What makes a planet habitable and gives it the ability to sustain life? In 1953, Hubertus Strughold proposed the idea of a habitable zone, which is a region outside of the sun that allows for atmospheric pressure and the ability to support liquid water. The distances of the regions from their sun can vary in different solar systems, but are based off of position in the solar system and the amount of radiation given off from the sun. The habitable …show more content…
On the other hand, the outer boundary of the habitable zone is the distance where not only water freezes, but so does carbon dioxide. The amount of carbon dioxide that is found in a planets atmosphere depends on the distance from the sun, but is still vital to sustain life because carbon dioxide is needed for the greenhouse cycle that warms planets and creates conditions where liquid water can exist. In the inner boundary, CO2 is an extremely light gas, but near the outer boundary carbon dioxide is a solid. Due to the state of carbon dioxide, given relative positions in the habitable zone, Earth-like planets close to the inner edge are expected to have a water-rich atmosphere (Earth), while planets farther out in the habitable zone have a greater abundance of carbon dioxide in the atmosphere and are more likely to contain frozen water rather than liquid