Jupiter was once twice as large as it is today
To better understand Jupiter's primordial stages, researchers turned to the tiniest of the planet's 92 known moons. Almathea and Thebe respectively circle Jupiter at slightly tilted orbits roughly 112,400 and 138,000 miles above the planet's cloudtops.
By analyzing the dynamics of these orbital discrepancies along with the planet's conservation of angular momentum, the team could estimate its radius and interior state at about 3.8 million years after the solar system formed its first solids. At that time, the sun was surrounded by a disk of material known as a protoplanetary nebula that was gradually dissipating as it coalesced into the planets we know and love. Based on their calculations, researchers believe early Jupiter was 2 to 2.5 times larger than it is today with a much more powerful magnetic field.
'It's astonishing that even after 4.5 billion years, enough clues remain to let us reconstruct Jupiter's physical state at the dawn of its existence,' said Fred Adams, one of the study's co-authors and a University of Michigan professor of physics and astronomy.
By focusing on the directly measurable information from Jupiter's moons and the conservation of its angular momentum, the team was able to sidestep many of the common uncertainties that plague planetary formation models. These often require astronomers to make assumptions about variables like gas opacity, accretion rate, and heavy element core mass.
According to the team, their new calculations enhance more than experts' understanding of Jupiter. These factors can be applied to the evolution of other giant planets as they circle stars. They also suggest that gas giants generally form through core accretion–or when a gas rapidly gathers around a core of ice and rock.
'Our ultimate goal is to understand where we come from, and pinning down the early phases of planet formation is essential to solving the puzzle,' said Konstantin Batygin, a Caltech planetary science professor and study co-author. 'This brings us closer to understanding how not only Jupiter but the entire solar system took shape.'
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Miami Herald
19 hours ago
- Miami Herald
‘Inverse' vaccines may hold key to challenge autoimmune diseases
NEW YORK, June 30 (UPI) -- For the millions of Americans battling autoimmune disorders, new hope may be on the horizon in the form of reverse or inverse vaccines -- injections that target a specific part of the immune system. experts told UPI. However, these injections work differently from conventional immunizations like the flu shot and currently available immunosuppressant treatments for autoimmune conditions. They work by targeting only the specific part of the immune system that's behind diseases such as lupus, multiple sclerosis, psoriasis, rheumatoid arthritis and Type 1 diabetes, the experts say. 'Inverse vaccines are being developed to treat undesired immune responses, [and] for these situations, the body is reacting to something that is not dangerous,' said Lonnie Shea, a researcher in biomedical engineering at the University of Michigan who has studied inverse vaccines and worked on some of the key technology behind them. 'A vaccine activates an immune response to a specific antigen,' Shea told UPI via email. Inverse vaccines are being developed to treat undesired immune responses, [and] for these situations, the body is reacting to something that is not dangerous. Essentially, an inverse vaccine 'aims to decrease the response to a specific antigen, like insulin in Type 1 diabetes,' he added. First line of defense When healthy, the immune system is the body's first line of defense against diseases such as cancer and infections caused by viruses and bacteria, according to the National Institutes of Health. However, if the immune system isn't working properly, it can erroneously attack healthy cells, tissues and organs, causing autoimmune diseases that can affect any part of the body, weakening function and potentially leading to death, the NIH says. More than 80 autoimmune diseases are known, some of which are caused by exposure to environmental toxins and have no discovered cure. At least 15 million people in the United States, or about 5% of the population, have an autoimmune disease, the agency reports. Although no cure exists for these conditions, symptoms can be managed with drugs called immunosuppressants, which as the name suggests 'broadly reduces your immune system response,' Shea said. These drugs, which are typically administered via monthly injections, can have significant side effects, including making those taking them more susceptible to infections, according to the NIH. Many people taking them also have to be careful taking traditional vaccines, such as flu shot or COVID-19 shots because of their impact on the immune system. Training the immune system Developed by researchers at the University of Chicago and elsewhere, inverse vaccines use synthetic nanoparticles attached to specific disease-related proteins, or antigens, to train certain parts of the immune system to behave differently, limiting the attacks that cause autoimmune diseases, neurologist Dr. Lawrence Steinman said. With the inverse vaccines currently being studied, the nanoparticles are designed to mimic human cell death, which is a normal process in the human body, according to the 2021 study that first documented their effectiveness in people with celiac disease, another autoimmune disorder. Dying cells are considered foreign bodies, but the human immune system knows not to attack them. As a result, with the nanoparticles in inverse vaccines, the immune system can be trained not to attack them, or the proteins attached to them, which effectively short-circuits the process behind autoimmune diseases, Steinman said. 