Author: martianjoe

Title: Atomic Space Batteries: The Future of Spacecraft Power on This Week In Space

In a recent episode of the popular podcast This Week In Space, hosts Rod Pyle and Tariq Malik dove into the fascinating topic of atomic space batteries. Joined by Dr. Robert O’Brien, an expert in the field, they discussed the potential of powering spacecraft with radioisotope thermoelectric generators (RTGs).

Episode 170, fittingly titled ‘Atomic Space Batteries!’, brought this intriguing yet complex subject to light, making it accessible and enjoyable for all space enthusiasts. The trio explored how RTGs, also known as atomic batteries, could revolutionize space exploration by providing a reliable and long-lasting power source for spacecraft.

RTGs work by converting heat released from the natural decay of radioactive isotopes into electricity. This method of power generation isn’t new – NASA has been using it since the 1960s. However, the recent resurgence of interest in this technology indicates that it still holds enormous potential for the future of space exploration.

Dr. O’Brien, a leading figure in this field, explained the advantages of RTGs. They are compact, robust, and can function for decades without refuelling, making them ideal for long-duration missions. He mentioned that the Mars rovers, Spirit and Opportunity, which exceeded their planned lifetimes, and the Voyager spacecraft, still communicating with Earth after more than 40 years, are shining examples of RTGs’ reliability.

However, the hosts and their guest also touched on the challenges of using RTGs. The key concern is the safety of using radioactive materials. Dr. O’Brien clarified that while RTGs indeed use radioisotopes, they are designed in a way that the radioactive material is contained securely, even in the event of a launch failure. He also pointed out that the radioactive isotopes used, such as plutonium-238, do not pose a significant radiological hazard to humans or the environment.

The conversation then pivoted towards the future of RTGs. According to Dr. O’Brien, the continual advancements in RTG technology could open up new possibilities for space exploration. He envisions missions to the outer planets, like Uranus and Neptune, or even to the Kuiper Belt, a region beyond Neptune filled with icy bodies and remnants from the early solar system.

The podcast episode ended with an exciting note on the potential for RTGs to power future lunar or Martian habitats. The idea of setting up a stable, long-lasting power source on another planet no longer seems like science fiction but a real possibility.

Episode 170 of This Week In Space served as a reminder of the enormous potential that lies in the intersection of science and technology. The conversation on atomic space batteries offered a glimpse into a future where spacecraft are powered by robust and reliable RTGs, extending our reach into the cosmos.

For those interested in delving further into this topic, the episode can be accessed via the link below. Immerse yourself in the world of atomic space batteries and envision a future powered by this remarkable technology.

Read more from the original source here: [https://www.space.com/entertainment/space-movies-shows/this-week-in-space-podcast-episode-170-atomic-space-batteries](https://www.space.com/entertainment/space-movies-shows/this-week-in-space-podcast-episode-170-atomic-space-batteries).

Title: Setting Foot in the Cosmos: Senegal Joins the Artemis Accords

The West African nation of Senegal has officially inscribed its name among the nations committed to the peaceful exploration of space. This development makes Senegal the 56th country to sign the Artemis Accords, a document outlining a shared vision for international cooperation in space exploration. The signing also places Senegal as only the fourth African nation to join this significant global initiative.

Named after the Greek goddess of the moon and NASA’s ongoing project to return humans to the lunar surface, the Artemis Accords represent a global commitment to creating a peaceful, transparent, and cooperative environment for space exploration. Participants of the Accords pledge to adhere to principles such as peaceful exploration, transparency in activities, mutual assistance, and the protection of heritage sites on the moon, among others.

Senegal’s commitment to the Artemis Accords is a significant milestone, demonstrating its readiness to participate in the global dialogue about space exploration and its future. As the 56th signatory, Senegal joins an international group that includes both established and emerging space-faring nations. It also marks the growing interest in space exploration within the African continent, with Senegal following in the footsteps of countries like Egypt, Nigeria, and South Africa.

This development is not only a testament to Senegal’s commitment to global cooperation and scientific innovation but also a clear signal of the universal interest in space exploration. Space is a shared frontier, and its exploration can bring about new discoveries and technological advancements that benefit all humankind.

The signing of the Artemis Accords by Senegal is a reminder that space exploration is not just the domain of a few powerful nations but a global endeavor that requires the participation and cooperation of all countries. It underlines the importance of international partnerships in pushing the boundaries of human knowledge and capabilities.

