I have written several articles the environment. A list of links have been provided at bottom of this article for your convenience. This article will, however address different aspects on the environment and the planet in general.

Who discovered dinosaurs?

In 1677, Robert Plot is credited with discovering the first dinosaur bone, but his best guess as to what it belonged to was a giant human. It wasn’t until William Buckland, the first professor of geology at Oxford University, that a dinosaur fossil was correctly identified for what it was.

When did dinosaurs become extinct?

Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years. If all of Earth time from the very beginning of the dinosaurs to today were compressed into 365 days (one calendar year), the dinosaurs appeared January 1 and became extinct the third week of September. (Using this same time scale, the Earth would have formed approximately 18.5 years earlier.) Using the same scale, people (Homo sapiens) have been on earth only since December 31 (New Year’s eve). The dinosaurs’ long period of dominance certainly makes them unqualified successes in the history of life on Earth.

What is the death of a dinosaur called?

The Cretaceous-Tertiary extinction event, or the K-T event, is the name given to the die-off of the dinosaurs and other species that took place some 65.5 million years ago. For many years, paleontologists believed this event was caused by climate and geological changes that interrupted the dinosaurs’ food supply.

How many dinosaurs were killed?

The results of this study, which were based on estimated real global biodiversity, showed that between 628 and 1,078 non-avian dinosaur species were alive at the end of the Cretaceous and underwent sudden extinction after the Cretaceous–Paleogene extinction event.

A brief history of dinosaurs

Dinosaurs ruled the Earth for about 174 million years. Here’s what we know about their history.

Dinosaurs were a successful group of animals that emerged between 240 million and 230 million years ago and came to rule the world until about 66 million years ago, when a giant asteroid slammed into Earth. During that time, dinosaurs evolved from a group of mostly dog– and horse-size creatures into the most enormous beasts that ever existed on land.

Some meat-eating dinosaurs shrank over time and evolved into birds. So, in that sense, only the non-avian dinosaurs went extinct. (For the purposes of this article, “dinosaurs” will refer to non-avian dinosaurs, unless otherwise stated.)

During the roughly 174 million years that dinosaurs existed, the world changed greatly. When dinosaurs first appeared in the Triassic period (251.9 million to 201.3 million years ago), they roamed the supercontinent of Pangaea. But by the time the asteroid hit at the end of the Cretaceous period (145 million to 66 million years ago), the continents were in approximately the same place they are today.

he oldest unequivocal dinosaur fossils, dating to about 231 million years ago, are from Ischigualasto Provincial Park in northwestern Argentina, and include the genuses Herrerasaurus, Eoraptor and Eodromaeus. Scientists are still debating whether Nyasasaurus, a genus found in Tanzania that dates to about 240 million years ago, is also an early dinosaur or a dinosauromorph, a group that includes dinosaurs and their close relatives, said Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland.

Whenever they first appeared, the dinosaurs’ unique anatomy set them apart from other animal groups. Dinosaurs are archosaurs, a clade (different groups of animals that share a common ancestor) that includes crocodilians, pterosaurs, dinosaurs and birds. The archosaurs emerged after the end-Permian extinction about 252 million years ago. Over time, some archosaurs, including dinosauromorphs, adapted an upright posture, meaning they had legs under their bodies, rather than out to their sides.

“Sprawling is all well and good for cold-blooded critters that don’t need to move very fast. Tucking your limbs under your body, however, opens up a new world of possibilities,” Brusatte wrote in “The Rise and Fall of the Dinosaurs: A New History of a Lost World(opens in new tab)” (William Morrow, 2018). As archosaur evolution progressed, dinosauromorphs gained long tails, big leg muscles and extra hip bones that enabled them to move quickly and efficiently, Brusatte wrote.

Some dinosauromorphs evolved into dinosaurs. The differences between the two are small, but dinosaurs’ anatomy offered increased benefits, including arms that could move in and out, neck vertebrae that could support stronger muscles than before, and a joint where the thigh bone meets the pelvis, Brusatte wrote.

This unique anatomy helped dinosaurs become successful. Having an upright posture also freed the hands, allowing dinosaurs such as iguanodonts to grasp branches and carnivorous dinosaurs to claw and kill prey, noted Gregory Erickson, a paleobiologist at Florida State University. Ultimately, having free arms “allowed gliding then flight in birds,” he said.

Moreover, dinosaurs were likely warm blooded, according to research on their growth rates. “When you become a warm blooded animal, you can operate 24/7,” Erickson told Live Science. “You’re not at the whims of the environment in terms of being active.”

Initially, dinosaurs were not as diverse as the crocodile-like archosaurs they were living alongside, Brusatte noted. In fact, dinosaurs “didn’t become too successful right away; the crocs ruled the Triassic, then the end-Triassic extinction hit and the dinosaurs survived and took over.”

The clade Dinosauria (which means “terrible lizard” in Greek) was coined in 1842 by the English paleontologist Richard Owen, who included the meat-eating theropod Megalosaurus, the long-necked sauropodomorph Cetiosaurus and the ornithiscian Iguanodon as the first known species in the clade, according to the book “Dinosaurs Rediscovered(opens in new tab)” (Thames & Hudson, 2019).

Each of these dinosaurs, it turns out, represents one of the three major dinosaur groups.

TYPES OF DINOSAURS

As of 2021, there were 1,545 scientifically described dinosaur species, according to the Paleobiology Database. About 50 previously unknown species are described each year, meaning there’s roughly one newfound species described each week, Brusatte said.

All of these dinosaurs fit into one of three groups: Ornithischia, Sauropodomorpha and Theropoda.

Ornithischia dinosaurs include beaked plant-eaters, such as Stegosaurus, duck-billed dinosaurs (also called hadrosaurs), as well as horned dinosaurs like Triceratops and armored dinosaurs like Ankylosaurus. Some ornithischians walked on four legs, while others walked on two.