'Instead of immunizing the recipient to a viral infection, the inverse vaccine tolerizes the immune system, so it will not attack our own tissues,' Steinman, who has written about inverse vaccines, told UPI in an email. Several companies are running clinical trials of inverse vaccines, including Cour Pharma, which recently completed successful phase 2 clinical trials for their use in celiac disease and another autoimmune disease, primary biliary cholangitis, according to Shea at the University of Michigan, one of the researchers who started the company. Additional trials -- phase 2 studies are the second stage in the drug research and development process -- are starting for myasthenia gravis and Type 1 diabetes, he added. Although more research is needed before the shots become available, a process that could take five years or more, inverse vaccines offer key advantages, Shea said. For example, unlike immunosuppressants with their monthly dosing, the effects of inverse vaccines appear to last longer, perhaps for as much as a year, similar to conventional vaccines, research suggests. They may also work for people with severe, life-threatening allergies, such as peanut allergies, according to Shea, who has published a study in this area using mice. However, there's also the 'risk that instead of tolerizing the human immune system to the target, the process induces conventional immunization, which would make autoimmune conditions like Type 1 diabetes and multiple sclerosis worse,' Steinman said. However, 'We have come close to success in some early-stage trials,' he said 'Thus far, none of the results are sufficiently robust for submission in the FDA approval process.' Copyright 2025 UPI News Corporation. All Rights Reserved.
Scientific American
a day ago
- Scientific American
How China Could Win the Race to Return Rocks from Mars
On May 14, 2021, China's Tianwen-1 lander plummeted from space to streak through the skies above Mars's vast plain of Utopia Planitia, with an aeroshell protecting it from the heat and plasma of its high-speed atmospheric entry. After unfurling its parachutes and pulsing its engines to zero in on an amenable landing site, the spacecraft touched down safely onto the Red Planet, where it deployed a rover, Zhurong, to explore the surrounding alien landscape. This engineering feat was hugely significant, confirming China as a major player in planetary exploration. With Tianwen-1's touchdown, China became the only other nation ever to successfully land on Mars besides the U.S. Moreover, the mission also paved the way for a far more ambitious and unprecedented project. That project, Tianwen-3, is set to launch via two Long March 5 rockets from Wenchang spaceport on the Chinese island of Hainan in late 2028. One launch will carry Tianwen-3's lander, while the other will transport the mission's Mars orbiter, which is also an Earth-return vehicle. The mission aims to collect samples of Martian rock and soil for delivery back to Earth, where subsequent studies could, potentially, redefine our understanding of life itself and our place in the cosmos. 'Tianwen-3 will be the first mission aiming to bring back material from another planet to search for signs of life,' says Li Yiliang, a professor of astrobiology at the University of Hong Kong and one of the authors of a paper published in Nature Astronomy on June 19 that offers new details on the mission. (Tianwen-2, another Chinese sample return mission, launched in May 2025 but is bound for a near-Earth asteroid as well as a comet; China has also pulled off two successful lunar sample return missions, Chang'e 5 and Chang'e 6.) On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Tianwen-3 will use the same approach as Tianwen-1 to make planetfall in a yet-to-be-selected landing area. The vagaries of spacecraft engineering, however, demand the site should be somewhere in the midlatitudes of the planet's northern hemisphere; it also must be at an altitude of at least three kilometers below the planet's average elevation so that more of Mars's thin air can serve to slow Tianwen-3's descent. The lander will use proven tech from China's lunar explorations, drilling as deep as two meters for subsurface samples and scooping up material from the surface. Additionally, a helicopter drone—following the lead of NASA's pioneering Ingenuity flights —will collect selected additional rock and loose particle samples from within around 100 meters of Tianwen-3's landing site. The lander will operate for around two months on the surface, in which it will use scientific payloads such as a ground penetrating radar and a Raman spectrometer to gather more data on the broader geological context for collected samples. When the time comes, it will fire off a solid rocket booster to send a canister containing at least 500 grams of material into Mars orbit to dock with the waiting orbiter-returner spacecraft. The eventual return trip should bring Tianwen-3's samples home sometime in 2031. Once on Earth, the samples will be swiftly secured and transported to a custom-built Mars sample laboratory, where they'll be extensively analyzed while carefully following 'planetary protection' policies meant to prevent any potential otherworldly cross-contamination. Although Tianwen-3's objectives range from investigating Mars's interior to studying its wispy atmosphere, scientists working on the mission are most eager for what it might reveal about the planet's possible former or even extant life. If, in fact, anything ever dwelled on the Red Planet, then Tianwen-3's samples could conceivably contain various telltale signs of its presence—so-called