Venus Could Still Harbor Ancient Microfossils, Says Geologist

Venus could still harbor ancient microfossils that are both accessible and readily detectable if microbial life ever developed there. Or so says a prominent British geologist.

Richard Ghail, a geologist at Royal Holloway, University of London, told me in his office this past week that he remains agnostic about whether Venus ever had life. But if it did, its remaining microfossils most likely would still be detectable in ancient rocks in Venus’ highland regions.

In fact, in Ghail’s view, even though present-day Venus has temperatures that typically reach 450 degrees Celsius and surface pressures some 92 times that of Earth, the planet is more likely to have developed complex microbial life than Mars, he says.

You would absolutely not find organic material in such fossils, says Ghail. But fossilization turns the organic material into silicates, and silicates are fine up to a 1000 degrees Celsius, he says.

That’s in contrast to the mainstream views of many astrobiologists who are typically skeptical about how microfossils could have survived such extreme conditions over billions of years.

So, I don’t see that there’s any reason why they wouldn’t sit there at 400 degrees, especially there in the tesserae highlands, Ghail told me in his office.

Venus’ tesserae —- rough country, highland regions which make up about eight percent of the planet’s surface —- are tectonically deformed areas that may be remnants of ancient continental crust.

In really old 3.5-billion-year-old rocks in Venus’ highlands, it’s possible to preserve fossils, says Ghail. And he says it’s likely that you would find a pattern of algal matter, stromatolites (essentially microbial reefs generated by cyanobacteria), or at least something similar.

Although Ghail also remains agnostic on whether Venus ever had oceans, he says if it did, life almost certainly would have evolved there.

If Venus had oceans, I think for a billion or two billion years or longer, the planet would have been quite earthlike, says Ghail. He notes that in a similar timeframe some 3.5 billion years ago, Earth evolved life involving bacterial colonies, algal mats, and stromatolites.

The idea would be to look for the morphologies of such life using a balloon-type structure that would move about and hover just above Venus’ surface.

It would be very easy to build a sort of low-density submarine-like spacecraft that would float in Venus’ dense atmosphere, says Ghail. You could just fly a meter or two above the surface and then land where you need to land, he says.

As for how this atmospheric spacecraft spot microfossils?

You’d be looking for the structures in cliff faces in the rock, says Ghail. You would photograph or film these cliff surfaces and look for those microfossil structures, he says. Then when they were found, the same balloon-like atmospheric submarine would land near them; take some samples, and do some in situ sample analysis, he notes.

But Ghail admits there are still technical hurdles to overcome.

The longest any lander has survived so far is about two hours, says Ghail. But we’re starting to see development of technology that could cope with such surface conditions. For instance, he says, silicon carbide chips can work in temperatures up to 1000 degrees Celsius.

Even so, there’s work to be done on developing the right kind of camera system for such a microfossil-hunting mission. And Ghail says that current Venus to Earth communication systems would still be hamstrung by relatively low upload rates.

But all the principles are there for developing that sort of technology, he says, and I think that one day we’ll do it.