TRANSCRIPT: Life on Io?

One of great unknowns of our solar system is whether it hosts other life, particularly microbial. I say the words other life carefully because there are two types of potential life in our solar system for us to consider. The first of these is life that evolved independently of earth life without any influence from here. This would be truly alien life and would give us an indicator that microbial life in the universe at large is probably common.

The other potential for life in the solar system is life transported from earth via panspermia getting deposited somewhere else and gaining a foothold. Our planet is teeming with microbial life, some of it extreme and possibly able to survive the rigors of space. It's entirely possible that we, the human race, will not claim the title of being the first life from earth to colonize other worlds.

This has led me to research just where either of those forms of off-earth life might exist in our solar system. There are obvious candidates such as Mars or Europa, but there were other candidates that surprised me when I went searching for the science on the subject. This video is the first in a series on this channel exploring those places, and this candidate is one that if it does harbor life, it's probably going to be centuries before we know about it.

That's because it would be exceedingly hard to verify its existence. It's Jupiter's moon Io and the reason for why it's going to be a while is that there is just no compelling reason to try to land on this moon. Studies from spacecraft passing by from afar are feasible, but expensive and with life there only just being within the realm of possibility it seems that Io will not be a priority for exobiological study for some time.

First there's just not much on the surface, it's basically just a big ball of mostly sulfur compounds. And a lander might well melt as it's the most volcanically active body in the solar system kept so by intense gravitational flexing it as it orbits. But volcanism is a dual-edged sword. While it can easily kill life, it can also provide an energy source for its genesis and indeed some models for how life arose on earth depend on the presence of volcanoes.

A possible way for life to survive on Io was presented by Dr. Dirk Schulze-Makuch in a 2010 paper in the Journal of Cosmology, link in the description below. The key to the possibility of microbial life on Io is linked to its history. Io is old, having formed about 4.5 billion years ago and today it has the least water out of any object in the solar system.

But that may not have always been so.

Objects in the outer solar system are typically rich in water ice anyway, and the models suggest that Io formed in an area where water ice was particularly plentiful in the Jupiter system. Given geothermal heating, some of that water might have been liquid opening up the possibility for the chemistry of life to get going, at least for a while, this would have had to happen within the first ten million years of that moon's existence. And, as we learn more about the early conditions present in the Jupiter system, it may be the case that it was  always impossible for life to arise on Io. But, at least right now, there is a chance.

Now, life on Io's surface is improbable and not just because of the volcanic activity. Jupiter blasts its surface with very high levels of radiation, and that likely precludes any possibility of panspermia or at least makes the chances low unless it happened very early on and native life could not arise there now. But beneath the surface of Io the conditions might be just  right for microbes originating from Io's early history to hold out.

Jupiter's radiation long ago deprived Io of its surface water, but below the surface there may be carbon dioxide and water in liquid form. And Io could well have several other potential liquid solvents for life including hydrogen sulfide, sulfur dioxide and even sulfuric acid.

Another important factor to consider would be the presence of lava tubes. Lava tubes are rich abodes of life here on earth and may also be so on Io. They provide protection from radiation and can be moist environments and also temperatures within the tubes could be both constant and warm.

But that's not the only way. The paper advances another model where the microbes might exist as dormant spores underground for very long periods only to be activated when lava is flowing on the surface above warming any fluids below to liquid temperatures and allowing a blossoming of life for a time before it once again goes dormant.

So while life on Io is a long shot, and there are far better candidates in our solar system that we must look at first, Io may one day prove to be more interesting than we might have imagined.

Thanks for listening! I am futurist and science fiction author John Michael Godier currently with a new book in the works, it's called Supermind and a 5000 word excerpt is up at Amazon Kindle Scout, link in the description below, check it out and if you like it give it a nomination! And be sure to check out my other books at your favorite online book retailer and subscribe to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects of this amazing universe in which we live.