Voyager 2:
Tilted on its side so that its rotational pole points toward the
Sun,
Uranus and its
system of rings
and satellites resembled nothing so much as a bull's eye target for Voyager 2 on the third
stage of its Grand Tour of the outer solar system. A rare planetary alignment allowed the
spacecraft to visit the four giant outer planets
Jupiter,
Saturn, Uranus, and
Neptune, a feat not likely to be
repeated in our lifetimes. Voyager 2 flew by Uranus at a distance of 107,000 kilometers
(66,500 miles) from the planet's center, threading through a broad ring system of dust- to
boulder-sized particles. Ten new moons were imaged, in addition to the five moons
already known. The geological jumble of
Miranda may indicate partial
internal melting and episodic upwelling of icy material, possibly triggered by multiple
meteor or asteroid impacts with Miranda. At the time of Voyager 2's visit, Uranus's
atmosphere showed few features, possibly due to the planet's pole-on orientation to the
Sun at that time. Also unusual is the planet's magnetic field, which is tilted by 60 degrees
with respect to the rotational axis, and offset from the center of the planet by a third of its
radius. Following its historic encounter with Uranus, Voyager 2 continued on to Neptune,
and today continues its journey toward interstellar space, diving below the ecliptic
plane.
Visit the Voyager 2 Website
Both Voyager spacecraft carry a greeting to any form of life. The message is on a 12-inch gold-plated copper disk (right) containing sounds and images that portray the diversity of life and culture on Earth.
