Saturn Flashcards
What are the two dominant rings of Saturn, and what divides them (name in order closest to the sun) (Which is the brightest and most massive)
From the closest to Saturn of these, which two less visible ring sets orbit closer still to saturn
B-ring (the brightest and most massive)
Cassini Division
A-ring
(D-ring and C-ring, with the former being closest to Saturn)
What are the next three moons after Mimas in size order
Hyperion
Phoebe
Janus
How many satellites does Saturn have, and how many have been named
82 officially recognised
53 named
What is noticeably different about the orbit of Iapetus compared to the other major moons
What three other features/facts is Iapetus remarkable for
Its not in the same plane (cause unknown)
It is the largest body in the Solar System known not to be in hydrostatic equilibrium
Its famous two-tone colouring
A massive equatorial ridge running 3/4 the length of the moon
Why is Tethys bright
It gets sandblasted by particles from the E-ring
Who first discovered the split in Saturn’s rings
Who first determined the true nature of Saturn’s rings
Giovanni Cassini (of course) in 1675
James Clark Maxwell in 1859 (showing through maths that they could not be solid planes or ringlets)
What allows Saturn’s rings to stay bright
collisions (otherwise they would become darker because of the accumlation of dust)
You known the order of the major moons, but what about the order by size
Titan,
Rhea
Iapetus
Dione
Tethys
Enceledas
Mimas
Who (and when) discovered Saturn’s rings
Who had nearly discovered Saturn;s rings
Christian Huygens (in 1655), the same year he discovered Titan
Gallileo in 1610, but he accounted what he saw to two big-moons.
Which two moons did Cassini discover in 1684
Dione and Tethys
(he had discovered Rhea and Iapetus earlier)
What is the remarkable feature in Saturn’s northern hemisphere
A long-lived hexagonal cloud structure more than 27,000km across on the the north polar region
Thought to be caused by circumpolar jet stream, and its unlike any other storm yet seen in the Solar System
The soutern pole is also dominated by a large storm
How many more time more massive is Saturn than the Earth
95.2
What ring is famously created by particle ejected by cryovolcanism from the tiger-stripes of the southern polar region of Enceledas.
Betweem the orbits of which moons can it be found
- what is unusual about this ring compared to the other main rings
- what does this ejecta mean from Tethys, the next moon out
The E ring. It is distributed between the orbits of Mimas and Titan
It is 2,000 km wide (c.f. tens of meters of other rings)
Particles of the E-ring tend to accumulate on moons that orbit within it. The equator of the leading hemisphere of Tethys is tinted slightly blue due to infalling material. The trojan moons Telesto, Calypso, Helene and Polydeuces are particularly affected as their orbits move up and down the ring plane. This results in their surfaces being coated with bright material that smooths out features.
Hyperion
Hyperion is one of the largest bodies known to be highly irregularly shaped (very spongy looking too), often assumed to be the remains of a larger moon broken up by an ancient collission
It likes between Titan and Iapetus
What is Saturn’s axial tilt
26.7 degrees similar to earth so has seasons in a similar way)
Why is Saturn much less dense than Jupiter
Its a lot less massive, that allows its outer layers to expand out further, and with that greater volume its density decreases
What element dominates in Saturn, even out to its 1,000km atmosphere
What are the clouds in the atmosphere made from (by upper and lower layers)
What gives Saturn its colour
Hydrogen
clouds are from ammonia compounds and water
In the upper atmosphere clouds are ammonium hydrogen sulphide and in the lower levels its water ice
The ammonium compound haze gives Saturn its colour
How far from the Sun is Saturn (in AU)
9.58
How long is a day on Saturn
10.66 hours
Why is the cryovolcanism on Enceladus
It lies in an orbital resonance with Dione, so basically it is due to the competing gravity of Dione and Saturn producing tidal heating
How long does Saturn take to orbit the Sun
29.46 earth years
What is the name of the reoccuring giant feature on Saturn, and who first discovered it
Great White Spot (here seen stretching out)
Asaph Hall in 1876 (and famously be comic actor Will Hay in 1933)
What interested feature did NASA scientists report seeing in April 2014 on the A-Ring
possible formative stage of a new moon near the outer edge of the A-ring
What is the gravity of Saturn at the equator
1.02
Why haven’t the main rings collesced into a single moon
they are within Saturn’s Roche lobe, so its gravity won’t let them do it.