biosignatures. A convincing biosignature could come in different types, Li says. For example, Tianwen-3's scientists will be seeking molecules directly produced by Martian organisms to fulfill known biochemical functions, akin to the DNA and RNA molecules that life-forms on Earth rely on to store and transmit genetic information. Another biosignature is biogenic isotope fractionation—the distinctive way that living organisms alter the natural ratios of stable isotopes in their ecosystems; on Earth, for instance, biochemical processes such as photosynthesis prefer the lighter carbon-12 rather than heavier carbon isotopes, leading to detectable shifts in the proportions of these isotopes with respect to the surrounding environment. A third approach, Li adds, would be to look for fossil evidence, such as the imprints that microbes may leave behind in mudstones and other fine-grained sedimentary rocks. China's astrobiological focus for its Martian explorations is 'a laudable, ambitious goal,' says Mahesh Anand, a professor of planetary science and exploration at the Open University in England. 'This is exactly what we have been recommending over the years: to look for any signs of biogenic activity or even just to understand that there was a habitable environment. The rest of the global planetary science community would love to get answers to these questions.' China's approach is simpler in many ways than the U.S.-led Mars Sample Return (MSR) mission, which is a joint project between NASA and the European Space Agency (ESA). MSR's workhorse, NASA's Perseverance rover, is already on Mars, where it has spent more than four years collecting dozens of carefully selected samples from Jezero Crater, a diverse site harboring an ancient river delta and other complex geological features that may preserve evidence of past life. In contrast, Tianwen-3's sampling will be limited to its immediate surroundings, which will probably be more drab—because although a boring, flat landscape may be of less astrobiological appeal, it is far easier to land on. And the spacecraft's landing ellipse—the area within which Tianwen-3 is most likely to touch down—spans some 50 by 20 kilometers, meaning a precision touchdown to visit any especially alluring targets is highly unlikely. But, largely because of its greater complexity and cost, MSR is under threat of cancellation from the Trump administration following years of delays and cost overruns. The project's potential elimination, however, would be only one of many grievous blows to NASA's science, the funding for which the Trump administration has proposed to cut by nearly half. 'The reason why NASA went with Perseverance as this first step was so that you would have this curated, intentionally selected and well-recorded process and contextual process of where these rocks came from,' says Casey Dreier, chief of space policy at the Planetary Society, a U.S. space science advocacy group. 'This isn't intended in any way to denigrate the achievements of the Chinese robotic program, but in general I think you can characterize a lot of [its] framing as symbol-driven and capability-focused over the direct science return.' China's more basic engineering-led plan, with the science trailing after, may put limits on the questions Tianwen-3 can realistically answer. But this methodical, step-by-step approach to progressively building and demonstrating critical capabilities is exactly what has now positioned China to take the lead in the race to return rocks from Mars. Meanwhile, the far more elaborate MSR has floundered. Dreier says that this moment, in which the U.S. appears to be ceding leadership in this area to China, will have implications for global space exploration. 'The U.S. needs to lead and work with its allies to continue to invest in these big, bold efforts to make potentially historic discoveries,' Dreier says. If the White House has its way, he adds, then Perseverance's samples might only find their way back to Earth after an even more complex, expensive and distant human spaceflight program led by SpaceX lands astronauts on Mars. Which means, for now, China will get its shot at a major first in space exploration. 'The way I look at it is that China is starting to explore Mars,' Anand says. The richer science on offer from a complex MSR-style plan is enticing, he says, but sticking to simplicity and clearly achievable near-term results 'probably has a higher chance of returning science than planning on something that might take decades.' U.S. and European scientists have for generations seen obtaining samples as a 'holy grail' for Mars exploration. For China, retrieving Martian material fits into the strategic framework of its broader, solar system-encompassing Tianwen program, the name of which translates to 'heavenly questions.' Beyond Tianwen-3 and its already-launched asteroid-and-comet-bound sibling Tianwen-2, there is also Tianwen-4, slated for liftoff around 2029, which will target the Jupiter system and its intriguing Galilean moon Callisto. Future missions in the Tianwen series, including to the ice giants Uranus and Neptune, are also under consideration. For Li, Tianwen-3 remains the Tianwen program's most compelling project, in part because its path to Mars and back is so straightforward; although lofty, its objectives still appear eminently within reach. 'It is important for humanity to understand its position in the solar system and the universe,' he says, because this would mark a profound milestone in human history. And, on the threshold of attempting to bring back the first samples from Mars—with the possibility of finding the first-ever evidence for alien life within them—China is now uniquely poised to achieve this milestone.
