Category: Analysis

Source: The Conversation – USA – By Paul C. Sereno, Professor of Paleontology, University of Chicago

My fixation on a small, desolate locale in the heart of the Sahara Desert started with a single line buried in a 630-page tome in French about the rocks of the central Sahara: “Dent de Carcharodontosaurus saharicus Depéret,” which translates to “tooth of Carcharodontosaurus saharicus Depéret” – “Depéret” refers to the scientist who originally named the species.

The intrepid French geologist Hugues Faure (1928-2003) had collected one saber-shaped tooth in the early 1950s at a small exposure he labeled “Akarazeras” on one of his maps, identifying the tooth as belonging to the T. rex-size predator Carcharodontosaurus. That beast was named years before based on fossils in the Western Desert of Egypt, and Faure correctly figured the tooth and outcrop in Niger might be the same age. Faure’s tooth, unfortunately, was never figured or photographed and has been lost.

In the 70 years since Faure’s account, no paleontologist had ventured back to this hyperarid, windswept landscape to attempt to relocate Akarazeras. In truth, the tooth might have been all that was there, and the site itself could easily have disappeared under drifting dunes. Yet, after reading about it early in my career as a paleontologist, Akarazeras became my fossil Shangri-La, a place I dreamed of visiting.

Akarazeras relocated

With a small exploratory team in 2019, I followed a desert trail to the remote oasis of Tanout, the closest inhabited point to Akarazeras. There we refreshed our supplies – food, water and fuel – to survive a three-day foray in the open desert in search of the locale. Besides binoculars, we had a few gadgets Faure couldn’t have imagined: GPS hand units and a drone.

Navigating using Faure’s map brought us to a flat, barren spot with nothing in sight to the horizon. We drove several kilometers to the north, climbed to the top of our vehicles and launched the drone. One of my team members spotted a low rocky outcrop at distance.

Soon after arriving at the exposure, we found several Carcharodontosaurus teeth and, a short distance away, the rim of an infilled, hand-dug well. We had found Akarazeras. By the next afternoon, we had finished packing up a few dozen fossil teeth and bones. We probed in every direction and sent the drone farther to see if there was anything else to find. Nothing but sand.

A chance encounter

That might have been the end of the story had not a tall, lanky man arrived in our Tanout campground the evening we returned. Looking like a Tuareg Marvel character, Abdoul Nasser stood next to his Honda motorbike, dressed in a full-length black overcoat, a cheche head wrap, sunglasses and a sheathed sword slung over his shoulder.

“I can take you to some large bones, farther than Akarazeras,” he said in Tamasheq, with guides translating to French. This seemed more than a boast or scam. I decided to devote our final three days to this venture.

A day and a half later, we had spent half our fuel chasing our motorbike guide over an endless dunescape. Just as we questioned going farther, Abdoul slowed to a stop in front of the largest fossil hind leg I had ever seen, its thigh bone nearly 6 feet (2 meters) long.

As the sun set, we scurried from skeleton to skeleton – it was a veritable dinosaur graveyard. The next morning we had a half-hour at this place locals called Jenguebi before we had to leave. I and my colleague, Spanish paleontologist Dan Vidal, quickly collected large jaw pieces of what we assumed was Carcharodontosaurus.

Epiphany in the lab and field

Back in Chicago, the cleaned and assembled jaw pieces told another story. They belonged to the giant fish-eating dinosaur called Spinosaurus, which refers to a group of semiaquatic, T. rex-size beasts known from the northern shores of Africa.

For more than two years, plans to return to Niger were scuttled by the pandemic. Finally, in 2022, I led an international, 20-person field crew with a larger guard back to Jenguebi to see whether we could turn up more of the elusive predator.

I was busy arranging the campsite an hour after arriving when Dan Vidal approached, wide-eyed.

“You won’t believe what we just found … the snout end of our skull!”

The team quickly gathered around the toothed bone jutting from the surface of the desert, some in tears, bearing witness to an extraordinary discovery. The snout end fit onto one of the jaw pieces we had collected in 2019. Hours later, Dan approached again with a curved bone in hand.

“What do you think this is?” he asked, wanting confirmation for what we both immediately recognized as a landmark discovery.

The scimitar-shaped bone he held came from the top of the skull. Unlike the low, fluted crest atop the cranium of Spinosaurus from Egypt, called Spinosaurus aegyptiacus, this bone swept upward and backward over the orbital – the space for the eyes. In the cool of the evening, the team gathering around Dan and his laptop to get a glimpse of an initial skull reconstruction, an assembly of digital versions of the bones we had discovered. In awe, we saw the Jenguebi spinosaurid for the first time, a spectacular southern variant of the sail-backed predator first described in Egypt in 1915.

