In the new issue of Smithsonian, I've got an article about life on Mars. I'm not writing about anything NASA has actually found, but instead about the difficulty of just recognizing life, even if the evidence is in your hand (or in your rover's spectrometer). While the chances of life existing today on the surface of Mars aren't fantastic, a lot of researchers are pretty optimistic that there are fossils to be found. But it turns out that fossils of microbes are even more difficult to identify. You just need to consider some of the fierce debates over some of the oldest fossils on Earth--a topic I've written about before on the Loom here.
Some magazines will only let you see their articles on-line if you subscribe. Sometimes you can read the text for free. Smithsonian, incredibly enough, puts pdf's of their articles online for a month. So if you ...
