Cosmology is truly a remarkable science. Okay, all science is remarkable, but cosmology deals with something so neat and simple—the beginning of the Universe, where all of our reality was governed by fundamental physics. That simplicity is seen through the blurred vision of time, though. The remarkable part is how much detail we can extract from the fuzzy forms that are visible of the past.
One of those details is nucleosynthesis. The Big Bang theory predicts the elemental make up of the early Universe with amazing accuracy. Except for lithium. Lithium is either hiding, or there is an eater-of-lithium that shares an apartment with its better known cousin, the eater-of-socks. In lieu of evidence for an eater-of-lithium, scientists have been trying to figure out what might have prevented lithium from forming in the first place. One solution: a new particle that seems promising.
In the early Universe, there were no atoms or molecules as we know them today. The Universe was made up of protons and electrons that had too much energy to stick together, so they formed a kind of fluid, mixing and flowing around each other. But, as the Universe expanded, the fluid cooled, some of the protons began to stick together, grab a neutron or two, and form the first heavier elements.