There is a relationship in the universe. One planet is completely “fascinated” by another planet, and there is always only one face to it. Yes, that is “tide lock”. Now the moon is locked by our earth’s tides. So, is it possible that the earth is also locked by tides? How will life on earth survive?
Will the earth be locked?
Tidal locking is also called gravitational locking, captive rotation and rotation orbital locking, that is, due to gravity, a hemisphere of a rotating celestial body always faces the partner celestial body, and the time required to rotate around its own rotation axis and around the partner celestial body It takes as long as the rotation time. Usually, only satellites are locked onto larger celestial bodies by tides. However, if the mass difference between two objects and the distance between them are relatively small, then the two celestial bodies may be tidally locked to each other, such as Pluto and its moon Charon.
Although tidal lock is more common in the solar system, what kind of celestial body will be locked by tide depends on the orbital distance, the mass of the two celestial bodies, and the ductility of the orbiting object. For stars, celestial bodies closer to the star are more likely to be “caught” by it, but if the gravitational force of the star is strong enough, the celestial body in the habitable zone may also be within the range of the stellar tide lock. The earth is located in a habitable zone. Is it possible that it can also be locked by the sun?
Judging from the current situation, the earth is still unlikely to be locked by the solar tides. On the one hand, of course, it is because the distance between the earth and the sun is safe; on the other hand, the little brother of the earth, the moon, interferes with the sun’s action on the earth. Although the sun is the leader of the solar system, the moon is closer to the earth, so it has a greater effect on the earth. The moon is dragging the earth’s “hidden legs” every year, slowing it down gradually. If it continues, the earth and the moon may tidal lock to each other.
However, humans may not be able to see that scene, because before that scene, the earth and the moon were swallowed by the sun that evolved into a red giant star.
Now suppose the earth is locked by the tide, what will happen? Under normal circumstances, when a planet is locked by tides, one side will always be day, and the other side will always be night. The situation on the earth is roughly the same, but scientists have also said that it is still uncertain what specific changes will occur on the earth.
Exoplanets have given us some inspiration. Researchers have discovered that there may be oceans on planets that are locked by tides around dark, small, and cold red dwarfs, and the environment on these planets does not seem so harsh. Martin Heath of Greenwich College in the United Kingdom found in a study that when the planet’s oceans are deep enough, sea water can flow freely under the ice cap on the shadow side, bringing heat to cold areas, and the temperature on the shadow side is not lower than Very cold. And if the planet’s greenhouse effect or stellar radiation is strong enough, ocean heat transfer may even make the entire planet ice-free.
In 2013, in a simulation study, researchers at the University of California established a climate model for tidal-locked planets. The results show that clouds will form on these planets, which will reduce the temperature difference between the light and dark sides and make the planets more habitable.
The earth also has oceans and a thick atmosphere, and it is still far from the sun. This means that if the earth is locked by the tides, its environment should be similar to the planets around the red dwarf, but better than them. Some researchers have obtained some possible results through computer simulations and studies on ocean heat transfer.
First of all, because the earth is far away from the sun and has a very thick atmosphere, even on the side facing the sun, the temperature will not be very high and the ocean will still exist. On the dark side, the temperature will naturally be very low without the warmth of the sun all year round. However, due to the temperature difference between the light and dark sides, the air on both sides will be exchanged. More importantly, there are oceans on the earth that cover most of the world. The difference in temperature and density in different sea areas will promote the flow of sea water and heat. This may mean that the sun facing side will not be very hot. Although part of the ocean and land on the back sun side may be covered with ice, some areas may be above 0°C.
Second, the earth no longer has four seasons as it does now. Ice on the back side of the sun will cause the global sea level to drop, exposing more land on the side of the sun, which will increase the reflection of the ground, making it difficult for clouds to form, and rainfall is scarce. And near the twilight line between Chaoyang and Beiyang, the climate there is different. After being locked by the tides, the temperature difference between the light and dark sides of the earth will be very large, which may cause extreme weather such as wind and snow often appear at the junction of light and dark.
It is worth mentioning that more rocks and minerals will be exposed after the sea level drops. They weather quickly under the action of sunlight and wind, and accelerate the release of carbon dioxide and other gases into the atmosphere, which may intensify the global greenhouse effect. This has an impact on the climate of the entire planet.
How to live on a locked earth?
How will the changes in the earth’s environment locked in by the tides affect the lives of humans and other creatures on the earth?
In 2017, scientists discovered TRAPPIST-1, a red dwarf star with extremely low surface temperature, about 39 light-years away from the Earth. This red dwarf has 3 planets in the habitable zone that may have oceans. However, the planets of the TRAPPIST-1 star system are all locked by tides.
Researchers believe that the strong wind blowing on those planets continuously blows the minerals and nutrients on the planet into the ocean, which means that there may be marine life in the ocean, and there may even be complex marine animals. Landing creatures may live near the junction of light and dark, and they can fix themselves on the ground in a hurricane and will not be blown away. In addition to larger animals, there may be some species that resemble water bear insects. This kind of “super” creatures are extremely vigorous and can survive for many years without water and food, can survive in a vacuum, and can tolerate With the impact of gamma radiation and solar wind, they can survive in any environment. In the air, there may be gelatinous jellyfish. This invertebrate can drift in a storm without being torn apart by strong winds.
So, what about the situation on Earth locked by tides? If humans were still on the earth at that time, the main settlements were also at the junction of light and dark, because the temperature there was not too cold nor too hot, there was not so strong sunlight, and there was liquid water. But given that the climatic conditions there are also relatively harsh, humans may place their homes underground. Considering that the human science and technology level at that time should be much higher than it is now, it can effectively transfer heat on both sides of the light and dark, so it is possible to establish settlements in a wider area on both sides of the junction of light and dark.
By then, many terrestrial animals on the earth will become extinct due to environmental changes and destruction of their habitats. Only some of them will survive. In order to adapt to the environment, they will also evolve corresponding abilities, such as on planets like TRAPPIST-1. The same ability as an animal that can hold oneself in the wind. Plants will also experience mass extinctions, and only those plants that can hold onto the soil firmly and can withstand drought, heat, or cold can survive. Similar to the planets of TRAPPIST-1, there will also be organisms living in the oceans of the earth, and the organisms in the oceans of the earth may be much more advanced than the marine life on the planets of TRAPPIST-1.
Of course, this is only what the earth might look like after it is locked by the tides. How the earth will change and how the living things will survive are also related to where the earth is facing the sun. If the land is facing the sun, the earth will be hotter because the land is more capable of reflecting sunlight than the ocean. If the middle of the Pacific Ocean faces the sun, then Africa and Europe will be frozen in cold darkness. In short, what will happen to the earth locked by the tides is still a mystery.