Robert Inventor

Now that Philae has woken up, we may be on the brink of major steps forward in our understanding of comets. We already know that comets have high proportions of dust and organics - perhaps 30%. Now we'll be able to look at these close up. Why, though, do most scientists expect to find only pre-biotic chemistry in comets? Is there any chance of finding life there? Also, where else in the solar system can we look for life and prebiotic chemistry? 

Now that Philae has woken up, we may be on the brink of a major step forward in our understanding of comets, and we expect to find some interesting chemistry. Perhaps 30% of its composition consists of organics, and now we'll be able to look at it close up. Why, though, do most scientists expect to find only pre-biotic chemistry? Is there any chance of finding life? Also, where else can we look for life and prebiotic chemistry in the solar system? 

The ancient oceans of Jupiter's Europa and Saturn's tiny Enceladus are hidden beneath an ice sheet kilometers thick. They may have ET microbes, even multicellular swimming creatures around hydrothermal vents. Or they could have imperfectly reproducing "protocells"; a window into the first stages of evolution. These conditions, which make them so habitable, and interesting for astrobiology, may also make them especially vulnerable to invasive species. Cassini orbiter found geysers at the south pole of Enceladus, continually venting sea water from its ocean into space, as ice particles. This may give us a wonderful opportunity to look at ET life in our solar system without interference from Earth life.

The ancient oceans of Jupiter's Europa and Saturn's tiny Enceladus are hidden beneath an ice sheet kilometers thick. They may have ET microbes, even multicellular swimming creatures around hydrothermal vents. Or they could have imperfectly reproducing "protocells"; a window into the first stages of evolution. These conditions, which make them so habitable, and interesting for astrobiology, may also make them especially vulnerable to invasive species. Cassini orbiter found geysers at the south pole of Enceladus, continually venting sea water from its ocean into space, as ice particles. This may give us a wonderful opportunity to look at ET life in our solar system without interference from Earth life.

If an extraterrestrial race - or indeed later civilization on the Earth looks at the relics of our space explorations - one thing they might notice is our fondness for placing flags and pennants in space. All the space faring nations have signed the Outer Space Treaty. So these are not claims of territory (forbidden by the treaty) but rather, celebrations of national pride and accomplishment.

Elon Musk, and NASA both have in mind the idea of doing interplanetary voyages straight away, aiming for Mars, with Obama going so far as to say about the Moon: “But I just have to say pretty bluntly here: We’ve been there before.”. If you hold that view, you are undoubtedly in distinguished company. Now - there are two things here - yes we've been to the Moon before - but is that the end of all interest in it? But first - how ready are we for interplanetary voyages? 

The present day habitability of Mars is an area of research that has exploded hugely in the last decade, to the extent that it's often hard to keep track of everything that's going on. This is by way of background material for my other articles on habitability of Mars.

I've talked before about how life on present day Mars could be vulnerable to Earth life. If only humans could be sterilized of other life, like a plant seed. But sadly, we can't do that, and it would kill us to try. Recent ideas, and experiments in Mars simulation chambers suggest that there may be liquid water habitats on the surface of Mars. They may be no more than droplets of water a few millimeters in diameter, but these still are, as Nilton Renno said, "Swimming pools for a microbe".

I've talked before about how life on present day Mars could be vulnerable to Earth life. If only humans could be sterilized of other life, like a plant seed. But sadly, we can't do that, and it would kill us to try. Recent ideas, and experiments in Mars simulation chambers suggest that there may be liquid water habitats on the surface of Mars, maybe just a few mm scale droplets of water, but places where life could survive. And humans can't go anywhere without taking hundreds of thousands of microbe hitchhikers along with us. So - if we can't go to the surface of Mars right away - where can we go?

Our Earth is the only planet we know with life visible from orbit.

Many people worry about the possibility of the end of all life on our planet. However, the Earth is by far the most habitable planet in our solar system and there's no reason to expect that to change for hundreds of millions of years. The Earth may become uninhabitable between 500 million and a billion years from now. That may seem a short time, when you compare it with the billions of years the Earth has evolved for. But compared with the length of time there have been humans on the Earth it's a very long time. To get an idea of who may need to deal with this issue, the idea is, to look at the last billion years. And then think about where we or our evolutionary cousins might be after another billion years after that. First some background though.

Many ETs are non technological. Like parrots or elephants, or dogs just not physically easily capable of making complex things however much they want to. Or live in sub surface oceans like Europa - if they live in the sea that also makes them likely to be non technological e.g. can't use fire easily. And may not know that the rest of the universe exists. Such an ET could even live in our solar system. We could have ETIs in the subsurface oceans of Europa, Ganymede, Titan and Encladus and if they were non technological we'd have no idea at all that they exist, and they wouldn't know that we exist.