The general consensus is that Theia crashed into Earth billions of years ago and led to the formation of the Moon. The story doesn’t end there though since there are a few lines of evidence to suggest the Moon could have been captured by the gravitational pull of the Earth instead. The orbit of the Moon is one such observation that leads to a different conclusion for it’s in-line with the plane of the ecliptic rather than the Earth’s equator. A team of researchers have suggested capture theory was the Moon’s origin.  The Giant Impact Theory is by far the most widely accepted theory to explain the origin of the Moon. In the theory, Theia is thought to have crashed into the Earth 4.5 billion years ago. Following the catastrophic impact, debris from Earth and Theia was ejected out into space and, over time the material is thought to have coalesced to form the Moon. There is a lot of evidence to suggest this, such as the lunar composition which is very similar to the mantle of Earth.  This image shows what the collision between Earth and Theia might have looked like. Image: Hagai Perets The data collected from lunar soil samples from over 6 Apollo missions revealed calcium rich, basaltic rocks. The composition was identified by chemical and isotopic analysis and was dated at 60 million years after the formation of the Solar System. Using this information, planetary scientists concluded that, due to the similar with the Earth’s mantle, the Moon must have formed from the collision. That was back in 1984.  A new piece of research published in the Planetary Science Journal by Darren Williams from Penn State Behrend in Pennsylvania and Michael Zugger from the Applied Research Lab at Penn State proposes an alternative. They suggest that instead, the moon was captured during a close encounter between a young Earth and a terrestrial binary — the moon and another rocky object. This is not a unique idea though since it has been seen to happen elsewhere in the Solar System. Williams points out that Triton, the largest moon of Neptune may have experienced a similar origin. Triton is thought to have been a Kuiper Belt object that got pulled into an orbit by Neptune. Of the Kuiper Belt objects, 1 in every 10 are thought to be binary objects supporting the theory that the Moon’s formation could well have involved a binary pair. The orbit of Triton around Neptune is retrograde, meaning it moves opposite to the direction of the rotation of the planet. It’s also tilted by 67 degrees to the equator of Neptune.  Global color mosaic of Neptune’s largest moon, Triton, taken by NASA’s Voyager 2 in 1989. (Credit: NASA/JPL-Caltech/USGS) The team argue that, even though Earth could have captured an object larger than the Moon, the orbit is unlikely to have been stable. In the capture scenario, the original lunar orbit would have started as an ellipse but, through the effects of tides, been altered. By calculating the tidal changes, the team identify that initial lunar orbit would have contracted over thousands of years, becoming more circular at the same time. It’s this orbit that we see today.  Now we see the tidal forces causing the Moon to slowly drift away from Earth at a rate of 3cm per year. The team’s calculations showed mathematically that a binary exchange captured satellite may well have led to the behaviour shown by the Earth-Moon system. If this was the case, it doesn’t explain how the Moon formed, just how it came to be a part of our planetary system.  Source : What is the moon’s true origin story? The post Was the Moon Captured? appeared first on Universe Today.

The hits just keep on coming from the Mars Perseverance rover. It’s exploring Jezero Crater on the Red Planet, looking for evidence of microbial life in the planet’s ancient (or even recent) past. Recently it spotted a very strange-looking rock with black and white stripes. Its appearance and location sparked a lot of questions. Perseverance team members have named it “Freya Castle.” From the image, this chunk looks remarkably similar to metamorphic rocks on Earth. The most familiar are gneiss, marble, and schist (to name a few). According to Jeffrey Kargel of the Planetary Science Institute, who speculated on what Freya Castle could be, it resembles a very high-grade type of rock similar to what we find here at home. “It looks like and plausibly is, a metamorphic rock containing feldspar or other white-ish minerals arranged in something called boudinage,” he said. “That word stems from French, relating to a chain-link sausage-like structure. In the case of rocks, it forms when you have layered material, usually sedimentary rocks, where the layers are compressed from above under conditions of high heat and pressure. Much of the rock responds plastically squishing down and spreading out.” Kargel, who is not associated with the Perseverance mission, pointed out that the conditions under which Freya Castle formed on Mars would be similar to Earth’s. “Those conditions have been common on Earth, and erosion then eventually exposes the rocks at the surface. If this is an indigenous Mars rock, it likely would have undergone metamorphism in the lower crust, and then an impact blasted it out, and the rock landed where the rover could examine it,” he said. Other transport possibilities include a deposit by fluid delivery, which makes sense since water has flooded the crater in the past. An example of gneiss metamorphic rock from Sabino Canyon, in Arizona (USA) as a comparison to the Freya Castle rock on Mars. Courtesy Jeffrey