Search for life on Mars may be misled by ‘pseudo fossils’

Distinguishing between so-called pseudofossils and what could be evidence of past life on Mars is key to the success of current and future missions to search for traces of life on the Red Planet. About 4 billion years ago, Mars must have been temporarily habitable as we know it.

Astrobiologists from the University of Edinburgh and Oxford University have studied all the known processes that could have created fossil-like deposits in rocks on Mars.

They have identified dozens of processes—and possibly many yet to be discovered—that could form structures very similar to those formed by simple microscopic life forms that may have lived on Mars before.

Among the “real-life” samples that can form these processes are deposits resembling bacteria cells, and carbon-based molecules very similar to the building blocks of all life as we know it.

Because traces of life can be well imitated by non-biological processes, the origins of any fossil-like samples found on Mars are likely to be very mysterious, the researchers say.