In many of the unsolved mysteries of the world, many explorations and discoveries of life have made human beings understand and summarize the corresponding regularity of the changes in the earth's environment. We often use "environmental change" to guess the possibility of a species renewing or dying.
Over the course of 4.6 billion years, many lifes have evolved or changed over several generations, with primitive marine single-celled, multicellular, aquatic and terrestrial, and two organisms evolving. But according to the research of scientists, during this time period, there have also been many devastating disasters, resulting in the extinction of species, large-scale organisms disappearing directly in the current disaster, and the earth seems to have been reshuffled many times.
In these "mass extinction events", we seem to be slowly discovering some patterns, such as the time period between events is almost 26 million years.
This may be a coincidence, but when humans find that this "coincidence" in some sense coincides with other variable conditions in the universe, these "mass extinction events" are no longer a purely natural choice.
<h1 class="pgc-h-arrow-right" data-track="5" > extinction</h1>
There have been five large-scale extinction events on Earth, namely the Ordovician mass extinction, the Devonian mass extinction, the Permian mass extinction, the Triassic, and the Cretaceous mass extinction (dinosaur mass extinction).
We can try to summarize these "mass extinction events":
Ordovician mass extinction
The Ordovician (Second Paleozoic) mass extinction event occurred in the late period, about 440 million BC.
In this extinction event, the Earth's climate gradually declined, glaciers sealed the seawater, global sea level declined, marine ecosystems were destroyed, various invertebrates in the water faced an existential crisis, and finally about 85% of the world's species perished.
Devonian mass extinction
The Devonian (Quaternary Paleozoic) mass extinction event also occurred late in this period, around 365 million BC. This event is somewhat different, going through two peaks, with about 1 million years in between.
Similarly, due to the sudden cooling of the global climate and the shrinking of the ocean area, it was undoubtedly a major disaster for the Devonian Period of the "Fish Age".
Permian mass extinction
The Permian (Last Paleozoic) mass extinction event occurred about 250 million years ago.
Scientists speculate that the event was caused by falling sea levels and continental drift, with all the land connected together, the coastline drastically reduced, the desert expanding, the ecosystem damage severely, and the creatures that lost their living space had to die. Finally, about 96% of the species on Earth went extinct, the biological system was completely renewed, and dinosaurs took to the stage of history.
Triassic mass extinction
The Triassic (between the Mesozoic First, Permian, and Jurassic) mass extinction events occurred around 195 million BC.
The cause of the extinction event is not clear, scientists have only found in a series of investigations and research actions that there was a decline in sea level at that time, and then a recovery, but at this time the sea water has changed, and there has been a large-scale lack of oxygen. As a result, about 76% of species went extinct, mainly due to the disappearance of marine life.
Cretaceous mass extinction (dinosaur mass extinction)
The Cretaceous mass extinction event is best known, occurring around 65 million BC.
Volcanic eruptions and intense extraterrestrial movements occurred during this event, after which the atmosphere was severely polluted and sunlight could not pass through the clouds as usual and normally reached the surface. Due to lack of light and heat, the global temperature dropped, a large number of animals and plants died, and dinosaurs also lost their dominant position and gradually disappeared.
In addition, scientists have done research and analysis of the 10 known extinction events on Earth, put forward many hypotheses and speculations, and the saying that "planets hit Earth" is the most common and generally accepted. They also surveyed the ages of different craters and the extinction events of life, and found that the death of life on Earth was cyclical, about 26 million years or so.
The most typical example is the formation of the Chicxulub impact crater on the Yucatan Peninsula 65 million years ago, and the six largest impact craters in the world are linked to several mass extinctions.
<h1 class="pgc-h-arrow-right" data-track="24" > periodic law</h1>
According to the existing research results of human beings, in the entire solar system, extraterrestrial object impact events are likely to be related to the rotational movement of the solar system following the Milky Way.
The solar system is orbiting the Milky Way, about 250 million years after completing a week of rotation. During this period, the cosmic space environment of the solar system will change accordingly with the change of position in the Milky Way, and it will also affect the movement of other celestial bodies in the solar system.
For example, when the solar system is in an orbital motion, it will inevitably pass through other parts of the Milky Way, coincide with other celestial bodies and material regions of the stars, or pass by. At this time, celestial bodies and materials in the same space may not be able to pass through the Oort cloud on the outer periphery of the solar system, but they can produce gravitational or magnetic field effects on each other, so that some comets in each other's space are out of their original orbits, and small bodies in the solar system are offset inward, and finally hit other celestial bodies, including The Earth, resulting in a mass extinction event.
Among them, the law of the deviation of the comet's orbit is the focus of scientists' research.
<h1 class="pgc-h-arrow-right" data-track="29" > solar companion</h1>
Orbiting the primary star is called a companion star, which is two stars that rotate around each other.
The Solar Companion Star, a hypothetical object scientists use to explain the cause of a mass extinction event on Earth, is known as Nemesis, also known as the "Vengeance Star."
When the planet and the Sun orbit each other, every 26 million years apart, there will be an "intimate distance" between each other, which is also a "perihelion" for the companion star.
Subject to gravitational pull, so that some comets and other asteroids in the interior of the solar system are shifted, while some celestial bodies are affected by the gravitational pull of the earth, infinitely close to the earth, the closer the distance, the faster the speed, and finally directly hit the earth, resulting in the existing organisms on the earth facing disaster, large-scale extinction.
Combined with the rotational motion of the sun in the Milky Way, scientists have concluded that about 26 million years apart, the sun companion is affected by other interstellar material in the Milky Way, which shifts the orbit of the celestial body and causes periodic celestial impact events.
Although there is not enough evidence to prove the existence of a companion star, scientists have found that the difference between its perihelion and aphelion point can reach nearly 900 astronomical units based on the change in the eccentricity of the orbit of a dwarf planet outside the orbit of Pluto, and such a surprising change can indirectly provide the possibility of the existence of a solar companion.