Finding evidence for the first life ever to emerge on planet earth is a long, tough slog. But oddly enough, real answers may ultimately come from Mars.

As Earth cools, a crust forms over it. Mounded bacterial formations called stromatolites appear in shallow waters of the early oceans, and small land blocks collide with one another to produce the ...

These are preserved examples of what are called stromatolites. They are created when many millimetre-scale layers of bacteria and sediment build up over time into larger, dome-like forms.