Michele Dougherty, a Professor of Space Physics at Imperial College, revealed a strange anomaly related to Saturn’s magnetic field on Netflix documentary Death Dive to Saturn. She explained: “We think that the rotation axis of the planet and the magnetic axis of the planet, at this stage, as far as we can tell, are lying on top of each other.” Prof Dougherty, who was Principal Investigator of the operation, data collection and analysis of observations from the magnetic field instrument on board Cassini, added: “If we’re seeing what I think we’re seeing, the internal field is generated in a different way that people think, or the field is dying.”
Japheth Yates, an Internal Research Fellow in the European Science Agency’s Science Department, told Express.co.uk his colleagues in the scientific community were still trying to work out precisely what was going on.
He said: “I’m not exactly sure what Michele meant by the field dying but planetary magnetic fields do ‘die’.
“It happened to Mars, it used to have a magnetic field many millions of years ago and then something happened that disrupted the convection deep inside Mars which eventually ended the dynamo process, leading to the eventual loss of most of its atmosphere.”
However, he added: “With regards to, the extreme alignment of Saturn’s magnetic and rotational axes, this is still an ongoing field of research. It is not fully understood why this is the case.
Cassini has completely changed our understanding of Saturn, said Dr Yates
Scientist Michele Dougherty
Dr Yates said the subject was being intensely scrutinised, saying: “We now know that Saturn’s magnetic field is aligned with its rotation axis to within 0.01 degrees.
“As Michele mentioned, the fact that Saturn’s magnetic and rotation axes are aligned disagrees with the planetary dynamo theory but there are theories that may explain it.
“To my knowledge, the leading theory at present explaining why there is such extreme alignment is that there is a highly-conductive atmospheric layer between Saturn’s ‘deep core/interior’ (where the main dynamo is generated) and the atmosphere that we can see.
“This layer rotates at a different speed to the rest of Saturn and as it’s electrically conductive it electromagnetically filters or shields out the parts of Saturn’s magnetic field which are ‘not aligned’ with the rotation axis.”
An artist’s impression of the Cassini probe heading towards Saturn
Dr Yates said whatever was happening would have wider implications for mankind’s understanding of other planets in the solar system, as well as exoplanets beyond it.
He explained: “Mercury also has an essentially aligned magnetic and rotation axis although I’m not very familiar with the Hermean system so I can’t comment as to why that is.
“Nevertheless, understanding why our planets are the way they are allows us to learn how they, and other solar systems, were formed and our own origins.”
In terms of Saturn as a whole, Dr Yates stressed both it and Jupiter likely played an important role in the development of the solar system, not least Earth itself.
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A picture of Saturn taken by Cassini
The surface of the moon Titan
He said: “We aren’t absolutely sure about all the details regarding the Solar System’s formation.
“It is likely that the presence of Saturn and Jupiter in the outer Solar System has had an effect on the development of life on Earth.
“These giants essentially protect the inner planets from some comets and asteroids bound for the inner solar system from the distant reaches of the solar system.
“Sometimes they eject them from the solar system while other times these objects are pulled into Jupiter or Saturn (eg Shoemaker-Levy 9).
Saturn is the sixth planet from the Sun
Cassini has completely changed our understanding of Saturn and its system
“Life, as we know it, takes a long time to get established. During this time the more stable conditions are the better for life to emerge and evolve.
“Without Jupiter and Saturn, there may have been much more cataclysmic asteroid and comet impacts with the Earth, possibly frequently enough to inhibit the emergence of life. So in a way, we may owe our existence to these giant planets out in the solar system.”
Death Dive to Saturn focused on the pioneering Cassini probe, which has revolutionised understanding of the planet, with the title a reference to the decision to crash the spacecraft into its surface at the end of the mission.
Dr Yates said: “Cassini has completely changed our understanding of Saturn and its system. Probably one of the most significant surprises was the discovery of liquid water geysers shooting out of Enceladus’ southern polar region.
“Before Cassini, we only had a couple of flybys lasting hours. Now we have over a decade of basically continuous observations with multiple scientific instruments. We have answered many questions but also have found so many more that need answering which is one of the reasons why planetary science and astrophysics are so exciting.
“There is so much out there that we don’t know. We are constantly solving mysteries and finding new ones. Saturn most certainly holds more secrets, some we will discover by analysing the rest of the data we got from Cassini, some will be answered using remote observations from Earth and others will have to wait until we next return to the Kronian system.”
ESA opted to prioritise its Jupiter Icy Moons Explorer mission, which will look at Jupiter’s icy moon Ganymede and answer questions on its sub-surface ocean and Solar System origins, over the proposed Titan Saturn System Mission, meaning there are no immediate plans for a Cassini successor.
However, Saturn is far from forgotten, and Dr Yates said: “NASA has just selected a mission in their New Horizons program called Dragonfly which will fly around and collect samples on Saturn’s moon Titan.”
The exciting project will involve a rotorcraft, complete with eight rotors, flying on Titan, with Dr Yates saying: “Dragonfly will investigate the origins of the solar system and of life.
Saturn pictured with its distinctive rings
“Titan is an analog to a young/early Earth and studying this moon and taking samples can shed light on the early days of our own planet and the ingredients that could have led to life starting here.”
As for Saturn itself, Death Dive to Saturn makes it clear its spectacular rings will not last forever.
Dr Yates said: “The rings do have an ‘expiry date’. Eventually, most of the ring material will probably fall into Saturn.
“Scientists at the University of Leicester have observed so-called ‘ring-rain’ where ring particles fall into Saturn’s atmosphere.
“They estimate that the rings will be completely gone within the next 300 million years and more probably in around 100 million years which is a relatively short time for our solar system. But humans will be able to gaze at Saturn’s rings for countless generations to come.”