Sauropodomorpha dinosaurs were long-necked, pot-bellied dinosaurs that had tiny heads and column-like limbs. This group includes sauropods (such as Diplodocus), their smaller antecedents (including Chromogisaurus) and extra-large sauropods known as titanosaurs (such as Dreadnoughtus and Argentinosaurus), which are among the largest land animals that have ever existed.

Theropoda is a group of meat-eating dinosaurs, although some (such as Chilesaurus diegosuarezi) changed their diet to be herbivorous or omnivorous. Theropods include Tyrannosaurus rex and Velociraptor, as well as birds, which evolved from small theropods.

So, how are these groups related? It’s up for debate. Ornithischian dinosaurs have a backward-pointing pubis bone in the hip, earning them the name bird-hipped dinosaurs. (However, they are not the ancestors of birds; theropods are.) Meanwhile, theropods and sauropodomorphs have saurischian or “reptile hips,” which are also seen in modern crocodiles and lizards, according to the book “Dinosaurs Rediscovered.”

Historically, it was thought that the reptile-hipped theropods and sauropodomorphs were more closely related to each other than to ornithischians. However, a 2017 study in the journal Nature(opens in new tab) uprooted the dinosaur family tree by suggesting that ornithischians and theropods were more closely related, based on analyses of 74 dinosaur species, Live Science previously reported. Shortly after, another 2017 study in the journal Nature(opens in new tab) found that neither family tree, as well as a third that is rarely considered, is statistically significant from the other, meaning all the suggested family trees are equally plausible until more evidence comes forth.

WHEN DID DINOSAURS LIVE?

Dinosaurs lived during most of the Mesozoic era, a geological age that lasted from 252 million to 66 million years ago. The Mesozoic era includes the Triassic, Jurassic and Cretaceous periods.

Dinosaurs arose from small dinosauromorph ancestors in the Triassic period, when the climate was harsh and dry. They faced “competition from the croc-line archosaurs for tens of millions of years, [but] finally prevailed when Pangaea began to split,” Brusatte told Live Science. At this time, volcanoes erupted along the cracks of the supercontinent, causing global warming and mass extinction, he said.

During the Jurassic period (201.3 million to 145 million years ago), dinosaurs rose to dominance and some grew to huge sizes. For example, Vouivria damparisensis, the earliest titanosaur, dates to 160 million years ago. It weighed about 33,000 lbs. (15,000 kilograms) and measured more than 50 feet (15 meters) long. Iconic dinosaurs from this period include Brontosaurus, Brachiosaurus, Diplodocus and Stegosaurus. During the Jurassic, flowering plants evolved and birds, including Archaeopteryx, first appeared. There was “a small extinction at the end of the Jurassic that we still know little about,” Brusatte said.

In the Cretaceous period, dinosaur dominance continued as the continents moved farther apart. Famous dinosaurs from this period include T. rex, Triceratops, Spinosaurus and Velociraptor. The largest dinosaurs on record, including Argentinosaurus, date to the Cretaceous. The Cretaceous period ended with the Cretaceous-Tertiary (K-Pg) extinction event, when a 6-mile-wide (10 kilometers) asteroid collided with Earth, leaving an impact crater more than 110 miles (180 km) in diameter in the Yucatan Peninsula of what is now Mexico.

The impact area, known as the Chicxulub (CHEEK-sheh-loob) crater, has evidence of “shocked quartz” and small glass-like spheres known as tektites, which form when rock is rapidly vaporized and cooled — geologic clues that a space rock struck there with incredible force, Betsy Kruk, an associate paleontologist with Paleo Solutions, a paleontological consulting company based in California, previously told Live Science. Chemical analyses from the sedimentary rock at Chicxulub melted and mixed together at temperatures on par with an asteroid strike about 66 million years ago, she added.

WHAT IS THE LARGEST DINOSAUR? THE SMALLEST DINOSAUR?

Some dinosaurs were enormous, but others were pipsqueaks. The smallest dinosaur on record is an avian dinosaur that’s alive today: the bee hummingbird (Mellisuga helenae) from Cuba, which measures just over 2 inches (5 centimeters) long and weighs less than 0.07 ounce (2 grams). As for extinct, non-avian dinosaurs, there are a few contenders for smallest beast, including a bat-like dinosaur from China named Ambopteryx longibrachium that measured 13 inches (32 cm) long and weighed about 11 oz (306 g), according to a 2019 study in the journal Nature(opens in new tab).

Titanosaurs were the largest dinosaurs. However, because paleontologists rarely find an entire skeleton, and because soft tissues, such as organs and muscles, rarely fossilize, it’s challenging to determine dinosaur mass. However, contenders for the title of world’s largest dinosaur include Argentinosaurus, which weighed up to 110 tons (100 metric tons), an unnamed 98 million-year-old titanosaur from Argentina that weighed upward of 69 tons (63 metric tons), and Patagotitan, which also weighed in at 69 tons.

The longest dinosaur was likely Supersaurus, a Jurassic sauropod that was at least 128 feet (39 meters) long, and possibly even reached 137 feet (42 m) in length, according to unpublished research presented at the Society of Vertebrate Paleontology’s annual conference in 2021. Another contender is Diplodocus, a long and slender Jurassic sauropod that could reach lengths of 108 feet (33 m), according to a 2006 study in the New Mexico Museum of Natural History and Science Bulletin(opens in new tab).

The tallest dinosaur is likely Giraffatitan, a 40-foot-tall (12 m) sauropod dinosaur from the late Jurassic, about 150 million years ago, which lived in what is now Tanzania.

PTEROSAURS ARE NOT DINOSAURS

Many amazing animals lived during the dinosaur age, and some are confused with dinosaurs. The most common misconception is calling pterosaurs dinosaurs: They are not. Pterosaurs are winged reptiles and archosaurs, meaning they are relatives of dinosaurs, but they are not dinosaurs.

