June 9, 2016
Two Super-Earths In One Planetary System: Incentive For Aliens To Become Space-Faring?

The discovery of two super-Earths in a single planetary system has produced an interesting view as to how alien life might develop. The two massive planets, Kepler-62e and -62f, are thought to be water worlds, their respective surfaces covered almost entirely or perhaps entirely with water. But if alien life emerged on one or both of the planets, scientists posit that this could possibly be an incentive for intelligent life to progress into space-faring beings.

The Daily Galaxy reports that two exoplanets were discovered in April in the habitable zone -- a region surrounding a stellar mass where life is believed to be sustainable -- around Kepler-62, which sports a train of five planets in all. A subsequent study has found the two planets, which orbit the type K star (Kepler-62 is a bit smaller and somewhat cooler than the Sun), to be super-Earths. Those same planets were modeled by the Harvard-Smithsonian Center for Astrophysics (CfA) and found to be water worlds, their surfaces reflecting no land, only worldwide oceans.

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Says Lisa Kaltenegger of the Max Planck Institute for Astronomy and the CfA, who is lead author of the study, "These planets are unlike anything in our solar system. They have endless oceans. There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy. Nonetheless, these worlds will still be beautiful, blue planets circling an orange star — and maybe life's inventiveness to get to a technology stage will surprise us."

Two worlds, both possibly harboring the ingredients with which to generate and possibly sustain alien life. Could such water worlds -- or at least one of them -- see the emergence not only of living organisms but the eventual evolution of intelligent life? And what if both worlds developed living organisms that evolved into intelligent beings? Could these organisms then be enticed to travel into space? The researchers posit that there just might be an incentive for just such an extra-planetary push.

Co-author and Harvard astronomer Dimitar Sasselov explains.

"Imagine looking through a telescope to see another world with life just a few million miles from your own. Or, having the capability to travel between them on a regular basis. I can't think of a more powerful motivation to become a space-faring society."
Some may think such an imaginative outlook to be just that -- fanciful imagination. But people on Earth have dreamed of space travel to other worlds, including our nearer neighboring planets Venus and Mars, not to mention the Moon, for centuries. Even in the absence of direct or empirical proof, the idea that alien life might be discovered on those worlds has been prevalent and even accepted -- by some -- at times (like when astronomer Percival Lowell popularized the idea that the "canals" on Mars -- those dark striations that criss-crossed the rusty orb's surface -- were proof that the Red Planet at least at one time sustained intelligent alien life). Given this, at least from a curiosity and exploratory perspective (and perhaps even a territorial expansion perspective), Sasselov's suggestion of alien life being motivated by a sister world with similar life-sustaining qualities seems quite plausible.

And yet, Kaltenegger's cautions -- encompassing the difficulty of intelligent life arising on planet of "endless oceans" -- are justified. Lack of metals and proper states or mediums in which to transform chemical molecules could be problematic for an emergent intelligence.

Kepler-62e is 60 percent larger than Earth, while Kepler-62f is about 40 percent larger (thus their designation of "super-Earths"). Neither is believed to have a significant atmosphere. Still, according to the computer models, Kepler-62e most likely has a heavier cloud layer than does Earth, given its proximity to its parent star. Kepler-62f likely would need an intensified greenhouse effect to remain a water world, because its distance from its star would make it icebound.

Sasselov notes that both super-Earths have the potential to be "life-friendly" and "would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future."

Sasselov and Kaltenegger's work was accepted for publication in The Astrophysical Journal.

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NASA's Kepler Mission announced in early May the verification of 1,284 new planets, with an additional 1,327 candidates that could potentially be verified as planets with further study. It is the largest number of verified planets released to date. The new collection brings the total of verified exoplanets to more than 3,200.

Nine of the new group of exoplanets are believed to orbit their respective stars in their habitable zones, bringing that exclusive number of worlds up to a total of 21 exoplanets. And as the number of exoplanets grow, so do the number of those that might be habitable and might be Earth-like. Some may be super-Earths. And with Earth-like -- or super-Earth-like -- conditions, alien life emerging, and perhaps even some day attaining space travel capability, remains at least a plausible possibility.