Space exploration is not solely about reaching new frontiers; it is about understanding our place in the universe and working together to ensure a peaceful and beneficial exploration for all. The Artemis Accords serve as a cornerstone for these efforts, guiding the actions of nations as they make their mark on the cosmos.

In joining the Artemis Accords, Senegal has taken a substantial step towards playing an active role in the peaceful exploration and utilization of space. This move solidifies its place in the international space community and sets the stage for future collaborations and discoveries in the final frontier.

As we look to the stars, we are reminded of the vast potential that space exploration holds. It is a journey that we must undertake together, respecting international laws and principles, and fostering a spirit of cooperation and mutual benefit. In this grand adventure, every nation, big or small, has a role to play, and Senegal’s commitment to the Artemis Accords is a testament to this shared global vision.

Read more from the original source here: [https://www.space.com/space-exploration/senegal-becomes-56th-country-to-sign-artemis-accords-for-peaceful-space-exploration](https://www.space.com/space-exploration/senegal-becomes-56th-country-to-sign-artemis-accords-for-peaceful-space-exploration).

Title: Astronomers Predict the Universe’s ‘Endgame’ to happen sooner than expected

Astronomers have now adjusted the cosmic clock, predicting that the universe will ‘die’ or reach its end in 33 billion years, a lot sooner than previously anticipated.

A team of theorists, after extensive research and calculations, have come up with this startling prediction. They have marked the beginning of the end to be in about 10 billion years — which is less than the present age of the universe, currently estimated to be about 13.8 billion years old.

This prediction, while seeming alarming, does not indicate any immediate threat to us or our planet. In fact, it speaks more to the grand cosmic scale, which is incomprehensibly vast and ancient when compared to our human timescale.

These theorists have based their predictions on the concept of ‘cosmic senescence’ or the death of the universe. This idea suggests that over time, the universe will slowly run out of fuel, with stars burning out and galaxies fading away, eventually leading to a state known as ‘heat death’.

In this predicted state, the universe will have reached a state of maximum entropy, where all matter and energy are evenly distributed, and there are no gradients—which are required to sustain information processing, one form of which is life.

The ‘heat death’ scenario, however, is not the only possible endgame for the universe. Other theories suggest a ‘Big Rip’, where the universe will continue to expand until it rips itself apart, or a ‘Big Crunch’, where the universe’s expansion slows down and reverses, causing it to collapse onto itself.

The new prediction of 33 billion years until the universe’s end is based on the rate of the universe’s current expansion, and the amount of dark energy present. Dark energy is a mysterious force that is believed to be driving the universe’s accelerated expansion.

This forecast may seem dire, but in the grand scheme of things, it’s just another reminder of the universe’s constantly evolving and changing nature. It also underscores the importance of continued space exploration and research to understand the mysteries of our universe better.

These predictions, while fascinating, are based on our current understanding of the universe and its laws. As we continue to explore and learn more about the cosmos, these predictions may well change.

As humans, our lifetimes are but a blink in the cosmic timescale. But our quest for understanding the universe is an ongoing journey that continues to offer awe-inspiring insights and revelations about the vast cosmos we call home.

Read more from the original source here: [Astronomers calculate that the universe will die in 33 billion years — much sooner than we thought](https://www.space.com/astronomy/astronomers-calculate-that-the-universe-will-die-in-33-billion-years-much-sooner-than-we-thought).

Title: Unraveling the Science Behind Asteroid Impact Calculations

As we turn our gaze towards the night sky, the vast expanse of space can both fascinate and intimidate. Among the countless celestial objects, asteroids often pique our curiosity and, at times, concern. The scrutiny is not without reason, particularly when one such as the 2024 YR4 asteroid is predicted to come close to Earth. But how do scientists calculate the probability of an asteroid hitting Earth?

Asteroids, remnants from the early solar system, travel in their orbits around the sun. Occasionally, their paths cross Earth’s orbit, leading to potential close encounters or even collisions. To predict such events, scientists employ a blend of mathematics, physics, and cutting-edge technology.

The first step involves tracking and cataloguing asteroids, a task executed by dedicated programs such as NASA’s Near-Earth Object Observations (NEOO). These programs use ground-based telescopes to observe and record data about asteroids, including their size, shape, rotation, and most importantly, their orbit.

