See: http://www.bbc.com/news/science-environment-26553115
There has been a question among geologists about whether hydrogen is an essential element in the earth's makeup, or whether it was brought in from elsewhere (e.g., from comets). The new finding suggests that hydrogen has been here from early on. I find it interesting that there is evidence for large amounts of water (and hydrogen) deep within the earth, together with a lot of nickel and iron. Eric
