A habitable zone is the region around a star where an Earth-like planet can maintain liquid water on its surface. The habitable zone is the area that might potentially support life.
From the center of the earth to the far galaxies we find evidence that life arose from cosmic processes. The iron in our blood and the calcium in our bones were made inside stars. All silver and gold was forged by stars that exploded long ago.
The habitable zone first included the orbits of Venus to Mars, planets close enough to the sun for solar energy to make the chemistry of life, but not so close as to boil off water or break down the organic molecules on which life depends. The habitable zone may be larger than originally considered. The strong gravitational pull caused by large planets may produce enough energy to sufficiently heat the cores of orbiting moons. Life has proven itself tough here on Earth. It may be able to thrive in more extreme environments.
An imaginary spherical shell surrounding a star throughout which the surface temperatures of any planets present might be helpful to the origin and development of life as we know it. The single most crucial factor to the evolution of terrestrial life has been the ready availability of liquid water.
The "habitable zone" denotes the region around the star where we could in principle find liquid water, i.e. at a temperature between 0 and 100°C. It is also called the "Goldilocks Zone" (not too hot and not too cold). The figure shows the "habitable zone" in a star mass graph (in solar masses)./ semi-major axis (in astronomical units). Around more massive stars, the "habitable zone" is located in more distant regions. Copyright : Paris Observatory / UFE