Once an asteroid’s orbit is known, scientists can predict its future path using the laws of physics. The asteroid’s speed, direction, and the gravitational pull of the sun and other planets are all taken into account to calculate where it will be at a specific time. This process is known as orbit determination.

However, even with precise calculations, predicting an asteroid’s path is not 100% accurate due to the Yarkovsky effect. This is a tiny force exerted on a spinning object when it radiates heat, leading to a slight change in its orbit. While this effect is minuscule, over time, it can result in significant changes in the asteroid’s path.

To account for these uncertainties, scientists use a method called Monte Carlo simulations. This involves running thousands of simulations with slightly altered initial conditions to account for potential changes in the asteroid’s path. The output is a range of possible paths, with some scenarios leading to an Earth-impact.

The potential impact probability is then calculated by dividing the number of simulations leading to Earth-impact by the total number of simulations run. If the output is a small number, the asteroid is deemed a low threat. However, if the probability is higher, scientists will monitor the asteroid more closely and consider potential deflection strategies.

The case of the 2024 YR4 asteroid is an example of this process, with its potential impact being calculated and monitored. This constant vigilance ensures we are not caught off guard by these celestial wanderers.

In conclusion, predicting an asteroid’s path is a complex interplay of observation, calculation, and simulation. Despite the challenges, scientists worldwide are committed to safeguarding our planet from potential asteroid impacts. Their meticulous work not only unravels the mysteries of the universe but also serves as our first line of defense against these space-based threats.

Read more from the original source here: [https://www.space.com/astronomy/asteroids/how-do-scientists-calculate-the-probability-that-an-asteroid-could-hit-earth](https://www.space.com/astronomy/asteroids/how-do-scientists-calculate-the-probability-that-an-asteroid-could-hit-earth).

Title: Marvel Cinematic Universe: A Stellar Deal on Disney Plus Subscriptions Ahead of New Fantastic Four Release

As we prepare for the launch of the much-anticipated Marvel’s Fantastic Four: First Steps, space enthusiasts and fans of superhero sagas alike have a reason to rejoice. An exclusive offer from Disney Plus is making it easier than ever to catch up on all Marvel cinematic content with over 40% off on a range of subscriptions.

The Marvel Cinematic Universe (MCU) is not just a series of superhero movies. It is a vast, interconnected cosmos of storylines and characters that have captivated audiences worldwide, much like the allure of our own cosmos has fascinated mankind throughout history. This discount opportunity provides the perfect chance to embark on an interstellar journey through this universe, from Iron Man’s maiden flight to the epic battles of Avengers: Endgame.

The upcoming Fantastic Four: First Steps promises to introduce a new chapter into the MCU, focusing on the much-loved team of four scientists who gain superpowers after an accidental exposure to cosmic rays during a mission to outer space. To fully appreciate the storyline’s intricate connections and the depth of Marvel’s cosmic canon, it’s essential to have a comprehensive understanding of the previous MCU movies.

Disney Plus is the definitive platform for streaming all Marvel content, given that it houses the entire collection of MCU films and series. The 40% discount on various subscriptions is an outstanding opportunity for both new and returning viewers to navigate the expansive Marvel universe in chronological order and at a reduced price.

Marvel’s treatment of space in its movies has always been a source of intrigue for space enthusiasts. The intergalactic adventures of characters like the Guardians of the Galaxy, Thor’s extraterrestrial homeland Asgard, and the cosmic entities like Thanos add a distinct cosmic flavor to these superhero narratives. This makes the MCU not just a thrilling saga of superheroes, but also a creative exploration of space and interstellar phenomena.

As we anticipate the release of Fantastic Four: First Steps, there’s no better time to revisit these cosmic narratives or experience them for the first time. Whether you’re a fan of space exploration, a devotee of the Marvel universe, or simply looking for a captivating cinematic journey, this Disney Plus offer is a chance to immerse yourself in a universe where science, fantasy, and adventure intertwine.

As we look to the stars and marvel at the mysteries of the cosmos, let us also delve into the Marvel Cinematic Universe, where heroes, aliens, and cosmic entities bring space adventures to our living rooms. Take advantage of this exclusive offer and prepare for the Fantastic Four’s forthcoming space adventure.

