THE LAST DAY OF DINOSAURS ReYOUniverse

Dinosaurs ruled the Earth for 160 million years. It seemed they would forever dominate the biosphere. But one day, their world was destroyed by a huge rock the size of Everest falling from space. This is the story of how the era of ancient reptiles came to an end. The last day of dinosaurs. Earth, 66 million years ago. The end of the Cretaceous period of the Mesozoic era. The parts of the Pangea supercontinent almost completely drifted apart. The planet looked very similar to its modern state, but not quite the same. South and North America have finally split by the end of the Cretaceous period. Africa, Australia and Greenland have the same shape as today. At the same time, the outlines of Europe and Asia were just starting to form. The mountain ranges of Siberia, Mongolia, the Andes and the Cordillera. The continents were actively emerging. The Cretaceous period lasted 79 million years and became the longest period of the Mesozoic era. The planet's climate changed several times during this time. It was relatively cool by the end of this period. Ice caps have formed at the poles. Winters have become harsher. In some places, the temperature dropped below minus 10 degrees Celsius, and as low as minus 45 degrees Celsius in Alaska. But still, the world was warmer than it is now. Lush vegetation covered the continent's surface. It was during this period that flowering plants emerged. Conifers, ginkgo and other trees from previous eras formed thick forests, which also included modern-looking walnuts, ash and beech. The sod produced by these trees made the top layer of soil more fertile for newly emerging herbs. With the advent of flowering plants, insects also had to evolve. Butterflies and bees started to fly, spreading pollen. Seeded fruits developed from pollinated flowers, providing food for many animal species, including birds. This was what drove the evolution of some herbivorous dinosaurs, as well as many mammalian species. The number of carnivores, ungulates, insectivores and primates increased under these favorable conditions. Admittedly, they haven't yet become as large as they are now. Most mammals back then were small rodents and predators. For example, a fossilized head of a 20-centimeter-long Cronopio dentiacudis was found in Argentina. This small mammal is called the saber-toothed squirrel because of its elongated muzzle with long fangs. Presumably, this species ate some insects. But larger animals have already appeared. In Madagascar, the remains of a huge Ventana certici marmot were found. This herbivorous mammal had a rather unusual appearance. It had massive crests on either side of its skull for self-protection and an excellent sense of smell. The animal weighed 9 kilograms and was three times bigger than modern marmots. However, Rapenomamus was the real giant among the mammals of the Cretaceous period. It had a 1-meter body and weighed 12 to 14 kilograms. Outwardly, Rapenomamus resembled the modern Tasmanian devil or a squat dog. This predator even hunted small or newly hatched dinosaurs. And yet, dinosaurs were the pinnacle of prehistoric evolution. They were at the top of the Mesozoic food chain. A great number of dinosaur species of various sizes populated all continents. The smallest were Ocudentavis congre. The head of this miniature reptile was no longer than 14 millimeters, beak included. Unfortunately, paleontologists haven't yet found the bones of the torso. But given its head size, this dinosaur wasn't bigger than a modern hummingbird. According to some estimates, the largest animal that has ever lived on Earth is Alamosaurus. These dinosaurs were 29 meters tall, weighed 38 tons, and had a 12-meter long tail. Five hours till the impact. The day terrestrial life was changed completely. All animals, young and old, were going about their day as usual, doing some foraging and hunting. A herd of 50 Alamosauruses went to the Yucatan Peninsula looking for some fresh greenery. These giants were herbivores. They had to consume up to a ton of vegetation per day to stay in shape. It could take them a few days to eat leaves from an entire forest, which made them lead a nomadic lifestyle. A middle-aged predatory Tarbosaurus, living on the territory of present-day Mongolia and China, was also looking for food. This 14-meter long species is considered the largest among the predatory dinosaurs of the Cretaceous period. Our Tarbosaurus set out to hunt for prey in the floodplain. Medium-sized animals and small dinosaurs would often come there for a drink, so the hunt was going to be a success. Like any Tarbosaurus, this reptile walked on two hind legs. Its two-fingered forelimbs were disproportionately small relative to the rest of the body. And yet, they were very helpful in holding the prey or catching fish with long claws. Tarbosaurus's main weapon, though, was about six dozen of long, sharp teeth, reaching up to 85 millimeters. Three hours till the impact. Meanwhile, one adult Pachycephalosaurus was also going about his day in North America. This 4.5-meter long dinosaur weighed about 450 kilograms and looked quite formidable. Its skull was protected by a 25 centimeter thick bone dome that surely softened the blows when the great reptile fought its enemies. The back of the dome had bony projections and short spikes protruding upwards from its muzzle. Pachycephalosaurus was primarily herbivorous. It crushed leaves, seeds, and fruits with its relatively small, sharp teeth. However, it appears this dinosaur also included meat in its diet. It ate small amphibians, shell-less animals, mammals, perhaps even newly hatched dinosaurs. On this day, our Pachycephalosaurus got closer to the ocean, where it found many trees with nutritious seeds. It could also eat plenty of huge ammonite mollusks, lizards, and other critters in small lagoons. Meanwhile, a female Ankylosaurus went into the forest to grab some lunch in Western North America. She was guiding four newly hatched cubs. This reptile looked like a nightmarish chimera. It reached the size of a rhinoceros or even an adult African elephant. The body of this tetrapedal monster was covered in powerful bone armor, and it had a massive club-like knob on its tail. But despite its intimidating appearance, Ankylosaurus was a harmless herbivore. The mother with the cubs didn't seek to kill anyone with her club. The tail served to protect against predators and cannibal reptiles. And so, being protected by their mother's formidable tail, the family went into a thick forest near the newly formed Rocky Mountains. 