Back in the lab, we coined a species name in Latin that captured our collective “astonishment” upon its discovery, Spinosaurus mirabilis.

An organization I launched with Nigeriens, NigerHeritage, has visualized new museums in the country’s capital, Niamey, and closer to the fossil sites in Agadez that will preserve and display these and many other fossils. A secure homecoming for these remarkable finds also involves a new generation of Nigerien museologists, scholars and museums.

An inland fish-eater

Other animals at the site included two new long-necked plant-eaters, a partial skull of Carcharodontosaurus, a large skull of a freshwater fish and fossil wood. All of the fossils came from a layer of river-borne sediment less than a meter thick, indicating they lived in the same forested inland area far from a marine coastline.

In recent years, the giant fish-eater Spinosaurus has been depicted in Hollywood’s “Jurassic World Rebirth” as a swimming, diving ocean predator alongside other undoubtedly marine creatures like mosasaurs. In 2020, a team of researchers had reinterpreted Spinosaurus aegyptiacus in this way.

Dubbed the “aquatic hypothesis,” the key inspiration was the discovery that the sail on its back extended over its tail. The structure of the tail and other lines of evidence, however, led me and my research team to an alternative view of the fish-eater – as a shallow-water, wading, ambush predator with little capacity for swimming and none for diving.

Aside from its crest, S. mirabilis is very similar to its cousin S. aegyptiacus from the northern coast of Africa. Their lifestyles likely also were very similar.

Evolutionary stages

The early record of spinosaurids, known only from a few teeth, is rooted in the Jurassic, when they first gained a taste for fish. Over the past few years, researchers have found spinosaurid fossils in many locales in rocks of Early Cretaceous age in southern Europe and Asia, sites that once were near the ancient Tethys Sea. At that time, 115 to 130 million years ago, spinosaurids had split into two subgroups – baryonychines and spinosaurines – that collectively dominated the Tethyan realm as the largest predators of the day.

By the dawn of the Late Cretaceous, only spinosaurines remained as larger and more specialized and flamboyant fish-eaters on the southern side of the Tethys Sea in coastal and inland habitats.

S. mirabilis is among the last of these great predators. It is perhaps best understood as a “hell heron,” the likes of which we can only imagine when observing the more graceful, if less fearsome, herons of today.

Paul C. Sereno received funding from an anonymous donor for the 2022 expedition and subsequent research on the new spinosaurid.

– ref. Paleontologists uncover a new ‘Spinosaurus’ species by following a clue from a decades-old book into the Sahara Desert – https://theconversation.com/paleontologists-uncover-a-new-spinosaurus-species-by-following-a-clue-from-a-decades-old-book-into-the-sahara-desert-274182

Source: The Conversation – USA – By Erin Potter, Lecturer in Geography and Ph.D. student in Earth Sciences, Binghamton University, State University of New York

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

What was the very first plant in the world? – Ivy, age 6, Phoenix

Long before dinosaurs roamed the land, Earth looked very different from the planet we know today. Around 500 million years ago, most of Earth’s surface was bare rock and dry soil. There were no trees, no grass and no flowers. Life existed almost entirely in the oceans.

Then something amazing happened: Plants began to grow on land.

This moment was one of the most important events in Earth’s history because it changed the planet forever. As a geoscientist, I am interested in changes in the diversity of flora and fauna – that’s plants and animals – over time.

Predecessors of plants lived in water

The story of plants begins in the water. The earliest plantlike organisms were simple, tiny green life-forms such as algae. You can still see algae today as seaweed along beaches or as green slime on rocks in ponds.

Algae have lived in Earth’s oceans and lakes for over 1 billion years. They can make their own food, using sunlight, water and carbon dioxide to create sugars. This process is called photosynthesis; it releases oxygen – the gas we need to breathe – as a byproduct.

At first, Earth’s atmosphere had very little oxygen. Over millions of years, photosynthesizing organisms like algae and some bacteria slowly released oxygen into the air. This change, sometimes called the Great Oxygenation Event, made it possible for larger and more complex life to evolve. Without oxygen-producing organisms, animals, including humans, could never have existed.

Scientists believe the first true plants evolved from green algae around 470 million years ago. These early plants lived in shallow water near shorelines, where conditions changed often. Sometimes they were underwater, and sometimes they were exposed to air. This habitat helped them slowly adapt to life on land.

Getting a foothold on dry land

Moving onto land was not easy. Water plants are supported by water and can absorb nutrients easily, but land plants faced new challenges. How would they avoid drying out? How could they stand upright without floating? How would they get water and nutrients from dry ground?

