Images: Life on the Seafloor and Elsewhere in the Solar System
The 3,000-pound active sulfide chimney "Roane" is retrieved from the seafloor during an expedition in July 1998 led by John Delaney of the University of Washington. Studies of geochemical conditions and microbial communities within the hot, sulfide-rich interiors of the chimneys may shed light on the origin of life on Earth and the possibility of life on other planetary bodies.
A mosaic of digital images shows the sulfide chimney "Roane" before it was retrieved from the seafloor in 1998. The fluids vented by Roane supported a variety of microorganisms.
Io, a moon of Jupiter (top), where surprisingly active volcanism was detected by NASA's
Voyager I probe (above) in 1979.
In the late 1970s, two unique research vehicles, WHOI's Alvin (above) and NASA's
Voyager I, made separate but complementary discoveries in inner and outer space. By discovering thriving biological communities near seafloor volcanic vents, Alvin helped show that water plus volcanism can support life without sunlight. Voyager I discovered active volcanism on Jupiter's moon Io, showing that volcanism was more common in the solar system than previously believed. These two ideas have only recently combined to guide scientists' search for life on other planetary bodies.
Alvin dove onto a recently erupted volcanic zone along the East Pacific Rise near 10°N, where scientists found fresh lava and huge billowing mats and clusters of bacterial products.
A simplified version of the phylogenetic tree created by Carl Woese (University of Illinois) shows the three domains of life: Bacteria, Eucaria, and Archaea. In 1993, scientists discovered massive outpourings of hyperthermophilic Archaea on erupting mid-ocean ridges.
These drawings depict two proposed models of the subsurface structure of Jupiter's moon Europa. No conclusive proof has yet been found that an ocean exists on Europa, but geologic features on its surface, imaged by NASA's
Galileo spacecraft, might be explained either by the existence of a warmer, convecting ice layer, located several kilometers below a cold, brittle surface ice crust (top model), or by a layer of liquid water with a possible depth of more than 100 kilometers (bottom model). If an ocean 100 kilometers (or 60 miles) deep existed below a Europan ice crust 15 kilometers (10 miles) thick, it would be 10 times deeper than any ocean on the earth and would contain twice as much water as the earth's oceans and rivers combined.
The icy exterior of Europa, a moon of Jupiter, may be hiding a deep ocean and interior volcanism--two necessary ingredients for life. The gravity field on Europa is about one-seventh that of the earth. NASA
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