The order Crocodilia includes extinct and living crocodiles and their close relatives. Crocodilians are archosaurs, but they are not dinosaurs. Living crocodilians and birds (which are dinosaurs) are the only surviving members of the Archosauria clade.

The Mesozoic oceans teemed with sea life, including predatory reptiles known as mosasaurs (such as Mosasaurus), plesiosaurs and ichthyosaurs. However, none of these reptiles are dinosaurs.

DID DINOSAURS HAVE FEATHERS?

Yes, some dinosaurs flaunted feathers, as do their bird descendants. Feathers don’t fossilize well, but some remarkable fossils, especially those from Liaoning province in China that were buried in the aftermath of a volcanic eruption, have preserved feathers. Here are a few examples: Zhenyuanlong suni, Yutyrannus huali and Jianianhualong tengi.

It’s unclear why dinosaurs first evolved feathers, but they could have been used for the following: as insulation to keep dinosaurs and their incubated eggs warm; for display to use for communication between dinosaurs, such as courtship displays; and for gliding or powered flight, Michael Habib, a research associate at the Dinosaur Institute at the Natural History Museum of Los Angeles County, previously told Live Science.

Initially, it was thought that only theropods and their descendants sported feathers, but researchers have also found downy feathers on the plant-eating ornithischian dinosaur Kulindadromeus zabaikalicus, suggesting that feathers were more widespread than previously thought, a 2014 study in the journal Science found.

It’s possible that pterosaurs had feathers, according to a 2018 study in the journal Nature Ecology & Evolution(opens in new tab), but more feathered specimens need to be found and analyzed to say so for sure.

Notably, even T. rex had feathers. However, depictions of dinosaurs rarely have feathers in popular culture, including the “Jurassic Park” movies. Paleontologist Jack Horner, who served as a scientific adviser on some of the “Jurassic Park” movies, remembers telling director Steven Spielberg that the dinosaurs should have feathers.

“Even when ‘Jurassic Park’ came out [in 1993], we knew that Velociraptors should have feathers, but at that time, it would have been technically difficult to do it, just from a CG [computer-generated] point of view. And Steven wasn’t really too excited about it, anyway. When I told him they should be colorful and they should be feathered, and he said, ‘Feathered Technicolor dinosaurs aren’t scary enough,'” Horner previously told Live Science.

COULD DINOSAURS FLY?

Some dinosaurs could fly, including the earliest known bird — Archaeopteryx — discovered in Germany and dating to about 150 million years ago, during the late Jurassic.

However, unlike most birds today, extinct dinosaurs likely just flew short distances. Research shows that powerful leg muscles, big wings and a relatively small body size were needed for takeoff and flight in ancient birds and bird-like dinosaurs, Habib previously told Live Science. His research suggests that the bird-like dinosaurs Microraptor, Rahonavis, and five avian genuses — Archaeopteryx, Sapeornis, Jeholornis, Eoconfuciusornis and Confuciusornis — would have been able to launch (without running) from the ground to initiate flight.

The bat-like dinosaur Yi qi, dating to China’s Jurassic period, had wings, according to a 2015 study in the journal Nature(opens in new tab). However, it likely didn’t have powered flight and was probably a terrible glider, a 2020 study in the journal iScience(opens in new tab) found.

WHY DID DINOSAURS GO EXTINCT?

It’s up for debate how well the dinosaurs were doing before the asteroid crashed into Earth. A handful of studies suggest that in the late Cretaceous, dinosaur extinctions were rising and diversity was declining, especially among herbivorous dinosaurs. But these studies rely on incomplete fossil data and models that may not tell the whole story, Live Science previously reported.

Even if dinosaur diversity was dropping, it’s possible they could have bounced back had the asteroid not hit, Brusatte told Live Science. Dinosaurs lived on every continent, including Antarctica, and they filled different rungs in various ecosystems, from plant-eater to apex carnivore. “Dinosaurs had experienced many rises and falls in diversity over their 150-plus million year evolutionary history,” he said. If the mass extinction hadn’t happened, it’s possible “They would still be thriving today as more than birds.”

In the aftermath of the asteroid collision, long-term pain followed chaos. The collision caused massive destruction, including a shockwave, heat pulse, wildfires, tsunamis (including an immediate mile-high tsunami), volcanic eruptions, lethal acid rain and earthquakes. Dust and grime that the asteroid kicked up hovered in the air. “This rain of hot dust raised global temperatures for hours after the impact, and cooked alive animals that were too large to seek shelter,” according to Kruk. “Small animals that could shelter underground, underwater, or perhaps in caves or large tree trunks, may have been able to survive this initial heat blast.”

The dust and particles remained in the air, blocking the sun for several years afterward and causing a nuclear winter that cooled the planet and led to the deaths of countless plants and animals, Brusatte and Kruk said.

“Smaller, omnivorous terrestrial animals, like mammals, lizards, turtles, or birds, may have been able to survive as scavengers feeding on the carcasses of dead dinosaurs, fungi, roots and decaying plant matter, while smaller animals with lower metabolisms were best able to wait the disaster out,” Kruk previously said. Moreover, the asteroid also pulverized carbon-rich rocks, which released carbon into the atmosphere and led to “global warming for a few thousand years,” after the nuclear winter ended, Brusatte said.

Scientists used to wonder if the Deccan Traps volcanic eruptions in what is now India played a role in the mass extinction. But recent studies “show that the Deccan probably had very little impact,” Brusatte said. It was “most likely an innocent bystander” — the asteroid is what caused the extinction.

For myriad reasons, it’s currently impossible to bring extinct dinosaurs back. While dinosaur proteins and blood vessels have been found, scientists have yet to rigorously identify DNA from an extinct dinosaur. DNA begins decaying the moment an organism dies, but parts of it can be preserved in the right circumstances. That said, the oldest sequenced DNA on record belongs to a roughly 1 million-year-old mammoth, and dinosaurs went extinct about 66 million years ago.

