Just what, exactly, are those blobs on the lander legs of Phoenix, the erstwhile mission to Mars’ northern plain? In our December feature coverage of the mission, we raised Nilton Renno’s incredible claim: that the deliquescent salt perchlorate (one of the mission’s most surprising finds), lowers the melting point of ice so much that droplets of briny water grew on the lander’s legs. While there is plenty of evidence for water ice on Mars — and evidence also that this water flowed in Mars’ geologic past — this would be the first evidence for liquid water in the present, at the surface. Phoenix took pictures that showed the blobs growing over time, and, even more provocatively, moving (but not yet devouring).

The hypothesis is percolating (perchlorating?) through the media again, now that Nilton, a University of Michigan professor, is preparing to talk on the subject next week at LPSC. As far as I can tell, little has changed since December: Nilton says that the conditions for briny water under the lander make thermodynamic sense, whereas other members of the Phoenix science team say no, the legs are too cold, and those blobs are just nuggets of frost.

It’ll be a shame if this terrific scientific dispute can’t be resolved. Let’s hope something comes out of LPSC next week. Stay tuned for more from our “In the Field” blog.