How much more energy does Saturn pump out than it receives from the Sun, and why
2.5
essentially it is still under gravitational contraction and the sorting of less/more dense material acts as a heat pump
what is thought to have triggered to two tone colouration of Iapetus
dust from collisions on the moon Phoebe
claim to fame
Phoebe - thought to be a captured planetesimal from the Kuiper belt.
It was the first satellite to be discovered photographically (It was discovered by William Henry Pickering on 17 March 1899 from photographic plates that had been taken starting on 16 August 1898 at the Boyden Observatory near Arequipa, Peru, by DeLisle Stewart)
What is the cloud top temperature on Saturn
-140C
What is the equitorial diameter of Saturn in km
What is you include the main elements of the ring-system
120,536km
>270,000km
Which ring is the outermost discrete ring of Saturn (main rings), and also the most active ring in the solar system
When was it discovered
What moons hold it together
F-ring
Its features change on a timescale of hours
Discovered in 1979 by Pioneer 11
Held together by Promotheus and Pandora, which orbit inside and outside it.
Who (and when) discovered the moon Rhea
What is its one interesting point
Where does it rate in solar system moon sizes (diameter in km, if you feel like it)
It was discovered in 1672 by Giovanni Domenico Cassini.
It is the smallest body in the Solar System confirmed to be in hydrostatic equilibrium.
It is the ninth largest, and tenth most massive moon (c1530km diameter)
Phoebe Ring, discovered in Oct 2009
- It was discovered using NASA’s infra-red Spitzer Space Telescope, and was seen over the entire range of the observations, which extended from 128 to 207 times the radius of Saturn
The ring’s particles are presumed to have originated from impacts (micrometeoroid and larger) on the moon Phoebe
What is the walnut (flying saucer) shaped second-innermost moon of Saturn
Within what Gap (and ring system) does it orbit
What is the other flying saucer shaped moon that orbits at the outer edge of the same ring, thereby constraining the outer edge of the ring
Pan (only 28km average diameter)
Encke Gap of the A-Ring
It is responsible for keeping the gap free of material
Atlas (onlu 30km mean diameter) - is the shepherd moon of the outer edge of the A-Ring
What is the name of the huge rift zone on Tethys that runs nearly three quaters of the way around the moon
Ithaca Chasm
Which two moons orbit in the Lagrangian points of Tethys
and which two in the Lagrangian points of Dione
Tethys: Telesto and Calypso
Dione: Helena and Polydeuces
How many moons of Saturn are tidally locked
16
What two moons are known as the Siamese twins of Saturn because they are in nearly the same orbit (a 1:1 resonance)
What interesting thing do they periodically do
Epimetheus and Janus (5th and 6th closest to Saturn respectively)
They periodically swap orbits
Epimetheus and Janus may have formed by the break-up of one moon. (Albeit if they did so, it was early in the life of Saturn, becauase of the age of their surfaces)
Where is the F-ring, and what ring is the next one out (and what is next after that)
It is the next one out from the A-Ring,
After F it is G Ring, then E Ring
What is the two names for the 29 outer moons that orbit Saturn in a retrograde motion
The Norse Group (or the Phoebe Group)
Which moon is responsible for the Cassini Division and why
Mimas
The CD is in a 2:1 resonance with Mimas
What are the two subgroups within the Norse Group of satellites
What do the norse group have in common
Skathi subgroup
Narvi subgroup
The Norse group, are retrograde irregular satellites
Aside from the major satellites and Norse group,
what are Saturn’s two other notable moon groups
For kudos what are the two main moons in these groups
Who many moons are in the Norse group?
Inuit Group - Siarnaq (40km across) - five prograde moons
Gallic Group - Albiorix (32 km across) - four prograde moons
both probably formed from the break up of a larger progenitor
29 Norse moons
How old are Saturn’s rings thought to be?
What is the best guess (it isn’t known for sure) of where the rings come from
A few hundred million years
A single moon, half the mass of Mimas may have been torn apart.
It could potentially be cyclical, with rings turning into moons, and moons turning into rings
What was the first spacecraft to visit Saturn and in what year
What was its main discovery
Pioneer 11 in 1979
The F ring
When did voyager 1 and later voyager 2 pass Saturn
V1 - 1980
V2 - 1981
They both provided great details on the rings
What was the first spacecraft to orbit Saturn
What year
Cassini
2004
