Hubble’s new observations of Jupiter’s Great Red Spot, collected over 90 days between December 2023 to March 2024
Astronomers have observed Jupiter’s legendary Great Red Spot (GRS), an anticyclone large enough to swallow Earth, for at least 150 years. But there are always new surprises – especially when the NASA/ESA Hubble Space Telescope takes a close-up look at it.
Using Hubble Space Telescope data spanning approximately 90 days (between December 2023 and March 2024) when the giant planet Jupiter was approximately 740 million kilometres from the Sun, astronomers measured the Great Red Spot’s size, shape, brightness, colour, and vorticity over one full oscillation cycle. The data reveal that the Great Red Spot is not as stable as it might look. It was observed going through an oscillation in its elliptical shape, jiggling like a bowl of gelatin. The cause of the 90-day oscillation is unknown. Credit: NASA, ESA, A. Simon (GSFC)
Hubble’s new observations of the famous red storm, collected over 90 days between December 2023 to March 2024, reveal that the GRS is not as stable as it might look. The recent data show the GRS jiggling like a bowl of gelatin. The combined Hubble images allowed astronomers to assemble a time-lapse movie of the squiggly behaviour of the GRS.
“While we knew its motion varies slightly in its longitude, we didn’t expect to see the size oscillate. As far as we know, it’s not been identified before,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This is really the first time we’ve had the proper imaging cadence of the GRS. With Hubble’s high resolution we can say that the GRS is definitively squeezing in and out at the same time as it moves faster and slower. That was very unexpected, and at present there are no hydrodynamic explanations.”
Hubble monitors Jupiter and the other outer solar system planets every year through the Outer Planet Atmospheres Legacy program (OPAL) led by Simon, but these observations were from a program dedicated to the GRS. Understanding the mechanisms of the largest storms in the solar system puts the theory of hurricanes on Earth into a broader cosmic context, which might be applied to better understanding the meteorology on planets around other stars.
Using Hubble Space Telescope data spanning approximately 90 days (between December 2023 and March 2024) when the giant planet Jupiter was approximately 740 million kilometres from the Sun, astronomers measured the Great Red Spot’s size, shape, brightness, colour, and vorticity over a full oscillation cycle. The data reveal that the Great Red Spot is not as stable as it might look. It was observed going through an oscillation in its elliptical shape, jiggling like a bowl of gelatin. The cause of the 90-day oscillation is unknown. The observation is part of the Outer Planet Atmospheres Legacy program (OPAL). Credit: NASA, ESA, A. Simon (GSFC)
Simon’s team used Hubble to zoom in on the GRS for a detailed look at its size, shape, and any subtle colour changes.
“When we look closely, we see a lot of things are changing from day to day,” said Simon.
This includes ultraviolet-light observations showing that the distinct core of the storm gets brightest when the GRS is at its largest size in its oscillation cycle. This indicates less haze absorption in the upper atmosphere.
“As it accelerates and decelerates, the GRS is pushing against the windy jet streams to the north and south of it,” said co-investigator Mike Wong of the University of California at Berkeley. “It’s similar to a sandwich where the slices of bread are forced to bulge out when there’s too much filling in the middle.”
Wong contrasted this to Neptune, where dark spots can drift wildly in latitude without strong jet streams to hold them in place. Jupiter’s Great Red Spot has been held at a southern latitude, trapped between the jet streams, for the extent of Earth-bound telescopic observations.
The team has continued watching the GRS shrink since the OPAL program began 10 years ago. They predict it will keep shrinking before taking on a stable, less-elongated, shape.
“Right now it’s over-filling its latitude band relative to the wind field. Once it shrinks inside that band the winds will really be holding it in place,” said Simon.
The team predicts that the GRS will probably stabilise in size, but for now Hubble only observed it for one oscillation cycle.
“This is a great example of the power of Hubble’s exquisite imaging for monitoring of the atmospheres of the outer planets,” said co-investigator Patrick Irwin of the University of Oxford. “With these new observations we were able to study the dynamics and evolution of the GRS over three months, building on our understanding of the long-term properties of Jupiter obtained from the OPAL program over the past decade.”
The researchers hope that in the future other high-resolution images from Hubble might identify other Jovian parameters that indicate the underlying cause of the oscillation.
Saturn is truly the lord of the rings in this latest snapshot from NASA’s Hubble Space Telescope, taken on July 4, 2020, when the opulent giant world was 839 million miles from Earth. This new Saturn image was taken during summer in the planet’s northern hemisphere.