Yahoo
a day ago
- Yahoo
Massive ‘double detonation' spotted by astronomers for the first time
Some stars are so primed for greatness that they blow up twice. For the first time, a team of astronomers have found direct visual evidence of a star that met its fiery end by detonating two times. The team using the European Southern Observatory's Very Large Telescope (ESO's VLT) found this double explosion in the centuries-old remains of a supernova designated as SNR 0509-67.5. They found patterns that confirm its star suffered two explosive blasts. The findings are detailed in a study published July 2 in the journal Nature Astronomy and offers a new look at some of the universe's most important explosions. The majority of the universe's supernovae are the explosive deaths of massive stars. One important supernova variety comes from an unassuming source–white dwarfs. These celestial bodies are the small, inactive cores left over after larger stars–similar to our sun–burn out of all their nuclear fuel. White dwarfs can also produce what astronomers call a Type Ia supernova. 'The explosions of white dwarfs play a crucial role in astronomy,' said Priyam Das, a study co-author and PhD student at the University of New South Wales Canberra, Australia. 'Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved.' A great deal of our knowledge of how the universe expands rests on understanding Type Ia supernovae. These types of supernovae are a primary source of Earth's iron–including the iron pumping around in your blood right now. Type Ia supernovae generally start with a white dwarf that is one star in a pair. If the other star orbits close enough, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf grabs matter from its companion–until it reaches a critical mass. Then, it's time for a single, great, fiery explosion. However, recent studies have hinted some Type Ia supernovae may be better explained by a double explosion that is triggered before the star reaches this critical mass. [ Related: Astronomers find spiraling stars heading towards a rare cosmic explosion. ] The supernova in this new study–SNR 0509-67.5–is roughly 160,000 light-years away from Earth in the constellation Dorado. The astronomers describe a new image they took with data from the ESO's VLT that proves this hunch about double explosions was correct. Some Type Ia supernovae explode through a 'double-detonation' mechanism rather than just one. In this new model, the white dwarf forms a blanket of stolen helium around itself. Helium is a chemical element that can become unstable and ignite. If that happens, the initial explosion generates a shockwave that travels around the white dwarf and inwards. This triggers a second detonation in the core of the star, which ultimately forms the supernova. Previously, there has been no clear, visual evidence of a white dwarf undergoing a double detonation. Astronomers have predicted that this process would create a distinct pattern or fingerprint seen in the supernova's still-glowing remains. They theorized that this clue would be visible long after the initial explosion, partially because the remnants of such a supernova would have two separate shells of calcium. Astronomers have now found this kind of calcium fingerprint in a supernova's remains. According to Ivo Seitenzahl, a study co-author and nuclear astrophysicist from Germany's Heidelberg Institute for Theoretical Studies, these results show 'a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the 'double-detonation' mechanism does indeed occur in nature.' The team detected these calcium layers–shown in blue in the image–by observing supernova remnant SNR 0509-67.5 with the Multi Unit Spectroscopic Explorer (MUSE) on ESO's VLT. The findings provide strong evidence that a Type Ia supernova can feasibly occur before its parent white dwarf reaches a critical mass. Type Ia supernovae are also important for astronomers because they behave in very consistent ways and have predictable brightness–no matter how far away they are. This level of consistency helps astronomers measure distances in space. While using Type Ia supernovae as a cosmic measuring tape, astronomers discovered the accelerating expansion of the universe. The team behind this groundbreaking discovery was awarded the Physics Nobel Prize in 2011. Studying how these supernovae explode will help us understand why they have such a predictable and consistent brightness. 'This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,' said Das, describing the 'beautifully layered structure' that a supernova creates. 'Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.'
