Tidally locked planets are those planets which, due to the action of tidal forces, are always turned to one side of their star. What would happen if a comet crashed into them? Scientists have found that this event could greatly affect their climate.
Comets, planets and water
What happens if a comet crashes into a planet that always has one side turned toward its star? Recently, three British scientists attempted to answer this question in two papers they published in scientific journals.
It should be said at once that the orbital speed or the movement of the planet in orbit will not be affected by a collision with a comet of normal size. The latter has too little mass for that. Nevertheless, the consequences of this event will be truly global.
In the distant past, bombardment of Earth and neighboring planets by comets was commonplace. They are thought to have brought 0.02% water to our planet. Although not much, this substance largely determines the climate of our world.
Subsequently, comet impacts have become rarer, but as the Podkamennaya Tunguska event in 1908 or the Shoemaker-Levy comet debris impacts in the 1990s have shown, these events remain likely. Plus, they can greatly affect the Earth’s climate.
Tidally locked planets
On the other hand, some other star systems have such a thing as tidally locked planets. In the simplest version of the explanation, they are worlds always turned to one side of their star. Actually they rotate around their own axis, but tidal forces so slow down this process that it is synchronized with the orbital motion, which leads to the fact that on one side of such a planet is eternal day and on the other — night.
All of this is especially important when it comes to red dwarfs. They make up 75% of all stars in the Sun’s neighborhood. Therefore, many Earth-like planets are expected to orbit around them. However, most of them are tidally locked, causing much debate about their climate.
Most scientists still agree that tidally locked planets have a chance at Earth-like conditions. But what happens to these exotic worlds if a comet crashes into them, of which there must be many in other systems as well.
Results of the study
That’s the question a new study has attempted to answer. First, the authors had a model developed of how a comet collides with a planet. They coupled it with a model of a tidally locked planet and saw what would happen.
And it turns out that even if the comet collides with the planet at right angles, it won’t reach the surface. It would collapse and explode directly into the atmosphere. And nevertheless, it will have a huge impact on the climate. Because this will release a large amount of heat and water.
All of this will lead to significant variations in temperature, pressure and humidity across the planet. They won’t calm down for 15 years either, so they may indeed cause global climate change.
According to phys.org