Some scientists are studying how to reverse-engineer birds into dinosaurs, including the so-called “dino-chicken,” which would have a lengthened tail, teeth, arms and fingers. One group even gave chicken embryos dinosaur-like snouts. However, the “chickenosaurus” wouldn’t be a replica of an ancient dinosaur, but rather a dinosaur-like bird, the researchers told Live Science.

ADDITIONAL RESOURCES

Look up your favorite dinosaur on the Dino Directory from the Natural History Museum in London.
Learn amazing dinosaur facts from the American Museum of Natural History in New York City.
Take free, online college-level classes about the dinosaurs on Coursera, including “Dino 101: Dinosaur Paleobiology(opens in new tab)” and “Paleontology: Theropod Dinosaurs and the Origin of Birds(opens in new tab).”

Did THIS wipe out the dinosaurs? It’s not what you think

MASSIVE volcano eruptions may have played a major role in wiping out the dinosaurs, casting doubt over the cause generally accepted by the scientific community – an asteroid which smashed into the Gulf of Mexico 65 million years ago.

Two separate studies published in the academic journal Science have looked at lava formations in the Western Ghats mountain range in India.The range was formed as a result of an enormous eruption across the country’s Deccan Plateau over a one million-year period. A total of one million cubic kilometres of lava was ejected.

Geologists refer to the result as the Deccan Traps.

The two independent teams used state-of-the-art geo-dating techniques to try and establish how much of the lava detected within the Western Ghats erupted before the K-Pg extinction, and how much afterwards.

Their findings suggest the widely accepted theory that the asteroid, called the Chicxulub Impact after the region of modern day Mexico where the 10 kilometre crater is located, was the sole cause of the massive catastrophe, known as the Cretaceous-Paleogene (K-Pg) event, which resulted in the extinction of 75 percent of all living creatures, including all of the dinosaurs.

One group, led by Courtney Sprain, a geoscientist from the University of Liverpool, concluded that 75 percent of the lava erupted after the K-Pg boundary, reducing the chances of it being the main cause of the extinction.

It is widely accepted that an asteroid crashing into the Gulf of Mexico was responsible

However, the other, led by Blair Schoene of Princeton University, US, found half of it was expelled beforehand, which if true would make it a major contributory factor at the very least.

The Princeton team also concluded the K-Pg extinction came directly after a big surge in Deccan Traps activity, during which an estimated 160,000 cubic kilometres of magma erupted a few tens of thousands of years before the asteroid impact.

The report concludes: “We estimated Deccan eruption rates with uranium-lead (U-Pb) zircon geochronology and resolved four high-volume eruptive periods.

“According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction.

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According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction.

The Deccan traps cover much of India

“These findings support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath.”

Professor Schoene, an associate professor of geosciences, added: “Everyone has heard that the dinosaurs died from an asteroid hitting the Earth.

“What many people don’t realise is that there have been many other mass extinctions in the last 500 million years, and many of them coincide with large volcanic outpourings from the massive volcanoes known as flood basalts or large igneous provinces.”

Prof. Schoene’s team identified four eruption “pulses”, two of which took place before the mass extinction.

He explained: “The first two pulses correspond with a period of time where climate fluctuated from cold to hot to cold again, and many scientists think this indicated an initial disruption to the climate that may have contributed to the mass extinction event.

“Our data show that maybe the second pulse could have played an important role in the extinction itself because it happened right before it.”

His Princeton colleague Gerta Keller added: “Deccan volcanism is the most likely cause of the dinosaur mass extinction.

“The Chicxulub impact may have contributed to their demise, though the timing and environmental effects of this impact still remain to be determined.

Asteroid that killed off dinosaurs may have plunged Earth into two YEARS of darkness

THE asteroid that killed off the dinosaurs may have plunged Earth into darkness for TWO YEARS, according to new research.

The study suggests massive amounts of soot, lofted into the air from global wildfires following a massive asteroid strike 66 million years ago, would have thrust Earth into darkness for many months.

Researchers say that the extended period of darkness would have shut down photosynthesis, drastically cooled the planet, and contributed to the mass extinction that marked the end of the age of the dinosaurs.

The new details about how the climate could have dramatically changed following the impact of a 10-kilometre wide asteroid were published in the journal Proceedings of the National Academy of Sciences.

The researchers used a computer model to paint a picture of how Earth’s conditions might have looked at the end of the Cretaceous Period, information that paleobiologists may be able to use to better understand why some species died, especially in the oceans, while others survived.

Scientists estimate that more than three-quarters of all species on Earth, including all non-avian dinosaurs, disappeared at the end of the Cretaceous and beginning of the Paleogene periods, an event known as the K-Pg extinction.

Evidence shows that the extinction occurred at the same time that a large asteroid hit Earth in what is now the Yucatán Peninsula.

Researchers say the collision would have triggered earthquakes, tsunamis, and even volcanic eruptions.

Evidence shows that the extinction occurred at the same time that a large asteroid hit the Earth

Scientists also calculate that the force of the impact would have launched vaporised rock high above Earth’s surface, where it would have condensed into small particles known as spherules.

As the spherules fell back to Earth, they would have been heated by friction to temperatures high enough to spark global fires and broil Earth’s surface.

A thin layer of spherules can be found worldwide in the geologic record.

Study leader Doctor Charles Bardeen, of the National Centre for Atmospheric Research (NCAR) in the US, said: “The extinction of many of the large animals on land could have been caused by the immediate aftermath of the impact.

“But animals that lived in the oceans or those that could burrow underground or slip underwater temporarily could have survived

“Our study picks up the story after the initial effects – after the earthquakes and the tsunamis and the broiling.

“We wanted to look at the long-term consequences of the amount of soot we think was created and what those consequences might have meant for the animals that were left.”

The researchers used the most recent estimates of the amount of fine soot found in the layer of rock left after the impact, as well as larger and smaller amounts, to quantify the climate’s sensitivity to more or less extensive fires.