Kargel, PSI. What Kind of Rock Is It? So, what’s the story with this rock? Based on the image, it looks pretty out of context with much of the dust and sedimentary material in the crater. That makes it worth reviewing the region in a bit more detail. An impact some 3.8 billion years ago carved out Jezero Crater. It lies on the western edge of a large impact basin called Isidis Planitia. A large impact created that basin during an impact about 3.9 billion years ago. At some point in the distant past, water filled Jezero at least twice. There’s a river delta as well as flow channels exiting the crater. Sedimentary rocks as seen by Perseverance rover at “Enchanted Lake” in Jezero Crater on Mars. Courtesy: NASA/JPL-Caltech Where there’s water, there’s sediment, which hardens into sedimentary rock. ( The main types of rock are igneous (volcanic or intrusive in origin), sedimentary (deposited by wind or water), and metamorphic.) Not surprisingly, the Perseverance rover continues to find sedimentary deposits and layers at Jezero. The delta is clay-rich, and the crater contains other materials known to be in contact with water. However, some of the rocks in Jezero are also igneous. That means they were created by volcanic activity and somehow brought to the crater. NASA’s Perseverance rover, which is searching for signs of ancient life on Mars. Some of the rocks in this image are volcanic in origin. (credit: NASA/JPL-Caltech/MSSS) That brings us back to Freya Castle, which looks metamorphic at first glance. Such rocks have experienced some kind of heat, pressure, or other kinds of geologic stress. That process changed them from one type to another. It also altered the texture of the original rock and the mineral composition. Creating a Metamorphic Rock On Earth, metamorphics are a large part of our planet’s crust. They can form deep under the surface where temperatures and pressures are high. Tectonic activity also forces metamorphism. So do impact events. Both heat and compress the surrounding rock. An impact also “excavates” rocks out from deep beneath the surface and tosses them across the surface. Volcanism could be another culprit, sending hot magma into cracks and openings of existing rocks and “morphing” them. Metamorphism can also be the product of the action of hot, mineral-rich fluid injected into other rocks by hydrothermal activity. If that happened, the fluids could have found their way into the layers. The result would be deposits of “intrusive” minerals, resulting in a layered look. An example of folded metamorphic rock from Norway. Courtesy Siim Sepp, CC BY_SA 3.0 On Mars, all these processes also occurred throughout history. A good analysis of the rock’s minerals could give more details about the mineral makeup of Freya Castle. That would settle the question of what kind of rock it is. Such studies could also give some insight into conditions on Mars at the time it formed. One thing to keep in mind is that Perseverance looked at Freya Castle with its Left MASTCam-Z camera. A closer study of the rock’s mineralogy and chemistry using its onboard spectrometer could reveal far more information about Freya Castle’s origins. Planetary scientists raised questions about whether the Perseverance team might send the rover back to do a mineralogical study. For now, however, the MASTcam imagery has prompted much speculation. “If the rock turns out to be metamorphic and from the lower crust of Mars, it might be a very rare opportunity to examine a rock from an extremely ancient period–perhaps a former sedimentary rock that formed when Mars was extremely young, formed as the Martian crust was just developing,” said Kargel. “It might possibly bear evidence of the oldest hydrosphere known on Mars, or anywhere in the Solar System.” How Did It Get There? Regardless of its makeup, planetary scientists now need to determine how this unusual rock got to Jezero Crater in the first place. Since the region has been inundated at least twice in Mars’s long history, the most likely interpretation is that it formed elsewhere and was likely blasted out from below the surface during an impact. Then, it got carried along by water. There’s evidence in the Perseverance image of slight rounding of the protruding edges to support the idea of fluid transport. Materials in a flood can get eroded as they tumbled and bounced along in the water. One scientist at PSI suggested that the rounding shows the rock got carried across at least a few kilometers. At least one “outlier” suggestion is that maybe the rock has an Earth origin. An ancient impact on our planet could have sent Freya Castle out to Mars, where it landed as an Earth meteorite. That’s not a likely origin, however, since the dynamics of getting Earth meteorites out from Earth to Mars are complex. Freya Castle’s existence at Jezero Crater points out the historical forces that shaped the planet. In particular, it’s a clue toward understanding the complex sequence of events that brought this rock to its current resting place in Jezero Crater. It takes time to analyze those events and the rock itself, which is likely what the Perseverance team is doing as the mission itself continues its trek across the Martian landscape. Note: Special thanks to researchers at the Planetary Science Institute for discussing specific aspects of metamorphic rock formation with the author. For More Information A Striped SurpriseWhat are Metamorphic Rocks The post Perseverance Finds a Strange Black-and-White Striped Rock on Mars appeared first on Universe Today.

