You know, everyone loves a good secret passageway or shortcut. But what about a shortcut in space? How does that even work? Well, its time to read about the amazing world or wormholes.
So what exactly is a wormhole? Think of it as some sort of bridge structure linking together different parts of our universe and allows us to travel the universe at speeds greater than the speed of light. The term was first coined by John Wheeler in 1957, though the concept came much earlier when some other physicists had studied them, and then Einstein published his theory of general relativity with them included. Wormholes came about when first trying to find some mathematical solution to black holes. More on this later!
So what do these exactly look like? The most common description you’ll see visualized is a tunnel connecting two separate points of a flat plane. But something to note that this is only a simple way to describe the concept, and it is actually slightly different from that. First off, the spacetime continuum, basically the universe we live in, is four-dimensional, not just a flat sheet of paper. This means that you wouldn’t really observe a wormhole as literally a hole in space, but instead as a sphere of warped space, kind of like a black hole. In fact, black holes and wormholes on the outside look a lot like the same thing, which leads us to talk about the main two different types of wormholes.
First up is the Einstein-Rosen bridge, or non-traversable wormholes, though called one-dimensional tubes at the time. These were the first kind to be studied, and they are wormholes that you as a human can’t travel through. They result from the work of many physicists but became popularized through Einstein’s theory of general relativity along with the work of this colleague, Israeli physicist Nathan Rosen. The idea was described as black holes that can lead to other sections of our universe, sort of like a portal.
Materials that go inside of the black hole would later be spewed out of something called a white hole, which is a region where nothing can enter, only escape. There are some theories that mention the idea of particles being shot out into some sort of parallel universe where time runs differently compared to our own. Anyways, this is the less exciting version of the wormhole since it doesn’t have any use for us as humans. Research by Wheeler and physicist Robert Fuller showed that these Einstein-Rosen bridges would be super unstable if they linked together two different sections of our universe and that it would collapse before anything could make it to the other side.
This leads us to talk about traversable wormholes, aka the ones you would see in modern science fiction. You’re able to freely travel through these, which makes them more exciting to us since we can start to think about applications to our own lives. You might be wondering, how did we go about solving the previous issue of the wormhole collapsing in on itself? Well, that’s all due to our good friend called exotic matter. What is this exotic matter you say? Well, let me explain.
So we all know about matter, which is basically everything in our universe that has mass and is taking up some sort of space. Exotic matter, also known as negative matter, is the complete opposite of matter as we know it. It has what we call negative mass, a theoretical concept that exerts a negative pressure, basically pushing everything away from it. Exotic matter would help us stabilize the wormhole by pushing on the tunnel section of the wormhole, allowing anything to travel through it. This is still all still something hypothetical, and to make things worst, exotic matter also violates all laws of physics. Though research shows apparently if exotic matter existed in the liquid instead of solid form, the math can work out.
Even though I describe these two types of wormholes as the main types, it all goes much deeper than that. There are wormholes that connect different parts of our universe, but they can also connect different universes altogether. There are some that are two-way, and also some that are one-way (such as a black hole). Also, even though wormholes can be seen as some sort of shortcut that connects two points in our universe that are millions of light-years away, they can also connect together two points only a couple of meters away. It is possible for wormholes to even end up being a longer route than just directly going to that endpoint!
So how exactly would travel through a wormhole work? Well, to start off, they’re theorized to be pretty tiny, so it may be difficult to even try to get through it in the first place. But for the sake of theorizing, let’s say we did get through one. Travel wouldn’t be instantaneous, it would still take time to get from one place to another. Also, time dilation would at some point become an issue and is a huge factor in why some physicists don’t believe they actually exist. Time travel within a wormhole would allow many paradoxes to occur, which definitely violates the laws of physics. I’ll talk more about time travel in my next post!
So, how possible are wormholes to exist? Can we expect to see one in our lifetime? The answer is most likely no. They’re only theoretical at the moment, but I have some hope based on the success of Einstein’s theories being proven to be correct. Though despite all of this, lots of research has and still is being put into the field.
A group of physicists published a paper in October 2019 that focused on how to observe a wormhole. Due to the nature of the wormhole, we’re most likely going to find one at places that have extreme gravitational conditions, such as near a black hole. The researchers focused on a wormhole that could be present near Sagittarius A*, a supermassive black hole at the center of our Milky Way galaxy. Basically, stars on either side of the wormhole are influenced by each other’s gravity, meaning that if we were to detect these small deviations in the spacetime continuum, we could probably infer where this wormhole should be. Pretty cool right?
So wormholes are definitely something many of us would like to see actually become real one day. For now, though, it looks like we’re going to have to stick to using good old fashioned rocketry to travel across our universe.