So you may well be wondering how Mars could be the ancestral home for life here on Earth. Well, it's a theory and nothing more, but it does have some evidence backing the case, and that's more than enough to pique some interest and write about.
Over the last few years, the data collected by NASA's Mars Rovers has continued to shed light on the conditions that were present on the red planet before it became a desert. The years old hypothesis that Mars was once a wet and warm environment have proven correct. All evidence seems to be pointing towards the idea that Mars once had a water cycle that was almost identical to Earth's, where rain water formed Glaciers, glaciers formed rivers, and rivers flowed back into great oceans.
Liquid water is of course one of the biggest give ways that life may have existed on Mars at some point in the past, but it is not the only scrap of evidence that supports the theory. Within the dry Martian landscape where great rivers and lakes once existed, the Martian rovers have discovered that within the ancient clay lies complex minerals such as magnesium and boron that are essential for the building of RNA and DNA. Through the rover's on board lab it also appears as though the water had a neutral PH balance, and this most likely provided a habitable environment for basic microbes.
So despite evidence suggesting that conditions were at the very least possibly favourable to life's development, what connects life on Earth with that of Mars, and how could Mars be our ancestral home?
The answer lies with a theory called 'Panspermia'. Whilst the name sounds like it something to do with pornography, it's actually a theory suggesting that life is seeded throughout the cosmos by basically pigging backing on space rock and icy comets to new destinations. Whilst this theory has very little concrete evidence, many in the Scientific community, even well known ones like Stephen Hawkings believe that it could be a viable answer. What is most titillating is that there are actually some signs that the theory has some traction.
The possible evidence for life beginning on Mars comes from an meteorite known lovingly as ALH84001. Found in Antarctica in 1984, it's content still remains a hot subject among scientists and the public alike. The reason for the interest comes from small 'fossils' which were found embedded in the rock which resemble basic lifeforms. When you consider that this rock has reportedly come from Mars from over 15 million years ago (the rock having been formed 4 billion years ago during the Martian's wet period) it is certainly interesting to consider the possibility that life throughout the universe is abundant, and bizarrely mobile.
This alone however is not even the most interesting aspect of this potential smoking gun. There has been a study which has worked out that approximately one billion tons of Martian rock has arrived here on Earth since the two planets formed, and out of those, many will have reached their destination between the two planets within twelve months. With a journey time of one year, it is not completely 'out there' to suggest some basic extremophile lifeform could survive the journey to plop into a warm Earth ocean.
To add even more credibility to the theory, the meteorite sample from ALH84001 was found to have not heated internally during entry into Earth's atmosphere. As the rock became super-heated externally, the metallic components in the rock actually created a mini-magnetosphere effect which shielded the rest of the rock inside from the intense heat. If an extremophile organism was present inside a Martian meteorite then it is quite conceivable that it could survive the relatively short journey from Mars to either begin life or perhaps even diversify basic microbes here on Earth.
|The microbe 'fossils' found in the Mars meteorite.|
In the study it suggests that rocks coming from Mars to Earth may have been a regular occurrence over the solar systems history (Earth rocks making a Mars bound journey would have been much more difficult due to Earth's greater gravitation influence.) We also have to accept that Mars would have formed and cooled sufficiently for life to start much quicker than Earth will have, giving life a bit more time to get ready to make the journey here, adding yet another logical point to this idea.
Bizarrely, scientists have however now begun to look into the Martian dryness as a sign that life may have started there. Confused? In short, certain elements in the cocktail of ingredients needed to create life actually need dry conditions to form. Although Mars was generally a wet planet in its early conception, there were large parts of dry desert too, and this is where many of those fundamental elements could have been cooked up. There is evidence to suggest that those elements could not have existed here on Earth early on and that basically, life started on Earth before it should have done.
In 2013, many newspapers and news outlets ran the story about the possibility of Mars being our ancestral home (have a read of the BBC and National Geographic ones,) but this still doesn't explain where the life on Mars first came from. We've merely set the clock back a few hundred million years.
There are two other interesting things to consider which loop back to this Panspermia idea. Firstly is the discovery of sugar in space, with news reports back in 2012 reporting that they were abundant around young sun-like stars, it may indicate that life may simply be a normal component in a solar systems creation (sugar is a major building block in RNA.) Secondly, there is an idea which was ripped off from a theory originally applied to technology; 'Moore's Law'. It was suggested last year that by working backwards in complexity, assuming life should follow a predictable evolution process, that life ought to be ten billion years old. All things considered however, it is interesting that science is now beginning to take the idea of life being seeded here as a serious concept.
In conclusion then, we may all very well have Martian ancestors, who came here on the back of a meteorite after a violent explosion on the red planets surface. At the moment, although there are no ways to prove these theories, it does resonate with a certain degree of logic that life would act on a cosmic scale in much the same way that life does here on Earth. If you look at Antartica for an example, the coastline now has areas of grass growing where explorers have stepped on land without checking their shoes for attached grass seeds. If it can happen in Antartica, it can happen again.
In fact it would not be at all surprising to me if extremophile organism's exist out there on comets etc, with their entire purpose being simply to find other planetary bodies to deposit life onto. We're still awaiting the proper results to come back from the comet lander which has now fortunately come back to life, so with some luck these ideas will become more relevant in time.
You have to admit, there is an almost endearing feeling behind the prospect of all life sharing the universe - and when we do find ET, it may be quite disconcerting to realise our similarities far outstrip our differences.