Why is it important to search for exoplanets in triple star systems and how many can we find there? This is what a recent study accepted by Astrophysics & Space Science hopes to address as a pair of researchers from the University of Texas at Arlington investigated the statistical likelihood of triple star systems hosting exoplanets. This study holds the potential to help researchers better understand the formation and evolution of triple star systems and whether they are suitable to find life as we know it. Here, Universe Today discusses this incredible research with Dr. Manfred Cuntz, who is a physics professor at the University of Texas at Arlington and lead author of the study, regarding the motivation behind the study, the most significant results, the importance of studying triple star systems, and the likelihood of finding exolife in triple star systems. Therefore, what was the motivation behind the study? Dr. Cuntz tells Universe Today, “Ages and metallicity (i.e., the amount of heavy elements = elements other than hydrogen and helium) are fundamental properties of stars – a statement that applies to all stars. Considering that most stars (which however does not apply to the sun) are members of higher order systems – the study of stars in triple stellar systems is a natural extension of research focusing on single stars.” For the study, the researchers conducted a statistical analysis regarding both the ages and metallicities of triple star systems with a total of 27 confirmed exoplanets based on past research, with the number of exoplanets in each system ranging from 1 to 5. The ages of the triple star system ages, with margins of error, ranged between 20 million years old to 7.2 billion years old. For context, our Sun is estimated to be slightly more than 4.6 billion years old. The metallicities of the star systems, with margins of error, ranged between -0.59 to +0.56, which is often calculated based on the ratio of iron to hydrogen (Fe/H), and is also calculated with the equation X + Y + Z =1, with X being the fraction of hydrogen, Y being the fraction of helium, and Z being everything else (i.e., carbon, oxygen, silicon, iron, etc.). These values range between -4.5 to +1.0, with stars exhibiting 0, -1, greater than 0, and less than 0 indicating a star is equal in iron abundance to our Sun, one-tenth the iron abundance of our Sun, greater metal content than our Sun, and less metal content than our Sun, respectively. Therefore, what were the most significant results from this study? “Two highly significant results have been identified,” Dr. Cuntz tells Universe Today. “First, stars in triple stellar systems are on average notably younger than stars situated in the solar neighborhood. The most plausible explanation is a possible double selection effect due to the relatively high mass of planet-hosting stars of those systems (which spend less time on the main-sequence than low-mass stars) and that planets in triple stellar systems may be long-term orbitally unstable. The stellar metallicities of those stars are on average solar-like; however, owing to the limited number of data, this result is not inconsistent with the previous finding that stars with planets tend to be metal-rich as the deduced metallicity distribution is relatively broad.” The distances to the respective triple star systems range between 4.3 to 1,870 light-years from Earth, but only 6 of the 27 triple star systems reside within 100 light-years away. These six triple star systems include Alpha Centauri (4.3 light-years), Epsilon Indi (11.9 light-years), LTT 1445 (22.4 light-years), Gliese 667 (23.6 light-years), 94 Ceti (73.6 light-years), and Psi1 Draconis (74.5 light-years), with the number of total exoplanets (with exoplanet candidates) within each system being 3 (2), 1, 1, 2 (1), 1, and 1, respectively. For context, as of September 2024, the total number of confirmed exoplanetary systems within our cosmos is more than 4,300 that encompasses almost 5,800 exoplanets. But despite the small number of triple star systems that host exoplanets, what is the importance of studying triple star systems? Dr. Cuntz tells Universe Today, “Most stars (which however does not apply to the sun) are members of higher order systems, especially binaries – and in less common cases triple stellar systems, and systems of even higher order. Therefore, the study of planets hosted by triple stellar systems is a natural extension of the standard approach focusing on planets around single stars. The current study focuses on some of the properties of stars in triple stellar systems, which are also known to host (a) planet(s) – a relatively rare setting. The importance of the current study is to expand our general understanding of star-planet systems.” For Alpha Centauri, the exoplanet, Proxima Centauri b, has been confirmed to be terrestrial (rocky), approximately the size of Earth