Before Kepler 452b grabbed our attention with its near-Earth size orbit in the Goldilocks (liquid water) zone of a G2 sun like ours, the M dwarf stars were studied as possible candidates for other Earth twins, planets that might harbor life. The M dwarfs are ten times more numerous that G2 stars in the universe. In order to maintain liquid water, their planets would need to orbit a bit closer than we do to the sun. The M dwarfs’ planets should provide a fast wobble, orbiting in weeks or months. Planets in the Goldilocks zone should block out plenty of light as they pass by. They should be easy to find with NASA’s Transiting Exoplanet Survey Satellite, when it goes active in 2017.
The problem for life on M dwarf planets is that M dwarf suns are less luminous and more variable than G2s. Their xrays and ultraviolet
emissions could do damage to planets’ atmospheres. M dwarfs also live longer, which is good for evolution, but bad in that they take so long to form (hundreds of millions of years). That could boil off any planet’s water.
Meanwhile, closer to home, Jupiter’s moon Europa and Saturn’s moon Enceladus both contain vast oceans beneath volatile caps of ice. Science News March 2015 reported that the ocean beneath Enceladus’ icy crust has a high alkaline pH between 11 and 12. Its water-rock reactions could create molecular hydrogen, a possible energy source for life as found on Earth, along with handy organic compounds. However, Europa is closer, and it looks as if NASA will be checking it out.
Europa is remarkable for having twice as much water as Earth, 3 billion cubic kilometers. It will take us 6 years to get out there. Plans are to
launch in 2022 with 9 scientific instruments to check out the surface, sniffing and probing the cracked ice and surface waters as best NASA
can. The SLS rocket for the trip will be tested in 2018.
The possibility of finding signs (or remains) of life are higher than anywhere else in our solar system, except for Mars. Hot vents on the
ocean floor beneath the thick, craterless, fast changing icy surface could provide an environment suitable for primitive life. The moon’s
gravitational interaction with Jupiter and the other moons provides friction that could warm the ocean and urge life into existence.
Signs of such life could be found on the surface. The thick icy crust is not stable. The fact that ice circulates both up and down between the
surface and subsurface ocean has been noted. There is also a lake the size of Lake Erie on the crust, and liquid water has emerged from the Southern Hemisphere, as it has on Enceladus. Five hundred rem on the surface could cause trouble for electronics, however. Jupiter’s magnetic field is also a threat to the organic molecules of any surface life.
Since Jupiter’s radiation is so severe, heavy, expensive shielding is required. Therefore, the mission may orbit Jupiter, not Europa, and pass by the moon 45 times, as close as 15 miles. Electronics could survive 3 years. A landing on the –210 degree F surface of Europa to collect ice would need to be scouted. Heated legs on the lander might be a better idea to probe the ice than a javelin.
See Popular Science September 2015 for a detailed review. The article notes that warm inner oceans also exist on Ceres, Ganymede,
Callisto, Titan, Nimas, Triton and possibly Pluto, as well as Enceladus.
Author of The Archives of Varok
The View Beyond Earth (Book 1. Rewrite of A Place Beyond Man 1975)
The Webs of Varok (Book 2.)
Nautilus silver award 2013 YA
ForeWord finalist 2012 adult SF
The Alien Effect (Book 3.)
An Alien’s Quest–Reconciliation and Hope (Book 4. coming in 2015)
Excerpts, Synopses, Reviews, On Writing, Characters and More-
Other Book Reviews- www.goodreads.com/Cary_Neepe…
How the Hen House Turns- www.ladailypost.com
Complexity, Bio, Bibliography and Links- caryneeper.com
Astrobiology- astronaut.wpengine.com search:Who’s Out There