Scientists are re-thinking how to go about finding life on Mars, per a Scientific American dispatch from a recent conference of astrobiologists, geologists and others.

Key takeaways:

• Maybe we don't have to find life in water. Here on Earth, there are organisms that can survive without water for years and come back to life when conditions are wetter.
• We may have to drill into Mars to find evidence of past life. Yesterday, astrobiologists reported finding fossils of primitive microbes on Earth in what is today a hot, dry region of Australia that once had hot springs. Mars could have had the same environment in its past.
• Microorganisms may have traveled between Mars and Earth on meteorites. Robert Hazen told me yesterday it is entirely plausible that life could have arrived here from Mars but, given the Sun's gravitational pull, it is unlikely it traveled the other direction.