In the simulations, soot heated by the Sun was lofted higher and higher into the atmosphere, eventually forming a global barrier that blocked the vast majority of sunlight from reaching Earth’s surface.

Study co-author Prof Brian Toon, of the University of Colorado Boulder, said: “At first it would have been about as dark as a moonlit night.”

While the skies would have gradually brightened, photosynthesis would have been impossible for more than a year and a half, according to the simulations.

Because many of the plants on land would have already been incinerated in the fires, Prof Toon said the darkness would likely have had its greatest impact on phytoplankton, which underpin the ocean food chain.

The loss of the tiny organisms would have had a ripple effect through the ocean, eventually devastating many species of marine life.

The research team also found that photosynthesis would have been temporarily blocked even at much lower levels of soot. For example, in a simulation using only 5,000 million tons of soot – about a third of the best estimate from measurements – photosynthesis would still have been impossible for an entire year.

In the simulations, the loss of sunlight caused a steep decline in average temperatures at Earth’s surface, with a drop of 50 degrees Fahrenheit (28 degrees Celsius) over land and 20F (11C) over the oceans.

While Earth’s surface cooled in the study scenarios, the atmosphere higher up in the stratosphere actually became much warmer as the soot absorbed light from the Sun.

The warmer temperatures caused ozone destruction and allowed for large quantities of water vapour to be stored in the upper atmosphere.

The water vapour then chemically reacted in the stratosphere to produce hydrogen compounds that led to further ozone destruction.

The researchers say the resulting ozone loss would have allowed damaging doses of ultraviolet light to reach Earth’s surface after the soot cleared.

Dr Bardeen added: “An asteroid collision is a very large perturbation – not something you would normally see when modeling future climate scenarios.

“So the model was not designed to handle this and, as we went along, we had to adjust the model so it could handle some of the event’s impacts, such as warming of the stratosphere by over 200 degrees Celsius.”

He added: “The amount of soot created by nuclear warfare would be much less than we saw during the K-Pg extinction.

“But the soot would still alter the climate in similar ways, cooling the surface and heating the upper atmosphere, with potentially devastating effects.”

A second asteroid may have struck during the dinosaurs’ demise

A possible crater buried under the West African coast may have come from a space rock that crashed into Earth around the time of the cataclysmic Chicxulub impact.

In a catastrophic instant some 66 million years ago, the course of life on Earth was forever changed. A six-mile-wide space rock slammed into the coast of Mexico’s Yucatán Peninsula—and it kicked off a global cataclysm. The towering tsunamis that followed crashed on shores for thousands of miles. Wildfires raced across vast swaths of land. And the vaporization of rock along the seafloor unleashed gasses that sent the climate into wild swings—all of which led to the extinction of some 75 percent of all species, including all non-avian dinosaurs.

But this might not be the whole story. Buried under layers of sand on the coast of West Africa are hints that the giant space rock might not have been alone.

Researchers discovered a possible crater that spans some 5.3 miles wide, revealed in seismic surveys of the seafloor, according to a new study published in Science Advances. The crater, dubbed Nadir after a submarine volcano nearby, appears to have been carved by the impact of a space rock at least a quarter of a mile wide—and it may have formed around the same time as the Chicxulub crater, the expansive scar in Earth’s surface from the dinosaur-killing asteroid.

“A lot of people have questioned: How could the Chicxulub impact—albeit a huge one—be so globally destructive?” says study author Veronica Bray, a planetary scientist from the University of Arizona. “It might be that it had help.”

The object that created Nadir would have been considerably smaller than the Chicxulub impactor, so its effects were likely regional. But if confirmed, the second meteorite strike in quick succession could have delivered a one-two punch in the global catastrophe at the end of the Cretaceous period, according to the study. In one scenario, the pair of asteroids could have come from a single parent body that fractured in two before colliding with Earth’s atmosphere and punching the ground more than 3,400 miles apart.

While additional analysis is needed to confirm the suspected crater’s age and identity, and whether it’s linked with Chicxulub, scientists are cautiously excited about the potential for a newfound impact site.

Earth’s record of ancient impacts is woefully incomplete thanks to the planet’s active geologic churn. Swaths of the surface are recycled into the planet’s mantle, while other areas are repaved with fresh volcanic rock, and still others are ground away by shifting glaciers. Only about 200 impact craters have been confirmed on the planet, which prevents scientists from fully understanding how these strikes affected the ancient Earth—and what role they might play in our planet’s future.

“Earth does a great job of destroying impact craters,” says Jennifer Anderson, an experimental geologist who studies impact cratering at Winona State University but was not part of the study team. Because of the planet’s active geology, she says, “any discovery of a new impact crater on Earth is always important.”

A seismic surprise

Like many discoveries, the possible new crater was found by accident. Geologist Uisdean Nicholson of Heriot-Watt University in Edenborough was interested in reconstructing how South America broke apart from Africa roughly 100 million years ago.

For clues, Nicholson examined the features beneath the seafloor between the two continents, collaborating with the commercial companies WesternGico and TGS for seismic data. The analysis tracked how seismic waves ricocheted underground to illuminate subterranean features. Almost immediately, Nicholson spotted something odd.

An expert in seismic surveys, Nicholson has seen the data for many features that create lumps and dips in the layers underground, such as salt domes rising through denser surrounding rock. But the wiggles of the data before him hinted at something more cataclysmic. “I’ve never seen anything like it,” he says.

Nicholson reached out to other scientists, including Bray, to ask if they thought this could be an impact crater, and they all agreed: The feature consists of a depression surrounded by a rim with a prominent peak at its center, which is common among such craters.

By analyzing the structure’s shape and size, the team modeled how it might have formed. The results suggest the crater came from the impact of a space rock roughly a quarter of a mile wide that screamed through the atmosphere, hitting the sea surface at nearly 45,000 miles per hour. As it plunged into the ocean, Bray says, it “would move through the water like it wasn’t even there.”

