What is a wormhole?
A wormhole is a theoretical tunnel through space-time that could connect two distant points in the universe, creating a shortcut. Wormholes are allowed by Einstein's equations but have never been observed.
In 1935, Albert Einstein and Nathan Rosen described a mathematical bridge connecting two regions of space-time, later called an Einstein-Rosen bridge. The term wormhole was coined by physicist John Wheeler in 1957. A common analogy is a worm boring through an apple to get from one side to the other, rather than crawling around its surface.
Most theories suggest that natural wormholes, if they exist, would collapse almost instantly or be too small to use. Keeping one open might require exotic matter with negative energy, which has never been found in useful amounts. Physicists study wormholes to better understand gravity and quantum physics.
Wormholes in fiction
Wormholes are popular in science fiction as a way to travel across the galaxy quickly. The 2014 film Interstellar, with scientific advice from Nobel Prize-winning physicist Kip Thorne, showed a wormhole near Saturn as a sphere through which another galaxy could be seen.
Did You Know?
Some physicists have speculated that wormholes, if they could be built, might even allow time travel, though this raises many paradoxes.