Enceladus has been observed blasting water vapour in to space,
and now thanks to the Cassini spacecraft, we have actually collected a sample of this vapour. After
finding organic molecules in the vapour, some scientists believe Enceladus could be home to a
subsurface ocean hosting alien life. Stick around to find out what we saw on the strange moon.
Discovered in 1789 by William Herschel, Enceladus is Saturn s sixth largest moon, although it s only
around a seventh of the size of our Moon. Covered mostly by fresh, clean ice, it is one of the most
reflective bodies in the solar system, causing the moon to have a glistening white appearance.
The surface temperature reaches a high of just minus 198 degrees Celsius, although
the moon may be warmer towards the centre. Little was known about the small moon until
the two Voyager missions passed nearby in the 1980 s. Voyager 2 managed to capture a
few sensational colour images of the moon, which were promptly beamed back to Earth.
From studying these images, scientists deduced that the mysterious moon should
be further explored, and so Enceladus was added as a priority destination for the Cassini mission.
The frozen moon was intensely studied as the Cassini spacecraft began its first of many flybys
in 2005, revealing the surface and environment of the moon in greater detail than ever seen before.
The moon s exterior appeared to show a tiger stripe pattern on the surface, a result of looming
shadows created by 500 metre high ridges, likely created by tectonic activity within the moon.
As the Cassini probe continued its study, more revelations were made apparent. In particular,
Cassini discovered water-rich plumes venting from the south polar region of Enceladus,
which became an area of great interest to NASA scientists. These jets continuously blast around
250 kilograms of water into space every second at speeds in excess of 1200 miles-per-hour.
This is powerful enough to allow most of the water particles to escape Enceladus weak gravity,
and form what is now known as Saturn s E-Ring, which is blue in colour.
Cassini, although not designed to sample the ejected vapour, managed to collect and analyse
some of the moisture by improvising the use of its onboard cosmic dust analyser. NASA scientists were
quick to redirect the probe to pass through these newly discovered plumes, in order to detect what
substances were contained within them. After collecting and analysing the samples;
water, nitrogen, carbon-dioxide and methane were all detected within the material ejected by the
plumes. This provided evidence for a large, subsurface ocean under the moon s South Pole,
making it one of the prime locations to find extra-terrestrial life in our solar system.
In 2018, after further analysis of the samples collected by Cassini,
scientists reported the existence of complex macro-molecular organics in the jet plumes.
These organics are better known to us as amino acids, which are the building blocks for life
as we know it. These amino acids would have most likely formed around hydrothermal vents at the
bottom of the ocean, and are so a strong indicator of hydrothermal activity in the moon s subsurface
ocean. Enceladus also has an elliptical orbit, meaning that the moon will experience
strong tidal forces from Saturn which could potentially heat up a liquid core. Combined,
these observations provide substantial evidence for the existence of warm pockets of liquid water.
These small pockets may possibly provide the right environment to host an oasis of life.
Similar conditions were believed to have been present at the beginning of life on Earth,
as the hydrothermal activity provides nutrients for the amino acids, which can then be used
by micro bacteria to provide life giving energy. This means that Enceladus has all
the right ingredients to sustain alien life, albeit on a bacterial level. For this reason,
Enceladus has become a prime destination for future scientific missions, although this time
the missions are a part of a new space race to find alien life.
Many missions have been proposed to assess the astrobiological potential in the Southern Ocean
of Enceladus, six of which are currently under study. These vary from collecting more data from
the water-rich plumes, to landing a manoeuvrable IceMole probe on the icy surface of the moon.
NASA s current leading proposal is the Enceladus Life Finder Mission. This would see another
Cassini-like space probe sent to further analyse the frosted moon s geyser plumes, although this
time it would fly ten times closer to the surface in order to collect more complete samples.
These samples should contain ice particles from the moon s subsurface ocean, which could contain
more concrete evidence astrobiologists need to identify microbial life.
Opposing NASA s planned mission is the German Aerospace Centre s Enceladus Explorer. This
ambitious mission plans to land an equipped, manoeuvrable IceMole probe on the surface of
Enceladus, which would melt its way through the surface ice to emerge into the moon s Southern
Ocean. As a result, the IceMole probe would be able to collect undisturbed high-quality
samples from within the ocean, which could then be inspected for life in great detail.
Other, similar missions are under study by the NASA Jet Propulsion Lab and The European Space
Agency, all with the goal of investigating the potential of life on Enceladus.
Hopefully one of these missions will soon be given the green light, and one day in the not too
distant future, mankind might be able to confirm the existence of extra-terrestrial life.
So, does alien life exist on one of Saturn s moons?
Enceladus has all the right ingredients to host an oasis of aquatic, alien life, although it
could equally just be another uninhabited, stunning spectacle in our solar system.
While Enceladus is likely to have a subsurface ocean,
we now know for sure that there are surface lakes on Titan,
another moon of Saturn. These lakes are made of methane and other hydrocarbons, but maybe
a different type of life has evolved there. The Cassini spacecraft deployed a probe to Titan
and captured video from the surface. Click here to see the video and all the other
amazing discoveries of Cassini. Here s an interesting fact:
Did you know that the footprints on the moon left by the apollo missions will
likely stay there for 100 million years? With no atmosphere, wind or water, the only thing
to erode them will be micro-meteorites. Or, potentially, one big meteorite.
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