Saturn’s moon Enceladus could provide a ‘free lunch’ to aliens as scientists probe if the ocean-covered world could ever sustain life
- High levels of carbon dioxide imply a lower more Earth-like pH level in the ocean
- Scientists suggest that living microbes could feed on this fuel, or chemicals
- Enceladus is a small moon, an ocean world about 310 miles (500 km) across
- In 2005, the Cassini spacecraft made the discovery that Enceladus is an active moon that hides a global ocean of liquid salty water beneath its crust
High concentrations of carbon dioxide and hydrogen on the subsurface ocean of Saturn’s moon Enceladus could provide fuel for alien life, experts claim.
Scientists suggest that living microbes could feed on this fuel – a chemical broth dubbed a ‘free lunch’.
They say that its presence however, could also suggest ‘that there is hardly anyone around to eat it.’
This could mean microbes aren’t present in high enough quantities to consume all of the available energy.
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High concentrations of carbon dioxide and hydrogen on the subsurface ocean of Saturn’s moon Enceladus could provide fuel for alien life. This illustration shows NASA’s Cassini spacecraft through the plume of Saturn’s moon Enceladus
Enceladus, Saturn’s sixth largest moon, is an ocean world about 310 miles (500 km) across.
Its salty subsurface ocean is of interest to planetary scientists because of the similarity in pH, salinity, and temperature to Earth’s oceans.
In 2005, the Cassini spacecraft made the discovery that Enceladus is an active moon that hides a global ocean of liquid salty water beneath its crust.
It also found that jets of icy particles from that ocean, laced with water and simple organic chemicals, gush out into space continuously from it.
The material shoots out at about 800 miles per hour (400 meters per second) and forms a plume that extends hundreds of miles into space.
Some of the material falls back onto Enceladus, and some escapes to form Saturn’s vast E ring.
The new study has found that the plumes aren’t chemically the same as the ocean from which they erupt and that the eruption process itself changes their composition.
The plumes provide an ‘imperfect window’ to the composition of Enceladus’s subsurface ocean and that the plume composition and ocean composition could be much different.
That, they find, is due gases separating, which allows some components of the plume to erupt while others are left behind.
Scientists suggest that living microbes could feed on this fuel – a sort of chemical as a ‘free lunch’ or it could mean ‘that there is hardly anyone around to eat it.’ This could provide a potential fuel for life and but it may mean microbes just aren’t abundant enough to consume it
Using a computer simulation that accounts for the effects of the separation, they found ‘significant differences’ between Enceladus’s plume and the chemicals in the ocean.
Previous interpretations, they found, underestimate the presence of hydrogen, methane, and carbon dioxide.
‘It’s better to find high gas concentrations than none at all,’ said lead researcher Dr Lucas Fifer.
‘It seems unlikely that life would evolve to consume this chemical free lunch if the gases were not abundant in the ocean.’
Those high levels of carbon dioxide also imply a lower and more Earthlike pH level in the ocean of Enceladus than previous studies have shown. This bodes well for possible life, too, Fifer said.
‘Although there are exceptions, most life on Earth functions best living in or consuming water with near-neutral pH, so similar conditions on Enceladus could be encouraging,’ he said.
‘And they make it much easier to compare this strange ocean world to an environment that is more familiar.’
WHAT IS ENCELADUS AND COULD IT HOST ALIEN LIFE?
Enceladus (pictured) is Saturn’s sixth largest moon, at 313 miles wide (504 kilometres)
Enceladus is Saturn’s sixth largest moon, at 313 miles wide (504 kilometres).
It is an icy satellite with hydrothermal activity – a rare combination – with vents spewing water vapour and ice particles out from a global ocean buried beneath the moon’s frozen crust.
A handful of worlds are thought to have liquid water oceans beneath their frozen shell, but only Enceladus sprays its ocean out into space, where a spacecraft can sample it.
According to Nasa observations, the plume includes organic compounds, volatile gases, carbon dioxide, carbon monoxide, salts, and silica.
Microbes on our planet either produce these compounds or use them for growth, leading some to speculate that tiny organisms live in Enceladus’s hidden ocean.
This means that while Enceladus may look ‘inhospitable’ like Saturn’s other moons, it is a prime candidate in our search for alien life.
