|Carbon Dioxide %||0.03||95.3|
|Carbon Monoxide %||-||0.07|
|Mass (kg)||6.0 x 1024||6.4 x 1023|
|Mean density (g/cm3)||5.52||3.94|
|Escape velocity (m/sec)||11200||5000|
|Average distance from Sun (AU)||1 (150 mill. Km)||1.52 (228 mill. Km)|
|Rotation period (hours)||23.93 (day)||24.62 (sol)|
|Revolution period (days)||365.26||686.98|
|Mean surface temperature (oC)||+15||(+20) -63 (-140)|
The question of the origin of life is one of the most fundamental questions in science. Of all other planets in our solar system, Mars is the most Earth-like and remains our best chance to find life, presumably microbial life, which is found in even the most extreme environments on Earth.
The study of Mars requires the full spectrum of investigative techniques known to science. It is by nature cross-disciplinary, which is reflected in our research team including institutes of physics, geology, chemistry and biology. Such collaboration is vital if we are to answer the questions of our origin and the possibilities of extraterrestrial life.
Vital to all forms of life on Earth is the presence of liquid water. The most recent orbital and ground observations of Mars by the Martian satellites and rovers on the surface have made astonishing discoveries of vast ancient oceans, riverbeds, lakes and flow channels. In addition, huge quantities of subsurface water (ice) have been discovered spanning the entire Martian surface. A challenge for simulation experiments is now to find under which conditions, how and where liquid water can be found on Mars.
Current models of early Mars (3.8 billion years ago) show it to be a warmer and wetter planet than today. They predict a higher atmospheric pressure at that time; temperatures above zero and oceans of liquid salt water. This resembles a hydrological cycle like the one known on Earth today and would cause a strong weathering environment. It could have been an environment supporting life.
Loss of a protective magnetic field and reduction of volcanic outgassing left the atmosphere unprotected to UV radiation and the solar wind erosion of light gasses and molecules like water, ammonia and methane, but leaving e.g. oxygen, nitrogen and carbon dioxide.
The surface of Mars today is a harsh place. The thin atmosphere (around 7 mbar of, mostly, CO2) does not act as the greenhouse we know from the Earth’s atmosphere. The heat flux of radiation coming from the sun heating the planet surface leaves as long-wave radiation freely to space. Only close to the surface, at low latitude locations, the temperature around noon can exceed zero. In this environment, organic matter will not survive UV radiation.
NASA’s Viking missions, though still under dispute, saw no signs of organic matter on the Martian surface. Furthermore, they indicated that the surface minerals were not only highly oxidized, but also highly oxidizing. Organic matter getting into contact with this surface material will decompose into CO2. It is still an open question what this oxidizing agent is.
Looking at Mars with a pair of binoculars or a telescope reveals a red planet. Fine red dust covers nearly all the planet surface and is dispersed in the lower atmosphere. From time to time storms entrain dust high into the atmosphere leaving the planet surface invisible for months. From the NASA Mars Exploration Rovers the chemical composition of the dust is known. However, the formation of the red colour coming from iron in oxidation state three is still unknown.
Modelling, laboratory work, wind tunnel and environmental chamber experiments are all tools used by the Mars Simulation Laboratory in projects to solve some of the challenging and important questions about surface processes on Mars.