The collision would have unleashed the energy of 5,000 megatons of TNT, the team estimates, almost instantly vaporizing the water and layers of the seafloor below. Then a shockwave would have raced across the surface, causing once solid rock to flow like liquid. Within minutes, the seabed would have rebounded upward in a central peak and then collapsed back on itself. The result would be a mound within a bowl-like depression in the middle—exactly what the scientists think they’ve discovered buried off Africa’s west coast.

By correlating the sediment layers in this area with dated samples at other sites, researchers estimate that the feature formed roughly 66 million years ago—tantalizingly similar to Chicxulub.

A planetary one-two punch?

Studying the environmental consequences of the Nadir event could help us better understand what future impacts might do to our planet. The theoretical Nadir impactor would have been comparable in size to the asteroid Bennu, which has a 1-in-1,750 chance of colliding with Earth over the next three centuries, making it one of the most likely asteroids to hit our planet. Such an event would be far from insignificant, stirring tsunamis for hundreds of miles. Or as Bray puts it: “It’s big enough to wipe out a city or two.”

But what the discovery means for our understanding of the events immediately following the Chicxulub impact and the end of the dinosaurs’ reign remains uncertain. The energy released by the Nadir impact and its environmental consequences would have been dwarfed by the six-mile-wide Chicxulub asteroid’s collision with Earth and the global cataclysm that followed.

“That is simply a different league,” says Martin Schmieder, an expert in large impact structures at Neu-Ulm University of Applied Sciences in Germany, who reviewed the study ahead of its publication.

But the Nadir impact could have “added insult to injury” in an already devastated ecosystem, Bray says. There’s also the question of whether there were other impacts around this same period. The study authors note that at 65.4 million years, the Boltysh impact crater in Ukraine is slightly younger than Chicxulub.

Clusters of strikes from the fragments of comets or asteroids have previously been documented on Earth and other worlds. For example, near where Anderson lives in the upper U.S. Midwest, a trio of craters dates back roughly 460 million years. They are part of a spike in impacts during the Ordovician period, which scientists have tied to a possible collision in the asteroid belt that sent a parade of meteorites hurtling toward our planet over millions of years .

However, identifying these clusters in Earth’s spotty record of ancient strikes presents a challenge. An impact the size of Nadir is estimated to occur slightly less than every 100,000 years, Schmieder says. “So this could basically happen anytime.”

And for Nadir itself, more study is needed to determine how it formed at all.

“This is an exciting discovery,” Gareth Collins, a planetary scientist who specializes in impact cratering at Imperial College London, says via email, though he cautions not much can be concluded yet about the find. Direct samples are needed to confirm the feature’s origin as well as more precise dates for the possible impact that formed it.

The study authors have already applied for emergency funds to drill into the Nadir formation and collect samples of the possibly shocked, melted, and jumbled crater rock, as well as the sediment layers above. The thickening bed of sand and mud atop the buried structure may have not only preserved the features of the crater, but it could help reveal the state of ocean life in the years after the impact—providing a trove of new data about what happens to our planet when an asteroid strikes.

“But of course,” Bray says, “we’ll only know for sure when we drill into it.”

New study reveals stunning details about extinction of dinosaurs

The infamous meteor that killed off the dinosaurs 66 million years ago was found to have struck Earth during the northern hemisphere’s springtime — and that understanding could lead to more profound revelations about the unknowns of the planet.

These findings, published today in the journal Nature, shed light on why some species of mammals, crocodiles, turtles, and birds, improbably survived the Cretaceous era’s extinction event, a team of European scientists from Vrije Universiteit, Uppsala University and the European Synchrotron Radiation Facility recently reported.

Researchers found that the planet’s seasonal climate might have inadvertently protected some of those prehistoric animals when the Chicxulub meteorite landed in Mexico’s Yucatan peninsula, causing apocalyptic, global tsunamis and lasting effects that wiped out the dinosaurs, forever changing the planet.

“Annual life cycles, including seasonal timing and duration of reproduction, feeding, hibernation and aestivation, vary strongly across latest Cretaceous biotic clades,” the paleontology team wrote.

“We postulate that the timing of the Chicxulub impact in boreal [northern] spring and austral autumn was a major influence on selective biotic survival.”

Opposite to our spring, colder weather months in the southern hemisphere may have also acted as a protecting agent from the devastation in ways the planet’s warmer top half couldn’t, the scientists found.

“Large-scale wildfires raging across the Southern Hemisphere may have been evaded by hibernating mammals that were already sheltered in burrows in anticipation of austral winter,” the authors wrote.

Researchers also discovered that the fallout from the meteorite — rather than its impact — is what killed off the dinosaurs, and changed life on Earth going forward.

“Although direct effects of the impact devastated a vast geographical area, the global mass extinction probably unfolded during its aftermath, which involved rapid climatic deterioration estimated to have lasted up to several thousands of years.”

These revelations came after the team studied preserved fish bones that had experienced the immediate ramifications of the meteorite’s impact.

The fish had been buried alive by chunks of sediment that drastically shifted when the flaming rock made impact with the planet, within the first hour of collision.

The studied samples were found in the southwest region of North Dakota during August of 2017. The area contained “valuable proxies for reconstructing the environmental, climatological and biological conditions” in the area during the Mesozoic era, according to their field report.

After being excavated, the specimens were analyzed by a particle accelerator at the ESRF facility in Grenoble, France, one which can create the brightest X-rays on Earth.

That synchrotron X-ray tomography led to the determination that fishes’ bone composition — which change season to season on a micro level — correlated with springtime in what is now Northern America, according to SciTechDaily. “We saw that both cell density and volumes were on the rise but had not yet peaked during the year of death, which implies that growth abruptly stopped spring,” Dennis Voeten, researcher at Uppsala University, told the outlet.

