All the stars, planets, and galaxies that can be seen today make up just 4 percent of the universe. The other 96 percent is made of stuff astronomers can't see, detect, or even comprehend.
These mysterious substances are called dark energy and dark matter. Astronomers infer their existence based on their gravitational influence on what little bits of the universe can be seen, but dark matter and energy themselves continue to elude all detection.
"The overwhelming majority of the universe is: who knows?" explains science writer Richard Panek, who spoke about these oddities of our universe on Monday (May 9) at the Graduate Center of the City University of New York (CUNY) here in Manhattan. "It's unknown for now, and possibly forever."
In Panek's new book, "The 4 Percent Universe" (Houghton Mifflin Harcourt, 2011), Panek recounts the story of how dark matter and dark energy were discovered. It's a history filled with mind-boggling scientific surprises and fierce competition between the researchers racing to find answers.