Read more from the original source here: [https://www.space.com/entertainment/save-over-40-percent-and-watch-marvel-movies-ahead-of-fantastic-four-first-steps](https://www.space.com/entertainment/save-over-40-percent-and-watch-marvel-movies-ahead-of-fantastic-four-first-steps).

Title: Astronomers Uncover 1,000-Year-Old Betelgeuse Mystery Through First Ever Sighting of Its Secret Companion

In a remarkable breakthrough, astronomers have managed to capture the first ever images of Betelgeuse’s long-theorized companion star, finally solving a mystery that has puzzled scientists for centuries.

Betelgeuse, one of the brightest stars in our night sky and a prominent part of the Orion constellation, has been a subject of intrigue due to its perplexing dimming patterns. These fluctuations in brightness have been observed for over a millennium, leaving astronomers to speculate about the possible causes. The most compelling theory suggested that Betelgeuse had a secret companion star whose orbit was affecting its light.

In a ground-breaking discovery, that theory has been confirmed. Astronomers have now captured the elusive companion of Betelgeuse on camera, shedding light on the cause behind the star’s mysterious dimming.

The images were captured using advanced telescopic technology that allowed the researchers to peer deeper into the cosmos than ever before. This first-ever sighting of Betelgeuse’s companion star provides a solution to a mystery that has lingered since ancient times, when the first records of Betelgeuse’s irregular brightness were made.

Betelgeuse is a red supergiant star located about 700 light-years away from Earth. Despite being hundreds of times larger than our Sun and millions of times more luminous, its brightness as seen from Earth varies over time. This has led to numerous theories over the years, with the idea of a companion star being one of the most intriguing.

This discovery is not just a significant achievement in terms of astronomical research; it also underscores the rapid development of technology that allows us to explore the universe in greater detail. The ability to image a companion star over 700 light-years away is a testament to the power of modern telescopes and imaging techniques.

The unveiling of Betelgeuse’s secret companion also has implications for our understanding of stellar evolution and behavior. It provides scientists with valuable insights into the life cycle of giant stars and the complex relationships they can have with their neighbors.

With this breakthrough, Betelgeuse continues to be one of the most intriguing stars in our night sky. Its mysterious dimming patterns are no longer a puzzle, but the star and its newly discovered companion promise to be a valuable source of information for future astronomical studies.

The universe is vast, and its secrets are numerous. With every mystery we solve, new questions arise, driving our curiosity and our desire to explore. The discovery of Betelgeuse’s companion star is a significant step forward in our cosmic journey, reminding us that the universe is full of wonders waiting to be discovered.

Read more from the original source here: [https://www.space.com/astronomy/astronomers-crack-1-000-year-old-betelgeuse-mystery-with-1st-ever-sighting-of-secret-companion-photo-video](https://www.space.com/astronomy/astronomers-crack-1-000-year-old-betelgeuse-mystery-with-1st-ever-sighting-of-secret-companion-photo-video).

Title: South Korea Sets Sights on the Moon with Plans for a Lunar Base by 2045

South Korea has taken a giant leap forward in its ambitions for space exploration, with the government recently revealing its long-term plans to establish a base on the moon within the next two decades.

The proposal is a part of the country’s broader vision for space exploration, which aims to propel South Korea into the ranks of the international space community’s leaders. The timeline for this ambitious project outlines completion by 2045, a goal that, if achieved, would place South Korea among the first nations to establish a permanent base on the moon.

The South Korean government views the moon base project as a pivotal step in developing the country’s technological capabilities and strengthening its position in the global space industry. The lunar base would serve as a platform for scientific research and exploration, potentially offering new insights into the moon’s geology and resources and possibly providing a springboard for further exploration into the solar system.

While the details of the moon base’s construction and operation remain under wraps, the project’s ambitious nature signals South Korea’s commitment to pushing the boundaries of human exploration and technology. As a nation that has already made significant strides in technology and innovation, the move towards space exploration seems a natural progression. South Korea launched its first lunar orbiter, the Korea Pathfinder Lunar Orbiter (KPLO), last August, marking an essential first step in the country’s lunar exploration program.

However, the project is not without challenges. The moon’s harsh environment, logistical complexities, and the significant costs associated with space travel are considerable hurdles to overcome. Despite these challenges, South Korea’s determination to establish a lunar base underlines their commitment to scientific advancement and exploration of the unknown.