Resources

nationalgeographic.com, “A second asteroid may have struck during the dinosaurs’ demise: A possible crater buried under the West African coast may have come from a space rock that crashed into Earth around the time of the cataclysmic Chicxulub impact.” BY MAYA WEI-HAAS; express.co.uk, “Did THIS wipe out the dinosaurs? It’s not what you think: MASSIVE volcano eruptions may have played a major role in wiping out the dinosaurs, casting doubt over the cause generally accepted by the scientific community – an asteroid which smashed into the Gulf of Mexico 65 million years ago.” By Ciaran McGrath; express.co.uk, “Asteroid that killed off dinosaurs may have plunged Earth into two YEARS of darkness: THE asteroid that killed off the dinosaurs may have plunged Earth into darkness for TWO YEARS, according to new research.”; livescience.com, ” A Brief History of Dinosaurs.” By Laura Geggel; livescience.com, ” Why don’t we have many giant animals anymore?” By MichaEL Dhar; nypost.com, “New study reveals stunning details about extinction of dinosaurs.” By Alex Mitchell; facty,com, “What Happened to the Dinosaurs?” By Neil;

Addendum

Why don’t we have many giant animals anymore?

Prehistoric giants used to populate the Earth. These behemoths included mighty dinosaurs, airplane-size pterosaurs, massive crocodiles and snakes, and even armadillos the size of cars. But today, there are just a few big animals on our planet.

What happened? Why aren’t there many giants left anymore?

First of all, there’s plenty of fossil evidence that the ancient past really did have larger animals — beasts that were humongous but also larger, on average, than today’s creatures, Greg Erickson, a vertebrate paleobiologist at Florida State University in Tallahassee who specializes in ancient reptiles, told Live Science. Ever since scientists unearthed the first known stash of dinosaur bones, in the 19th century, researchers have put forth ideas to explain why giants were common millions of years ago but less so today. But no one can point to one definitive answer, Erickson said. “It’s so multifactorial.”

Several major differences between dinosaurs and today’s largest animals, the mammals, may help explain the loss of behemoths, however. Along with other giant reptiles, dinosaurs could adapt to different niches as they grew bigger over life, hunting smaller prey as juveniles and larger victims as adults. In part, they could do this because they swapped out sets of teeth over a lifetime. “They replace their teeth constantly, just like sharks do. But along the way they could change the type of teeth,” Erickson said. Crocodiles, for instance, go from “needle-like teeth to more robust teeth. Mammals don’t have that luxury.”

Put another way, as some reptilian youngsters ballooned into hulking adults, they traded their relatively puny juvenile teeth for bigger weapons, allowing them, in turn, to hunt bigger meals to fuel their larger bodies.

In dinosaurs, too, air sacs likely extended from their lungs to their bones, creating sturdy but light scaffolding, Edinburgh University paleontologist Steve Brusatte told Scientific American(opens in new tab). That gave dinosaurs skeletons that were “still strong and still flexible, but lightweight. That helped them get bigger and bigger and bigger,” Brusatte said. “The same way that skyscrapers are getting bigger and bigger and bigger because of the internal support structures.” (Of course, though air sacs helped make for strong, lightweight bones, no animal could actually get as big as a skyscraper. That’s because body weight grows much faster than bone strength as animals increase in size, as physicist Neil deGrasse Tyson has explained(opens in new tab).)

Mammals lack such air sacs, though, “that can invade the bone and lighten up the bone,” Brusatte said, “So elephant size or a little bit bigger, that might be the limit as to where mammals, at least on land” can get. … You can’t really get mammals, it doesn’t seem, to be the size of dinosaurs.”

As warm-blooded, or endothermic creatures, mammals also need a lot of fuel. “Elephants are full endotherms, and the dinosaurs, at least the herbivorous dinosaurs, probably mostly were not,” Geerat Vermeij, a professor of geobiology and paleobiology at the University of California, Davis, told Live Science. “So the food requirement for, say, a gigantic elephant would be … perhaps 5 times greater than that of even the very largest dinosaurs.”

Paleontologists have debated whether dinosaurs were cold- or warm-blooded. But current science places many animal species on a gradient between cold- and warm-bloodedness, and dinosaurs were probably “on the low end of the warm-blooded range,” Erickson said. That made a large body less energetically expensive for dinos.

Huge size also requires the right environment. In a 2016 study published in the journal PLOS One(opens in new tab), Vermeij concluded that giantism depends mostly on sufficient resources produced and recycled by “highly developed ecological infrastructure.” In other words, the ecology needs to produce sufficient oxygen, food and habitat to grow a truly giant creature. Such ecologies had seen great development by the middle Triassic period, near the beginning of the age of dinosaurs, Vermeij wrote.

In one potentially important environmental change, ancient atmospheres had higher concentrations of oxygen. This may have played a role in gigantism, particularly among insects. Wingspans among prehistory’s biggest bugs tracked ancient increases in oxygen concentration, a 2012 study in the journal Proceedings of the National Academy of Sciences(opens in new tab) reported.

Brewers of gigantism shouldn’t forget the crucial ingredient of time, either. Though animal lineages tend to get larger over the generations, it takes a vast amount of evolutionary time to reach giant sizes, Erickson said. And mass extinction events tend to wipe out larger creatures, Vermeij said, so these events can leave giant-animal slots unfilled for tens or hundreds of millions of years. “It took about 25 million years for the first mammals to reach a ton in weight,” he said. In the case of woolly mammoths, decimated by climate change and human hunters just 10,000 years ago, it may not be a coincidence that we modern humans don’t see such huge creatures: Our own ancestors helped kill them off not so long ago.

For Vermeij, the most comprehensive explanation for decreasing size comes not from physiology or environment, but from social structure. “The evolution of … organized social behavior, not just herds but really organized hunting” in mammals introduced a new form of dominance, he said. “Group hunting by relatively small predators makes even very large prey vulnerable. Individual gigantism has in effect been replaced on land by gigantism at the group level,” he wrote in the 2016 study. That is, smaller individuals working together, as happens with wolves and hyenas for example, may constitute a more effective way of getting big than building a huge body. As a result, “gigantism lost its luster on land,” Vermeij wrote.

