Information about the extinction of dinosaurs
According to the German magazine Science Illustrated, Joerg Farr, a professor from the Institute of Astrophysics in Bonn, said that the earth fell into a strong cosmic particle flow "storm" 60 million years ago. When encountering such a storm, various particles entering the earth's atmosphere at high speed will reach hundreds of times as usual, tearing the molecules in the atmosphere into condensation nuclei necessary for the formation of rain, which will eventually lead to the thickening of clouds in the earth's atmosphere, frequent rainfall and a sudden drop in temperature.
Scientists believe that the explosion of cosmic particle flow caused the drastic change of the earth's climate conditions, and dinosaurs that could not adapt to this climate change became extinct in a short time.
In the Mesozoic era in the history of the earth, there were many kinds of reptiles-dinosaurs. Hundreds of dinosaur fossils have been found in the world, and such a huge animal group that ruled the earth for10.6 billion years suddenly collapsed at the end of Cretaceous. Wrote a puzzling chapter in the history of biology
So far, all kinds of explanations about the extinction of dinosaurs can't be justified. In recent years, the hypothesis that asteroids hit the earth put forward by American physicist Luis Alvarez has attracted much attention. He found that the content of trace element jujube iridium in the upper stratum of the late Cretaceous in gubbio suddenly increased by more than 30- 160 times compared with other strata, and then people came to the same conclusion from sampling tests all over the world, and the abnormal increase of iridium in the late Cretaceous strata was indeed universal. So Alvarez thinks that an asteroid with a diameter of about 10 km hit the earth at the end of Cretaceous, and the dust produced covered the sky. It caused great changes in the surface climate environment and led to the extinction of dinosaurs. However, there are many doubts about explaining the increase of iridium content in rock formations and the extinction of dinosaurs caused by the impact of asteroids on the earth.
1. Asteroids are generally composed of silicon and iron, so it is impossible for such a huge asteroid to fall to the surface of the earth even after a long time, and such a large meteorite has never been found on the earth;
2. At the end of Cretaceous, most rock formations were igneous rocks formed by lava cooling, and sedimentary rocks formed by dust accumulation only occupied a small part of the surface. Can the dust raised by the asteroid impact bury most of the animals and plants on the earth in rocks thousands of meters deep?
3. Can iridium contained in asteroids be evenly distributed and cover the whole earth's surface? Iridium also exists deep in the earth. Why only speculate that iridium comes from outside the earth and not from inside it?
As we know, thermonuclear reactions inside the earth will continuously accumulate enormous energy. Once the crust can't bear it, the internal pressure will break through the crust and suddenly release to form a big explosion. Iridium date, an element mainly existing in the core of the earth, was brought to the surface of the earth's crust by lava eruption during the Big Bang. It is recognized that the clay layer at the end of Cretaceous was formed by a large amount of volcanic dust accumulation. Therefore, the general increase of iridium content in the strata at the end of Cretaceous proves that the crust erupted violently at that time.
Fossil archives tell us that most dinosaurs died and most dinosaur eggs were produced at the end of Cretaceous, and all the dinosaurs and dinosaur eggs found were preserved in the stratum under the thin clay layer rich in iridium, which is consistent with the time of a series of global crustal structural changes such as large-scale orogeny at the end of Cretaceous recognized by geologists.
In recent years, hundreds of protoceratops and Ankylosaurus fossils were unearthed in Bayin Mandu Lake stratum in Inner Mongolia at the end of Cretaceous, and a large number of complete dinosaur bones were piled up in groups. Judging from the burial posture of the remains, they died in extreme pain, including the bones of a whole group of baby dinosaurs. This scene shows that they are catastrophic collective deaths, and the bodies are quickly buried in situ after death (many dinosaur fossils in other parts of the world also have similar death characteristics). At the same time, it is found that the local fossil-bearing rock stratum is brick red silty rock stratum, which is the best environment for fossil formation. It can be speculated that the process of environmental upheaval is quite sudden and short-lived. Because, if the earth's environment changed gradually over a long period of time and the dinosaur population gradually died out, they wouldn't have left so many dinosaur eggs and a whole group of young fossils afraid of agriculture. Therefore, most dinosaurs should have died in large numbers because of sudden devastating disasters when their living environment was basically normal.
A large number of animals and plants reflecting the characteristics of the earth's environment at that time showed that before the end of Cretaceous, the density and thickness of the earth's atmosphere were much higher than now, the surface was relatively flat, and the world was in a very warm and humid climate. At that time, the temperature difference between the polar regions and the equator was very small. In the 1980s, Canadian geologists discovered a fossil forest in ellesmere island, which was dominated by water jackets, and there were animal fossils such as crocodiles in the forest, indicating that the polar regions used to have a tropical climate. The natural environment is the main factor that determines the existence form of life. After the Big Bang, when the hot and humid environment on which giant dinosaurs lived no longer existed, even if some of them survived, they could not adapt to the different relatively cold and dry climates in cold and warm seasons and continue to survive. So the extinction of most dinosaurs is natural.
There are also some surviving dinosaurs (mostly smaller) and some animals that have evolved into primitive birds and mammals as early as Paul's time, following the laws of natural selection and survival of the fittest. In a relatively harsh environment, after 70 million years of continuous evolution, most species have changed their original forms, from cold-blooded animals to cold-tolerant warm-blooded animals (birds, mammals and humans). Of course, after every large-scale species evolution, some species will remain intact. For example, after fish evolved into amphibians, fish continued to survive, and very few reptiles (crocodiles, scorpions, etc. ) still maintains the original form of dinosaurs 70 million years ago.
The biological remains in the earth's rock strata reveal that in the history of biological evolution, there will be a mass extinction every once in a while. The extinction of dinosaurs at the end of Cretaceous is not the only disaster in the history of biological evolution. In an earlier era, there was a "Cambrian Big Bang" phenomenon in which most invertebrates suddenly appeared in a short time. Just like the evolution of organisms from single cell to multi-cell, reptiles to mammals, it needs an evolutionary process (such as 1984, the discovery of Chengjiang fossil group in China).
So far, there is no obvious evidence that the extinction of dinosaurs was caused by asteroid impact. However, the fact that the geological structure of the earth continues to change frequently shows that the environmental "catastrophe" caused by periodic crustal structure changes has always played a leading role in the process of biological evolution. Of course, the gradual evolution of small-scale species also runs through the whole process of life evolution. Periodic celestial explosion (such as nova explosion) is an indispensable link in the evolution of all planets, including the earth. Marine fossils and seabed minerals in those mountains are the best explanation for the end of the dinosaur era caused by the drastic changes in the earth's crust.