How life gets started: hydrothermal vents, panspermia and what counts as living
Nick Lane argues life began as chemistry in hydrothermal vents, Betül Kaçar discusses panspermia and rerunning the tape of life, and Nathalie Cabrol focuses on the nature of life and not just its origin. Their different starting points matter because the definition of life decides where and how we search for it.
Is the origin of life settled? Show answer
No. The three researchers start from different questions, and none claims the matter is resolved.
Where does Nick Lane think life began? Show answer
In alkaline hydrothermal vents, as a continuous reaction of hydrogen with carbon dioxide. He calls it a minority view.
What three features of life does Lane look for in an environment? Show answer
Cells, carbon chemistry and electrical charge across membranes. Vents supply pores, hydrogen and natural charge.
Why does Lane reject the nutrient soup idea? Show answer
A soup has no structure and no continuous growth, so saying it became alive is like invoking a miracle.
When does chemistry become biology, in Lane's account? Show answer
When information such as RNA enters a system that is already growing and reproducing, giving natural selection something to act on.
What machinery does Betül Kaçar put at the center? Show answer
Translation, the system that converts genetic information into proteins, found in every cell on Earth.
What does the genetic code suggest to Kaçar? Show answer
It is so well optimized that a great deal of evolution must have happened before the last universal common ancestor.
What is panspermia, and why do the three set it aside? Show answer
The idea that life came from space. It moves the question elsewhere and is hard to test, though ingredients do arrive that way.
What question does Nathalie Cabrol rank highest? Show answer
The nature of life. Understanding what life is would give a universal signature to search for.
What is the shadow biosphere? Show answer
The proposal that life arose more than once on Earth in forms so different that our tests cannot detect them.
What do all three expect about life elsewhere? Show answer
Simple, microbial life is likely far more common than complex or intelligent life.
What finding would prove an independent origin of life on Mars? Show answer
Life built from the opposite mirror-image molecules, according to Lane.