2 Hours Till The Impact Meanwhile, young reptiles had a real massacre in North America, hundreds of kilometers away from the site of impending disaster. Some absent-minded Carnotaurus wandered into the territory of the Tyrannosaurus rex and didn't notice the owner in time. At the speed of up to 50 kilometers per hour, Carnotaurus could easily run away from its opponent, who can only run at 40 kilometers per hour. But the T. rex came into view too unexpectedly. The intruder's smell gave it away a while ago. T. rex had an excellent sense of smell compared to other dinosaurs. And in terms of eyesight precision, even a hawk might be jealous of this predator. In addition, the reptile's vision was binocular. Its eyes could look in different directions. And then the input from each eye was combined to create a single visual image. This enabled the dinosaur to accurately determine the distance to its prey. And so, the T. rex furiously attacked the enemy to protect its territory and get a delicious meal at the same time. You see, this dinosaur never missed a chance to enjoy the flesh of its own kind. It was up to Carnotaurus now to fight back. If we saw this fight and had to take a bet, everyone would put their money on the T. rex. The Carnotaurus had no chance. The weight difference was huge. Tyrannosaurus weighed up to 6.8 tons and outweighed Carnotaurus by almost 5 tons. Its muscle mass, and therefore strength, was multiple times greater. Even with its horn-like projections above the eyes, the Carnotaurus had no chance to fight off the T. rex's super powerful jaws. Tyrannosaurus quickly tore the opponent to pieces and began its feast right away. It was a great stroke of luck for the reptile. According to some estimates, T. rex needed up to 100 kilograms of meat per day. This is equivalent to daily intake of three or four lions. As it was preoccupied with lunch, the reptile didn't care to look up. And so, it missed the bright light in the sky that was growing bigger by the second. 10 minutes till the impact. A huge asteroid was approaching the planet. In a few minutes, it will kill 75% of all living creatures, causing the Cretaceous-Paleogene extinction event. In 1980, scientists proposed a hypothesis that it was the asteroid impact that led to this disaster. They found far more iridium in 66 million-year-old clays around the world than in layers above and below. This is a very rare substance on Earth. But there's a lot of it in some types of asteroids, which is why iridium is sometimes dubbed a space metal. Scientists suggested that the metal was probably brought by an asteroid in a collision event. Ten years later, another team of researchers determined the exact site of the impact. A crater with a diameter of 180 kilometers was discovered in the Yucatan Peninsula and was named Chixulub. Its age coincides with the dinosaur extinction. Chixulub has a large amount of iridium, and as you move away from the crater's center, less and less metal is found. In addition, 25,000 animal fossil fragments were recently found in New Jersey quarries. These creatures died on the same day at the end of the Cretaceous period. This was another evidence of the mass extinction that followed the asteroid impact. Two Minutes Till the Impact While our Tyrannosaurus was enjoying its lunch, a 10-kilometer rock weighing several trillion tons flew into the atmosphere. The gravity's pull was becoming exceedingly stronger, accelerating the object to a fantastic 20-kilometer-per-second speed. Like a piston, the asteroid squashed one 20-kilometer air column after another. Along with friction, this process heated the giant rock to tens of thousands of degrees Celsius, making it much brighter than the sun. At the same time, the Tyrannosaurus was having a little break from its lunch. It lifted its head up and was blinded by the light of the blazing sky. The dinosaur quickly lowered its head, closing its eyes. But the light was burning them, even through closed eyelids. The heat incinerated the reptile's skin, set fire to the trees and grass around it. A second later, the asteroid disappeared over the horizon, leaving the glowing sky behind. Tyrannosaurus Rex got a little break, but only for a moment. Nothing was happening for a few seconds, but then the sky got blindingly bright. The asteroid crashed into the Gulf of Mexico near the northern coast of the Yucatan Peninsula. The energy released by the impact was approximately equivalent to 10 billion Hiroshima atomic bombs. In a second, the asteroid penetrated about 20 kilometers into the Earth's crust. The whole globe was shuddering like a thousand bells from the impact. To put this into perspective, a relatively recent Krakatoa volcano eruption caused half of a crew member's airdromes to rupture on one of the ships 70 kilometers away. The asteroid's impact was a million times more powerful. Furthermore, shockwaves rushed in all directions, faster than the speed of sound right after the collision. They were so strong that they skinned animals alive, lifted them up into the air, swirled