The universe contains much less lithium than the Big Bang predicted
Modern chemistry and the Big Bang theory agree on almost everything, except for a missing stash of lithium that seems to have vanished.
According to our best models of the early universe, the first few minutes after the Big Bang should have produced a specific amount of lithium-7. However, when astronomers point their telescopes at the oldest stars in the galaxy, they find only one-third of the expected amount. This 'Lithium Problem' suggests that either our understanding of the birth of the universe is flawed, or something is systematically destroying this element.