Are We Alone in the Universe? A Response for both Theists and Atheists

Yesterday I created a survey on Twitter in which I asked respondents to indicate whether they believe in space aliens. Of the 2,357 respondents, 12% were theists who said “yes,” 20% were theists who said “no,” 43% were atheists who said “yes,” and 25% were atheists who said “no.”  In other words,  38% of theists said they believe in space aliens, while 67% of atheists said they believed in space aliens.


Several of the theists who responded positively indicated that they believed the earth is populated with “fallen angels” or “demons,” which is why they chose their answer.  Numerous atheists commented that I should have asked a probability question because they believe the probability of advanced life in the universe is high enough to warrant a positive answer.

What’s going on here? Aren’t atheists the same respondents who require theists to provide physical evidence to support our theistic positions? With zero physical evidence and only evidence in estimates such as the Drake equation with numerous unknowns, it seems many atheists are ready to accept possibilities of space aliens using methodologies that they reject when applied to God. In other words, though they have not physically seen space aliens (e.g., higher life forms from other planets), they acknowledge their probability. Though they also have not physically seen God, they refuse to acknowledge His probability.

Based on these findings, the intention of this blog is to offer the probability of the conditions required to sustain higher forms of life on earth, so people can consider the improbable planet in which we live and the statistically miraculous odds we’ve overcome. My hope is that atheists will apply their same methodology of using probabilities to the case for a higher, intentional, omnipotent and personal power.

The Ten Habitable Zones Required to Sustain Higher Life Forms

Hugh Ross points out in his book “Improbable Planet” that ongoing studies on the convergence of the habitable zones on the earth suggest that to sustain life, we could not modify any of their conditions. The habitable zones are as follows:

The liquid water habitable zone requires an appropriate level of atmospheric pressure and temperature. James Kasting found that a planet orbiting closer than 95% of the Earth’s distance from the sun would experience a runaway evaporation. The atmospheric pressure on Mars is too low, so a drop of water would evaporate in a second.

The ultraviolet habitable zone can neither be too strong not too weak to provide for life’s needs. The range for humans is exceptionally narrow, with some UV exposure necessary for vitamin D production, yet too much exposure can cause life-threatening melanoma and blindness. The liquid water and ultraviolet zones must overlap to make conditions right for life, ruling out 97% of most planetary systems for hosting life.

The photosynthetic habitable zone requires the following factors to fall within highly specific ranges: light intensity, ambient temperature, carbon dioxide concentration, seasonal variation and stability, mineral availability, liquid water quantity, and atmospheric humidity for land-based life. “Over the past 3.9 billion years, earth has undergone some dramatic variations in solar luminosity and spectral response, and these variations impacted all seven conditions for photosynthesis. Detailed models of the early history of the sun and earth (between 4.0 and 3.0 billion years ago) show that surface radiation levels were at least thousands times higher in the 2,000 to 3,000 angstrom wavelength range than current levels in this range” (Ross, 2016, p. 86).

The ozone habitable zone describes the distance from a star where an ozone shield can potentially form. The ozone in the earth’s stratosphere absorbs 97-99 percent of the sun’s short wavelength (2,000 to 3,150 angstrom), while allowing much of the longer wavelength (3,150 angstrom) of beneficial radiation to penetrate through to the earth’s surface (Ross, 2016). “For the level of stellar UV emission to be sufficiently stable for life’s sake, the host star’s mass much be virtually identical to the sun’s” (Ross, 2016, p. 87).

The earth further has an optimal rotation-rate habitable zone. “The faster the rotation rate, the more distant from the host star the water, UV, photosynthetic, and ozone habitable zones would be. Rotation rate would also impact (in different ways) the breadth of all these habitable zones” (Ross, 2016, p. 88).

The tilt of a planet’s rotation axis relative to its orbital axis determines the temperature of a planet’s surface. The higher the obliquity, the warmer the planet’s surface and the greater the obliquity, the further the water, UV, photosynthetic, and ozone habitable zones are pushed from the host star.

The distance range from a host star where the planet is near enough for life-essential radiation but far enough from tidal locking is referred to as the tidal habitable zone. “The tidal force a star exerts on a planet is inversely proportional to the fourth power of the distance between them. Thus, shrinking the distance by one half increases the tidal force by 16 times. If a planet orbits too close to its star, it becomes tidally locked (as the moon is tidally locked with earth), which means one hemisphere faces permanently toward its star” (Ross, 2016, p. 88-89).

