Lun 29 Dic 2014
On Earth, it is assumed that life started in the water, after all, we do most chemical reactions in some liquid solution or other because it allows molecules to move about, meet each other and react. Water, being the most abundant solvent, is the best candidate to be the medium where the chemical reactions that lead to life started.
Initial life forms were drifters, that is, the currents, waves, tides and storms were the ones that moved them from one place to another, including dry land. Populating dry land requires several abilities. As an organism it needs to survive. As a species, it needs to reproduce. Each of these requirements can be broken down into further abilities which would be very hard to acquire all at once.
Out of the mechanisms that transport drifters, tides are the only one that happens with predictable regularity. Any living water organism thrown on dry land by a storm is, most likely, doomed. Unless it somehow developed while still in the water the means not only to survive but to reproduce, its unexpected fall on dry land is the end of the story for its genetic line.
Tides are the only mechanism that provide a means for drifting water organisms to experience living in a dry environment and return to the water to reproduce and pass on the traits that allowed it to survive. As the process is repeated over and over, more and more abilities can be acquired and passed on to later generations until reproduction itself can happen on a dry environment. On Earth, some species like frogs have never developed the ability to reproduce on dry land. Others either provide a wet environment, be it external such as an egg or internal like mammals, where the new organism can develop.
Can life prosper on land in either of the planets in the novel? Mother and Heaven face each other showing the very same face much like the Moon does to Earth but in their case, the effect is mutual. This is called gravitational or tidal locking. Wikipedia has a good explanation for the process. When a body is gravitationally locked to another, it has almost no tides. It would still have small tides from its sun but they would be irrelevant to our discussion.
Thus, could have land life prospered in Mother and Heaven? It might but, admittedly, the chances would have been much smaller. Gravitational locking is a process that occurs over a long time and is not simultaneous, the smaller body falls first to the influence of its larger neighbor. Life might have settled dry land on the larger planet while it wasn’t still locked to its neighbor. Life might also develop along rivers that grow and fade with rain. Most tropical areas on Earth have wet seasons when rain falls regularly every afternoon as the atmosphere cools down and cannot hold that much water vapour in it. These showers are not as reliable as tides, but they might serve.
So, it might be less likely than on Earth, but life on either Mother on Heaven cannot be ruled out.
As I mentioned in the afterword, initially I thought the planets might have been populated by space travelers, hibernation being a trait genetically introduced on the original travelers to withstand the long travel times. Over time, the sleeping pattern adapted to the day/night cycle of Heaven and Mother, but that seemed a pointless and much abused story line so I dropped it.