Mars and Earth pose partial solutions to the problem of life’s origins; each occupies opposite positions within our habitable zone. Although both are within the habitable zone, we as a species flourish on one rather than both. Approximately 4 billion years ago both planets seemingly possessed habitable environs. And, experts agree that both planets were wet and warm approximately 4 billion years ago. However within the next 500,000, 000 years, the planets’ evolutionary paths diverged to where we cannot readily grasp how life took a strong foothold here and not there.
Presently, Mars’ surface is dry, cold, radiation-beaten, but there has been a hint of methane from past data. Other than methane, scientific instruments did not detect other organic matter. Perhaps the methane emanates from under the surface—thus the exact source is undefined. While the majority of Martian meteorites are laden with organic molecules; some of which are not naturally found upon the Earth. It is certain that a mission to sample “true Martian crust” with tandem sample return will address the questions of organic material. Thus, further experimentation with Martian samples could address of possible sources of contamination and even the potential existence of “fossils.” So, the Alan Hills meteorite could serve as a template for why researchers either fooled themselves much as Schiaparelli did or the finding of a long-lost, Solar System cousin.
By contrasting the two planets for present habitability, a strong candidate emerges to explain the differences is the lack of a strong magnetic field for Mars. The Martian core is said to be cold, and inactive—there seems to be no active plate tectonics, either. Earth, however, possesses an active geology and a molten nickel/iron core. Mars may be smaller than the Earth, but the question of current habitability might further hinge upon the nature of their interiors. Does Mars possess enough internal, subsurface energy gradients to harbor life—in a manner of speaking? Life exists nominally when energy disequilibria allows a habitat to “form.” The finding of methane could be very simply explained by inorganic chemical processes or a subtlety of life not currently understood.