We think that life came from non-life, from the increasing complexity of chemical reactions between biomolecules present on the primordial Earth. But what about the universe? How did it come to be if there was nothing before? iStockphoto hide caption

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To children the world is a vast experiment, a laboratory of how things interact with one another. iStockphoto.com hide caption

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If Gravity carries a clear message, it is that the universe is hostile to life. Courtesy of Warner Bros. Pictures hide caption

itoggle caption Courtesy of Warner Bros. Pictures

Kind of cute. But pretty stupid. A scale model of a baby sauropod in its egg. Tim Boyle/Getty Images hide caption

itoggle caption Tim Boyle/Getty Images

An illustration shows how the planet Kepler-36c might look from the surface of the neighboring Kepler-36b. David Aguilar/Harvard-Smithsonian Center for Astrophysics/NASA hide caption

itoggle caption David Aguilar/Harvard-Smithsonian Center for Astrophysics/NASA

Will we need to tread lightly, in deference to the locals, when finally do make it to Mars? Pat Rawlings/SAIC/NASA hide caption

itoggle caption Pat Rawlings/SAIC/NASA