Are We Alone in the Universe? By Amelia Dunlop Year 10
For over 50 years, scientists and astronomers have been trying to search the universe for any signs of extraterrestrial life outside Earth. Currently, Earth is the only known planet in the universe to host life forms, but with the help of advancing technology and research, scientists are slowly discovering more answers of whether we really are alone in the universe. The Habitable Zone In order for any life to exist, an exoplanet must be inside the habitable zone (or Goldilocks Zone) - the area around a star in which liquid water can be maintained on the surface of a rocky planet. The exoplanet must also have an atmosphere with the correct percentage and ratio of gases in the air for life to be sustained. To estimate whether a planet falls within the habitable zone, astronomers determine the distance between the exoplanet and the star, and the star’s size and energy output. Earth is within the habitable zone in our solar system, Venus being slightly within the inner edge and Mars being near the outer boundary. Exoplanets that orbit stars in other solar systems are sometimes too far away to determine if they have an atmosphere or whether the conditions allow them to support life. According to the Habitable Exoplanets Catalogue in March 2018, 53 exoplanets could have the capability to support and sustain life, and 13 of those exoplanets could have the potential to be habitable. Recently discovered rocky exoplanets Proxima Centauri b and c, and TRAPPIST-1 e, f and g, are all within the habitable zone of their red dwarf star and their size and position in their solar system resemble that of Earth’s.
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