One of the operating principles of physical cosmology, indeed a central tenet of the materialist atheistic position, is the Copernican principle, or the notion that the Earth is not in a central, specially favored position in the universe. One of the great champions of this notion was Carl Sagan, who saw earth not as privileged, but one of billions of possible worlds that contained life in the vast Cosmos, a mere pale blue dot in the darkness of space.
Recent facts however suggest that this notion is at best premature, if not all together wrong. Despite the fact that we have catalogued over 300 exo-planets, none of them appears to be anything like earth in terms of its ability to sustain life. And we are discovering that our planet sits in a sweet spot/Goldie Locks zone in terms of its position in the universe, the galaxy, the solar system, and in terms of its geological make-up. We are in fact not ‘ordinary’ at all in cosmological terms, but very privileged.
Now comes one more bit of evidence to add to this notion. Scientist have found that occupying a habitable zone is even more complex than previously thought:
Astronomers hunting for planets orbiting nearby stars similar to the sun are looking for signs of rocky, Earth-like planets in a “habitable” zone, where conditions such as temperature and liquid water remain stable enough to support life.
New findings from computer modeling indicate that some of those exoplanets might fluctuate between being habitable and being inhospitable to life because of the forces exerted by giant neighbors with eccentric orbits.
A lone Earth-like, or terrestrial, planet with a generally circular orbit toward the inner edge of its sun’s habitable zone could be expected to remain within that zone, said Rory Barnes, a University of Washington postdoctoral researcher in astronomy. Adding a planet comparable to Jupiter to the system, however, and giving it a highly elliptical orbit — similar to most exoplanets discovered so far — can cause strange things to happen to the smaller planet, possibly causing it to cycle between habitable and uninhabitable conditions.
What is even more interesting is that having a large gas like planet in one’s neighborhood is actually beneficial, provided they are stable in correctly placed orbits – they effectively deflect and absorb objects coming in from the edges of the solar system that could bombard earth. But if the orbits vary widely, the potential effect is disastrous for inner planet – again we are privileged to not have that be the case in our solar system, an apparently rare condition.
So we are less a pale blue dot in the universe as we are a rare gem of great value; someone seems to want us here.