Thursday, October 31, 2013

The impossible planet

Artist's reconstruction of Kepler-78b near its sun.
Image source.
Astronomers are constantly scanning the skies for earth-like planets around other stars (exoplanets) to determine how unique our own planet is.  During this search, an earth-sized planet was discovered orbiting very closely and quickly around its star.  Further investigation of the data found that the planet, called Kepler-78b, is a bit less than twice the mass of earth, and has roughly the same density, leading the researchers to conclude that it is primarily composed of iron and rock, largely molten.

This created a problem for them, however.  According to current models of planet formation, a planet like this could not have formed so close to this star, as the star would have been larger than the orbit of the planet at the time of its formation.  They say it also could not have formed at a distance and moved closer, because the inward momentum would have plunged it directly into the star rather than forming a semi-stable orbit.  They have yet to devise an explanation, labeling it a mystery planet for now.

It is important to note that the planet itself was not directly observed.  Exoplanets are usually inferred from their gravitational and eclipsing effects on the stars they orbit.  While there are some assumptions and interpretations involved in this method, I don't think it is worth attacking, so I will assume for now that it is accurate.

The unexpected proximity of this planet to its star is somewhat common among exoplanet study.  Typically, planets closer in size to Jupiter are found orbiting a star on a very tight path, partially because larger planets are easier to detect.  Their proximity is often attributed to migration from a more distant orbit, an explanation that apparently does not suit Kepler-78b.  Creationists claim that strange planet orbits are much more readily explained by recent special creation instead of complex migration movements.  Of course, such a possibility cannot be considered by the naturalistic worldview, so adherents to the Big Bang model of universal origins will continue to view the most popular secular theory of solar system formation as the most likely explanation.

As with dinosaurs, the existence of exoplanets may initially trouble some creationists, but this need not be the case.  Despite the long association of other planets with extraterrestrial life, alien lifeforms remain strictly absent from our observations.  I acknowledge that extraterrestrial life is not directly discounted in the Bible, but various theological reasons make it unlikely.  Humans and our planet are of central focus in the biblical narrative.  Earth is described as being created before any other heavenly bodies, and it was here that the Son of God was incarnated, died, and resurrected.  I find it difficult to believe that such a sacrifice could take place several times on other planets.  Additionally, Adam and Eve were given dominion over all of creation, and all of creation was cursed at their fall.  It would make no sense if extraterrestrial life forms, particularly intelligent ones, were cursed for our sin, as Adam and Eve could not have had dominion over them.  If the alien life was therefore not cursed, then other theological difficulties arise.  So, while it is not unbiblical to search for extraterrestrial life, I see the massive amounts of money, time, and effort spent looking for it as a waste.

Regardless of my personal views on the search for alien life, I appreciate the amount of knowledge of our universe that such searches have acquired.  The vastness and intricacy of the cosmos continually reflects the majesty and infinitude of our God, so I will rejoice.

"The heavens declare the glory of God; the skies proclaim the work of his hands.  Day after day they pour forth speech; night after night they reveal knowledge."  -Psalm 19:1-2

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