The Last Planets
Next to Jupiter are Saturn, Uranus and finally Neptune. Saturn
is the second largest planet in the solar system. Like Jupiter,
Saturn and Uranus are made up of gases. All three planets have
rings, but it is Saturn’s rings that are the most spectacular.
Quick Q’s:
1. How big are Saturn’s
rings?
Saturn’s rings can
be up to 1 kilometre
(0.6 miles) thick
and stretch for over
280,000 kilometres
(175,000 miles).
2. When were Saturn’s
rings discovered?
Saturn’s rings were first
observed by Galileo
through a telescope
in 1610.
3. Who discovered
Uranus?
Uranus was the first
planet to be seen
through a telescope.
It was discovered in
1781 by astronomer
William Herschel.
Q Why do Saturn’s
rings shine?
A Saturn’s rings
consist of dust particles
and pieces of ice that
can be quite large. The
ice pieces reflect light,
causing the rings to shine.
Q What gives Uranus and Neptune
their blue colour?
A Both planets contain methane. Sunlight
is reflected by clouds under the methane
layer. Only the blue portion of the reflected
light passes through the methane layer, so
they appear to be blue.
Q Why do seasons on Uranus last for
over 20 years?
A Uranus has a very peculiar orbit, unique
in the solar system. The planet is tilted in
such a way that its poles face the Sun directly,
so that Uranus spins from top to bottom. It
acts like a cylinder that is rotating on its ends
instead of rotating on its sides. Scientists
believe that another planet-like object might
have crashed into Uranus, knocking it over
on to its side. The long seasons are caused by
the planet’s unusual orbit.
Q Are there winds on Neptune?
A Neptune is the windiest planet in our
solar system. Winds on this planet can
reach speeds of about 2,000 kilometres per
hour (1,200 miles per hour). That is more
than ten times the speed of the strongest
hurricane on Earth.
Saturn’s rings
Saturn has seven large
rings, each made up of
thousands of smaller
rings. These are among the
brightest objects you can
see through a telescope.
Cloudy over Neptune
The clouds over Neptune are always being blown about
by the strong winds on the planet.
Strange rotation
Uranus rotates from top to bottom as it orbits the Sun.
Probing far
The Cassini space probe is expected to send us better
photographs of the far planets.
3
4
5
1
2
URANUS
1 Pole
2 Equator
3 Juliet
4 Bianca
5 Puck
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