The moon base project also holds potential benefits beyond scientific research. It could pave the way for commercial activities, such as lunar tourism and mining for resources like Helium-3, a potential future energy source. These possibilities could further stimulate South Korea’s economy and strengthen the country’s position in the competitive space race.

South Korea’s moon base vision is a testament to the country’s ambitious aspirations in scientific research and technology. The next few decades will undoubtedly be a thrilling time as we watch South Korea make strides to conquer the final frontier, and perhaps inspire other nations to pursue their own lunar ambitions.

As humanity continues to look to the stars for answers and inspiration, South Korea’s ambitious project serves as a potent reminder of our collective potential. The dream of a moon base, once confined to the realms of science fiction, is now a tangible goal within our grasp.

As we enter a new era of space exploration, South Korea’s lunar base project underscores the words of renowned science fiction writer Arthur C. Clarke, “The only way to discover the limits of the possible is to go beyond them into the impossible.”

Read more from the original source here: [https://www.space.com/astronomy/moon/south-korea-wants-to-build-a-moon-base-by-2045](https://www.space.com/astronomy/moon/south-korea-wants-to-build-a-moon-base-by-2045).

Title: Catch the Moon’s Final Dance with Pleiades this Year on July 20

Skywatchers, prepare to be enthralled as the moon performs its last ballet with the Pleiades star cluster this year on July 20, before sunrise. The moon’s crescent limb will weave a cosmic tapestry as it cloaks and uncovers stars from the iconic cluster, creating a mesmerizing spectacle for stargazers worldwide.

Known to many as the ‘Seven Sisters,’ Pleiades is an open star cluster located in the constellation of Taurus. It is easily visible from virtually every corner of the globe, making it one of the most recognized celestial landmarks. On July 20, the moon, in its waning crescent phase, will pass through this cluster, resulting in an awe-inspiring event known as a lunar occultation.

During this unique celestial event, the moon’s crescent limb will appear to gradually cover some stars in the Pleiades cluster before unveiling them again. The process of the moon ‘hiding’ these stars and then revealing them provides a breathtaking view for those who appreciate the artful dance of celestial bodies.

To enjoy this spectacle, observers need no special equipment. The event will be visible to the naked eye, although binoculars or a small telescope can enhance the experience, providing a closer look at the moon’s interaction with the Pleiades stars.

The time to witness this event will vary depending on your geographical location, with the general window being just before sunrise. The exact timing can be checked using various astronomy apps and websites, which provide real-time updates on celestial events.

This lunar occultation is not just an enticing show for stargazers but also an interesting event for scientists. Observations of such events provide valuable insights into the moon’s orbital path and the detailed structure of the Pleiades star cluster. This allows scientists to further their understanding of these celestial bodies and their interactions.

So, mark your calendars for July 20, and make sure to look up before sunrise. Whether you’re an astronomy enthusiast or just someone who appreciates the beauty of the night sky, this event is not to be missed. Witness the moon’s last dance with the Pleiades this year, a beautiful ballet of cosmic proportions, as it weaves across the cluster, cloaking and revealing the stars in a show of celestial hide-and-seek.

Remember, there’s a whole universe out there, filled with mysteries and wonders waiting to be discovered. And sometimes, all it takes to explore it is to simply look up.

Read more from the original source here: https://www.space.com/stargazing/see-the-moon-cross-the-pleiades-for-the-last-time-this-year-on-july-20.

Title: Meteor Impact: A Catalyst for a Grand Canyon Cataclysm 56,000 Years Ago

Imagine a time when the Grand Canyon, one of the world’s natural wonders, looked markedly different. A recent study suggests that a meteorite impact thousands of years ago may have triggered a massive landslide that reshaped the Colorado River, forever altering the landscape of the national park.

The Grand Canyon, famed for its layered bands of red rock revealing millions of years of geological history, is a sight to behold. However, 56,000 years ago, the awe-inspiring panorama we are familiar with today may have been a dramatically different scene.

Scientists have long pondered the origins of a significant landslide in the Grand Canyon known as the ‘Western Landslide.’ The landslide, which occurred roughly 56,000 years ago, is one of the largest on Earth, spreading across 3.5 miles and reaching depths of up to 1,300 feet. It’s so big, in fact, that it is visible from space. But what caused such a colossal shift?