The ninth zone is referred to as the atmosphere habitable zone. “The effective protection offered by a star’s atmosphere depends on the star’s mass and age, as well as on the density of the interstellar medium in which the star resides…The question for habitability is whether, at any given time in a star’s burning cycle, the star’s astrosphere covers the orbit of a planet with the just-right level of protection – neither too strong of a stellar wind nor too weak, all within a region overlapping the liquid water, UV, photosynthetic, and tidal habitable zones” (Ross, 2016, p. 91).

The final zone that scientists have discovered is the atmospheric electric field habitable zone. All planets with an atmosphere are also covered by an electric field. Venus, though it is of similar size and gravity as earth differs from earth in the strength of its electric field.Scientists recently discovered that Venus has a 10 volt electric field so powerful that it sucks oxygen right out of the atmosphere and into space. Earth, in contrast, has a weak electric field (less than 2 volts), which prevents the forceful escape of oxygen or ocean water (Steigerwald, 2016).

All of these habitable zones need to overlap perfectly to offer the existence of life other than the most primitive unicellular forms. According to Stanford and MIT physicists Dyson, Kleban, and Susskind, the appearance of life in the universe requires “statistically miraculous (but not impossible) events.” Of the 3,618 planets that have been discovered to date by astronomers, only one meets all ten habitable zone conditions: earth (Ross, 2018).

The Milky Way Galaxy’s Unique Characteristics

Our galaxy is also unique. Only 6% of non-Dwarf galaxies are spirals like the Milky Way, while the other 94% are either ellipticals or irregulars (Ross, 2018). Neither of the latter can sustain life. Star formation ceases in elliptical galaxies before the interstellar medium becomes enriched enough for heavy chemicals, while large irregular galaxies have active nuclei that spew out life-destroying radiation and small irregular galaxies have insufficient quantities of the heavy elements required to sustain life (Ross, 2018).

“One reason why life can exist in the Milky Way Galaxy is that the galaxy’s spiral arms are very stable, well separated, highly symmetrical, free of significant warps or bends, and relatively free of spurs and feathers. In part, these spiral arm conditions are possible because the MWG is dominated by yellow stars complemented by significant populations of blue stars. Our galaxy’s mass and size is fine-tuned for life. A smaller galaxy will have its spiral structure more seriously disrupted by encounters with other galaxies. A larger galaxy will possess a much larger supermassive black hole in its nucleus” (Ross, 2018, pp. 203).

“The MWG galaxy is like no other. The known galaxy that comes the closest is NGC 4945…However, x-ray observations reveal that the nucleus of NGC 4945 emits copious amounts of deadly radiation,  probably powered by a super-massive black hole very much larger than the MWG” (Ross, 2018, pp.  205).


In conclusion, my hope is that this short essay will convince those who consider probabilities when making decisions about issues for which they do not have physical evidence (e.g., space aliens) will apply their same approach to the question of whether God exists.

“The heavens declare the glory of God; the skies proclaim the work of His hands.” Psalm 19:1

“For since the creation of the world God’s invisible qualities – His eternal power and divine nature – have been clearly seen, being understood from what has been made, so that people are without excuse.” Romans 1:20

A secondary purpose of my article is to answer the question “Are we alone in the universe?” In my survey, I would have answered no, though the Bible does not offer us an answer to that question. It seems to me that the chances of higher forms of life someplace in the universe are minuscule, so until we have evidence to the contrary, I reject the notion.


Dyson, L., Kleban, M. & Susskind, L. (2002). Disturbing implications of a cosmological constant. JHEP -0210: 011. Accessed November 19, 2018 at

Ross, H. (2016). Improbable Planet. How Earth Became Humanity’s Home. Grand Rapids, MI: Baker Books.

Ross,  H. (2018). The Creator and the Cosmos: How the Latest Scientific Discoveries Reveal God. Covina, CA: Reasons to Believe.

Steigerwald, B. (2016). Electric wind can strip earth of potential oceans, atmospheres. NASA’s Goddard Space Flight Center. Accessed November 19, 2018 at


2 Replies to “Are We Alone in the Universe? A Response for both Theists and Atheists”

  1. Thank you for this thoughtful and well researched post! You help me think through my own faith more deeply and you help me understand the arguments of those who don’t believe, so I can more readily handle it with quiet peace. God bless you!

    Liked by 1 person

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