The Difference Between Dark Matter, Dark Energy And Ghosts

The Difference Between Dark Matter, Dark Energy And Ghosts : 13.7: Cosmos And Culture : NPR: "Over the last few decades, scientists have built a new picture of the universe where about 95 percent of its stuff comes in a "dark" form (27 percent being dark matter and 68 percent being dark energy). But what exactly do physicists mean when they talk about something being "dark?""