Latest news with #ThePlanetaryScienceJournal
Yahoo
27-05-2025
- General
- Yahoo
Scientists Puzzled by Mysterious Motion in Atmosphere of Saturn's Moon
Researchers have found that the thick and hazy atmosphere enveloping Saturn's largest moon, Titan, behaves in a very peculiar way. As detailed in a new paper published in The Planetary Science Journal, a team of scientists analyzed 13 years' worth of thermal infrared observations recorded by NASA and the European Space Agency's Cassini-Huygens mission. Their finding: that Titan's atmosphere wobbles like a gyroscope as it shifts with the seasons of its nearly 30 Earth-year cycle, instead of spinning in line with its surface. "The behavior of Titan's atmospheric tilt is very strange," said lead author and University of Bristol postdoctoral researcher Lucy Wright in a statement about the work. "Titan's atmosphere appears to be acting like a gyroscope, stabilizing itself in space." The discovery makes the moon, which has already captured the attention of astronomers for its suspected bodies of liquid and planet-like dimensions — it's larger in diameter than Mercury — an even more intriguing candidate for a closer look, since it appears to have its own, independent climate system. Given the latest discovery, though, scientists are now facing even more riddles about the unusual celestial body. "We think some event in the past may have knocked the atmosphere off its spin axis, causing it to wobble," Wright posited. "Even more intriguingly, we've found that the size of this tilt changes with Titan's seasons." "What's puzzling is how the tilt direction remains fixed in space, rather than being influenced by the Sun or Saturn," coauthor and University of Bristol planetary scientist Nick Teanby added. "That would've given us clues to the cause. Instead, we've got a new mystery on our hands." The findings could influence NASA's upcoming Dragonfly mission, which is tentatively scheduled to launch no sooner than 2028, and will see a massive rotorcraft attempt to descend through Titan's extremely dense atmosphere to explore its surface. It won't be a walk in the park, as it will have to endure temperatures around -300 Fahrenheit while keeping itself airborne with a surface pressure one and a half times that on Earth and winds of up to 20 times faster than the moon's rotation. How the atmosphere "wobbles" on its own could allow scientists to get a better idea of how to keep Dragonfly operational, and where to touch down. The new findings could also have far-reaching implications, forcing us to reevaluate our understanding of the Earth's atmosphere. "The fact that Titan's atmosphere behaves like a spinning top disconnected from its surface raises fascinating questions — not just for Titan, but for understanding atmospheric physics more broadly, including on Earth," said coauthor and NASA Goddard planetary scientist Conor Nixon in the statement. As for the chances that we'll encounter extraterrestrial life on the surface of Titan, astronomers aren't exactly hopeful. In a recent study, scientists concluded that Titan's rivers and lakes of liquid methane make it quite inhospitable to life as we know it. However, they found that a tiny amount of glycine-consuming microbes could, in theory, survive in its oceans. More on Titan: Titan Covered With Fragments of Obliterated Moons, Scientists Say
Forbes
01-04-2025
- Science
- Forbes
Mars Moons Phobos And Deimos Are Not Captured Asteroids, Says Paper
artist's interpretation of the red planet Mars' mysterious moons of Deimos and Phobos have long puzzled planetary scientists. For decades, it was thought that they were simply asteroids that had been gravitationally captured into Mars' orbit. But in the last decade or so, planetary theorists have warmed to the notion that the most likely scenario for the origin of both moons stems from a large Mars impactor creating a debris ring around the red planet from which both moons may have coalesced. It's also possible that Deimos and Phobos formed from the same disk of material that formed Mars itself, some 4.6 billion years ago. Yet a new paper accepted for publication by The Planetary Science Journal confirms that neither moon was gravitationally captured by Mars. Today, the moons orbit Mars at average distances that range from some 23,463 km for Deimos to only 9376 km for Phobos. Even so, the authors are still puzzled over whether Phobos, in particular, formed early or late. Phobos could have formed billions of years ago at more than twice its current distance from Mars, or it could have formed only 100 million years ago some 20 percent further away from Mars, Matija Cuk, the paper's lead author and a planetary dynamicist at the SETI Institute in Mountain View, Calif., told me via email. Mars with its two cratered moons Phobos and Deimos. Elements of this image furnished by NASA. We included "lumps" in Mars' gravity field, and also the full gravity of the Sun, says Cuk. Our model also used direct numerical simulations, meaning that we modeled orbits from scratch and do not use time-saving approximations, he says. Even so, the dominant hypothesis now is that they both may have formed from the aftermath of a large impactor that formed a debris disk around Mars, says Cuk. As for their being captured asteroids? Phobos and Deimos have orbits that are close to the Mars' equator, indicating