Wind, Water, and the Sand of Mars: Part I

Vast regions of the Northern Hemisphere of Mars

I am starting my regular reading of the dissertation, Wind, Water, and the Sand of Mars, written and researched by my friend Briony Horgan.

The name, The Sands of Mars, is inspired by a 1951 novel by Arthur C. Clarke. In the book, “an intrepid traveler reaches Mars to discover that it is populated by kangaroo-like aliens and that the low albedo regions are vast fields of rubbery plants.” Love it! Reminds me of pulp comics of the same era that would proclaim Venus’ thick clouds, presumed in error to be water instead of sulfur dioxide, hid vast oceans of water and species of gilled merpeople. I believe radio observations identified the chemical makeup of the clouds…

Whatever exists on these planets they will eventually be understood after planetary exploration, and certainly seems to always be vast. What more exotic word for the large stretches of the mystery filled unknowns is there?

In the specific case of Mars, the low albedo regions really are vast. The northern lowlands of Mars are smooth, stretching across nearly the entire northern hemisphere of Mars (blue region, figure), except for the rocky region that I believe contains Mons Olympus (red and white, figure) and a raised basin at the northern pole.

As Briony writes, “clear identification of the processes that did the resurfacing [smoothing the surface and removing cratering] and constraints on the timing of the resurfacing have both become apparent only in more recent mapping efforts (e.g., Tanaka et al., 2003). Without access to sample-based laboratory isotope dating methods, estimates of the ages of planetary surfaces are determined by comparing the size distribution and density of impact craters on the surface to [expected impact rates determined from the density and mechanics of asteroids in the solar system during the lifetime of Mars].”