A new study conducted by researchers at Yale and the University of Leeds suggests that lightning could have unlocked the phosphorus necessary for creating biomolecules that eventually led to life on Earth. The lead author of the paper, Benjamin Hess, says that the team’s work helps understand how life could’ve formed on Earth and how it might form on other planets similar to Earth.
Hess’ team believes that the whole process starts with phosphorus. Researchers say phosphorus is a crucial ingredient necessary for the formation of life, but billions of years ago, it wasn’t easily accessible on Earth. Phosphorus is typically locked inside insoluble minerals on the Earth’s surface.
That fact has led scientists to wonder how Earth’s phosphorus was transformed into a usable form required to help create DNA, RNA, and other biomolecules. Researchers first looked at the possibility that meteorites turned phosphorus into a usable form. The team thought that meteorites perhaps contained a phosphorus mineral known as schreibersite, which is soluble in water. However, the theory that meteorites released the phosphorus is unlikely because the number of meteorite collisions with Earth between 3.5 and 4.5 billion years ago was low.
The team believes there was another source of phosphorus found in schreibersite. Researchers say the material can also be found in certain types of glass called fulgurites. Fulgurites form when lightning strikes the ground. The glass contains some of the phosphorus from the surface rock, but it’s in a soluble form.
The researchers used computer modeling and estimated that the early Earth saw between one and 5 billion lightning flashes each year compared to about 560 million flashes per year today. Out of those 1 to 5 billion lightning flashes, between 100 million and 1 billion would have struck the ground annually. Over billions of years, that would add up to as much as one quintillion strikes and quite a bit of usable phosphorus.