Sitting in a small French bistro across from Pershing Square in downtown Los Angeles, Clifford Johnson held the pumpkin-hued drinking straw parallel to the table.

"Essentially, this straw has two to it. I can walk along the straw," he explained, running his index finger along the length, "or I can walk around the straw." His finger traced the object's glossy curved surface.

Johnson, professor of physics and astronomy at USC Dornsife, was explaining how the universe could hold extra, hidden dimensions.

"But let's imagine the straw is really, really long and thin, and I'm walking along the length and I don't have the equipment to look at very, very small distances." With those limitations, a traveler would only be able to see the one dimension of length ahead and behind.

Johnson motioned toward a point past the noisy traffic and pedestrians passing by, across the street. "It's basically the same as if I took the straw over there. You would see its orange length, but you wouldn't see the roundness. Still," he said, his finger again circling the straw, "notice everywhere I am in the one-dimensional universe, I could go around if I wanted to. That extra dimension is always with me."

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