Is Methane on Mars Evidence of Life?

Anyone who stays on top of new discoveries outside of our home planet will tell you that every answer we get brings us more questions. Every time we think we have something figured out, something totally unexpected hit us out of nowhere. The more we figure out, the more we realize we don't really know anything. One recent discovery has added fuel and even more confusion to a very heated debate that has gone on throughout history: "Are we alone?"

Recently small amounts of methane were found on Mars. Why is this significant? It could possibly be evidence that there is, or was at one time, life on Mars. This would have a profound impact on almost every aspect of our lives. History, astronomy, biology, even religion would be changed forever.

Methane is a gas that is fairly common throughout the universe and even our own solar system. It has many sources. Some are biological and some are geological. Telling where exactly it comes from is nearly impossible unless you are in the perfect place at the perfect time. There are, however, a few things that can help us make an educated guess.

Several places in our solar system, we find methane that is produced from geological activity. Iron oxide, which contributes to the red color of the Martian surface, releases methane as it is converted to certain minerals. This could be occurring where heat from active vulcanism, water and the iron oxide are coming together with the carbon dioxide-rich atmosphere. In all our years of observing Mars, we have not seen any evidence of current volcanic activity.

Another possible geological source is from iron oxidizing. Mars has plenty of iron in its crust. As iron oxidizes, or rusts, it gives off some methane. However, most of Mars' iron is already in the form of iron oxide. With that much methane being given off, it should be abundant and it is not.

Geological sources are not the only sources for methane, though. Some of the earliest and most primitive life on Earth were microbes that produced methane. Although we haven't found actual life on Mars yet, it stands to reason that any life forms we were to find, would be very primitive, similar to that of Earth's early history. Since life does not seem to be abundant on Mars, the small amounts that would be possible would only release a trickle into the atmosphere, similar to the small amounts that were discovered.

On Earth, microorganisms live deep in the crust. One place in South Africa, they survive almost 2 miles deep by using oxygen and hydrogen formed when radioactivity breaks water molecules apart. Then, using the oxygen and hydrogen as well as naturally occurring carbon, theses pockets of life could survive for billions of years deep in the crust. The Martian geology is not totally different from ours making this a possibility, especially around the pockets of water discovered deep in its crust. This would create a constant, though small release of methane that would work its way to the surface.

Although we have not found actual life on Mars, the evidence has always pointed to the possibility of it being there in some form. The recent discovery of methane helps to reinforce the other evidence found in the past. Someday, if we keep looking, maybe we will find a last stronghold of life from Mars' ancient oceans.