To survive, early plants evolved important new features. One key adaptation was a waxy coating, called a cuticle, which helped keep water inside the plant. Plants also developed stronger cell walls that allowed them to stand upright against gravity. Simple rootlike structures, called rhizoids, helped anchor plants to the ground and absorb water and minerals from the soil.

The earliest land plants were very small and simple. They looked similar to modern mosses, liverworts and hornworts, which still grow today in damp places like forest floors and stream edges. These plants did not have true roots or stems, and they stayed close to the ground. Fossils of early land plants, such as Cooksonia, date back to about 430 million years ago and show small branching stems only an inch or two tall.

Even though these plants were tiny, they had a huge impact on Earth. As plants spread across land, their roots helped break down rocks into soil, a process called weathering. This created richer soil that could support more life.

Plants also released more oxygen into the atmosphere, improving air quality and helping animals breathe. Plants created new habitats and food sources, allowing insects and other animals to move from water onto land.

Increasing complexity across millions of years

Once plants became established on land, evolution continued. Around 420 million years ago, plants evolved vascular tissue: tiny tubes that transport water and nutrients throughout the plant. This adaptation allowed plants to grow taller and stronger because water could be moved upward from the roots to the leaves. These vascular plants included early relatives of ferns and club mosses.

With vascular tissue, plant life really started to flourish. By about 360 million years ago, vast forests covered much of Earth. Giant ferns and treelike plants, some over 100 feet (30 meters) tall, dominated the landscape. Over time, dead plant material from these forests was buried and compressed, eventually forming coal, which people still use as an energy source today.

Another major step in plant evolution was the development of seeds, around 380 million years ago, found in seed ferns. Other seed plants, such as early conifers – a group that includes modern pine trees – could reproduce without needing water for fertilization. Seeds protected plant embryos and allowed plants to survive harsh conditions like drought or cold.

The most recent major plant evolution happened around 140 million years ago, when flowering plants, what scientists call angiosperms, appeared. Flowers helped plants attract animals like insects and birds, which spread pollen and seeds. Fruits developed to protect seeds and help them travel. Today, flowering plants make up most of the plants we see, including trees, grasses, fruits and vegetables.

The first plants didn’t just survive; they transformed Earth. They changed the atmosphere, built soil, and created ecosystems that allowed animals to thrive on land. Thanks to plant evolution, Earth became a green, living planet full of diverse life.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Erin Potter does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. What was the very first plant in the world? – https://theconversation.com/what-was-the-very-first-plant-in-the-world-271828

Source: The Conversation – USA – By Michael Carrafiello, Professor of History, Miami University

Apollo 11 first landed astronauts on the Moon in 1969, but the journey to the lunar surface actually began 43 years before, in snowy Massachusetts.

Exactly 100 years ago, on March 16, 1926, Robert H. Goddard launched the first liquid-fueled rocket. Liquid-fueled rockets would eventually provide the power to send humans to the Moon. Still, Goddard’s vehicle was small, flew for only 42 seconds, reached a height of a mere 184 feet and sustained damage that created more doubters than believers in the prospects for human space flight.

Despite this less-than-spectacular start to the space age, Goddard’s rocket was the beginning of a century of innovation. Today, hundreds of rockets launch each year. Giant liquid-fueled rockets combine liquid oxidizer – a substance that releases oxygen – and liquid fuel. These create chemical reactions that produce the explosive thrust necessary to propel humans to the Moon.

As a historian, I’ve spent 40 years studying the winding path that led to the development of modern rocketry. I’ve also seen how, over the past few years, private companies have played a much larger role in spaceflight than they did throughout most of its history.

Early days of spaceflight

After Goddard’s first liquid-fueled rocket launch, the development of American rocketry crept along at a snail’s pace until World War II. Nazi Germany’s invention of the V-2 missile proved that rockets could provide immense strategic and scientific value during both war and peace.

In war, the V-2 terrorized Britain and its allies. In peace, scientists looked at launching artificial satellites, or “moons” as they were originally called, to survey weather and boost intercontinental communication.

The United States government did not invest heavily in rocketry throughout most of the 1950s. Then, on Oct. 4, 1957, the Soviet Union shocked the world by launching the world’s first artificial satellite, Sputnik I. Millions of Americans feared that the USSR would soon rain nuclear missiles on them.

President Dwight D. Eisenhower and his advisers, however, displayed little anxiety at this prospect. They believed that America’s problems down on Earth were more urgent than those that might emanate from space.

