Envisioning Hyperspace

Indeed, noted planetary scientist Carl Sagan learned of this possibility to his delight in the summer of 1985. At the time, he was working on a science fiction novel titled Contact and wanted his main character to traverse huge cosmic distances in very short time spans in a scientifically plausible way. Not being a specialist in general relativity, Sagan turned to one of the leading experts in that field, Kip Thorne, of the California Institute of Technology (or Caltech for short). “It occurred to me,” Thorne later wrote, “that his novel could serve as a . . . tool for students studying general relativity.” With this in mind, Thorne accepted the challenge and enlisted the aid of two of his doctoral students, Michael Morris and Ulvi Yurtsever.

After exploring the mathematical possibilities, they informed Sagan that a spacetime geometry incorporating the concept of wormholes as cosmic gateways was theoretically possible. One gateway might allow matter to enter “hyperspace,” a hypothetical region lying beyond normal space, and exit back into space

The late astronomer, planetary scientist, and author Carl Sagan depicted space travel via wormholes in his popular novel Contact.

at another similar portal. “To be sure,” John Gribbin points out, the physical requirements appear contrived and implausible. But that isn’t the point. What matters is that there seems to be nothing in the laws of physics that forbids travel through wormholes. The science-fiction writers were right hyperspace connections do, at least in theory, provide a means to travel to distant regions of the universe without spending thousands of years puttering along through ordinary flat space at less than the speed of light.

Sagan’s inquiry and the Caltech team’s calculations stimulated a sudden burst of interest in the scientific community. And since that time a good deal of research into wormholes and possible travel through them has been conducted. These efforts did not come out of a scientific vacuum, however. Decades before, a few scientists had considered the basic idea that wormholes might be a physical consequence of the warping of space by black holes. In 1916, shortly after Einstein’s and Schwarzschild’s equations for general relativity appeared, an Austrian scientist, Ludwig Flamm, examined them closely. Flamm pointed out that these equations allowed for some kind of invisible connection between two distinct regions of spacetime. German mathematician Hermann Weyl came to a similar conclusion in the 1920s.

In 1935, Einstein himself, working with a colleague, Nathan Rosen, explored the concept of this mysterious connection in more detail, including its relation to superdense objects. They conjectured that a sort of tunnel might exist inside a black hole. This tunnel, which would inhabit a region outside of normal space, might connect with another black hole somewhere else. For a while, researchers called such cosmic tunnels Einstein-Rosen bridges, after the men who first proposed them; only later did they acquire the name wormholes.