5 Million Miles From Io
Explanation:
Twenty years ago this month, NASA's
Voyager 1 spacecraft flew past Jupiter and its moons.
This sharp picture
of moon Io against a background of
gas giant Jupiter's diffuse swirling cloud bands was
recorded by Voyager's camera
from a distance
of about 5 million miles.
Even
this early image shows curious round features on Io's surface with
dark centers and bright rims more than 40 miles across.
Now known to be
volcanic in origin,
these features were then thought likely to be impact craters,
commonly seen on rocky bodies throughout
the Solar System.
But as
Voyager continued to approach Io, close-up pictures
revealed a bizarre world devoid of impact craters,
frequently
resurfaced by volcanic activity.
In fact,
Io's volcanism is so intense that subsequent Voyager images produced
an astounding discovery -
the first observed
extraterrestrial volcanic eruptions.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
