by Maia Weinstock
spacecraft, which has been diligently orbiting Jupiter for seven years, will soon meet a fiery demise. Yet even as its fuel dwindles and its instruments begin to fail, Galileo
continues to surprise scientists.
|Jupiter's moon Io (top) is the most volcanic world in the solar system. Galileo images show flows of dark lava and colorful sulfur ash from the volcano Culann Patera (middle). White patches might be sulfur dioxide snow (bottom right). |
Photograph courtesy of NASA/JPL.
In November Galileo
made its closest pass yet to Jupiter, skimming 89,000 miles above the planet's upper cloud layer. This approachthe 34th loop around Jupitersent the probe deep inside the planet's powerful radiation belts. A barrage of protons temporarily immobilized Galileo
's tape recorder, but engineers managed to recover data about Jupiter's magnetic field and its thin rings. During that same orbit, Galileo
made a close flyby of Amalthea, a ruddy, potato-shaped moon. Amalthea's gravitational tug on the spacecraft was far weaker than expected. Torrence Johnson, Galileo
project scientist at NASA's Jet Propulsion Laboratory, says the 170-mile-wide body is probably "a very porous rubble pile, made of light rock mixed with ice and a fair amount of empty space." NASA has also just released five new images of giant red-and-black volcanoes and lakes of sulfurous lava on Io, a hellish satellite the size of Earth's moon.
In September Galileo
will plunge into Jupiter's atmosphere, a strategy devised to prevent the spacecraft from contaminating Europa, the icy satellite that some scientists say could harbor life. But the probe will keep working to the end, gathering data about Jupiter's magnetosphere before burning up like a shooting star.