Looking for exoplanets that might harbor life and being realistic about the effort, both come clear in Elizabeth Tasker’s book entitled “The Planet Factory–Exoplanets and the Search for a Second Earth, Bloomsburb
Publishing Plc, New York and London, 2017. Another good source of information can be found at NASA’s Exoplanet Archive at exoplanetarchive.ipac.caltech.edu.
The problem of time’s length and the trauma that a young planet can sustain make the search for habitable exoplanets similar to finding needles in haystacks. One example is the history of Mars.
Mars is very small because Jupiter cruised into our inner solar system in the early years “gathering and scattering planetesimals.” Mars has a nice circular orbit, 10% as compared to Earth’s 1%, which means any collisions with early solid objects would collide slowly if at all.
Mars is also within the maximum temperate zone (.84 to 1.7 au) of our solar system, and it probably had surface water 3.8 billion years ago. However, it was apparently too cold to experience plate tectonics, as Earth has. Since it has a larger surface area for its volume, its interior heat was lost rapidly, which stopped the convection flow
between the planet’s mantle and core.
Four billion years ago a moon-size object hit Mars, which didn’t help matters. This tilted the surface so the northern surface was lower than the south, and thinner. Heat increased and the magnetic field was lost
in the north.
The sun has also been a nuisance for life that might have started on Mars. On March 8, 2015, NASA’s MAVEN spotted an impact on Mars of the sun’s coronal mass. The solar wind, that usually depletes Mars of gas at
100 grams per second, was bumped by a factor of ten. Not nice.
One thing becomes quite clear as I struggle through the too-clever jargon and verbiage of Elizabeth Tasker’s book “The Planet Factory”
(Bloombury Sagin, London and New York 2017): Our Milky Way seems to be filled with a wide variety of exoplanets orbiting all kinds of suns–so far none of which come close to being habitable.
Our early sun was probably more excitable. It led to Mars losing its magnetic field and eventually its “thicker, warm atmosphere.” Planet Earth has had better luck, time and time again according to Ward and
Brownlee’s 2000 classic: “Rare Earth–Why Complex Life is Uncommon in the Universe.”
It took a long list of lucky happenstances to produce the habitable planet Earth. Most of us are not going anywhere else, so we’d better take care of it: its precious gifts of potable water and edible flora and fauna–so astoundingly unlike our exoplanet neighbors.
Author of The Archives of Varok
The View Beyond Earth (Book 1.)
The Webs of Varok (Book 2.)
Nautilus Silver Award 2013 YA
ForeWord IBPA finalist 2012 adult SF
The Alien Effect (Book 3.)
An Alien’s Quest (Book 4. Released Nov.21, 2016)
Excerpts, Synopses, Reviews, On Writing, Characters and More-
Reviews of significant books- www.goodreads.com/Cary_Neeper
How the Hen House Turns- www.ladailypost.com
Complexity, Bio, Bibliography and Links- caryneeper.com
Astrobiology- astronaut.com search:Who’s Out There