How the Earth's Unique Planetary Position Shows Us God's Design
I was watching a NOVA television show on a plane ride home the other day, and a scientist was asked if there was life on other planets. His answer began with, “I believe...,” and he continued to say that because we have evidence of billions and billions of planets in our universe, then the possibility is very likely that there is life on some of them. Now, he certainly has a right to his opinion. We all do. But he stated his answer so matter-of-factly. He has absolutely no evidence of life as we know it to exist, but he definitely assumes it is there. That is not science. We can take the observable facts we have and lay them all out, but what we do with them becomes at best hypothesis, or more often conjecture or belief. That is how science works, but too many times scientists err by stating their beliefs as fact.
What do we know about other planets? Well, not too many details, but we DO know a lot about what it takes to sustain life as we know it on a planet.
You see, the Earth is in a perfect position in the solar system and the galaxy to support life.
First, living things need water occurring naturally in its liquid form. That means a planet needs to be close enough to its sun so water doesn’t freeze (like the ice caps on Mars) and it cannot be too close to the sun so the water remains as vapor. If our Earth was just 5% closer to our sun, all the water would turn to gas, creating a massive greenhouse effect and burning up all life. And if it was 20% further away from the sun, all the water would become ice, carbon dioxide clouds would form, and not enough sunlight would reach the land.
A planet needs to be orbiting just the right size star. Our sun is a Spectral Type G2 dwarf main sequence star. It puts out just enough heat for the Earth. If it was smaller, the Earth would have to be closer to it for warmth, but then the sun’s gravitational pull would be so strong that it would prevent the Earth from rotating, causing it to have a constant day side with too much solar radiation and a constant night side – too cold and no light for photosynthesis.
A planet needs to be protected by gas giant planets within its solar system. These massive planets: Jupiter, Saturn, Uranus, and Neptune shield the inner planets from comets and other large meteor-like objects. The massive gravitational forces of the larger ones also help to keep Earth’s orbit stable.
A planet needs to have a nearly circular orbit so that its distance from the sun is constant enough to provide constant temperatures. Some planets, like Mercury, Mars, and the dwarf planet Pluto have notably elliptical orbits, sometimes being closer to the sun (where they experience more warmth) and then further from the sun (where they experience more cold).
A planet needs to have an oxygen rich atmosphere to provide for a temperate climate and protection from radiation. Of all the seventy-some known planetary bodies in our solar system (including planets and moons), scientists have figured out that only seven have atmospheres. And out of those seven, only Earth’s atmosphere is made of gases that can sustain life. And it is the only atmosphere that is transparent. That means if you were able to stand on the others like Venus, Jupiter, or the moon Titan (which you couldn’t because you would die), you would be in a constant fog, unable to see anything.
A planet needs to be orbited by a large moon. Our moon is about one-fourth the size of Earth. It’s bigger than the dwarf planet, Pluto. Its gravity drives our oceans’ tides and propels the hydrologic cycle, keeps the Earth’s tilted axis maintained, and provides gentle seasons which are good for life cycles.
A planet needs to have a magnetic field. This is a result of the Earth’s liquid iron core movement. The magnetic field helps to shelter Earth from damaging solar radiation. If the field was smaller, the radiation would strip away the Earth’s atmosphere.
A planet needs to have relatively thin crust with tectonic movement so that the crust recycles itself as new crust forms and old crust moves down into the Earth’s mantle. This regulates the planet’s temperature and recycles chemicals.
A planet needs to have a proper ratio of liquid bodies of water to land. This way there is a more moderate shift in global temperatures and again helps drive the water cycle.
A planet needs to have land – to be a terrestrial planet, unlike Jupiter or Saturn which are made up of gases.
A planet needs to have a moderate rate of rotation so that each portion of the Earth is heated and cooled appropriately by the sun…kind of like a rotisserie oven!
And a planet’s sun needs to be located at a proper spot within a galaxy so that there is not too much affect from the galaxy’s massive center with its large gravitational force, and excessive debris that would constantly fall onto the planet.
If you assign probabilities to all of these components, the likelihood of a planet having all of these features is one thousandth of a trillionth. Now there are likely hundreds of billions of stars out there, but one thousandth of a trillionth is even smaller than that. WE ARE RARE!
I’m not saying that we know that there are no other habitable planets. We don’t. But we DO know that this situation is extremely unique.
We are in the perfect spot in our solar system for life to exist. Close enough but not too far. And interestingly, the Earth has an unusual atmosphere that is transparent to radio waves and visible light, yet it blocks other wavelengths that can be harmful. A rare situation of a transparent atmosphere allows us to be able to see the heavens. Isn’t it interesting that the perfect features that support living things allow those living things to observe the universe we are in?? Are the conditions for habitability and scientific discovery related?
Though our Earth is not the center of the solar system, our galaxy, or likely even our universe, isn’t it amazing to know that we are perfectly placed in a unique position and with unique features so that we are able to live. Add to that the interesting phenomenon of observability being linked to habitability. What keeps us alive also allows to see what’s out there.
So here’s where the “I believe” part comes in. FULL DISCLOSURE: This next part isn’t science; it is my conclusion. Our omniscient and omnipotent God has placed us in the perfect spot and provided for us the sun, surrounding protective planets, and awesome galaxy location for our survival as well as the opportunity to observe the amazing Creation he has made for us so we can give Him the glory!