to: The Rings of Uranus, The
THE RINGS OF URANUS:
In 1977, scientists tried to find
the exact diameter of Uranus. They planned to do so by studying how long
it took for the planet to cross in front of a specific star. As the
scientists watched, they saw the star blink out for a moment. It blinked
five times in all and then it passes out of view behind Uranus. As the
star came back out, it blinked five times once again. This made the
scientists realize that Uranus has rings.
The Voyager 2 has shown that all of
the giant planets have rings Uranus has eleven rings that circle the
planet from top to bottom. The rings are named for letters of the Greek
All of the rings are the same flat,
dark color. The dark color may come from black carbon coating the ice
that makes up the rings or methane gas. While Saturn's rings are very
bright and easily seen, it is puzzling why Uranus' is so dark. The rings
reflect very little light and only five percent of the sunlight is
reflecting back. Its rings are made of mostly ice boulders that are
three feet across. They are very narrow and flat. The widest part of
Uranus's last ring, the epsilon ring, is 60 miles across. The others are
only 1 to 2 miles and barely half a mile deep. The distance between the
rings varies between 208 miles and 1,784 miles.
The material in the rings is kept
from floating away by the gravitational force from the moons. A moon on
each side of the ring has a gravitational pull that holds the rings in
line. The moons seem to be made of the same material as the rings and
are the same flat, dark color.
We see Uranus as an aquamarine
planet. We see it as a blue planet because the reds and yellows in
sunlight are absorbed by methane gas and only the greens and blues are
reflected. The Voyager revealed very few clouds. However, the probe
detected bands surrounding the planet. The bands are believed to be
produced by convection currents. The lighter regions appear where warm
material flows upwards and the darker areas appear where the cooler
material flows downward.
The few clouds that were seen
indicate that there are strong winds on Uranus. The deep atmosphere is
very cold since it is so far from the sun. The small amount of solar
heat is spread from one place to another, most probably by the strong
winds that blow constantly.
This picture of Uranus was processed to
bring out the atmosphere, taken by the Voyager 2.