Breaking: Alien Life ‘May Be Thriving On Saturn’s Moon’
Alien life
may be thriving in a warm, underground ocean on Saturn’s icy moon Enceladus,
according to new research. Scientists say tidal forces could have kept the
subterranean sea liquid for billions of years – enough time for organisms to
have developed. The mysterious world has a very fragmented and porous rocky
interior, ideal conditions for flowing water with the friction creating 10
gigawatts of heat.
This amount
of energy would light and heat more than 7 million homes – and explains all the
global properties of Enceladus observed by Cassini. Earlier this year NASA's
spacecraft picked up the first evidence of chemical reactions deep below the
frozen crust – suggesting an environment capable of supporting life. It was one
of its final successes before plunging into Saturn’s atmosphere at the end of
its 12 year expedition to the ringed planet.
The latest
study published in Nature Astronomy is based on a state-of-the-art computer
model using Cassini’s observations. These showed Enceladus has a global ocean
fed by intense hydrothermal activity beneath the surface. Its measurements of
water escaping from geysers at the south pole showed the sea is salty – and
contains organic molecules. But tidal forces within the ice are not sufficient
to sustain this activity.
Without an
additional contribution the ocean would freeze in less than 30 million years.
So planetary scientist Dr Gael Choblet and colleagues explored the possibility
this additional heating comes from the effect of tidal forces acting on the
highly porous core.
They found
enough heat would be generated by the resulting hydrothermal activity to keep
the ocean liquid for “tens of millions to billions of years.” This heat is
dissipated mainly at the poles – explaining why the ice shell is thinner there.
The model suggests an ocean has existed within Enceladus for eons – even though
the small moon is only 887 million miles away from the Sun.
Dr Choblet
said: “What we show is hydrothermal processes probably provide means to have
efficient interactions between rocks and hot water in a large volume deep
within the moon. What had been shown earlier is hydrothermal processes were
very likely occurring right now within Enceladus. What we show in our study is
the context of this activity. We also suggest this activity is relatively
stable – for at least 10s of millions of years.”
He said the
life expectancy of the ocean and – perhaps more importantly – how long the
hydrothermal activity has been occurring would be key to the emergence of
microbes and other organisms.
Dr Choblet,
of Nantes University in France, said: “Only future missions equipped with
instruments capable of analysing the organic molecules in the plume with higher
accuracy than the Cassini measurements will tell us whether the required
conditions have been sustained long enough for life to have emerged on this
distant ocean world. Projected missions back to Enceladus are currently under
consideration – especially in the US.
If selected
these would already enable us to analyse the chemicals emitted though Enceladus
plumes with a much better precision than the instruments onboard the Cassini
spacecraft could – especially the complex organics. With a possible launch in
2024 this means that new, more precise use information could be obtained in the
2030s.”
In October
2015 NASA sent Cassini into a deep dive through one of the plumes of spray
which shoot up into the atmosphere through cracks in the ice, and discovered
hydrogen and carbon dioxide. Scientists are certain they were created by
reactions between warm water and rocks on the ocean floor.
Crucially,
if hydrogen is present it can mix with carbon dioxide to form methane, which is
consumed by microbes in the deep, dark seas of our own planet. Enceladus is the
sixth largest moon of Saturn.
It is around
310 miles in diameter and approximately 790 million miles from Earth.
Scientists had long suspected that liquid water could exist on the moon because
of the extreme tidal forces acting on the satellite from Saturn’s gravity.
Although
scientists previously thought Enceladus’ icy crust was around 13 miles thick,
Cassini found at the South Pole it could be as little as three miles deep. The
distant moon has long been hailed as one of the three best potential locations
for finding extraterrestrial life in the solar system. The others are Mars and
Jupiter’s satellite Europa. Such a discovery of even primitive microbes would
make it almost certain life is widespread throughout the universe.
Dr Choblet
said: “Chemical analyses indicate that the ocean is salty and is fed by ongoing
hydrothermal activity. Here, we show that more than 10 GW of heat can be
generated by tidal friction inside the unconsolidated rocky core. Water
transport in the tidally heated permeable core results in hot narrow upwellings
with temperatures exceeding 363K (90 degrees Celsius) characterised by powerful
hotspots of 1 to 5 GW at the seafloor, particularly at the south pole.” Recent
data from Cassini has shown that at the south pole, it could be as little as
three miles deep.
The release
of heat in narrow regions favours intense interaction between water and rock,
and the transport of hydrothermal products from the core to the plume sources.
We predict that this internal activity can be sustained for tens of millions to
billions of years.”
Via
Telegraph
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