What would it be like to live on another planet? Colonizing space may seem like an impossible dream, but scientists are taking the first steps towards it. NASA’s Kepler Project examines stars in an attempt to find Earth-like planets. If we can find a planet that has a similar environment and climate to Earth's, our descendants might live and work in a completely different solar system. Astronomers believe that a planet must be a certain distance from a star in order to support life. If a planet is in the middle of this circumstellar habitable zone, its conditions may be just right for life. To find this habitable zone, astronomers use absolute value inequalities.
Goldilocks and the Three Zones
Since these potentially habitable planets are not too hot and not too cold, scientists call them “Goldilocks planets,” after the famous fairy tale. The farther away a planet is from the center of the zone, the less comfortable it will be. Distance matters, but direction doesn’t. Planets that are too close to a star are too hot. Water would only exist as steam, and life needs liquid water to survive. Planets that are too far from a star will be too cold for life. Any water that exists would be frozen solid. Not every Goldilocks planet could support human life, but the zone helps scientists spot potential new homes.
Space telescopes like the Hubble (shown above) can only give us basic details about these far-flung planets. Before we can seriously think about colonizing them, we’ll need more information. Eventually, we may need to send probes to take pictures of and gather data about these alien worlds. Because other solar systems are so far away, it could be thousands of years before humanity is ready to live on a new, distant planet. Astronomers, however, are not giving up hope.
Planets that are located in the habitable zone of the star Gliese 581 may be able to support life. Gliese 581’s habitable zone is a distance of about 0.015 light years from the star. If Gliese 581 is located approximately 22 light years away from Earth, what is the closest and farthest distance one of its habitable planets could be from Earth?