Part 5/9:
Current observations reveal a striking inconsistency: the predicted amount of lithium in the universe based on Big Bang nucleosynthesis is approximately three times greater than what is measured today. When astronomers examine the light from stars, particularly ancient or primordial stars, they find an abundance of hydrogen and helium as expected, but a stark lack of lithium.
Moreover, researchers have found disproportionate levels of lithium-6—an isotope that is supposed to exist in far lesser quantities compared to lithium-7, the more stable variety. Some primordial observations suggest lithium-6 is found to be a staggering 1000 times more prevalent than anticipated. This discrepancy prompts scientists to reconsider longstanding assumptions regarding the conditions of the early universe.