In this photograph of a Greenland research site, arrows indicate the structures that a 2016 team of paleontologists suggested were created by microbial life. Notice that while most of the structures point in one direction, the red arrow shows that some point in the other direction. That’s a hint, other scientists now say, that these structures did not all grow upward from the sea floor.

In this photograph of a Greenland research site, arrows indicate the structures that a 2016 team of paleontologists suggested were created by microbial life. Notice that while most of the structures point in one direction, the red arrow shows that some point in the other direction. That’s a hint, other scientists now say, that these structures did not all grow upward from the sea