Every week, Dr. Michio Kaku will be answering reader questions about physics and futuristic science. If you have a question for Dr. Kaku, just post it in the comments section below and check back on Wednesdays to see if he answers it.

This week Dr. Kaku addresses the question of how you can create a universe from nothing. "If you calculate the total matter of the universe it is positive," Dr. Kaku says. "If you calculate the total energy of the universe it is negative, because of gravity." So what happens when you add the two together? Zero. "So it takes no energy to create a universe," Dr. Kaku points out. "Universes are for free. A universe is a free lunch."

Watch the video here:

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