In my earlier article, 'Where Did All The Martians Go?', I discussed the dramatic change in the climate of Mars, and the need for as many of its inhabitants as possible to evacuate the planet. But most would have had to stay. I wrote about the huge underground shelters that would be required: long term havens that would enable millions to survive for many generations until they too could be evacuated, or until the planet's atmosphere and environment recovered.
The entrance to one of those havens may now have been discovered.
|Near the south pole of Mars: the possible entrance to a huge underground survival facility, capable of sustaining thousands, if not millions, of Martians as their climate failed and surface survival became impossible.|
Found near the south pole of Mars by NASA's Mars Reconnaissance Orbiter, the hole, hundreds of metres in diameter, is possibly one of the main entrances to a vast underground complex. It was probably used for vehicles, including aircraft and spacecraft.
And there are likely to be many more such entrances, large and small. One example can be found on the slopes of Pavonis Mons, an extinct shield volcano in the Tharsis region of Mars near the planet's equator. Shown below, the hole could have been intentionally created to allow Martians to utilise the lava tubes of the extinct volcano to access a network of underground sanctuaries. Its equatorial location would have been very useful for more economical launches of spacecraft.
|Such holes can be naturally formed. This one is on Pavonis Mons, and is thought by some to be the collapsed roof of a lava tube. It could also have been intentionally constructed as an entrance to a massive shelter beneath the extinct volcano.|
There has been no real evidence of unnatural surface activity on Mars, which suggests three possibilities: all of the inhabitants have now left, they are surviving solely by subterranean means, or they have all perished.
The first possibility is the most unlikely. The effort to evacuate millions of inhabitants from the surface of a planet would be a gargantuan undertaking for even the most advanced civilisation. While a huge number of Martians will indeed have left the planet, most would have had to remain. Even if evacuations continued for thousands of years, which is a possibility, the remaining population would have continued to renew as generation after generation were born. And most may have wished to remain, having physically and mentally adapted to their subterranean existence.
The second possibility of the inhabitants still surviving underground right now also seem very unlikely, at least in large numbers. There is no evidence of the emissions that would be observable if there was a massive population still living there, even underground. Of course, they could be withholding their emissions to prevent detection and living in a perfectly contained and self-sustaining biosphere, but this would be almost impossible to achieve to a level where no emissions at all were made.
|A vast underground Martian city, home to possibly millions when war and climate change rendered the planet's surface uninhabitable. Could there still be millions of Martians living in such cities, undetectable within a perfectly contained biosphere?|
Unfortunately the most likely possibility is that all the inhabitants left in the subterranean facilities eventually died. If the sanctuaries were designed well enough they could have survived for thousands of generations - a remarkable achievement. But many millions of years later the likelihood of the sanctuaries still functioning is minuscule. At best there may be a few hundred Martians still eking out an existence in the huge and now deserted underground cities. If so it must be a lonely and grim experience.
The discovery of the huge potential sanctuary entrance near the south pole of Mars reinforces the need for a substantial human colony to be established to enable its exploration. If there is indeed an abandoned network of vast underground cities on the planet we need to explore them as soon as possible.
|The first colonists on Mars explore one of the entrances to an abandoned underground city|
As well as the thrill of discovering the remains of a lost extraterrestrial civilisation (with the remote potential of encountering surviving members of that civilisation), we would have the opportunity to find out exactly what calamitous events happened millions of years ago which forced the planet's population to retreat underground.