The earth is in a fever today! The average temperature of the planet has increased by 1 degree Celsius compared to pre-industrial levels, once it exceeds 15 degrees Celsius, I am afraid it will lead to an irreparable crisis.
The temperature of the Earth does determine the safety of countless creatures, but you may not know that the Earth has undergone countless abrupt climate changes in its 4.5 billion year history. For example, 56 million years ago, the earth's temperature rose by 5 8 degrees Celsius and ushered in a severe round of earthly extinction events.
The Earth's environmental history can be traced, and changes in climate are recorded at the geological level. According to geological surveys, about 56 million years ago, at the turn of the Paleocene and Eocene, the earth experienced a sudden global climate anomaly with a sudden increase in temperature, which is calledPaleocene-Eocene extreme heat event
The cause of this incident is still inconclusive. Some people believe that perhaps it was the North Atlantic igneous province event that caused a large amount of greenhouse gases to be emitted, causing the planet to warm. It is also believed that a comet may have crashed into the Earth, releasing a huge amount of energy and greenhouse gases, thereby raising the Earth's temperature. It is also believed that the planets of the solar system interfered with the Earth's orbit, causing climate upheaval.
However, it has also been suggested that the perpetrators of this incident can be traced even further back to the outer solar system – perhaps other stars that have caused the Earth's climate upheaval!
This may sound a bit outrageous, how can other stars be so far away that they can affect the Earth's climate? Don't worry, let's talk slowly.
In the geological study of this period of history, scientists not only discovered drastic changes in temperature, but also discovered an important piece of information, that is:Eccentricity of the Earth's orbitchanges. We know that the orbit of the planet is elliptical, and the smaller the eccentricity, the closer it is to the perfect circle; If the eccentricity is large, it means that the perihelion and aphelion points are much different.
According to current research, the eccentricity of the Earth's orbit increased significantly during the Paleocene-Eocene hyperthermic event.
In fact, it is normal for the orbit of a planet to change, after all, it is not only affected by the gravitational pull from the sun, but also by the gravitational interference of other large planets in the solar system, and it is indeed impossible to maintain a permanent orbit, and the earth is no exception.
Now that we have found the cause, as long as we continue to go back and calculate backwards, can we reverse the operating state of the earth's orbit at that time, so as to determine whether this event was caused by orbit changes?
Sorry, no. Because there's a serious issue at stake here, and that isN-body problem。Many people have a general understanding of this theory in the science fiction work "The Three-Body Problem", when there are three or more celestial bodies in a celestial system, the orbit of each celestial body cannot be calculated to the distant future, let alone extrapolate the distant past, not to mention that there are 8 planets in the solar system.
Therefore, the theory that the planets of the solar system interfere with the Earth through gravity, causing changes in orbits, and thus triggering the Paleocene-Eocene extremely hot event, is still only at the stage of conjecture, so it will inevitably be challenged by other conjectures.
For example, Nathan Kaib, a planetary scientist from the Institute of Planetary Sciences, and Sean Raymond, an astrophysicist at the Bordeaux Astrophysics Laboratory, believed that it was not only the planets of the solar system that affected the Earth's orbit at that time, but also stars outside the solar system!
My God, stars outside the solar system can still affect the Earth? Will we be affected now?
Don't worry, the Earth is relatively stable now, because the other stars are quite far away. It's just that at that time 56 million years ago, maybe a star broke into the solar system and caused such a big impact.
Stars are not "constant", everyone understands this truth. Despite the fact that the probability of a direct collision between stars is close to zero, there are still passing events from time to time. Throughout history, the solar system has welcomed the arrival and hasty departure of other stars.
Far aside, just 80,000 years ago, it is likely that a star named Wise J0720-0846ab was once close to the solar system, at a distance of only 1 light-year, much closer than Proxima Centauri today. You know, the radius of the solar system is thought to be between 1 2 light years, and according to this data, the star has really broken into the solar system.
About 2.8 million years ago, a sun-like star named HD 7977 also broke into the outermost structure of the solar systemOort Cloud。More recently, it was only 31,000 astronomical units, or 4,650 billion kilometers, or less than 05 light years. Compared to other stars that are thought to be "highly probable" to have passed by the solar system, this is currently the only star that has been confirmed to have ever broken into the solar system.
Even Proxima Centauri, the closest star to the solar system, continues to get closer. It is expected that in 3,000 years, it will be closest to the Sun, and the distance between the two sides will be reduced to 3 light-years, and then the two sides will wave goodbye.
According to astronomers' speculation,On average, every 1 million years or so, a star comes to a position just 50,000 AU from the Sun; On average, every 20 million years, a star breaks into the Sun just 10,000 AU away.
In other words, according to the time when the earliest human maiden Lucy appeared, there may have been 3 or 4 stars that have broken into the solar system; Since the extinction of the dinosaurs, there may have been 3 4 stars that have come to a position less than 1 6 light years!
As a result, Kaib and Raymond believe that the change in Earth's orbit 56 million years ago may have been caused by stars that broke into the solar system. Although such stars are not enough to directly plunder the planets of the solar system, they have the potential to cause serious orbital changes that can profoundly affect the planetary climate.
However, in the report, published in the Astrophysical Journal Letters, the two researchers did not explicitly state that the Paleocene-Eocene hyperthermic event was caused by other stars, after all, it is not easy to trace the positions of other stars so long ago. They think,We should not limit our gaze to the solar system entirely, after all, the solar system is not an isolated system in the Milky Way.
Whether the culprit is another planet in the solar system or a star hidden in the Milky Way remains to be discovered by future research.