What a Wormhole Might Look Like#

If you somehow spotted a wormhole in reality, here’s what it would probably look like:

• It would appear round, like a sphere.
• It would resemble a black hole a bit.
• Light from the other side would come through it, showing you a window to a place far, far away.

When you cross through it, the faraway place would fully appear, and your old home would start shrinking away into that shimmering spherical window.

But this brings up big questions: Are wormholes actually real? Or are they just fancy magic dressed up in the clothes of physics and maths? If they are real, how do they even work, and where could we possibly find them?

How Space Works (According to Einstein)#

For most of human history, we thought space was pretty simple – just a big, flat stage where everything happens. Even if you took away all the planets and stars, you’d still have that empty stage itself, just existing, unchanging forever.

Then Einstein’s theory of relativity came along and changed everything. It tells us that space and time work together to make that stage, and they aren’t the same everywhere. The things on the stage can actually affect the stage itself, stretching and warping it.

Think of the old idea of space like unmoving hardwood flooring. Einstein’s stage is more like a waterbed – it’s elastic. This elastic space can be bent, and maybe, just maybe, even torn and patched back together. This tearing and patching is what could possibly make wormholes real.

Let’s try to see this in 2D. Imagine our universe is a big flat sheet. If this sheet is bent in just the right way, a wormhole could connect two spots that are normally super, super far apart with a short bridge. You could cross this bridge almost instantly. This means you could travel across the universe even faster than the speed of light.

Finding Wormholes: Are They Out There?#

So, if they’re possible, where can we find a wormhole? Right now, only on paper.

General relativity says they might be possible. But that’s a big “might.” Just because the equations in general relativity have many possible answers doesn’t mean every answer describes something that actually exists in reality.

But, they are theoretically possible, and there are different kinds scientists talk about.

Type 1: Einstein Rosen Bridges#

The very first type of wormholes that scientists thought up were called Einstein Rosen Bridges. These suggest that every black hole is kind of like a portal to an infinite parallel universe.

Let’s try picturing this in 2D again:

• Empty space-time is flat.
• Objects sitting on it curve it.
• If you squeeze that object smaller, space-time gets more curved around it.
• Eventually, space-time gets so warped it collapses into a black hole.

When this happens, a one-way barrier forms, called the event horizon. Anything can fall into it, but nothing can ever escape. Everything that falls in seems trapped forever at the tiny point at the center, called the singularity.

But maybe there’s no singularity. One idea is that the other side of the event horizon looks a bit like our universe, but mirrored and upside down. In this mirrored universe, time runs backwards.

In our universe, things fall into the black hole. In that parallel universe with backwards time, the mirror black hole is actually spitting things out. This is a bit like a big bang but in reverse. This concept is called a white hole.

Here’s the catch: Unfortunately, Einstein Rosen Bridges can’t actually be crossed. It would take an infinite amount of time to get to the opposite universe, and they crimp shut in the middle anyway. So, if you fall into a black hole, you won’t end up being the stuff coming out of the white hole. You’ll just end up dead.

To zip across the cosmos in the blink of an eye, us humans need a different kind of wormhole – a Traversable Wormhole.

Type 2: Very Old String Theory Wormholes#

What if string theory (or one of its related ideas) turns out to be the correct way our universe works? If so, we might be really lucky! Our universe could already have a tangled mess of countless wormholes spread throughout it.

Here’s the idea:

• Right after the Big Bang, at scales much, much smaller than an atom, the universe experienced tiny, random fluctuations (scientists call these Quantum fluctuations).
• These fluctuations might have created many, many traversable wormholes.
• Threaded through these tiny wormholes were theoretical objects called cosmic strings.
• In the first incredibly short moment after the Big Bang (we’re talking the first billionth of a trillionth of a second!), the ends of these tiny wormholes were pulled light-years apart, scattering them all over the universe.

If wormholes were created in the early universe, whether with cosmic strings or some other way, they could be literally everywhere, just waiting for us to find them.

Are Supermassive Black Holes Wormholes?#

One of these early wormholes might even be closer than we think. From the outside, black holes and wormholes can look very similar. This has led some physicists to wonder if the supermassive black holes found at the center of galaxies are actually wormholes.

It would be incredibly hard to travel all the way to the center of our own Milky Way galaxy to check this out, though. But that’s okay! There might be another way to get our hands on a wormhole, even if it’s equally, if not more, difficult: we could try to make one ourselves.

Type 3: Manmade Wormholes#

If we wanted to build a wormhole that’s traversable and actually useful for travel, it would need a few key features:

• Connects distant points: It obviously needs to link two faraway places in space-time, like your bedroom and the bathroom, or Earth and Jupiter.
• No event horizons: It shouldn’t have any one-way barriers like event horizons, because we need to be able to travel both ways.
• Sufficient size: It needs to be big enough so that the extreme gravitational forces don’t crush or kill human travelers passing through.

The biggest hurdle we face is keeping these wormholes open. No matter how you make a wormhole, gravity tries to pinch it closed. Gravity wants to cut the bridge and leave only black holes at the ends.

Whether it’s a traversable wormhole with both ends in our universe, or one going to another universe, it will try to snap shut unless we have something holding it open. For the old string theory wormholes, that’s supposedly the job of the cosmic strings. For man-made wormholes, we need a different ingredient.

The Need for Exotic Matter#

To prop open a man-made wormhole, we need something called Exotic Matter.

• This isn’t like anything you’ve ever seen on Earth.
• It’s not even like antimatter, which is already pretty weird.
• It’s something totally new, different, and exciting, with properties so strange they’ve never been observed before.

What makes exotic matter special? It’s stuff that has negative mass.

• Regular matter, like people, planets, and everything else we see, has positive mass. Positive mass attracts things because of gravity.
• But negative mass would do the opposite – it would be repulsive! It would push things away instead of pulling them in.

This creates a kind of anti-gravity effect that could actually push outwards and prop our wormholes open.

Not only that, but this exotic matter would have to exert enormous pressure to force space-time open, even greater than the immense pressure found at the very centers of neutron stars. With enough exotic matter, we could potentially weave space-time into whatever shapes we wanted.

A Potential Candidate for Exotic Matter#

Believe it or not, we might already have a candidate for this strange exotic matter: the vacuum of space itself!

• Even in seemingly empty space, tiny Quantum fluctuations are constantly happening.
• These fluctuations momentarily create pairs of particles and antiparticles.
• Almost instantly, these pairs meet and annihilate each other, disappearing.
• The vacuum of space is basically “boiling” with these fleeting particle pairs.

We’ve already figured out ways to manipulate these vacuum fluctuations to produce effects that are similar to the negative mass we’d need to stabilize a wormhole.

Using Manmade Wormholes#

Once we figure out how to create and keep a wormhole open, the ends would initially be right next to each other. So, we’d then need to move one or both ends to interesting places.

• We could start simple, wiring up our own solar system. Imagine leaving one end of several wormholes in orbit around Earth.
• We could then flick the other ends out into deep space, maybe near other stars or interesting cosmic spots.

Earth could become a giant wormhole hub, connecting a vast human civilization spread out across light-years – all just a simple wormhole jump away.

The Dark Side of Wormholes#

However, wormholes have a scary side. Even creating just one wormhole seems to mess up the fundamental rules of the universe in significant ways.

• It could potentially create paradoxes related to time travel.
• It might violate the basic rule that cause always comes before effect (the causal structure of the universe).

Because of these serious issues, many scientists strongly believe that wormholes aren’t just impossible to build, but that they’re actually impossible to exist at all.

So, for now, the reality is that wormholes really only exist in our hopes and dreams, and on paper in the form of equations.