A recent study suggests the landslide may have been triggered by a meteorite impact. A team of geologists discovered a layer of microscopic spherules, tiny spherical particles, in the landslide debris. These spherules are often associated with meteorite impacts, formed when the intense heat of the impact melts the surrounding rock, which then cools into tiny glass beads as it’s ejected into the atmosphere.

While the evidence is not definitive, it offers a tantalizing hint that a cosmic event might be responsible for the massive landslide. The meteorite would have had to be large enough to generate an impact with the energy equivalent to a nuclear explosion. Such an event would undoubtedly have sent shockwaves through the region, potentially triggering the landslide and permanently reshaping the Colorado River that runs through the Grand Canyon.

This theory offers a unique perspective on how our planet’s topography can be dramatically influenced by events from space. “This study reminds us that Earth does not exist in a vacuum,” says one of the researchers. “We’re part of a dynamic solar system, and the interplay between Earth and its celestial neighbors can have profound effects on our planet’s surface.”

As scientists continue to unravel the complex history of our planet’s ever-changing landscapes, it’s clear that the story of Earth is intertwined with the cosmos. The potential meteor impact at the Grand Canyon is a testament to the power of these celestial interactions, offering a glimpse into the dramatic transformations that have shaped our world.

Understanding these processes not only provides insight into our planet’s past but also helps us prepare for potential future events. After all, as the saying goes, those who cannot remember the past are condemned to repeat it.

Read more from the original source here: [https://www.space.com/astronomy/earth/meteor-impact-may-have-triggered-massive-grand-canyon-landslide-56-000-years-ago](https://www.space.com/astronomy/earth/meteor-impact-may-have-triggered-massive-grand-canyon-landslide-56-000-years-ago).

Title: The Elusive Search for Alien Life: Earth-Size Exoplanets May Be Rarer Than We Thought

The search for extraterrestrial life just got a little more complicated, according to recent findings from NASA’s exoplanet-hunting Transiting Exoplanet Survey Satellite (TESS). The results suggest that Earth-size planets may not be as common as scientists had previously believed, a revelation that could significantly impact the ongoing quest to locate alien life.

NASA’s TESS satellite, launched in 2018, has the primary mission of discovering exoplanets — planets orbiting stars outside our solar system. The satellite investigates these celestial bodies by observing the dimming of starlight as planets pass in front of their host stars, a phenomenon known as a transit. Using this method, TESS has been instrumental in finding numerous exoplanets across the cosmos.

However, the recent analysis indicates that, of the 200 worlds investigated by TESS, many could be larger than initially projected. This means that the number of Earth-size planets — those most likely to harbor life as we know it — may be less prevalent than previously believed.

The search for alien life has long hinged on the assumption that Earth-size planets are the most likely to be habitable, largely due to our understanding of life’s requirements here on our home planet. These planets, scientists postulate, would likely have conditions and atmospheres similar to Earth, thus increasing the chances of them sustaining life.

The current findings, however, compel us to reassess this perspective. If Earth-size planets are indeed less common, it could potentially reduce the number of planets where life might develop, at least as we understand it.

Yet, it is important to note that this adjustment does not mean the search for extraterrestrial life is a lost cause. Rather, it simply adjusts our understanding of where life could potentially exist. It may also push scientists to expand their criteria for what an ‘alien habitat’ might look like.

The universe is an expansive and complex place, filled with a myriad of celestial bodies and phenomena. While the news about the scarcity of Earth-size planets may seem like a setback, it simultaneously opens up new avenues for exploration and discovery.

Moreover, the TESS satellite remains an invaluable tool in our extraterrestrial investigations. Despite the recent analysis suggesting fewer Earth-sized planets, TESS continues its mission of scanning the cosmos, and its ongoing work will undoubtedly yield more intriguing findings about our universe.

In the grand scheme, this study is a reminder of the fluid nature of scientific discovery. As we continue our exploration of the cosmos, we will undoubtedly encounter unexpected twists and turns — and each one brings us a step closer to understanding our universe and our place within it.

Read more from the original source here: [Bad news for alien life? Earth-size planets may be less common than we thought](https://www.space.com/space-exploration/search-for-life/bad-news-for-alien-life-earth-size-planets-may-be-less-common-than-we-thought).