Whenever we ask our star dome visitors to name the Solar System ringed planets, a choir of voices immediately says “Saturn”. A few people mention Uranus and, occasionally, Neptune. In fact, all the gas planet in the Solar System, Jupiter, Saturn, Uranus and Neptune, have rings around them. Maybe not as spectacular as those of Saturn, but still very interesting and even puzzling for astronomers. So let’s look at the less famous rings of Jupiter, Uranus and Neptune and learn about their origin, structure and composition!

1. Rings around gas giants in the Solar System

2. Rings of Uranus

3. Discovery
The rings around Uranus were first officially discovered in
1977 by J.L. Elliot, E. Dunham and D. Mink. The team of
astronomers spotted the rings using NASA infrared
telescope installed on transport aircraft. First they found
five main rings of Uranus, then another four during the
follow-up observations. The last four known rings were
discovered by the mighty Voyager-2 spacecraft and
Hubble telescope.
The discoverer of Uranus, German-British astronomer
William Herschel, also claimed that he observed one of
the rings of Uranus back in the 18th century. But neither
his own follow-up observations, nor the observations of
the other astronomers in the two following centuries could
not confirm the discovery. Most scientist agree that
Hershel could not have seen the ring with his telescope.
But other works point out that the position, orientation and
appearance of the ring described by Hershel is consistent
with modern observations of the biggest Epsilon ring.
Additionally, there is a number of reasons why the ring
was not visible again for so long. Mystery!

4. Composition and structure
At the moment we know 13 faint rings of Uranus. The
particles that make up the rings vary in sizes from grains
to 20 meter boulders. The rings contain very little dust.
They are thought to be made of ice mixed with some
organic material.
Origin
Astronomers think that the rings of Uranus formed when a
few of the planet’s moons collided (boom) and smashed
(ouch) to pieces some time 600 million years ago.

5. Rings of Jupiter
Two years after the discovery of Uranian rings, scientists
were surprised to find another ring system, this time around
the gas giant Jupiter.
Discovery
The rings were discovered not from Earth, but from space, by
Voyager-2 spacecraft in 1979 and later explored in more
detail by the space missions Galileo, Hubble, New Horizons
and Cassini.
Composition and structure
The faint rings of Jupiter are made of dust. There are four
distinctive rings in the Jovian system: the innermost halo
ring, the main ring and the two outer gossamer rings.
Origin
Scientist think that Jupiter’s ring system is about the same
age as the planet itself but the dust particles in the rings are
quite young.
The gossamer rings are called Amalthea and Thebe by the
name of the moons that “feed” the rings with dust ejected
from their surfaces during collisions with the particles from
the outside of the system. The two innermost rings are fed
the same way by the moons in the main ring.

6. Rings of Neptune
Rings around Neptune were the last to be discovered.
Discovery
In 1989 Voyager-2 zoomed past planet Neptune and finally confirmed the long
suspected existence of the rings. Starting from the discovery of Neptune many
astronomers reported seeing the events that hinted the presence of the rings but
the observations were inconsistent.
Composition and structure
Neptunian rings resemble those of Uranus, but contain much more dust (up to
70%).
There are five rings in the Neptunian ring system. They bear the names of the
scientists who made major discoveries about the planet:
•Galle made the first direct telescopic observations of planet Neptune based on
the calculations of the planet’s position he received from Le Verrier.
•Le Verrier discovered planet Neptune using only pen and paper. It was known
that Uranus’ actual orbit is slightly different from the theoretically predicted one.
Le Verrier thought that another planet’s gravity tugs on Uranus pulling it slightly
off-course. He calculated the new planet’s mass and position.
•Lassell discovered the Neptune’s biggest moon Triton just 2 weeks after the discovery of the planet itself.
•Arago suggested that his student Le Verrier studied the peculiar orbit of Uranus.
•Adams (independently from Le Verrier) used mathematics to predict the existence of Neptune. Adams ring
contains five bright arc-shaped dust structures. Scientists are not sure why the arcs don’t fall apart and and the
dust particles in them don’t spread over the whole ring.

7. Origin
Astronomers think that the rings of Neptune might be of
the same age and origin as the rings of its neighbour
Uranus and appeared after the fatal collision of some of
the Neptune’s former moons.
So it turns out Saturn’s rings are not unique. But they are
still out favourite!
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