Why Do Scientists Think Wormholes Might Exist?
If you listened to our last episode, you may have heard Oliver's question: "Do space wormholes exist?"
But did you ever wonder where scientists got the idea of space wormholes in the first place? The answer, like a lot of things in Physics, goes all the way back to Albert Einstein.
Einstein is of course one of the most famous scientists who ever lived, and that's for a good reason! In the early 20th century, he came up with The Theory of Relativity, which states that space and time are actually linked together, and that mass and energy are actually equivalent. These ideas completely changed the world in a lot of ways, and apply to technologies ranging from nuclear power to GPS.
Einstein's theory can be divided into two parts, "Special Relativity" and "General Relativity." Since we don't want to get too deep into math that even people with college degrees can't really understand (like me), we're not going to worry about them too much. Suffice to say, these two theories introduced the idea of space-time: which is the idea that both space and time form a single fabric that can bend and curve.
In this theory, Einstein proposed several equations (called "Field Equations") that would rule how objects should interact in space-time under certain conditions. And as Einstein's theory has been tested, these equations have been confirmed over and over again. Einstein's equations predicted things like black holes and gravitational waves, so when the equations show something to be possible, scientists take that seriously.
So, in 1916, a physicist named Karl Schwarzschild solved the equation to describe how spacetime curves around a sphere, which turned out to be the foundation for black hole physics. But when later mathematicians looked more deeply at the solution, they discovered something really weird: the equations could show not just one outside region, but two completely separate, flat universes connected together through a narrow passageway.
In 1935, Einstein, along with his co-author Nathan Rosen, described this geometry more completely. The object they described is known as an Einstein-Rosen Bridge. Using the equations behind Einstein's Theory of Relativity, they figured out that it's possible that two distant points in space-time could be connected to each other through a narrow bridge.
The image people often use to explain this phenomenon is of a pencil punched through a folded piece of paper. If an ant had to crawl across the entire surface of a piece of paper, it would take a long time--but if the paper is folded in half and a pencil punches a hole between the two ends, the ant could just crawl through the hole and get to the end immediately. Kinda like this:
Now, having to wrap your brain around the idea that three dimensional space can somehow fold around itself like a flat piece of paper is a whole other thing for all of us. Not to mention having to imagine that we're just like ants crawling on a flat surface. But putting that aside, the math says that wormholes are at least possible--even if we haven't found any, and a lot of the math also says that we'd need to have some pretty weird things happening for wormholes to be stable enough to travel through. If we can ever figure that out, traveling around space--which, in case you were wondering, is what scientists call "very big"--will become a lot more possible!
If you want to read Einstein and Rosen's original paper, where the Einstein-Rosen bridge is introduced (good luck with the math), you can find it here.
