Friday, 14 April 2017

One Giant Leap for Extra-Terrestrial Microbial Life

When people say 'it's not rocket science,' then this is what they mean. Well that and biology, chemistry, physics and all of the other elements that went to put together recent triumphs from NASA. Last year they brought us stunning images of and discoveries about Pluto. Earlier this year they brought us news of remarkably Earth like planets in a far away solar system. Yesterday they brought us long suspected but now confirmed news of the chemical makeup of Enceladus.

Enceladus is a tiny icy moon of Saturn, the sixth largest of our solar system's most enigmatic and beautiful planet. But, much as Saturn is a thing of beauty in the sky, scientifically Enceladus may turn out to be more beautiful still.

But first to the jaw dropping feat of engineering, chemistry and rocket science that brought us this news. The Cassini spacecraft, which is nearing the end of its life around Saturn, swooped down and sniffed one of the plumes that rises off the moon's surface suggesting vast oceans of liquid water beneath Enceladus's icy crust. This was suggestive of the possibility of life, but only by sampling the plume could evidence be gathered for the chemical makeup. And so Cassini was sent in for a closer look. And a sniff. It is a sniff that was only programmed after Cassini itself first detected these plumes back in 2005, a discovery that astonished and thrilled NASA and scientists around the world. Missions like these take years and often decades to plan and accomplish. Such is the vastness of our solar system that the men and women who plan them can spend their entire careers dedicated to planning and then waiting for the mission to be launched and to then reach its goal. That they were able to detect what had not even been suspected and then send the same spacecraft back for another look and a sniff is wonderful. It's an astonishing feat of human ingenuity and a technical tour de force.

And the news is that Enceladus really is every bit as fascinating and surprising as had been tentatively suggested. It is a vast ocean world. Well, I say vast. Enceladus is only 505 km across - small enough to fit into the UK. But the ocean, which washes around the entire sphere in a manner imagined in movies like Interstellar, is salty water, when previously it had been assumed that it was all ice. The gravitational effect of orbiting Saturn constantly squeezes the moon like a rubber ball creating vast amounts of heat energy meaning that underneath the ice and that ocean are hydrothermal vents. These spurt out into the atmosphere. Some of this falls back to the surface but a large part goes out into space and orbits Saturn as one of those beautiful rings we all know so well. If you ever wondered how it got them? Well this is part of the answer.

But more importantly, though this is not yet proof of the existence of extra-terrestrial life, it does mean that the conditions for it exist even on a tiny, icy moon over 1.4 billion km from the Sun. We had always assumed that the right conditions had to be within the so called goldilocks zone where the inner rocky planets are. Enceladus shows this is not necessarily the case. It can reasonably be inferred that there may well be more exceptions to this rule, so many in fact that it is not a rule at all. Extrapolate this around the entire universe and there must be life all over the place. Intelligent life may not be so common of course. But it is safe to assume that we are not alone, even if we are unlikely ever to run into ET or go on a Star Trek.

This weekend we celebrate Easter, a religious festival dreamt up by people who assumed, hardly unreasonably, that the Earth was flat and that we were at the centre of the solar system that had been created by a god for our benefit. Now we learn that life may well be littered around the cosmos and is common to the point of being commonplace. Of course many of us have been saying as much for years. Given this then perhaps now is the time to grow out of worshipping sky fairies and of killing or hating each other in their name. Why worship figments of our imagination when there is so much more of wonder to excite us and make us look to the skies?

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