in both radius and mass, and orbits within the habitable zone (HZ) of Proxima Centauri, one of the stars that comprise the Alpha Centauri triple star system. The only other terrestrial exoplanet orbiting within its star’s HZ is Gliese 667 Cc, whose mass and radius is larger than the Earth, designating it as a super-Earth. Therefore, given the small number of triple star systems that have exoplanets and even fewer that host terrestrial exoplanets orbiting in its HZ, what is the likelihood of finding exolife in triple star systems? “The only planet where we know for sure that life does exist is Earth,” Dr. Cuntz tells Universe Today. “However, through both observational and theoretical studies during many decades of committed work, scientists are convinced that exolife is almost certainly real. This statement should also apply to planets in triple star systems. However, those planets are typically subject to relatively variable environmental forcings (e.g., variable amounts of radiation received by the stellar components), which is expected to reduce the likelihood of advanced life forms, but should still permit microbial life, especially extremophiles.” As the number of confirmed exoplanets continues to grow, so should the confirmed number of triple star systems that host exoplanets, as well. When science fiction fans read about multi-star systems, they almost immediately think of the iconic scene in Star Wars: A New Hope of Luke Skywalker watching two stars setting on the horizon. While Tatooine was habitable for humans and other interesting life forms, this might not be the case in the real world, as demonstrated by Proxima Centauri b currently being the only Earth-like exoplanet orbiting in its HZ within 100 light-years from Earth. Therefore, what constraints should scientists put on finding life in triple star systems? Should we instead study their moons, as the film Avatar depicted the semi-habitable moon, Pandora, orbiting a much larger exoplanet within the Alpha Centauri system? Are triple star systems with exoplanets as rare as the statistics show today? “The search for life outside of planet Earth continues to be a fascinating topic,” Dr. Cuntz tells Universe Today. “Political and societal support for ongoing and future space missions is highly appreciated. We, as scientists, are grateful about the ongoing support by the taxpayers around the world, but especially here in the U.S.” What new discoveries about triple star systems will researchers make in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Reference: Cuntz, Manfred & Patel, Shaan D. “On the Age and Metallicity of Planet-hosting Triple Star Systems.” Astrophysics and Space Science (2024) (accepted) The post We Don’t See Many Planets in Old Triple Star Systems appeared first on Universe Today.

Matters become more confusing when you add pumpkins to the mix.

After 15 years Oasis is back with the brothers Liam and Noel Gallagher reunited and the first North American tour dates were announced. The band will perform first in Europe in July, August and September. But in August and September they will also play in the United States and Mexico. More dates can be announced soon and there is already speculation about shows in South America. There is still no information about who will be the other members of the band during the tour. The band was formed in 1991 and was together until 2009 when it was dissolved after many fights between the Gallagher brothers. All Oasis tour dates announced so far: July 4 – Cardiff Principality Stadium 5 – Cardiff Principality Stadium 11 – Manchester Heaton Park 12 – Manchester Heaton Park 16 – Manchester Heaton Park 19 – Manchester Heaton Park 20 – Manchester Heaton Park 25 – London Wembley Stadium 26 – London Wembley Stadium 30 – London Wembley Stadium August 2 – London, Wembley Stadium 3 – London, Wembley Stadium 8 – Edinburgh Scottish Gas Murrayfield Stadium 9 – Edinburgh Scottish Gas Murrayfield Stadium 12 – Edinburgh Scottish Gas Murrayfield Stadium 16 – Dublin Croke Park, Ireland 17 – Dublin Croke Park, Ireland September 27 – London, Wembley Stadium 28 – London, Wembley Stadium [embed]https://www.youtube.com/watch?v=048Xmm_EoyE[/embed] One of the most successful bands from the 90s, Oasis sold an estimated amount of more than 100 million records worldwide and influenced a whole new generation of artists. Centered on the brothers Liam Gallagher (Vocals) and Noel Gallagher (Main songwriter, guitarist and sometimes singer), the group was active from 1991 to 2009. They were the only two members who had been part of the band during all the years they were together and also the only two who appeared on all their 7 studio albums. Like all the brothers in the world, their relationship had many ups and downs until it really caused the end of the band.The post Oasis announces first North American tour dates appeared first on Rock And Roll Garage.