Romain Tartèse obtained a PhD in Earth sciences, studying 300 million years old granites in Western France. He then held postdoctoral positions at the Open University in the UK, where he carried out research on water in lunar basaltic rocks brought back by Apollo astronauts 50 years ago, and at the Museum National d’Histoire Naturelle in Paris where he worked on early terrestrial life remnants in 3.5 billion years old rocks. Romain returned to the UK in 2017 where he now works as a Research Fellow at The University of Manchester. There Romain works on various topics related to the volatile and organic inventory of early Solar System objects, investigating how and when water and other volatile species were delivered to inner Solar System planets such as the Earth, and the conditions that led to the appearance of life here.

Talk: What did early life on Earth look like?

Proving that micrometre-size carbon-rich fragments found in ancient rocks are remnants of early life forms is not easy. It is thus not surprising that every new study claiming to have found evidence for traces of life in rock units older than 3 billion years faces intense scrutiny, considering how important this question is if we are to understand where we came from. The oldest widely accepted evidence for terrestrial life is found in 3.4 billion years old rocks from Western Australia. Recently, scientists of two controversial studies argue that they have identified traces of ancient life in rock units from Northeast Canada that could be older than 3.9 billion years. This early time period around 4 billion years ago also seems to correspond to an enhanced bombardment flux of the Earth by extra-terrestrial objects. It is thus natural to wonder whether the building blocks from which life originated could have been delivered by asteroidal and cometary objects during that period of intense bombardment. This talk will review what we think we know on when life appeared on Earth and the conditions at that time, and discuss the possible role played by extra-terrestrial objects in seeding the Earth with life building blocks.