Wormholes

What would it be like to travel into another parallel universe like in Star Trek? Take shortcuts at ridiculous speeds? Or travel backwards against time? A wormhole would be theoretically the answer to that. 

Einstein's Relativity

We used to think of space as an empty stage, unchanging, however, Einstein's relativity changed that. Today we think of space as a stage full of celestial objects that bend space-time. 

This elastic-like space could be torn into and connect two distant end spots with a short bridge, which makes wormholes possible. This could help you travel through the universe, even faster than the speed of light, like a shortcut, making them appealing to space travel ideas. Some may argue that you can go back in time too, like a time machine. 

But sadly, we only found wormholes theoretically in general relativity and mathematics. We still haven’t found them observing the universe and they are very unstable. General Relativity is a set of mathematical equations that were published by Albert Einstein. But even with Einstein’s General Relativity, physicists spent decades trying to make it mathematically without breaking the laws of physics (e.g. the law of momentum).

Einstein Rosen Bridges 

This was the first kind of wormhole that was theorized, called the “Einstein-Rosen Bridge” discovered by Ludwig Flamm. They describe every black hole as some sort of portal into an infinite parallel universe. So if we imagine it as a 2-D stage like the stage that I was talking about before. And if we put like a celestial object, then we start compressing that object, it would get heavier and heavier, eventually space-time becomes so warped that it has no choice but to collapse into a black hole. The heavier it gets, the greater the bend of spacetime. And if you enter a blackhole, you would turn into spaghetti. After the point of no return, “The Event Horizon” You’ll be trapped forever at the singularity at the core, but that’s a prediction. 

One possibility is that the other side of the Event Horizon looks like our universe but mirrored upside down, where time runs backward in that parallel universe, that’s where the white holes come in. Ludwig Flamm realized another solution was possible, which he would call "white holes", he thought of it because of the symmetry of mathematics, 1 to -1 and 2 to -2 and so on. White holes are the opposite side of the black holes, or in other words, black holes are like one side of a wormhole. Black holes are dense bodies, nothing can escape from them. They are formed after the death of a massive star's core collapses inwards, its density goes to infinity, we call that a singularity. For example, there is a supermassive black hole, Sagittarius A, that lives at the centre of the Milky Way Galaxy. 

White holes repel while black holes attract, because of this, a wormhole would be like a one-way street. You can enter one but not leave one, because you wouldn't be able to pass the event horizon of a white hole since it is repelling you outwards. Einstein-Rosen Bridges can’t actually be crossed, it takes an infinite amount of time to cross over to the opposite universe, and it cramps shut in the middle making them highly unstable. Einstein-Rosen Bridges are useless for travel because they collapse quickly, you would need a very exotic type of matter(negative matter) to balance that force, making it possible to stay open longer. Negative energies can only be created when it's too tiny to counteract the wormhole's gravity. It’s possible that the Big Bang created tiny wormholes with small amounts of negative energies at the beginning of the universe. 

Traversable Wormholes

Is there another solution to this problem? Yes! Physicists worked out the math needed to make a stable wormhole called traversable wormhole, one that could be crossed in both directions. Which works by stabilizing it with exotic matter(negative matter), which is theoretical, but one problem that breaks the law of conservation of momentum, states that the momentum should remain constant if no force is applied, if we are to discover a wormhole, it shouldn't break any laws.

If string theory is ever correct in our universe, we could be lucky because our universe might even have a tangled with tons of wormholes. After the Big Bang, quantum fluctuations at the smallest subscales, very, very, very small, even smaller than an atom, may have created many Traversable wormholes, and through them are strings called “Cosmic strings”.