From rocks that formed around hydro-thermal vents some new claims have emerged.

These fossils were formed perhaps within a few hundred million years of the formation of the solar system.

"We found the filaments and tubes inside centimetre-sized structures called concretions or nodules, as well as other tiny spheroidal structures, called rosettes and granules, all of which we think are the products of putrefaction. They are mineralogically identical to those in younger rocks from Norway, the Great Lakes area of North America and Western Australia," Dr Dominic Papineau (UCL Earth Sciences and the London Centre for Nanotechnology).

"The structures are composed of the minerals expected to form from putrefaction, and have been well documented throughout the geological record, from the beginning until today. The fact we unearthed them from one of the oldest known rock formations, suggests we've found direct evidence of one of Earth's oldest life forms. This discovery helps us piece together the history of our planet and the remarkable life on it, and will help to identify traces of life elsewhere in the universe."

This is of interest in relation to Mars because Earth and Mars had liquid water on surface and were far more similar at this time in the evolution of the solar system.

Hydro-thermal vents currently support life in the depths of our oceans without sunlight.

Previously sunlight was thought to be a prerequisite for life, but the extremophiles that live at the bottom of the ocean around hydro-thermal vents have changed the thinking on all this.

These ecosystems are based on chemosynthesis and not photosynthesis.

Therefore life can evolve around hydro-thermal vents in the absence of sunlight a lot earlier on in the evolution of a planet and a solar system.

All the blocks necessary for supporting life are there already and not dependent on incoming solar radiation and maturation of an atmosphere.

Planets that are not within the Goldilocks zone could therefor also support these types of life forms since the energy inputs required come from geothermal(internal) heat.

Mars had plenty, based on all the volcanoes we can still see. But it radiated heat and cooled faster, due to its smaller size and ran out of internal heating.

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...and as usual those claiming cotroversy have already started.

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