Political pressure from the Senate majority leader, Lyndon B. Johnson, caused Eisenhower to reconsider. Late in 1958, the Republican president gave his consent for Congress’ establishment of the National Aeronautics and Space Administration. This new agency then went about selecting America’s first seven astronauts, introducing them to the nation in 1959.

Americans to the Moon

The arrival of a new, young chief executive, John F. Kennedy, sharpened the United States’ commitment to space. In September 1962, the president publicly challenged the nation to land an astronaut on the Moon before 1970. To Kennedy, the enormity of such a scientific and public achievement would provide unimpeachable proof to the world that the American way was superior to life behind the Iron Curtain.

JFK’s untimely death in the autumn of 1963 only served to strengthen the nation’s commitment to the late president’s lofty goal.

A mere five-and-a-half years later, astronauts Neil Armstrong and Buzz Aldrin walked on the lunar surface during the Apollo 11 mission. To get them there, NASA had spent nearly US$26 billion – $338 billion today. They had employed hundreds of scientists and engineers, and hired thousands of workers from dozens of contractors.

Yet, at almost the very moment the supreme triumph of Apollo 11 unfolded, public support for the manned space program evaporated. Preoccupation with the Vietnam War, economic inflation and nagging social and political inequality, as well as boredom with moonshots, led most Americans to turn away from the cosmos.

Richard Nixon, who followed Johnson into the Oval Office, slashed NASA’s budget. Three of the remaining lunar missions were abruptly and unceremoniously canceled. NASA had to abandon spectacular yet wasteful rockets like the Saturn V in favor of cheaper and more versatile launch vehicles.

Enter the Space Shuttle

Unlike earlier rockets, the next generation of rockets had to become almost completely reusable. The result: development of the Space Shuttle. NASA promised that the shuttle would launch no later than 1977 and that, when fully operational, it would rocket into orbit every two weeks.

That vision never materialized. By the time the first shuttle finally took off in 1981, it was grossly over budget. Problems with the heat tiles necessary for reentry persisted. Ultimately, the shuttles never came close to launching biweekly. Instead, only six to eight missions per year proved feasible. Worst of all, the program would eventually sustain two heartbreaking tragedies.

In 1986, the space shuttle Challenger exploded 73 seconds after takeoff. In 2003, Columbia – the first shuttle to ever reach space – disintegrated as it reentered the atmosphere over Texas. The following year, President George W. Bush announced that the remaining shuttle fleet would retire no later than 2011.

NASA’s air of invincibility and inexhaustible stream of funding had long vanished. The final shuttle flight served as a coda to the heady days of the 1960s and ‘70s.

Subsequent presidents talked of missions to Mars and created a Space Force, but the old Apollo launchpads at Cape Canaveral were abandoned, or “mothballed,” as NASA termed it. Thousands of workers were laid off. Leadership in space passed to private corporations like Elon Musk’s SpaceX and Jeff Bezos’ Blue Origin.

Enter private companies

As early as 2006, NASA began contracting with SpaceX to launch its payloads and astronauts to the International Space Station. By 2024, SpaceX had realized the unfulfilled vision of NASA, launching on a nearly biweekly basis.

Meanwhile, while NASA’s Artemis program plans to send a crewed mission around the Moon using a launch system developed by the agency, the program remains years behind schedule. To date, it has cost at least three times more than originally budgeted.

Across the Pacific, China has announced that it will place astronauts on the Moon by 2030, with missions to Mars planned after that. For America’s rival on the world stage, government, industry and science all move in concert. Compared with China, the United States’ future in space appears far less unified, coordinated and purposeful.

A dynamic president once galvanized the U.S. government and its people to produce a “giant leap for mankind.” But since that July day in 1969, leadership in space has steadily passed from government to private hands, with the future of American space flight appearing murky.

Michael Carrafiello does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. The first modern rocket launched 100 years ago, beginning a century of both innovations and challenges for spaceflight – https://theconversation.com/the-first-modern-rocket-launched-100-years-ago-beginning-a-century-of-both-innovations-and-challenges-for-spaceflight-269061

Source: The Conversation – USA (2) – By Kristi Girdharry, Associate Teaching Professor of Arts and Humanities, Babson College

I was early to the generative AI wave in higher education: I was among the first professors who teach writing to publish in an academic journal about generative AI and critical thinking, and I am now part of an interdisciplinary team at Babson College thinking about how AI is impacting education, industry and society.

But that does not mean I am all in on AI – nor am I anti-AI. I am pro-learning. As my co-authors and I argue in a forthcoming book on realizing the promise of higher education, even the most powerful tools are only as good as the learning environments we build around them.

