Some of those exoplanets found by NASA's Kepler spacecraft are teeming with life - at least in the fictional visits to them compiled by Kepler project scientist Steve Howell.
Howell, known to Tucsonans for his years of work as an astronomer on Kitt Peak and his lead guitar and harmonica with the AKA Blues Band, has detoured into science fiction in an attempt to "have a little more fun" with his scientific investigations of potentially habitable planets.
The release of the book "A Kepler's Dozen," edited by Howell and Kitt Peak telescope operator David Lee Summers, comes as the planet-hunting mission that inspired it has been idled, possibly for good.
Kepler was launched by NASA in 2009 with the explicit mission to point its telescope camera at stars in a discrete patch of the universe for signs of orbiting planets.
It has been successful.
Kepler has found more than 2,700 candidates and verified more than 100, including some in the habitable zones of their planetary systems - possibly having the Earth-like conditions necessary to support life forms we might recognize.
There are more planets to be found in the data already compiled, said Howell, even if NASA engineers are unable to stabilize the spacecraft. Two of its four reaction wheels have failed, and it can't hold its camera steady anymore.
The big problem with finding exoplanets, from a public interest point of view, is that it will be a long, long time before we can get close enough to see what's actually going on.
The closest Kepler candidate is "a few hundred light years away," Howell said.
It would take our fastest robotic spacecraft a few hundred years to reach it.
A human mission would be one of those no-return, multigenerational forays into deep space that is dreamt in science fiction, but not seriously contemplated.
So Howell and science-fiction author Summers decided to solicit fictional descriptions of planets none of us will ever see.
In their introduction, they compare the lag time between discovery and certainty to the late 1800s, after the orbits of Mars and Earth got close enough in 1877 for the telescopes of the day to observe what some interpreted as clouds, canals and vegetation on the red plant.
That spawned an explosion of science fiction by writers such as H.G. Wells and Edgar Rice Burroughs. It triggered generations of imaginations to ponder the existence of Martians - fantasies that lingered long after the canal theory had been debunked.
Astronomers haven't seen canals or vegetation on the Kepler candidates. They haven't, in fact, seen anything at all. Kepler measures light curves and assumes a planet has passed across the surface of a distant star when the light dims. Followup studies, many of them done on telescopes Howell once directed on Kitt Peak, rule out the presence of a binary star system.
Astronomers have been able to calculate the size, mass and orbit of the verified planets and their distance from the sun.
It's enough to declare some of them potentially habitable. The rate at which they are being discovered also makes it possible to posit that billions of habitable planets exist in our own Milky Way galaxy.
Astrobiologist Chris Impey of the University of Arizona thinks we'll get our first look at an exoplanet outside the Kepler field.
He's placing his bets on small, Earth-bound telescopes, like the MEarth project begun by Harvard-Smithsonian astronomer David Charbonneau. That network of small, robotic telescopes on Mount Hopkins in the Santa Rita Mountains south of Tucson is looking for planets in the nearby universe.
Charbonneau looks for planets orbiting nearby M-dwarf stars, which are smaller and cooler than our sun.
Planets orbiting M-stars could be a good deal closer to their sun and still be habitable.
Impey said other astronomers have proposed robotic missions to our closest stars. The Alpha Centauri system, for example, is only 4.3 light years away.
Tiny robots tethered to solar sails could theoretically achieve speeds of 1/10 the speed of light, making it possible to journey there in 40 to 50 years.
You would need a fleet of robots, Impey said, spaced out to relay information as they descend through the atmosphere of some theoretical, close-by, habitable planet.
In the meantime, you can simply read about what might be going on farther out in the cosmos, many years in the future.
The characters in "Kepler's Dozen" use warp drives and wormholes to get around the distance problem and genetic transformation to adapt to less than ideal conditions on the 13 Kepler planets featured in the collection of short stories.
Howell has fact-checked each story for fidelity to what is known about its host planet and each tale begins with a chart giving the planet's known characteristics.
Howell said he is saddened by the possible end of Kepler's mission, but elated by its overall impact.
"Chances are, we're not alone in the universe," he said. "And I think that's a pretty good discovery."
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More info about "A Kepler's Dozen" is online at: www.hadrosaur.com/ kepler.html
Contact reporter Tom Beal at email@example.com or 573-4158.