Lightning strikes could explain life on Earth

Lightning strikes on the early Earth over the course of 1 billion years could have been key to the formation of the first life on our planet, according to a new study.

The big question: What triggered the first forms of life to develop on Earth? This new study may help scientists find an answer to that enduring question.

What they found: The new study — in the journal Nature Communications — suggests trillions of lightning strikes spanning about 1 billion years helped create phosphorous, a key ingredient in the formation of life.

• During Earth's early days, more than 4 billion years ago, phosphorous — locked inside of minerals — wasn't easily available.
• Scientists have long thought meteorites rich in schreibersite — a soluble phosphorous mineral — may have crashed into Earth, allowing for the creation of life.
• Meteorites, however, don't fall to Earth at a consistent rate each year, making it harder to know just how much soluble phosphorous those space rocks could have created. But lightning is constant and can create glass containing soluble phosphorous as well, the authors of the study argue.

“This work helps us understand how life may have formed on Earth and how it could still be forming on other, Earth-like planets,” Benjamin Hess, an author of the new study, said in a statement.

Yes, but: Scientists aren't actually sure that the early Earth had much land at all. Some research today has pointed to the idea that our planet was once a world covered almost entirely in water.

• "The thing that gives me pause about this work is the assumption that there is plenty of land on the early Earth directly exposed to the air," Michael Wong, a researcher at the University of Washington who is unaffiliated with the new study, told me.
• "And even though there might have been some continental crust, that is not to be mistaken for land that is exposed to the air because you could have continental crust emerge completely underneath a very large ocean."