here are no known post-Big Bang processes which would produce
significant amounts of deuterium. Hence observations about deuterium
abundance suggest that the universe is not infinitely old, which is in
accordance with the Big Bang theory.
During the 1970s, there were major efforts to find processes that
could produce deuterium, which turned out to be a way of producing
isotopes other than deuterium. The problem was that while the
concentration of deuterium in the universe is |