
Managed by Caltech in Pasadena, California, the Jet Propulsion Laboratory led the development of the Europa Clipper mission in partnership with the Johns Hopkins Applied Physics Laboratory for NASA's Science Mission Directorate in Washington. The Applied Physics Laboratory designed the main spacecraft body in collaboration with the Jet Propulsion Laboratory and NASA's Goddard Space Flight Center, Marshall Space Flight Center and Langley Research Center. The Planetary Missions Program Office at the Marshall Space Flight Center in Huntsville, Alabama, executes program management of the Europa Clipper mission.
U of A Scientists Have Their Eyes on Europa, Jupiter's Mysterious, Icy Moon - UA News