Vacuum decay: The end of everything

There are many ‘end of the world’ scenarios that are commonly discussed. Like a meteor crash on Earth, we humans nuking ourselves to death, alien invasion and so on. But a meteor, we can destroy, nuclear war, we can avoid and aliens, they ain’t travelling far and wide for war right?

While most of these have even the slightest possibility of being avoided, there exists one scenario which could happen at this very moment, that we cannot escape. No, it’s not the Sun exploding, as that won’t happen for another 5 billion years.

But before you scream and hide under your blankets, let me elaborate on that. To start off with, we need to detour into some key concepts which play a major role in our understanding.

1. Energy Levels

Think of a ball on a hill. It lies on a the peak of the hill and a slight kick will send it rolling down to the bottom. At the top of the hill it has a high potential energy which it converts to kinetic energy by rolling down the hill.

This is something that happens with quantum particles, except it’s not a hill. Every particle has a tendency to occupy the lowest energy level or something known as the ground state, just as the ball wanted to reach the bottom of the hill to get rid of its potential energy.

For those of you with a scientific bend, this is according to the second law of thermodynamics which states that every system will eventually decay into its ground state.

2. The Higgs Field 

Keeping that in mind we move on to another key concept: the Higgs Boson. For most of you who don’t know, the Higgs Boson is an elementary particle that is responsible for a property, we humans call mass.  It was discovered in 2012 in the Large Hadron Collider by smashing particles at tremendous speeds.

But the Higgs Boson is just a small part of the larger Higgs Field. According to Quantum Field Theory, every particle is just an excitation in its corresponding field. To simplify things, consider a field synonymous with a sea of water and every excitation or ripple on its surface is a particle.

The Higgs Field surrounds us and is present in every nook and corner of the Universe. Every other particle interacts with this field in certain levels depending on what particle it is. The field prevents the particles from moving about. This resistance to movements is what we humans perceive as mass. Just as when you try to move a spoon through a bowl of thick syrup.

But the Higgs field is not the only one out there. There is the electromagnetic field, quark field, boson field and so on, each with their corresponding particle. As a side note, the study of these fields and their interactions with one another is what Quantum Field Theory is all about. More on that in a future post.

3. And finally, the end of the world

Anyways, after the Big Bang every field is theorised to have ‘rolled’ down to its ground state or lowest energy level. All except one: The Higgs Field. The Higgs Field is like the ball on the hill. With an energy level of 126 GeV or 126 giga electron volts, the Higgs Field is not in its lowest energy level (it is metastable). A slight push can send it tumbling down to an even lower energy level.

Peter Higgs, the scientist who theorised the existence of the Higgs Boson said that the Higgs Field can exist only at a certain energy level. Any more or less, the energy level, the laws of the Universe would have been completely different.

This is where the danger lies. If this jump to a lower energy level occurs somewhere in outer space a tiny ball will form. This ball will continue expanding at the speed of light in all directions. Inside this bubble, physics as we know it, will cease to exist. This means that the laws of science you may have learned throughout school, won’t hold true anymore.

So much for that maths test you gave, staying awake the whole night in preparation! None of your answers hold true anymore. Thus, as the ball passes you, who knows if your atoms will hold on.

This is called vacuum decay. The Higgs field is currently at false vacuum state. Any wrong push, can make it collapse to the true vacuum state. Which is why many conspiracy theorists were worried that the high energy particle collisions in the Large Hadron Collider may generate a vacuum decay. Don’t worry, it won’t.

But we are going off topic. Let me freak you out some more. The scariest thing about such a scenario is the fact that you won’t see anything incoming. As the ball expands at the speed of light, light can’t escape it to reach you and convey the message of the end.

It will be like, at one moment you are leisurely chilling out in your vacation; the next moment all your atoms are ripped apart. You won’t even realise what happened. Scary right?

Want more chills? Get ready. Vacuum decay can happen at any moment. It can happen right… NOW!! For all you know, such a ball may already have formed somewhere in the Universe and is making its way to us.

Ok, I think that is enough, let us look at the bright side. The probability of such an event happening is quite low. The observable Universe is a big place (93 million light years across), so it can happen anywhere. The chance that could happen somewhere dangerously close to Earth is one in billions! Moreover, the speed of light is slow. Well, quite fast in human standards (299,792,458 m/s), but quite slow if you consider the distances involved in this gigantic Universe.

As I said, the Universe is a big place, and the light from the closest star to the Sun itself takes 4.2 years to reach us, with that tremendous speed.

Was the Big Bang actually a vacuum decay?

An exciting possibility is that, the birth of the Universe, we call the Big Bang was actually a vacuum decay event, in an older pre-existing Universe!! Maybe, that Universe came from the decay of some other Universe and so on.

This theory is actually being considered by scientists to answer the question of what came before the Big Bang. Although nothing is confirmed, it seems like an interesting prospect that we arose from the death of another Universe.

Vacuum decay doesn’t necessarily mean the end of everything. It just means the change in the laws of science. Maybe, new life forms may form inside this vacuum decay ball. A crazy world where 1+1=3 maybe an universal truth.

Whatever the probabilities of such an event occurring, it is still an interesting (and frightening) hypothesis on how quantum fields behave and on the origin of the Big Bang itself.