The search for life in the solar system involves following the water and looking for the building blocks of life. In the next decade, we could possibly find evidence of past life on Mars, which had an atmosphere and a wonderful gravity level, making it a good candidate for carbon-based life.
This podcast discusses the challenges of searching for life on Mars and the discovery of microorganisms in UV environments that resemble those that made the first fossils on Earth.
The possibility of life on Mars and other planets is discussed, with the idea that life may have started on Mars and seeded Earth, as Mars was habitable before Earth for the type of chemistry that life on Earth is based on.
Life detection on Mars involves a series of steps that make the possibility of discovering life more and more unlikely, but still doesn't provide unambiguous evidence. Indirect evidence of existence, like carbon left by the activity of life, could be found on Mars.
The search for life beyond our planet is fueled by the possibility that there may be other forms of intelligent life that exist outside of our planet, especially since we know that the conditions to sustain basic life forms may exist on other planets.