their formation from a circumplanetary disk, the authors write. This means that they formed there and were not gravitationally captured by Mars, says Cuk. Yet Phobos is particularly puzzling. Phobos orbits faster than Mars spins, so it rises in the West and sets in the East, says Cuk. Because of this, Phobos' own gravity causes a slight flexing of Mars' surface which over time causes this Martian moon's orbit to decay and move closer to the red planet's surface, he says. Question is: How long has Phobos been moving inward and from where and when did it form? There are two distinct theories, one that Phobos formed relatively close to Deimos billions of years ago, and the other is that Mars has a repeating cycle of moons breaking into rings which then form new moons, says Cuk. Phobos is now spiraling into Mars and will be gravitationally pulled apart by Mars' gravity and within a few tens of millions of years, Phobos will become a ring of debris, says Cuk. It's a process that can repeat again and again. Each successive inspiralling moon will be torn apart which will result in the creation of a new ring of debris from which another moon will form. This would likely mean that Phobos and its predecessors were each relatively short lived. This would explain why we appear to have caught Phobos in the final stages of its life, says Cuk. Just based on the current orbits of Phobos and Deimos, we cannot tell how old Phobos is and how much its orbit has changed over time, says Cuk. Deimos is almost certainly billions of years old, while Phobos is either more than four plus billion years old, or some 100 to 200 million years old, he says. Either scenario could be true, says Cuk. As for which moon is most scientifically interesting? I prefer Deimos, says Cuk. Unlike Phobos, it has not moved much, and Deimos' orbital tilt may be the only evidence that Mars had other moons in the past, he says. But as Cuk points out, we are likely to know more about Phobos first, since Japan is launching its Martian Moons eXploration mission in 2026. If successful, MMX will return a Phobos sample back to Earth potentially decades before NASA returns samples from Mars' surface.
Iraqi News
31-01-2025
- Science
- Iraqi News
Moon Not as ‘Geologically Dead' as Previously Thought, Study Reveals
INA- sources Our planet's biggest satellite shows what seems like an unchanging face—the man in the moon never cracks a smile, after all—but a new study from a team including a University of Maryland researcher reveals that there's more going on beneath the lunar surface than previously believed. In results reported earlier this month in The Planetary Science Journal, two Smithsonian Institution scientists and a UMD geologist discovered that features located on the moon's far side were notably younger than similar landforms previously studied on the near side—findings that could have implications for future human exploration of the moon. 'Many scientists believe that most of the moon's geological movements happened two and a half, maybe three billion years ago,' said Jaclyn Clark, an assistant research scientist. 'But we're seeing that these tectonic landforms have been recently active in the last billion years and may still be active today.' Researchers have studied the moon's surface for decades to help piece together its complex geological and evolutionary history. Evidence from the lunar maria (dark, flat areas filled with solidified lava) suggested that the moon experienced significant shrinking in its distant past. Researchers suspected that large, arching ridges on its near side were formed by contractions that occurred billions of years ago—concluding that the moon's maria has remained dormant ever since. Using advanced mapping and modeling techniques, the team found 266 previously unknown small ridges on the moon's far side that called that view into question. The ridges typically appeared in volcanic regions that likely formed 3.2 to 3.6 billion years ago in areas where there may be underlying weaknesses in the moon's surface, according to the researchers. To estimate the ridges' age, the researchers used a technique called crater counting that showed the features were notably younger than other features in their surroundings. 'Essentially, the more craters a surface has, the older it is; the surface has more time to accumulate more craters,' Clark explained. 'After counting the craters around these small ridges and seeing that some of the ridges cut through existing impact craters, we believe these landforms were tectonically active in the last 160 million years.' Interestingly, Clark noted that the far-side ridges were similar in structure to ones found on the moon's near side, which suggests that both were created by the same forces, likely a combination of the moon's gradual shrinking and shifts in the lunar orbit. The Apollo missions detected shallow moonquakes decades ago; the new findings suggest that these small ridges might be related to similar seismic activity. 'We hope that future missions to the moon will include tools like ground-penetrating radar so researchers can better understand the structures beneath the lunar surface,' Clark said. 'Knowing that the moon is still geologically dynamic has very real implications for where we're planning to put our astronauts, equipment and infrastructure on the moon.'