So what does “getting learning right” look like in the age of generative AI? It involves a lot of experimentation and leaning in with students as a co-learner when I don’t have all of the answers, while remaining staunchly committed to sharing my expertise in writing, critical thinking and learning. I also hope that they trust me enough to follow my lead and persevere when the work becomes difficult.

From hope to grief

Navigating the rise of generative AI seemed easier to me in the earlier days. In spring 2023, for example, soon after ChatGPT went public, I asked students to use it to research their favorite musical artist and then fact-check the results as part of a unit in my senior-level social media class. The responses sounded polished and confident, but they were often wrong. Album dates were scrambled. Tours were invented. At one point, a student threw up her hands and shouted, “It lies!” The room erupted. The “lies” were especially apparent with less popular artists, about whom less had been written. “How might that translate to other knowledge areas?” I asked. They were pretty quick to thinking about whose voices might not make the cut in a different scenario.

While this was a promising start, by fall 2023 I found myself starting to grieve the passing of the pre-AI-everywhere world. Once again, I leaned in with my students, now in a sophomore-level research writing class. In their proposals, I included a new required section called “Be Better Than a Robot” – the gist being that if ChatGPT could write your research paper, what was the point of us spending weeks on it?

I asked: Where would your own work – your own human thinking – need to come in to create a tiny piece of new knowledge in the world? We practiced primary research, we used time during class for reading and annotating, and I extended deadlines to account for the rigor we were undertaking.

AI usage was discouraged but not outright banned: If used, careful and explicit descriptions of exactly how were required, and I even gave examples of things like brainstorming academic titles as a potential option. While not all of the final research projects seemed completely AI-generated, the few that did caused me to spiral – like it was my fault that I didn’t come down harder on not using AI when I was trying to be neutral and understand how we could use it as a tool and not as a replacement.

Cognitive blind spots

Since those early days in 2023, discussions around college students’ use of AI have only become more fraught and complicated. There are no easy answers, and there are a lot of fears about overreliance, loss of learning and even the value of a college degree. There are also plenty of ethical concerns that go beyond academic integrity, such as the environmental impact of AI and concerns over data and privacy. But AI usage is not slowing down.

Recent data from the Pew Research Center shows that more than half of teenagers are turning to AI for help with finding information and getting help with schoolwork. By the time these students arrive in my classes, many have already developed habits around these tools, and these habits may or may not serve their learning. For me, that’s not an argument for banning AI in the classroom, but rather an argument for taking it seriously.

But here’s the honest difficulty: When students use AI, they often can’t tell when they’re shortcutting their own thinking. A study published from late 2024 in the British Journal of Educational Technology found that students using ChatGPT improved their essay scores in the short term but showed no meaningful gains in knowledge. Moreover, they were prone to what the researchers called “metacognitive laziness,” meaning a dependence on the tool that undermined their ability to self-regulate and engage deeply in learning. This is a result of cognitive offloading.

Teaching discernment

At this point, I feel my role is shifting from neutral observer or co-learner to something more like a guide with a point of view. I know what rigorous thinking looks like in my discipline. I know the difference between a paper that has moved through genuine intellectual struggle and one that has been assembled. My job is to make that difference visible to students who may not yet have the experience to see it themselves.

So, yes, there are moments in my writing courses where I ask students to write without AI. Not as a purity test, although I could see it used that way, and not because I believe they’ll go on to spend their careers avoiding it, but because understanding what AI does to your thinking first requires knowing what your thinking can do without it.

This matters especially now as many college students I meet arrive already anxious, already performing, already optimizing for the grade rather than the learning. Many have spent years learning to produce the right answer rather than to wrestle with hard questions. Before they can develop discernment about any tool, they need something more foundational: a sense of their own thinking as worth trusting.

In practice, this looks like drafting with AI and without it, comparing versions, and being asked to justify choices out loud. It looks like noticing when the tool accelerates routine work and when it flattens complexity.

Like many faculty navigating this moment, I find myself in what Auburn University professors Christopher Basgier and Lydia Wilkes describe as an “unsettled middle,” neither fully embracing nor refusing the technology, but doing the uncomfortable work of engaging with it critically. My students, I’ve found, often end up in a version of that same uncertain space. Learning to sit with that uncertainty – to tolerate the slowness and mess of thinking things through rather than reaching for the frictionless answer – is where discernment begins.

If students are going to continue encountering these tools throughout their lives, then ignoring that reality does them no favors. My responsibility is to help them develop the judgment to decide when a shortcut is strategic and when it undermines their own thinking. That is pro-learning.

Kristi Girdharry does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. A writing professor’s new task in the age of AI: Teaching students when to struggle – https://theconversation.com/a-writing-professors-new-task-in-the-age-of-ai-teaching-students-when-to-struggle-276590