ISLAMABAD-About 80 percent of all the matter in our universe is invisible. Called dark matter, this mysterious substance is known to exist throughout the universe because of its gravitational tugs on ordinary matter. Yet despite its prevalence, dark matter continues to evade direct detection. Kathryn Zurek, a new professor of theoretical physics at Caltech, has some ideas about how to change that. “I develop theories of dark matter and then ideas for how one might experimentally detect it,” she says. “It’s risky research in the sense that we don’t know if we’ll actually detect dark matter. We need luck, hard work, and good ideas.” Dark matter permeates the galaxy and the universe. We are moving through the galaxy, and as we move, that creates a dark-matter wind that is moving through this room as we speak. We know about dark matter through its gravitational effects on normal matter, but it doesn’t give off any light so we cannot see it, and we don’t know what it is made of.