The second largest moon of Uranus and the
18th in order from the planet. Oberon was discovered by William Herschel
on Jan. 11, 1787. It is named after the king of the Fairies in Shakespeare's
A Midsummer Night's Dream and is also known as Uranus IV.
| Oberon, imaged by Voyager 2 on Jan. 24, 1986, from
a distance of 660,000 km.
Oberon's heavily cratered surface, featuring far more and larger craters
than do Ariel or Titania,
is clearly ancient. Some of the craters have bright rays similar to those
seen on Jupiter's moon Callisto
and some of the crater floors are dark – covered perhaps with a mixture
of carbonaceous substances and ice that erupted from below. Large faults
run across the entire southern hemisphere, indicating geologic activity
in Oberon's youth. In the image shown here, note the large mountain, about
6 km high, that stands out on the lower left limb.
||1787, by William Herschel
||582,600 km (361,860 miles)
||1,523 km (947 miles)
||0.729 km/s (2,624 km/h,
||13.463 days (13 d 11 hr)