Social organization may also help explain a rather, ahem, giant exception to the timeline traced here: In the ocean, the biggest animals to ever live still exist today: blue whales. Sea life, Vermeij said, makes long-distance communication more difficult, hindering the development of complex hunting groups. The evolution of such groups “has happened on land much more than, at least until recently, that has happened in the ocean,” such as with killer whales, he said.

What Happened to the Dinosaurs?

Hundreds of millions of years ago, when the continents had formed and long before human beings had even begun to evolve, it was dinosaurs that ruled the earth. Dinosaurs – which comes for the Greek for ‘terrible lizard’ – were a group of reptiles that dominated this very planet we stand on for more than 160 million years. Then, around 65 million years ago, more than 50% of the world’s species became extinct – dinosaurs included. Scientists are still at a loss as to why and how this mass extinction came to be. So, exactly what happened to the dinosaurs?

1. When Did Dinosaurs First Appear On Earth?

According to Paleontologists, dinosaurs first appeared around 240 million years ago. Throughout their existence, scientists have also identified three different epochs: the Triassic, Jurassic, and Cretaceous Period. Over this period, which is collectively known as the Mesozoic era, the Earth’s continents changed from a single supercontinent called Pangea and our planet as we know it today.

Did You Know? Most of the dinosaurs in the movie Jurassic Park were actually from the Cretaceous Period. Although ‘Cretaceous Park’ doesn’t exactly have the same ring to it, does it?

2. When Was the First Dinosaur Found?

The first actual documented evidence of dinosaurs came in 1822 when Mary Ann Mantell discovered some large teeth. At the time, she and her husband, Gideon, thought that they were the remains of a gigantic iguana. Twenty years after that, a scientist named Richard Owen realized that the teeth were different from that of an iguana. Therefore, if they weren’t the remains of a large iguana, what could they be? While that was happening in Britain, the U.S. had its own evidence to show, too. Scientists discovered massive footprints that they believed belonged to birds when, in fact, they belonged to dinosaurs.

3. Did Any Dinosaurs Survive the Extinction?

Whatever the means for the mass extinction of the dinosaurs, there were almost no survivors left. Every creature that weighed more than 100 grams was obliterated. That being said, some species found a way to survive. Alongside cockroaches and other invertebrates such as millipedes, there’s evidence that some of the smaller dinosaurs somehow managed to keep on going. The evidence we’re speaking of is birds.

4. Do the Dinosaurs Have Any Living Ancestors?

Scientists have always believed birds to be related to some of the smaller dinosaurs. However, during the 1990s, it was discovered that it wasn’t only the smaller dinosaurs such as Archaeopteryx that were ancestors of the birds we see and hear today. In fact, in recent years, paleontologists have found evidence that some of the larger creatures had feathers too. One of these is also a dinosaur that most of us know from its menacing appearances in the Jurassic Park’ movies: the velociraptor. Yep. Not so frightening-looking now, huh?

5. What Are the Most Common Extinction Theories?

Because nobody actually knows what brought about the extinction of the dinosaurs and probably nobody ever will, scientists only have their well-researched theories on the matter. Of these theories, there are several, which many believe each had their hand in the mass extinction. The best estimate that we have is that a number of factors came together to rid the planet of the giant beasts that once ruled it.

Did You Know? There wasn’t just one mass extinction. The Mesozoic Era didn’t just end with extinction – it began with one too.

6. Was There More Than One Extinction?

While there is no doubt that the mass extinction of the dinosaurs was the one that changed our planet the most, it wasn’t the only time Earth experienced a wipeout. As a matter-of-fact, the Earth has seen five major prehistoric extinction events known as the ‘big five.’ Three of these occurred during the Mesozoic period, with the first earning the nickname “The Great Dying” due to the loss of 96% of all species on the Earth. A second Mesozoic Era extinction came between the Triassic and Jurassic periods; this was the period that truly saw in the era of the dinosaurs.

7. An Asteroid or Meteor

One of Science’s most common theories on the extinction of dinosaurs involves a meteor or asteroid hitting the earth with such great velocity that its impact wiped them all out. When an asteroid collides with the Earth’s surface, the kinetic energy of its motion is converted into explosive energy. This blows out debris, dust, rocks, and a mass of energy that far surpasses the area of impact. As well as all of this debris being blown into the planet, it would have also sent it into the atmosphere. With so much dust shrouding the Earth’s orbit, the sun would have been blocked out for years, plummeting the planet into cold and darkness. As well as this, scientists have also more recently calculated that, after the impact, the debris could have also rained down balls of fire all over the world.

8. A Volcanic Eruption

Another common theory for the dinosaurs’ extinction lies in the magmatic hands of volcanoes. This theory is also rather easy to conceive; after all, we’ve seen volcanic eruptions in our own lifetimes that have majorly affected the planet. Scientists theorize that volcanic eruptions could have spewed toxic and sulfurous gases into the atmosphere, which essentially starved the dinosaurs of the air they needed to survive.

9. Climate Change?

One thing we hear a lot about these days is climate change. We’re even privy to being able to see just how climate change is affecting the Earth. After all, as well as the hole in the ozone layer, our polar ice caps are now melting. If only we could ask the dinosaurs, who very well could have succumbed to this themselves. Climate change is one of science’s more gradual theories for how the dinosaurs might have wound up extinct. However, there are also theories that climate change was even responsible for how well they flourished during the Jurassic and Cretaceous periods.

10. So What Happened to the Dinosaurs?

This is the question on everyone’s lips. It’s the question that paleontologists and other scientists have devoted their lives to for centuries. There’s a very possible theory that it was a combination of all of the above things that contributed to the mass extinction. That being said, there’s also the idea that because all of these things did happen, they could very well happen again. Perhaps in another 65 million years, a new race of living creatures will be asking themselves, “What happened to human beings?”

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