NASA’s Hubble Space Telescope captured this image of Saturn on July 4, 2020. Two of Saturn’s icy moons are clearly visible in this exposure: Mimas at right, and Enceladus at bottom. This image is taken as part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giant planets. In Saturn’s case, astronomers continue tracking shifting weather patterns and storms. Credits: NASA, ESA, A. Simon (Goddard Space Flight Center), M.H. Wong (University of California, Berkeley), and the OPAL Team
Hubble found a number of small atmospheric storms. These are transient features that appear to come and go with each yearly Hubble observation. The banding in the northern hemisphere remains pronounced as seen in Hubble’s 2019 observations, with several bands slightly changing color from year to year. The ringed planet’s atmosphere is mostly hydrogen and helium with traces of ammonia, methane, water vapor, and hydrocarbons that give it a yellowish-brown color.
Hubble photographed a slight reddish haze over the northern hemisphere in this color composite. This may be due to heating from increased sunlight, which could either change the atmospheric circulation or perhaps remove ices from aerosols in the atmosphere. Another theory is that the increased sunlight in the summer months is changing the amounts of photochemical haze produced. “It’s amazing that even over a few years, we’re seeing seasonal changes on Saturn,” said lead investigator Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Conversely, the just-now-visible south pole has a blue hue, reflecting changes in Saturn’s winter hemisphere.
Hubble’s sharp view resolves the finely etched concentric ring structure. The rings are mostly made of pieces of ice, with sizes ranging from tiny grains to giant boulders. Just how and when the rings formed remains one of our solar system’s biggest mysteries. Conventional wisdom is that they are as old as the planet, over 4 billion years. But because the rings are so bright – like freshly fallen snow – a competing theory is that they may have formed during the age of the dinosaurs. Many astronomers agree that there is no satisfactory theory that explains how rings could have formed within just the past few hundred million years. “However, NASA’s Cassini spacecraft measurements of tiny grains raining into Saturn’s atmosphere suggest the rings can only last for 300 million more years, which is one of the arguments for a young age of the ring system,” said team member Michael Wong of the University of California, Berkeley.
Two of Saturn’s icy moons are clearly visible in this exposure: Mimas at right, and Enceladus at bottom.
This image is taken as part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giant planets. In Saturn’s case, astronomers continue tracking shifting weather patterns and storms.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.
Press release from NASA, on Hubble capturing summertime data from Saturn.
UC Riverside-led research team’s model to explain photosynthesis lays out the next challenging phase of research on how green plants transform light energy into chemical energy
UC Riverside-led research team’s model to explain photosynthesis lays out the next challenging phase of research on how green plants transform light energy into chemical energy. Credits: Gabor lab, UC Riverside
When sunlight shining on a leaf changes rapidly, plants must protect themselves from the ensuing sudden surges of solar energy. To cope with these changes, photosynthetic organisms — from plants to bacteria — have developed numerous tactics. Scientists have been unable, however, to identify the underlying design principle.
An international team of scientists, led by physicist Nathaniel M. Gabor at the University of California, Riverside, has now constructed a model that reproduces a general feature of photosynthetic light harvesting, observed across many photosynthetic organisms.
Nathaniel Gabor is an associate professor of physics at UC Riverside. Credits: CIFAR
Light harvesting is the collection of solar energy by protein-bound chlorophyll molecules. In photosynthesis — the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water — light energy harvesting begins with sunlight absorption.
The researchers’ model borrows ideas from the science of complex networks, a field of study that explores efficient operation in cellphone networks, brains, and the power grid. The model describes a simple network that is able to input light of two different colors, yet output a steady rate of solar power. This unusual choice of only two inputs has remarkable consequences.
“Our model shows that by absorbing only very specific colors of light, photosynthetic organisms may automatically protect themselves against sudden changes — or ‘noise’ — in solar energy, resulting in remarkably efficient power conversion,” said Gabor, an associate professor of physics and astronomy, who led the study appearing today in the journal Science. “Green plants appear green and purple bacteria appear purple because only specific regions of the spectrum from which they absorb are suited for protection against rapidly changing solar energy.”
Gabor first began thinking about photosynthesis research more than a decade ago, when he was a doctoral student at Cornell University. He wondered why plants rejected green light, the most intense solar light. Over the years, he worked with physicists and biologists worldwide to learn more about statistical methods and the quantum biology of photosynthesis.
