Comment on What is this mystery rock that ‘appeared’ near the Opportunity rover on Mars? by Billy Joe

I am surprised that this discovery has not generated more discussion. There have been some who have observed that it is very much like some fungus on Earth.

This is almost exactly what you would expect to find in a silicon based life form that evolved to survive in a resource poor environment. Earlier on Mars there was water and a greenhouse gas, ammonia. When the magnetic field shielding was lost only things that could survive in the more hostile environment would survive. Silicon based forms using an ammonium solvent system could survive at lower temperature and higher radiation levels. Sulfur based reactions as we see in the deep ocean vents as energy sources here on earth would explain the concentrations of sulfur. Manganese and magnesium along with the abundant iron are logical building blocks. Silicon and other minerals that we associate with rocks make this life form much like a rock so it looks like a rock on the outside.

In a harsh environment it may take thousands of years for a life form to reach this size. Loss of fluid in the expanded form means that the time in this form must be limited. The more compact form is also better able to withstand radiation.