News Archive
http://solarsystem.jpl.nasa.gov/news/display.cfm?News_ID=1095
How Small Can Life Be?
16 Jul 2001
(Source: NASA Astrobiology Institute)
http://nai.arc.nasa.gov/index.cfm?page=small_life
By Leslie Mullen, Science Communications
NASA Astrobiology Institute
...
"Simpler forms of life are conceivable and probably existed early in the history of life," says Knoll. "One might envision a simple cell with only one class of informational macromolecule that would fit into a 50 nanometer sphere. The key, of course, is making the distinction between cells of familiar biochemistry and cells that may exist but for which we have no direct observational knowledge."
Folk disagrees with the determination of the panel, however. He believes the nanobe structures, which he says commonly range between 50 and 100 nanometers across, are viable life forms.
"The limit adopted by biologists is 200 to 250 nanometers on the basis that [the structures] must be large enough to contain a DNA or RNA strand, and have the ribosomes, etc., necessary to carry on metabolism," says Folk. "My opinion is that scientists do not know enough to set arbitrary limits on life. After all, pre-Pasteur, nobody even thought there were things such as germs, and pre-1890 nobody knew there were viruses."
Folk, for one, believes the nanobes in the Martian meteorite are definitely fossil structures indicative of past life. He also believes similar life forms are present in the Martian meteorite Dhofar 019, as well as the non-Martian Allende and Murchison carbonaceous meteorites.
...
"If current nanobes can be shown to be living entities, then Earth harbors life forms whose chemistry we do not understand," says Knoll. "That would be interesting."
Although such a revelation would change our comprehension of life, Knoll doesn't think it would dramatically affect astrobiology.
"We already acknowledge that unfamiliar life is possible," says Knoll. "I don't think that it would change the philosophy or search strategy for life detection."
"Until more advanced forms are discovered, nanobacteria are astrobiology," says Folk. "Nanobacteria are the primordial life form on Earth, as well."
...
http://solarsystem.jpl.nasa.gov/news/display.cfm?News_ID=1095
How Small Can Life Be?
16 Jul 2001
(Source: NASA Astrobiology Institute)
http://nai.arc.nasa.gov/index.cfm?page=small_life
By Leslie Mullen, Science Communications
NASA Astrobiology Institute
...
"Simpler forms of life are conceivable and probably existed early in the history of life," says Knoll. "One might envision a simple cell with only one class of informational macromolecule that would fit into a 50 nanometer sphere. The key, of course, is making the distinction between cells of familiar biochemistry and cells that may exist but for which we have no direct observational knowledge."
Folk disagrees with the determination of the panel, however. He believes the nanobe structures, which he says commonly range between 50 and 100 nanometers across, are viable life forms.
"The limit adopted by biologists is 200 to 250 nanometers on the basis that [the structures] must be large enough to contain a DNA or RNA strand, and have the ribosomes, etc., necessary to carry on metabolism," says Folk. "My opinion is that scientists do not know enough to set arbitrary limits on life. After all, pre-Pasteur, nobody even thought there were things such as germs, and pre-1890 nobody knew there were viruses."
Folk, for one, believes the nanobes in the Martian meteorite are definitely fossil structures indicative of past life. He also believes similar life forms are present in the Martian meteorite Dhofar 019, as well as the non-Martian Allende and Murchison carbonaceous meteorites.
...
"If current nanobes can be shown to be living entities, then Earth harbors life forms whose chemistry we do not understand," says Knoll. "That would be interesting."
Although such a revelation would change our comprehension of life, Knoll doesn't think it would dramatically affect astrobiology.
"We already acknowledge that unfamiliar life is possible," says Knoll. "I don't think that it would change the philosophy or search strategy for life detection."
"Until more advanced forms are discovered, nanobacteria are astrobiology," says Folk. "Nanobacteria are the primordial life form on Earth, as well."
...