Exobiology: Twilight Zones and the Extreme

We covered Ocean Worlds in our last Exobiology Blog, but those planets are pretty easy to imagine life teeming in. However, we now move on to a more extreme world, an inexplicable enigma. Tidally Locked planets. These planets are, by definition, planets that are tidally locked. On one side of the planet is infinite daylight and the other side harbors a perpetual night. To be tidally locked, a planet’s rotation around its axis is completed at the same time as its revolution. As this may be confusing, I will give a simplified explanation.  

An axis of rotation is an imaginary line that the planet rotates around. A rotation is when an object rotates around its axis; a revolution is when an object rotates around another object. Earth’s rotation takes 24 hours. While a revolution around the sun takes 365 days. In order to be tidally locked our rotation and our revolution around the sun would have to be the same.

We don’t think about this often, but the moon is tidally locked around the Earth, that is why if there were any government secret agencies on the dark side of the moon, we would never know. Anyways, it’s still hard to picture life on such planets. Tidally locked planets leave a small margin of hope for actual life to exist in these places.

Although it may seem impossible, there is a chance of life on these planets. In a place called the Twilight Zone, where night and day meet. The idea was that the daylight and night side would meet in a place mild enough for liquid water to exist. Chicago Geophysicist, Dorian Abbot, was posed with this question and replied that twilight zones weren’t needed if one has the right atmosphere. A literal atmosphere, not the figurative one. Normally, an atmosphere would transfer heat all around the planet, and provide most of the planet with sustainable water. A simulation was run by Abbot and Koll, in which they determined that some exoplanets have the chance to hold the right atmosphere and provide enough heat to warm the night side.

We covered the air and water of this planet, but now we need to cover the land and life of it. The key players of this planet are gases and rain. Rain would be able to watch over the temperature levels of this planet, cooling the warmer parts and keeping carbon monoxide in control. Nitrogen helps prevent water loss by trapping it in the lower parts of the atmosphere.

Life on this planet would have to be completely adapted to facing colder and warmer parts of the planet. In order to do that the most important thing would be a type of skin that could protect against heat and cold. Luckily for us, we already have this in our life. A husky. Huskies are special in the way that they possess a double coat, a double-skinned coat that protects against heat and cold. This is one of the reasons that one should never cut the hair of a husky. Now that we know how our life would look like on this planet, the last question would be if we could inhabit it. We probably could, as our technology is more than capable of lasting in extreme conditions, but we as life on Planet Earth are not adapted to these conditions, including plants. So until we find plants capable of surviving these conditions, we won’t last long in tidally locked planets.