Peter Ward, an investigator for the NASA Astrobiology Institute, discussed his new book Life as We Do Not Know It, which ponders the possible existence of alien life. Ward believes that scientists need to expand their classifications of what constitutes "life" and include such forms as viruses.He also argued that scientists should be open to the possibility that silicon or carbon-silicon bonds can generate lifeforms.

Ward reviewed the likeliest places for life in our solar system:

• Mars-- could likely have bacterial life but doubtful whether plants or higher forms are there.
• Venus-- might have a type of sulphuric acid-based life in its clouds.
• Jupiter's moon Europa-- An exciting target, with its 100 mile deep ocean.
• Saturn's moon Titan-- Contains lakes of methane that could foster carbon-silicon bonds which seem to work better at colder temperatures.

Life on Titan would be the most alien imaginable, said Ward, who advocated for manned missions to explore there even though it would take seven years for a crew to arrive. Visualizing what form alien life might take, he described single celled entities that could aggregate together to form huge spheres. Ward also touched on the efforts to synthesize alien life in various NASA labs. So far, microbial life has been created that from a chemical standpoint is unlike anything on our planet, he noted.