Life is a matter of physical forces and chemical reactions. We cannot yet define these "right conditions" with assurance, and the prime reason for the unmanned probes of Venus and Mars has been to search for some other form of life, and to give us more data on the limits within which life can evolve.

We are apparently out of luck with Venus, which has surface temperatures close to that of molten lead. Mercury is a lifeless ball of rock baked by the sun.

Mars is our best remaining hope as a home for extraterrestrial life, although it apparently is a dry, cold, and relatively inhospitable planet. We can imagine life surviving under present Martian conditions (even human life), but it is hard to imagine it evolving under such conditions. Perhaps Mars was a quite different planet earlier in its history.

Venus

Mars

Jupiter is rich in hydrogen, with lesser amounts of ammonia and methane, and it is not ridiculous to imagine liquid ammonia as a medium for life there instead of water. But we have no data or experience to make this more than pure speculation. Even this would still be "second-shell" life, using the same group of chemical elements as on Earth.

Beyond Jupiter, the low temperatures and resulting slowdown in chemical reactions make life hard to imagine. All that we can say is that, wherever life is found, we would expect it to be based on the firstand second-shell elements, hydrogen through fluorine.

Whether there is more than one pattern of reactions or choice of elements for life within this range, is impossible to say.

Jupiter