Since astronomers have discovered more than 5,000 exoplanets orbiting stars other than our Sun, many insist there must be life elsewhere in the cosmos. For those of us who believe in God, that isn’t really an issue. If there is life out there, God created it, but the Bible only speaks to our planet. However, the evidence is growing that our planet is more unique than most people realize. A “Goldilocks” planet is at the proper distance from its star so that the temperature is “just right” for liquid water to exist on the surface. Some exoplanets appear to be in the habitable zones of their stars, but many other factors must also be just right for life to exist there.
Most known exoplanets are like Jupiter, having no terrestrial surface. To support life, a planet must be the right size, have a stable orbit inside the habitable zone of a stable star, and have the right atmosphere. It must also have working plate tectonics and a large moon to maintain a stable axis tilt. To be just right for life to exist, a planet must also be in the habitable zone of its galaxy – not near the center, exposing it to lethal gamma-ray bursts.
Our Sun is a G spectral star, but only 9% of the stars in our galaxy are that type. M-class dwarf stars are the most common and long-lived stars, but they emit large amounts of radiation that would cook any life on their planets. Also, planets around such a star would become tidal-locked, with one side facing the star being excessively hot while the other remains cold.
Another star system requirement for life would be having outer planets large enough and in the correct position to sweep away asteroids and comets that would bombard an inner planet. To support life, a planet also needs a strong magnetic field to shield the surface from the star’s radiation and cosmic rays.
Our Earth is just right for life to exist. We are defining life as the biology books do: being able to move, breathe, respond to outside stimuli, and reproduce. Any conjecture about fire people or rock people is in science fiction – not scientific fact. The bottom line is that Earth is a special place created by God for a special purpose and is unique among all other objects in the cosmos.
— John N. Clayton © 2024
Reference: “Is Earth the Only Goldilocks Panet?” in Discover magazine, July/August 2024, pages 54 -57.