I’ve talked about Europa before in musing about the possibility of life elsewhere in the solar system, but it seems Saturn’s moon Enceladus is another good candidate. Excerpt:
With its curtain of geysers and internal ocean, Enceladus is unique. As a result, this small, icy moon is currently regarded as a potential host for life, and so no chance was taken that it might become contaminated by the Cassini spacecraft. Now new research, published in Nature Astronomy, suggests this ocean has existed within Enceladus for a very long time – possibly long enough to create the conditions to develop life.
The geysers are plumes of salty water-ice mixed with traces of carbon dioxide, ammonia, methane and other hydrocarbons that erupt along cracks in Enceladus’ south polar region. It was because of these geysers that scientists could work out that Enceladus must have an ocean below its icy crust and that the ocean is active (convecting). A subsequent observation that hydrogen was present in the plumes led to an additional conclusion, that hydrothermal activity – chemical reactions due to the interaction of water and rock – was taking place. But what scientists have failed to explain is what heat source could be powering this activity.
As more observations of the location of the plumes were made, the mystery of the missing heat source increased. The geysers are associated with features known as “tiger stripes” – a set of four, parallel depressions, about 100km long and 500m deep. The temperature of the stripes is higher than that of the rest of the icy crust, so it was assumed that they must be cracks in the ice. There are almost no impact craters in the tiger stripes region, so it must be very young, of the order of a million-years-old. Any model that purported to explain the heat source had also to account for its focused nature – the ocean is global, but why is only the south polar region active?
I’ve pretty much beat to death discussing the gobsmacking, world-changing implications of actually finding life – even microbes – somewhere in the solar system besides Earth. But the issue at the moment is whether we will continue to search for said life.
Being possessed of an insatiable curiosity myself, I am always a bit irked to find a stunning lack of that trait in others. There are plenty of folks who bemoan spending money on such exploration, no matter whose money is being spent. “Better to spend it on feeding people, housing the homeless, or (insert name of latest fad cause here.)” But I’d like to think that the human drive to explore, to discover, to learn, still drives us as a species.
Be there life or not, on Enceladus or elsewhere – let’s find out!