Eric Shear is a new MSc in the group this year, having previously obtained his bachelor's degree here at York. As our resident mission designor, he is exploring the Saturnian system in his MSc work. The image above is taken from the Cassini Mission.
By Eric Shear
There are still many
things in our solar system that our spacecraft have not yet gotten close to,
and Saturn’s ring system is one of them. It’s the biggest of all the gas giants’
ring systems and to date we do not know how old it is or how it formed in the
first place, or how it got so large compared to the rings of the other gas
giants. It appears to be an outlier – and a lovely outlier at that.
The Cassini probe
has been orbiting Saturn since 2004. It’s uncovered a lot since then, but there
is still one central mystery left to discover. It’s apparent when you look at
the rings themselves.
The estimated mass
of the rings is equivalent to a small ice moon, such as Mimas. That leads some
to believe that they were created by the breakup of a moon of similar size, perhaps even due to a cometary collision! [3] But these events are very rare and
unlikely to have occurred within the last billion years.
Yet the rings look
so young. Their pristine color is the result of >99% water ice. The slight
reddish color comes from impurities [2] which strongly absorb ultraviolet, as was
found by Cassini’s UVIS instrument. They are thought to come from meteoritic
infall [1], but if that really were the case, the rings should be much darker given
their age.
That paradox can
only be resolved by direct sampling of the ice particles within the rings,
ranging from less than 1 cm to 10s of meters in size. Knowing what the
impurities are will help us figure out what is causing the slight darkening,
and why the rings hasn’t darkened that much.
This is the
objective of the small spacecraft mission to Saturn in my master’s thesis. Stay
tuned!
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