Illustration of the Solar System by NASA more>>   


To support life, a planet must not only be located in a just-right location within a just-right galaxy in a just-right universe, it must also be located in a just-right solar system that has all the finely-tuned features necessary to permit a planet to support life.  As discussed in this article, Planet Earth resides in such a just-right solar system.


Earth Resides in a Just-Right Solar System

As discussed in An Introduction and Summary of the Evidence for the Existence of God from Design here >>, Christian apologists maintain that the hundreds of finely-tuned features scientists have discovered in the universe (all of which are necessary for life to exist) are most reasonably explained by the existence of an intelligent, transcendent Designer (like the God described in the Bible) rather than mere chance as proposed by Naturalists.

Not only is Earth located in a just-right location within a just-right galaxy (here >>) in a just-right universe (here>>) that operates under the just-right laws of physics (here >>), Earth is also located in a just-right solar system.  In order for a planet like Earth to be capable of supporting life, the planet must reside in a just-right solar system with the hundreds of just-right features necessary to support life on the planet.  Earth resides in a just-right solar system which, among hundreds of other features, has:

Without all of the just-right features, Earth would not be capable of supporting life.


Earth Has a Just-Right Parent Star (the Sun)

In order for a planet to be capable of supporting life, it must orbit a star (called its parent star) and the parent star must have all 140+ finely-tuned features scientists have discovered a parent star must have in order for the orbiting planet to be able to support life. [See, Hugh Ross, The Creator and the Cosmos, pgs. 179-180, 189-190, 121-124 (2001)]  Earth’s parent star, the sun, has all 140+ characteristics, including the following two examples:

Example No. 1 — Earth’s Sun has a Just-Right Mass
A star more massive than the sun would burn too quickly and too erratically to support life on any planet in the solar system. If the sun were less massive, Earth would have to be closer to the sun in order to get enough heat to support life. But, if Earth was closer to the sun, the sun would exert so much gravitational force on the earth that it would cause Earth’s rotation period to slow down causing one side of the planet to get too cold and the other side to get too hot to support life.  

In comparison to Earth, the sun is very massive.  Indeed, if the sun were the size of a basketball, then, comparatively, the earth would be less than the size of a ball bearing used in a BB gun.  The sun has the just-right mass to allow it to provide Earth with a stable environment with sufficient amounts of light and heat that can support life.

size-of-sun-re-earth-basketball1The Size of the Sun Relative to Earth more>>
Image Credit:

Example No. 2 — Earth’s Sun is a Single Star
To support life, a planet must be able to provide sufficient heat and light.  Consequently, life is not possible on a planet that does not orbit any star because the planet would be too cold and too dark to support life.

Life is also not possible on a planet that orbits a binary star system or a multi-star system because the gravitational forces exerted on the planet by the additional stars would frequently pull the planet out of a temperature zone where life could exist. Notably, excluding white dwarfs, stars are in a binary and multi-star system. Earth orbits a single star system which is the only kind of star system that can support life. [See, Hugh Ross, “Search for Planets Draws a Blank” (]


Earth Has a Just-Right Sister Planet (Jupiter)

Jupiter is the just-right size, the just-right distance from Earth, the just-right mass and is in the just-right location to shield Earth from being regularly bombarded with comets and asteroids deadly to life. 

Jupiter is 40 light minutes away from Earth (i.e., it takes 40 minutes for light, which travels at the speed of 186,000 miles per second, to travel from Jupiter to Earth.  Jupiter is also very massive in comparison to Earth — Jupiter could hold 100 planets the size of Earth.   Jupiter also outweighs the combined total all of the other planets in the entire solar system by 2 ½ times.

jupiter_earth_moon_comparison1Relative Sizes of Jupiter, Earth and the Moon >>
Image Credit:

Scientists estimate that without Jupiter being the size it is and positioned where it is in relation to the earth, comets and asteroids would strike Earth a thousand times more often than they do. One large impact (or several smaller impacts) would kill off all advanced life on Earth either from the initial blast or from the amount of debris ejected into the atmosphere which would subsequently prevent sufficient amounts of light and heat from reaching the surface of the earth. Without sufficient light and heat, Earth would quickly become too cold to support life.

[NOTE: Scientists believe a large asteroid or comet (about 6 miles across) impacted the Gulf of Mexico leaving an impact crater about 110 mile across and 12 miles deep.  The tremendous devastation caused by the impact is believed to have resulted in the extinction of about 3/4 of all species living on Earth, including the dinosaurs.]

Although Jupiter’s size does a good job of shielding Earth from being impacted by asteroids and comet impacts, if Jupiter was any more massive that it is or any closer to Earth than it is, Jupiter’s gravitational force would pull Earth out of its stable orbit around the sun.  If that were to happen, Earth would be subjected to dramatic temperature variations, unstable atmospheres, high velocity winds and a host of other problems associated with unstable orbits, all of which are deadly to life on Earth.

Jupiter is the just-right size, the just-right distance, the just-right mass and is in the just-right location to support and protect life, especially advanced life, on Planet Earth.


Earth Has a Just-Right Moon


             Full Moon  here >>     Image Credit:NASA/Sean Smith

The moon plays many important roles with respect to Earth’s ability to support life. For example, whereas the axial tilts of other planets in the solar system have greatly varied throughout their histories, the gravitational force exerted on Earth by the moon has kept Earth’s axial tilt at approximately 23.5° which is optimal for life on the planet because that degree of tilt provides Earth with moderate seasons and prevents extreme temperatures anywhere on the planet.

The gravitational force exerted by the moon also keeps Earth from rotating too quickly which is important to support life on the planet.  If the earth rotated too quickly, its inhabitants would be subjected to high velocity winds deadly to life. 

