Imagining early Earth as an exoplanet can help us search for alien life, scientists say

An interesting report showing where astrobiology is at. I note some comments in the article.

"Looking at Earth's life history, he said, provides an accessible framework to understand how microbes may behave on other planets, although such avenues might not tell us the whole story. But through his research on evolution, Goldman and collaborators are trying to understand scenarios by which life may arise. Today's life, he says, is cellular and based on DNA, but neither cells nor DNA were present in the earliest forms of life on Earth. By association, "these were things that had to evolve in early evolutionary history," he said. "So understanding how and why these characteristics of life evolved on early Earth can inform whether or not we would expect the same things to be present in extraterrestrial organisms."

Q: Does the fossil record show this about early life? I read about microorganisms dated some 4.28 billion years old in the Precambrian but nothing about life not having DNA or cells in those examples. This looks like abiogenesis experiments used to interpret the fossil record without evidence and using abiogenesis experiments that failed to create life from non-living matter as well as experiments that do not show the mix of gases used compared to what is needed to defend against the Faint Young Sun.

"Being a biologist, Kaçar said, is a vocation where you can study life across the universe. "Astrobiologists are going to change that," she said of the field of biology. "And that makes our job a really, very special one."

Okay, astrobiology is a science and will show life is out there, somewhere. At present, astrobiology is still seeking to confirm such a paradigm, i.e. necessary demonstration from nature.