life on Jupiter
There has been much speculation that any life on Jupiter,
or on other gas giants, might be ammonia-based
life. The possibility of "abundant biota" in the upper regions of Jupiter's
atmosphere was considered in a 1976 paper by Carl Sagan
and Edwin E. Salpeter1, three years after the fly-by of the first
Jupiter probe, Pioneer 10. Sagan and Salpeter
compared the ecology of the Jovian atmosphere with that of terrestrial seas
which have simple photosynthetic
plankton at the top level, fish at lower
levels feeding on these creatures, and marine predators which hunt the fish.
The three hypothetical Jovian equivalents of these organisms, Sagan and
Salpeter termed "sinkers", "floaters", and "hunters". They envisaged creatures
like giant gas-bags (see bubble life)
that move by pumping out helium and calculated
that the "hunter" variety might grow to be many kilometers across (and therefore
visible from space).
|A true-color simulated view of Jupiter composed of
4 images taken by the Cassini spacecraft on Dec. 7, 2000. To illustrate
what Jupiter would have looked like if the cameras had a field-of-view
large enough to capture the entire planet, the cylindrical map was
projected onto a globe. The resolution is about 144 km (89 miles)
per pixel. Jupiter's moon Europa is casting the shadow on the planet
|Artwork by Paul Calle of hypothetical
life in Jupiter's atmosphere
Jovian aerial life-forms like those described by Sagan and Salpeter are
portrayed in Arthur C. Clarke's short story
"A Meeting with Medusa" (in The Wind From the Sun). Ben Bova
refers in his novel Jupiter to
"[H]uge balloonlike creatures called Clarke's Medusas that drifted
in the hurricane-like winds surging across the planet. Birds that have
never seen land, living out their entire lives aloft. Gossamer spider-kites
that trapped microscopic spores. Particles of long-chain carbon molecules
that form in the clouds and sift downward, toward the global ocean below."
Bova speculates further that, in the high-pressure, liquid hydrogen ocean
that lies below Jupiter's thick atmosphere, are colossal, city-sized creatures
with intelligence. He follows the exploits of one of these sentient giants
Predators swarmed through Leviathan's ocean: swift voracious
Darters that struck at Leviathan's kind and devoured their outer members.
In recent years, astrobiological interest in the jovian system has shifted
from Jupiter itself to its larger moons, especially Europa,
Ganymede, and Callisto.
Read also about the possibilities for life on Mars,
Venus, and for extraterrestrial
life in general.
- Sagan, C., and Salpeter, E. E. "Particles, Environments and Possible
Ecologies in the Jovian Atmosphere," Astrophysical Journal Supplement,
32, 737 (1976).
FORMS OF LIFE