There’s a strong possibility of extraterrestrial life on the Jovian moons of Callisto, Europa, and Ganymede, but the idea of life on Jupiter itself seems far-fetched based on our current understanding of what life is and how it subsists.
Universe Today reached that conclusion last week in its article on the question:
“While the cloud tops could harbor life that is resistant to solar radiation, the atmosphere is in constant chaos. Convection forces the lower atmosphere upwards and colder areas of the atmosphere are constantly being sucked closer to the core. The churning would eventually expose any organisms to the extreme pressures nearer the core, thus killing any that may develop.”
When I was a child growing up in the 1980s, I ran across an astronomy picture book that speculated that jellyfish-like creatures might evolve on gas giants. The problem with gas giants is that their physiology is as close to that of a star as it is to that of a rocky planet, and presents some of the same practical obstacles to life. Assuming our understanding of Jupiter’s atmosphere is correct, the only kind of life likely to survive the planet’s extreme pressure and temperature ranges are the kinds of molecular-ecosystem life forms that might exist on neutron stars.
This doesn’t mean that there’s no life on Jupiter—but if there turns out to be any, it will either radically change our definition of life or radically change our understanding of Jupiter.