Because Earth’s axial tilt and Earth’s rotation period are just-right, Earth has a stable environment, with a steady climate and regularly occurring seasons. The gravitational force exerted by the moon on Earth’s oceans also causes the oceans to ebb and flow which not only keeps Earth’s shorelines rich in nutrients, but prevents the oceans from becoming stagnant and polluted.

Without the moon, or if the moon was not the just-right mass or was not the just-right distance from Earth, Earth would not have stable seasons, it would be subjected to unrelenting hurricane-like weather as well as deadly temperature fluctuations. Additionally, Earth’s shorelines would be extremely polluted and life-essential nutrients formed in the oceans would not regularly migrate to the shorelines of Earth’s continents for consumption by people, animals and plant life which are dependent on those nutrients for their survival. 

Earth has a just-right moon to support life on the planet.



Because Earth resides in a just-right solar system with all the just-right features necessary for life to exist on the planet (including a just-right parent star, a just-right sister star and a just-right moon) life can exist and thrive on the planet. 

As referenced in this article and other articles on this website, the exquisite precision and chance calculations involved with all of the numerous finely-tuned design features necessary for life to exist in the universe are astronomical — numbers like 1060 (the mass density of the universe here >>), 10100 (the weak nuclear force here >>), and 10120 (the energy density of the universe here >>). 

The incomprehensibility of this kind of fine-tuning is more fully appreciated when one considers that there are only about 1025 grains of sand on all the beaches on Planet Earth.  This means that fine-tuning in the order of 1060 is like saying not a single grain of sand could be added to or removed from one beach on Planet Earth without causing the entire planet to be incapable of supporting life. Indeed, this illustration is tremendously understated because it assumes a change in one part in about 1025 (the estimated number of grains of sand on Earth) whereas the total mass density of the universe must be fined-tuned to within one part in 1060 and dark energy must be fined tuned to 10120, which are substantially greater numbers than 1025.When one looks at the probability calculations for life to have developed by chance, the numbers are even more incomprehensible.  For example, just the chance of amino acids randomly coming together to form the 2,000 enzymes which are essential for life to exist has been calculated as only one chance in 1040,000 here >>. Taking all of the fine-tuned features that must exist in a life-permitting universe into consideration, Donald Page of Princeton’s Institute for Advanced Science has calculated that the odds of the universe developing by blind, random chance into a form suitable for life as one chance in 10,000,000,000124 here >>,  which is a number so large that it exceeds all imagination. [Ravi Zacharias, The End of Reason, pg. 35 (2008)]

As summed up by secular scientist, Fred Hoyle (a well-respected English astronomer who was primarily known for his contribution to the theory of stellar nucleosynthesis) —

A commonsense interpretation of the facts suggests that a super intellect has monkeyed with physics, as well as chemistry and biology, and that there are no blind forces worth speaking about in nature. The numbers one calculates from the facts seem to me so overwhelming as to put this conclusion almost beyond question. (Emphasis added). [Fred Hoyle, “The Universe: Past and Present Reflections,” Annual Review of Astronomy and Astrophysics 20, pg. 16 (1982)]

Consequently, Christian apologists maintain there simply is no compelling reason why belief in an intelligent designer (rather than random chance) is not a rational explanation, if not the most rational explanation, for the existence of the universe and life in the universe.  This is especially true when one considers the multiple independent lines of argumentation for God’s existence including:

  • God’s existence best explains why anything exists rather than nothing (an argument for the existence of a “first uncaused cause”) here >>
  • God’s existence best explains the cause of the universe coming into existence (the Kalam Cosmological Argument) here >>
  • God’s existence best explains all the mind-boggling, just-right design features scientists have discovered throughout the universe which make it possible for life to exist in the universe (the Intelligent Design aka Teleological Argument) here >>
  • God’s existence best explains the existence of objective morality
  • God’s existence best explains man’s search for, and innate belief in, meaning, purpose and significance

© 2012 by Andrina G. Hanson
Published: July 19, 2013 / Last Updated: October 10, 2017



Kenneth D. Boa and Robert M. Bowman, 20 Compelling Evidences That God Exists: Discover Why Believing In God Makes so Much Sense(River Oak Publishing, 2002)

William Lane Craig, On Guard: Defending Your Faith with Reason and Precision(Colorado Springs, CO: David C. Cook; New Edition, 2010)

Hugh Ross, The Creator and the Cosmos: How the Greatest Scientific Discoveries of the Century Reveal God(Navpress; 2 edition, 1995)

Hugh Ross, Why the Universe Is the Way It Is(Baker Books, 2008)

R.C. Sproul, Not a Chance: The Myth of Chance in Modern Science and Cosmology(Baker Books, 1999)

Lee Strobel, The Case For A Creator: A Journalist Investigates Scientific Evidence That Points Toward God (Strobel, Lee) (Zondervan, 2005)


Slideshow Photo: This illustration of the Solar System was downloaded from the NASA/JPL website. (Back to article >>)
Illustration of the Relative Sizes of the Sun and Earth:  This illustration depicts the relative size between the Sun and Planet Earth was downloaded from website. (Back to article >>)

Relative Sizes of Jupiter, Earth and the Moon This image shows a size comparison between Earth and Jupiter.  The image was downloaded from which states the image is in the public domain because it was solely created by NASA. (Back to article >>)
Picture of a Full Moon This photo was taken by NASA/Sean Smith and downloaded from the website. (Back to article >>)

Tags: axial tilt, axis, Christian, Earth, design, fine tuned design, finely tuned design, God, Hugh Ross, intelligent design, intelligent designer, Jupiter, just right, just-right, moon, parent star, solar system, sun