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Can There be Life Outside Earth?

  • Brandon Lie
  • May 9
  • 3 min read

Whether you’re a curious child stargazing at the infinite vastness of space, or an adult fixated on the unknown, I’m sure this question has popped up in your mind at some point. To this day, even the most brilliant of scientists do not have the answer. Of course, we have not yet discovered life outside our planet, but that doesn’t mean it doesn’t exist. In fact, some planets in our universe are possibly habitable, meaning that they could sustain life. 


The most important factor in determining if a planet is habitable is to determine whether it is in the “habitable zone” or “goldilocks zone” of its star. This zone is where the temperature of a planet is not too hot and not too cold for liquid water to exist, the elixir of life. These earth-like planets are called exoplanets. 


An example of these exoplanets is TRAPPIST-1e, a world located 39 light-years away (which means it would take light 39 years to travel from here to there). TRAPPIST-1e is a relatively small planet, only 69% of the Earth's mass, and one rotational cycle around its sun takes only 6.1 earth days (Nordseth, 2024). Despite its size, its shape and density suggests a rocky terrain, similar to Earth’s. Even though the planet is close to its sun, due to the star’s low energy output, the world could contain a stable climate. Studies have actually shown that TRAPPIST-1e may hold even more water than our Earth’s oceans (Wolf, 2017). 


A planet so far away from us that it takes 39 years for light to get there doesn’t seem promising, but we don’t even need to look that far. In fact, we need only go to the next planet in our solar system, Mars. Although Mars doesn’t currently hold any life, there is reason to believe that it once did. 


Scientists have discovered that Mars’s atmosphere holds a trace amount of water vapour. Its polar regions are covered in ice and permafrost is found in the red planet's subsurface. (Mars Education, Developing the Next Generation of Explorers, n.d.).


Of course, just because a planet is hospitable, does not mean it holds life. But just because we have not spotted any creatures on other planets it does not mean it is not possible. We just have to look smaller. 


Tardigrades, or more commonly known as Water Bears, have been discovered to be able to survive the harshness of space. They were first discovered in 1773 by German zoologist Johann August Ephraim Goeze while investigating moss samples. These microscopic creatures can adapt to the microgravity, extremely low temperatures, and the incredible levels of radiation found in space. They do this by entering a state of suspended animation. 


I’m sure you’ve heard of how the superhero Captain America got trapped in ice, where the temperatures were so low that his body did not age. Well, water bears do something similar. When they are outside water, they go into a state of suspended animation where they dry up and can survive years without conventional living conditions (Weisberger & Ghose, 2024).  When they find themselves in water again, they revive themselves and carry on with their lives.


Ultimately, the fact that we haven’t found life outside of Earth, is not a reason to give up our search. Nearly all of the most influential scientific discoveries have been made because we never stopped looking, and that proves that we should never stop exploring the unknown.



References


Nordseth, A. (2024, July 31). 6 Exoplanets in our Universe That Could Support Life Other Than Earth. Discover Magazine. https://www.discovermagazine.com/the-sciences/6-exoplanets-in-our-universe-that-could-support-life-other-than-earth


 TED-Ed. (2012, March 12). Why can’t we see evidence of alien life? [Video]. YouTube. 


Imster, E., & Imster, E. (2021, June 10). EarthSky | Why NASA sent tiny water bears 

into space. EarthSky | Updates on Your Cosmos and World. https://earthsky.org/space/water-bears-tardigrades-into-space-iss-experiment/


Weisberger, M., & Ghose, T. (2024, September 12). Tardigrades: Facts about one of the hardiest animals on Earth, and beyond. livescience.com. https://www.livescience.com/57985-tardigrade-facts.html

Wolf, E. T. (2017). Assessing the habitability of the TRAPPIST-1 system using a 3D climate model. The Astrophysical Journal Letters, 839(1), L1. https://doi.org/10.3847/2041-8213/aa693a



 
 
 

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