As promised, here is another look at this
image I mentioned in the Saturn video.
Find that video here if you haven’t seen
it already.
I said I was going to go into a lot more detail
as there’s so much to talk about in just
this one image.
So firstly, to give you a sense of scale,
this image is about 400,000 km across from
edge to edge.
In truth though, this image has also been
enhanced to make fainter objects brighter
in comparison to the very bright objects around
them.
NASA says this image as you see it now is
a balance between reality and beauty.
But know that nothing has been added, only
brightened.
Now normally this bright blue ring is not
visible on most pictures of Saturn.
The reason we see it now is because the Sun
is directly behind Saturn, and being in the
planet’s shadow means fainter objects become
more apparent.
The blue colour of the is due to diffraction.
The particles in this ring are fuelled by
this little 500 km wide moon here, Enceladus.
This moon has a lot of geysers shooting particles
into space.
Captured by Saturn’s gravity, these particles
remain in orbit and form the E Ring.
In fact you can see these geysers blasting
jets of particles even in this picture.
A close up of Enceladus looks like this.
Seen in ultraviolet, visible and infrared
lights, it’s an incredibly pretty moon with
relatively few surface craters, which means
it must be active with water volcanism to
renew the surface.
In fact, it’s covered in a very thick layer
of ice, which makes it one of the most reflective
objects in the solar system.
These water, or Cryovolcanoes blast about
200kg a second into space, at speeds of over
1,600kph.
It’s thought that a liquid water ocean is
under the ice particularly near the south
pole, and it’s under enormous pressure,
hence why these cracks are formed and water
is escaping.
Also in the vicinity of the E Ring are the
moons Tethys and Mimas.
Tethys is the biggest moon of Saturn in this
picture, being over 1,000km across.
It’s not too colourful as you can see and
has huge impact craters and rift valleys.
The biggest crater in particular makes it
look like a giant eyeball.
The biggest fault line is a massive 2000 km
long.
Like Enceladus, it is also covered in ice
and ice the second brightest moon of Saturn.
Mimas, on the other side of the picture, can
be seen creating a long shadow through Saturn’s
E Ring.
This is the moon that has been nicknamed the
death star due to its similar appearance!
It’s about 400km across and too is thought
to be made up mostly of water.
Let’s zoom out again.
The next closest ring to Saturn is the Pallene
ring.
It is very faint, but if I zoom in, it’s
this band through the center of the screen.
It’s named after the tiny Pallene moon,
which the Cassini probe actually discovered.
Pallene itself can’t be seen in this image,
as it’s less than 3km across, but it’s
thought this ring is the residual remains
of meteoroid impacts with the moon.
The next ring is easier to see again, the
G ring, and the next is the Janus/Epimetheus
Ring.
We’ll have to zoom in again to see that.
Like the Pallene Ring, it is made up of the
particles which have been knocked off the
two co-orbital moons, Janus and Epimetheus.
While still very tiny moons, they are big
enough to be seen in this image.
Janus is here, and Epimetheus is here.
Janus is about 200km across and Epimetheus
only 130km across.
And when I say they are co-orbital moons,
I really mean that.
Janus’ mean orbital radius is roughly 50km
less than Epimetheus, but this could change
every time the moons catch up with each other,
which happens about once every four years.
They last switched positions in 2006.
The next ring we see is the bright F Ring,
which houses the two shepherd moons, Prometheus
and Pandora.
I spent some time already discussing Prometheus
in the Saturn video so I won’t do it here,
but here you can see it tucked away inside
the F Ring.
Pandora is right on the other side.
Pandora is slightly smaller than Prometheus
at 81km across, but is found on the outside
of the F Ring instead of the inside.
Prometheus and Pandora can also get close
to each other, and whenever that happens they
perturb each other’s orbit.
They are called shepherd moons because they
keep the F ring narrowly confined, sometimes
even stealing some of the material themselves
when they get too close.
To finish talking about the rings, we have
the A, B, C and D rings.
Again look at the other Saturn video for more
info on them.
Finally, let’s look at the different planets
we can see here.
Yes, even though they are millions of kms
away, we can still see some of the solar systems
inner planets.
Mars is just above the E ring here, next is
Venus situated between the Pallene and G Ring,
and finally here we are on Earth, these blueish
few pixels.
That pixel jutting off the side of Earth is
actually our neighbour, the Moon.
