What is false vacuum decay?

Question

What is false vacuum decay?

In: 70

Answer 1

So, to explain this, I’m going to have to teach you about two things.

The first is a fun word used by scientists called “metastable”. This is fun word, because it means something that is stable, but not really.

Imagine you and your whole class of other 5yr old kids are having a race down a really narrow path. There’s only really room for two people to stand next to one another, but you want to win so everyone goes as fast as you can. You don’t want to trip up on someone else’s feet though, so everyone keeps a little bit of distance apart.

You’re all going to end up pretty evenly bunched up, and it’s probably not going to change much, so it’s kind of stable. But if someone in the group trips or slows down, the whole thing might end up with people getting scraped knees.

That’s “metastable”.

Ever tried building a really, really tall Lego tower? Imagine one so tall that if you give it the slightest push, it’ll collapse. That’s also “metastable”.

The second thing to teach you is about what “vacuum” means here. It turns out, space isn’t actually empty- it’s full of weird things called “fields” and “forces” that have been around since at least the beginning of the universe, and basically tell the stuff your body is made up out of, what it’s allowed to do.

One of these “fields” (very simply, types of energy/stuff that affects everything everywhere) was “discovered” by a guy whose last name was “Higgs”: as a result we call it the “Higgs Field”. This field helps to do something very important to the stuff your body, the earth you’re stood on and all the other stuff you can touch in the whole universe: it gives it something called “mass”.

Without this field, our universe would not be possible and we wouldn’t be able to live in it.

With me so far? Well, some people think this field might be “metastable” – stable but not really, and that one day it might collapse like that Lego tower. If that happened then it would be bad for anyone in a really big part of space, as it would destroy everything there.

Not to worry though: we don’t know that the Higgs field is metastable, and if it is it will be a long, long, long time before anything is likely to happen.