Understanding the universe and our place in it is the great journey of human science, and right now the best theory of... well... everything is a concept known as the Lambda-CDM (ΛCDM) model. With observable matter only making up roughly 5 percent of the universe, this model represents dark energy (Λ) and cold dark matter (CDM), which together are believed to make up everything else. There’s just one problem—dark matter and dark energy are invisible, and only weakly interacts with gravity.