When looking at the starry sky, have you ever thought that the Earth may not be the only place in our solar system that sustains life? To find out this, people never stop exploring the outer space and life beyond Earth:
The first message that human sent to extraterrestrial creatures is known as Arecibo message, which was used to celebrate the re-establishment of the Arecibo radio telescope in 1974. In 2014, NASA outlined its plan of searching life outside of the Earth in the next decades.
Arecibo message. The first message that human sent to outer space. Image by Wikimedia Commons. Link: https://commons.wikimedia.org/wiki/Category:Arecibo_message#/media/File:Arecibo_message.png
However, the universe is bigger than we can imagine. To narrow down the searching range, we need to know what kinds of conditions that a planet or moon is required to sustain life. According to Dr. Dave Brain, there are three conditions of sustaining life in a planet or moon.
Three Conditions
Energy On the Earth, life can obtain energy directly from the sun and creatures live underground or deep in the ocean can get energy from their unique chemical reactions. In our solar system, it is easy to find planets and moons that provide energy sources to life.
Food All the nourishments that life on the Earth requires are formed by only six chemical elements: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur. These elements can be found on most planets and moons.
Liquid Water Liquid water is the hardest condition to meet. Having liquid water is not simple as it seems to be for a planet or moon. It relates to many other factors of the planet or moon, such as atmosphere and magnetic field.
Ted Talk. What a planet needs to sustain life by Dave Brain. Link: https://www.youtube.com/watch?v=9RTkZaX1cH0
Possible Planets and Moons
Dr. James Green, NASA’s director of planetary science, gave his guess on possible planets and moons in the solar system that possibly fit the three conditions above and they are Mars, Titan, Europa and Enceladus. Considering the distance from the Earth, Mars is the most appealing one.
Mars On September 28, 2015, NASA confirmed that there is liquid water exists on Mars. Adding with the pervious findings that scientists observed and Curiosity, NASA’s Mars Rover provided, Mars became the first planet beside the Earth that meets the three conditions of life. On October 11, 2016, current American President Barack Obama set the goal of sending people to Mars by 2030s. New searches on Mars are ongoing and maybe one day, we can find life beyond Earth on Mars.
Ted Talk. 3 moons and a planet that could have alien life by James Green. Link: https://www.youtube.com/watch?v=P1sbSJK1LiI
-Yiwei Liu
