Saturn, the jewel of the solar system. A planet known for its
magnificent ring system made up of dazzling icy particles.
These rings, catch the sunlight and reflect it back, creating a spectacle visible even from
Earth. Other planets have rings, but none are as spectacular as Saturn's.
Intriguingly, scientists think that the rings might be the remnants of two former moons,
that perhaps collided millions of years ago.
But from that destruction, it seems a remarkable phenomenon is occurring, the birth of new moons.
Once thought to be static, Saturn's majestic ring
system seems to harbour the potential to create new worlds in our solar system.
So what is causing the formation of these new worlds? How many of them have we discovered?
And are they the beginning of a new single large moon?
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Before NASA's hugely successful Cassini mission, Saturn had only been visited by three passing
spacecraft, resulting in incredible, yet fleeting encounters that a lot of the time presented more
questions than answers. Cassini however, changed our understanding of the ringed gas giant.
For 13 years it orbited Saturn, unravelling many of its mysteries,
while capturing breathtaking images.
During its time at Saturn, Cassini allowed scientists to explore the
gas giant's atmosphere, capturing detailed images of colossal storms,
swirling cloud patterns, and the hexagonal jet stream at the planet's north pole.
A mysterious vortex unmatched anywhere else in the solar system.
It provided unprecedented views of Saturn's many moons, of which it has at least 146 orbiting it.
From the smog-covered Titan to the icy geysers of Enceladus,
these new views even ignited speculation about the potential for life beyond Earth.
And of course, the spacecraft explored the planet's magnificent ring system,
even entering the space between Saturn's cloud tops and the inner edge of the rings.
Passing so close in fact that it had to use its
radio dish as a shield against the icy particles it collided with.
How this spectacular feature formed is a mystery,
but scientists have proposed various theories to attempt to explain its origin.
One theory, for example, proposes that the
rings are simply the remnants of a failed moon formation process.
In this scenario, Saturn's gravitational pull prevented the accretion of a moon-sized
object within its rings, resulting in a vast disc of icy debris instead.
However, recent studies suggest that Saturn's rings may be much younger than previously thought.
Cassini found that the material within them
consists of icy fragments that are very pristine and unpolluted by dust.
Suggesting that the iconic rings must be fairly young,
possibly only a few million to a few hundred million years old.
For most of the solar system's 4.5 billion year history then,
the iconic Saturn probably looked much more bland.
One of the more recent theories is that Saturn's rings are the
remnants of two large ancient icy moons, that collided and shattered.
Since the collision, dynamic gravitational interactions shaped the resulting debris,
creating the magnificent ring system that we see today.
A series of seven concentric rings all varying in size and density.
However, it seems that this isn't just a spectacular field of ancient destruction,
because it turns out new worlds forming within it. The promise of new moons.
Called moonlets, these small, yet fascinating objects are believed to
form through the many complex gravitational interactions caused within the ring system.
When particles within the rings interact, they can clump together to form larger particles,
eventually growing into larger objects that are sometimes many kilometres wide.
They are essentially miniature moons in the making. In a way,
they are the embryos of new worlds.
They can be found throughout the ring system,
a moonlet called S2009/S1 for example, is located within the B ring, orbiting
only 117,000 kilometres (73,000 miles) from the gas giant itself.
Further out, in the A ring, many more moonlets have been discovered,
some of which have strange propeller like narrow gaps on either side of them.
One such is named Bleriot, one of the largest propeller moonlets discovered
so far, yet it is only around 860 metres across.
One well-known example of a newly forming moonlet is Peggy,
a little world discovered in 2013 orbiting at the very edge of the A ring.
Named after the discoverer's mother in law, Peggy was around 5 kilometres across (3 miles) and was
said at the time to be the first moon ever seen to be forming in front of our eyes.
When Peggy was seen again in 2014, however, it was far dimmer, suggesting that the moonlet
had been in a collision and later observations confirmed that Peggy had broken into two pieces.
Creating another chunk called Peggy B. And so, Instead of just catching
a moonlet in the act of forming, scientists also glimpsed a moonlet in the act of dying.
More than 150 of these moon embryos are embedded within the ring system and this
is only thought to be a small sample of the total population of such objects.
Hiding within the gas giants rings could be millions of these small
worlds. But unsurprisingly it seems that the environment they exist
within is unpredictable. Many of these new moonlets, like Peggy collide and break up.
So is it possible then, for Saturn's rings,
which are full of these miniature Moons, to one day form into a single large new moon?
Unfortunately, the answer is no. Saturn’s rings today live to close too the planet,
inside what's called the Roche limit, the farthest orbit where a planet’s gravitational
force is powerful enough to disintegrate larger bodies of rock or ice that get too close.
Any large object that crosses this limit, is torn apart by Saturn's powerful gravity,
which is possibly another theory as to what caused the rings in the first place.
However, it is possible, that the moons orbiting farther out, did form from this ring of debris.
Shepard moons such as Atlas, Epimetheus, Pandora, Daphnis or Pan for example all orbit Saturn at the
edge of the Roche limit, and likely formed from the same violent event that created the rings.
The innermost of these moons may even be the larger shards of the ancient destroyed
moons that have been growing by collecting up the ring material
since their birth possibly less than just a few hundred million years ago.
These shepherd moons wield enough gravity to herd icy ring particles
into place. Some like Atlas almost seem to tend to the rings by neatening the edges.
Others, like Pan and Daphnis, look as though they are mowing lanes between the rings.
But the rings sculpt the moons too, coating them with colorful
mounds of ice and crafting some unusual shapes. These young moons, it seems,
are the children of the destroyed. Slowly growing at the edge of their parent's grave.
So with the discovery of these objects is the suggestion that not everything
in the solar system formed over four and half billion years ago,
these moons could have formed as recently as 10 million years ago.
It is also quite possible that new moons are forming even today, right at this very moment.
The future of Saturn’s rings isn't known, some studies say it will slowly fall into
the gas giant, until in about 300 million years from now, it will vanish from view.
But in our age, the rings of Saturn are one of the
greatest wonders of the solar system. A place of destruction and creation.
A testament to how beautiful yet complex our tiny region of the universe can be.
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there is plenty more to come. Thank you for watching and I'll see you next time.