them around, and crushed everything even hundreds of kilometers away from the crater. The heaviest dinosaurs flew like balloons. The T-Rex sustained a severe concussion and died in an instant. Immediately, the shockwave lifted its body up into the air for several seconds. The wave continued to spread, going a few times around the globe. But even before killing the T-Rex, the asteroid destroyed the herd of Alamosauruses that we saw previously. Animals were grazing right next to where the infernal rock fell. Dinosaurs couldn't escape the unthinkable heat. It burned everything to the ground, turning animal bones to ashes. Meanwhile, the female Ankylosaurus with her four babies was peacefully eating leaves in the forest. They were hundreds of kilometers away from the impact site. However, they died even before the Alamosauruses. The red-hot asteroid caused huge fires while passing through the atmosphere. One of them broke out where a family of Ankylosauruses were grazing. The fire instantly incinerated the forest, leaving the reptiles no chance to survive. The asteroid also knocked out 15 trillion tons of rock from the planet and sent it high into the sky. A small portion flew into outer space while the remaining parts, including house-sized boulders, began to fall back from orbit. At the same time, glass rain started. It was raining hot 5-millimeter rock balls. The stone hail and the scorching rain have killed innumerable animals. However, the Pachycephalosaurus, who was hunting near the ocean in North America, was lucky. It didn't die from fires and boulders falling from the sky. But a bit later, when a gigantic 100-meter tsunami rose from the ocean. To get some idea about its scale, consider the devastating tsunami in Japan of 2011. Those waves were barely 10 meters high. Nonetheless, almost the entire island state incurred losses. But the giant tsunami caused by the asteroid impact went thousands of kilometers deep into the land. It flooded almost the entire territory of the future USA. Wave traces have even been found in North Dakota. One of these waves took the Pachycephalosaurus under, dragged its body into the ocean, and buried it in the abyss. The area of modern Mongolia. Just then, an elderly Tarbosaurus was looking for a prey. Here, 15,000 kilometers from the explosion epicenter, hundreds of dinosaur species still roamed wooded areas. Meanwhile, the disaster was getting closer by the minute. The asteroid impact triggered a series of terrible earthquakes, measuring up to 11.2 points. The tremors were about 50 times stronger than any earthquake known to humanity. The most powerful Great Chilean earthquake of 1960 had a 9.5 magnitude. Increasing this number by one point would mean 30 times more powerful energy release. The planet was shaking so hard that all the volcanoes woke up and began to erupt. About 70 billion tons of pulverized stones, soot, ash, and carbon monoxide rose up as a result of eruptions. Then they began falling back into the atmosphere. Their friction against the air caused enormous temperature increase. A huge hot cloud of dust stormed across the planet, burning everything in its path. It was approaching Mongolia at a speed of 18,000 kilometers per hour. The temperature here rose to 150 degrees Celsius an hour and a half after the impact. All living creatures died, or rather, almost all creatures. Our Tarbosaurus and several other animals managed to escape by hiding in an underground cave. They could hide out here while the killer cloud passed by. Soon, the temperature began to drop. This was followed by acid rain flooding the Earth because several hundred billion tons of sulfur compounds were being thrown into the troposphere along with other rocks. For weeks, sulfuric acid was pouring from the sky all over the planet. It poisoned the soil and water bodies. A dense blanket of dust, ash, and soot wrapped around the planet after volcanic eruptions, not letting any light and heat in. Even at noon, it was as dark as at night. The temperature dropped by 28 degrees Celsius. Impact winter set in. When hunger and thirst drove the Tarbosaurus and other animals out of the cave, they saw a world that looked strikingly different from before. It was cold, dark, and deserted. Only decay, fungi, and molds were able to reproduce under such conditions. There was no food for dinosaurs on the planet. Countless animals starved to death. Our Tarbosaurus didn't manage to survive either. Perhaps it was the last dinosaur on the planet. However, one can assume that occasional dinosaur eggs have been preserved intact somewhere underground. Young individuals hatched from them after some time. Tiny groups of dinosaurs emerged here and there. But cold weather, hunger, and disease contributed to their final demise. The era of dinosaurs came to an end. The Cenozoic era began. The dust clouds dissipated over the planet over the course of several decades, and heat and sunlight were finally able to reach the surface. Nature revived from the ruins. First, huge horsetails and ferns emerged yet again. They were closely followed by angiosperms and grass. Other animals who had been dominated by dinosaurs for millions of years were ready to march bravely into the new era. Mammals. Some of them survived the disaster in underground burrows. Others stayed on trees. They've become well adapted to extreme conditions, were quick to reproduce, and consumed relatively little food. They were guaranteed to thrive on the renewed planet. The success of mammalian evolution led to the emergence of Homo sapiens, who is now the dominant species on Earth. But we're a long way from setting the dinosaur's record as it's been a few million years since we've conquered the world. Only time will show if people will rule the planet for 160 million years, like ancient reptiles.