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The Illusion of Gravity

The force of gravity and one of the dimensions of space might be generated out of the peculiar interactions of particles and fields existing in a lower-dimensional realm

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Three spatial dimensions are visible all around us--up/down, left/right, forward/backward. Add time to the mix, and the result is a four-dimensional blending of space and time known as spacetime. Thus, we live in a four-dimensional universe. Or do we?

Amazingly, some new theories of physics predict that one of the three dimensions of space could be a kind of an illusion--that in actuality all the particles and fields that make up reality are moving about in a two-dimensional realm like the Flatland of Edwin A. Abbott. Gravity, too, would be part of the illusion: a force that is not present in the two-dimensional world but that materializes along with the emergence of the illusory third dimension.

Juan Maldacena is a theoretical physicist at the Institute for Advanced Study in Princeton, N.J. He is known for his contributions to the study of quantum gravity and string theory. In 2012 he received a Breakthrough Prize in Fundamental Physics.

More by Juan Maldacena
Scientific American Magazine Vol 293 Issue 5This article was published with the title “The Illusion of Gravity” in Scientific American Magazine Vol. 293 No. 5 ()
doi:10.1038/scientificamerican112005-3XKv2cHPCS1KAzeeP2ThtP

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