Richard Cogdell, a renowned botanist at the University of Glasgow in the United Kingdom and a coauthor on the research paper, encouraged Gabor to extend the model to include a wider range of photosynthetic organisms that grow in environments where the incident solar spectrum is very different.
“Excitingly, we were then able to show that the model worked in other photosynthetic organisms besides green plants, and that the model identified a general and fundamental property of photosynthetic light harvesting,” he said. “Our study shows how, by choosing where you absorb solar energy in relation to the incident solar spectrum, you can minimize the noise on the output — information that can be used to enhance the performance of solar cells.”
Coauthor Rienk van Grondelle, an influential experimental physicist at Vrije Universiteit Amsterdam in the Netherlands who works on the primary physical processes of photosynthesis, said the team found the absorption spectra of certain photosynthetic systems select certain spectral excitation regions that cancel the noise and maximize the energy stored.
“This very simple design principle could also be applied in the design of human-made solar cells,” said van Grondelle, who has vast experience with photosynthetic light harvesting.
Gabor explained that plants and other photosynthetic organisms have a wide variety of tactics to prevent damage due to overexposure to the sun, ranging from molecular mechanisms of energy release to physical movement of the leaf to track the sun. Plants have even developed effective protection against UV light, just as in sunscreen.
“In the complex process of photosynthesis, it is clear that protecting the organism from overexposure is the driving factor in successful energy production, and this is the inspiration we used to develop our model,” he said. “Our model incorporates relatively simple physics, yet it is consistent with a vast set of observations in biology. This is remarkably rare. If our model holds up to continued experiments, we may find even more agreement between theory and observations, giving rich insight into the inner workings of nature.”
To construct the model, Gabor and his colleagues applied straightforward physics of networks to the complex details of biology, and were able to make clear, quantitative, and generic statements about highly diverse photosynthetic organisms.
“Our model is the first hypothesis-driven explanation for why plants are green, and we give a roadmap to test the model through more detailed experiments,” Gabor said.
Photosynthesis may be thought of as a kitchen sink, Gabor added, where a faucet flows water in and a drain allows the water to flow out. If the flow into the sink is much bigger than the outward flow, the sink overflows and the water spills all over the floor.
“In photosynthesis, if the flow of solar power into the light harvesting network is significantly larger than the flow out, the photosynthetic network must adapt to reduce the sudden over-flow of energy,” he said. “When the network fails to manage these fluctuations, the organism attempts to expel the extra energy. In doing so, the organism undergoes oxidative stress, which damages cells.”
The researchers were surprised by how general and simple their model is.
“Nature will always surprise you,” Gabor said. “Something that seems so complicated and complex might operate based on a few basic rules. We applied the model to organisms in different photosynthetic niches and continue to reproduce accurate absorption spectra. In biology, there are exceptions to every rule, so much so that finding a rule is usually very difficult. Surprisingly, we seem to have found one of the rules of photosynthetic life.”
Gabor noted that over the last several decades, photosynthesis research has focused mainly on the structure and function of the microscopic components of the photosynthetic process.
“Biologists know well that biological systems are not generally finely tuned given the fact that organisms have little control over their external conditions,” he said. “This contradiction has so far been unaddressed because no model exists that connects microscopic processes with macroscopic properties. Our work represents the first quantitative physical model that tackles this contradiction.”
Next, supported by several recent grants, the researchers will design a novel microscopy technique to test their ideas and advance the technology of photo-biology experiments using quantum optics tools.
“There’s a lot out there to understand about nature, and it only looks more beautiful as we unravel its mysteries,” Gabor said.
Gabor, Cogdell, and van Grondelle were joined in the research by Trevor B. Arp, Jed Kistner-Morris, and Vivek Aji at UCR.
The research was supported by the Air Force Office of Scientific Research Young Investigator Program, the National Science Foundation, and through a U.S. Department of the Navy’s Historically Black Colleges and Universities/Minority Institutions award. Gabor was also supported through a Cottrell Scholar Award and a Canadian Institute for Advanced Research Azrieli Global Scholar Award. Other sources of funding were the NASA MUREP Institutional Research Opportunity program, the U.S. Department of Energy, the Biotechnological and Biological Sciences Research Council, the Royal Netherlands Academy of Arts and Sciences, and the Canadian Institute for Advanced Research.
The research paper is titled, “Quieting a noisy antenna reproduces photosynthetic light harvesting spectra.”
Press release from the University of California, Riverside
