To keep a wormhole open

To keep a wormhole open requires something almost as bizarre as a wormhole itself: exotic matter. Unlike ordinary matter, exotic matter always exerts a negative pressure. It you were to pump exotic matter into a tire, the more you put in, the flatter the tire would get. This, Thorne showed, was the key to surviving a fall through the throat of a wormhole. If enough exotic matter could somehow be fed into the wormhole's mouth, the powerful negative pressure that it generated would counteract gravity and prevent the gate from closing.

Strane as these concepts are, they do not violate the current laws of physics. Scientists already have indirect evidence for the existence of small amounts of exotic matter. But we are still a very long way from the technology needed to turn these theories into a workable method of intergalactic space travel. 1915: Albert Einstein publishes his General Theory of Relativity, incorporating field equations that express how matter has an effect on both space and time. 1916: German physicist Karl Schwarzschild solves field equations for a non-rotating black hole. He and Austrian physicist Ludwig Flamm simultaneously but independently suggest a tunnel through space-time between black holes. 1933: Einstein and fellow Princeton scientist Nathan Rosen solve Einstein's equations and derive the Einstein-Rosen Bridge - the first mathematically proven wormhole. 1948: Austrian mathematician Kurt Godel shows that tunnels in time may be possible. 1950s: Princeton scientist John Wheeler invents the term "wormhole." He coins the term black hole in the late 1960s. 1985: Caltech astrophysicist Kip Thorne and colleagues suggest in the scientific paper "Wormholes, Time Machines and the Weak Energy Condition" that traversable wormholes could exist.