Q: What is the “False Vacuum” and are we living in it?

Physicist: The False Vacuum is just another item on the long list of things to worry about, that are not worth worrying about, and that nobody can do anything about.  If you have any other worries, worry about those first.

In any physical system you’ll find that there’s an energy “ground state” that the system tries to approach.  For example, if you pour water into a bathtub there are a lot of ways that the water could arrange itself, but it will rapidly try to assume the ground state: being as low and still as possible.

In any physical system there’s a lowest energy state called the “ground state”.  If you allow the energy to drain out of a system, then it will approach its ground state.

Gravitational potential (the energy that something on a high shelf has more of, and that’s released when things fall) is the easiest example of an energetic system to picture.  Being on the ground is the lowest gravitational potential a thing can have (without digging); thus the name.

But in the tub example, the water in the tub doesn’t “know” about the drain or the area around the tub.  Given the chance the water would flow out of the tub and into a new, lower, ground state.  In fancy-math-speak, you’d say that the water in a tub is in a “local energy minimum”.  Within the tub, water definitely assumes the only ground state it can find.  However, if it jumped out of the tub, or somebody pulled the plug, then it would try to find a new, lower ground state and would find that it gained a bunch of new energy in the process (what with the flowing and splashing and whatnot).

There’s no good way to find out if you’re in a local “false” ground state or a true ground state.

The idea of energy levels, and ground states, and all that, applies to pretty much everything.  That includes electromagnetic fields and even particle fields.  A “particle field” is the quantum mechanical way of describing particles (all smeared out, instead of being all in one point), and each field has a pretty reasonable set of energy levels.  Every new particle elevates the energy level by one step, and the ground level is exactly what you’d expect: zero particles.

The vacuum is the most absolute ground state: no waves, no particles, nothing at all to elevate the energy above zero*.  However, all the dynamics of the universe are governed by differences in energy level.  For example, when you fill a tub it doesn’t matter if the tub is at the top of a mountain, or at the bottom of a mine, the water will behave the same way.  So, the idea behind a false vacuum is that what we consider the ground state of the universe isn’t really the ground state, and it may be possible to drop into an even lower-energy state (drain the tub, so to speak).  What we think is the ground state, the vacuum, may not be the true ground state.  So it’s called a “false vacuum”.

The “danger” of living in a false vacuum is that, under the proper circumstances the false vacuum can drop into the true vacuum.  The cause is usually described as a sufficient burst of energy to get the appropriate fields “over the hump” (picture above).  If the difference in energy between the false vacuum and true vacuum is large enough, then the surrounding space can likewise be tipped into the lower state.  In theory, a “false vacuum collapse” would expand at light speed (or about light speed) from the originating event, and destroy the heck out of everything in the affected, and ever-expanding, region.

It’s worth mentioning that the idea of a false vacuum is wild speculation and that there is no indication, not even a little, that the vacuum of the universe is a false vacuum and not the true ground state.  There’s a long history of spectacular bursts of energy in the universe, and none of them have tripped a collapse.  The ground state of the universe is kinda like a septuagenarian’s testicle; if it hasn’t dropped by now, it probably won’t.


*For subtle reasons, it turns out that you can’t quite reach zero and as a result the vacuum state has slightly more than zero energy.  This tiny difference is known as the “vacuum energy” or “zero point energy”, and it’s responsible for things like the Casimir effect.  By the way, there are some significant issues to work out involving a disagreement between the measured and predicted values of the vacuum energy.

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19 Responses to Q: What is the “False Vacuum” and are we living in it?

  1. Madhu says:

    Can the black-hole be called a true ‘vacuum’ ?

  2. The Physicist The Physicist says:

    Nope! There’s even energy tied up in the existence of gravitational fields, which black holes have in spades.

  3. Will says:

    If I remember correctly it’s actually impossible to have a true area of ‘nothing’, even if you somehow manage to remove literally everything from a section of space subatomic particles will still be popping in and out all over the place.

  4. The Physicist The Physicist says:

    You’re completely right, but I wanted to keep that issue separate (in the “*” section at the bottom).

  5. Jeff says:

    Is there any way to know if our universe is the true vaccum?

  6. The Physicist The Physicist says:

    Not really.
    If the vacuum state were a false vacuum state, then the universe either should have dropped to the true state, or the “barrier” between the false and true states is so insurmountable that it probably doesn’t matter.

  7. Maria says:

    Physicist, you have severely disappointed me by saying this event is extremely unlikely to happen! What a marvellous way to go, you wouldn’t know anything about it. No pain, no suffering, no awareness of the impending doom.
    Just one small question: I was wondering if the false vacuum could just apply to the earth, or also to our solar system, or our galaxy, or to the entire universe.

  8. Cal says:

    ^the false vacuum would have to apply to our whole universe

    It’s true it’s very unlikely, for if the change from false to true had happened in our universe, we wouldn’t be here to talk about it.

    If we are in the “false” vacuum, becoming a “true” vacuum would be the end of our universe as we know it

    If you believe in the multiverse theory, it makes sense. Other universes could be much closer to a “true” vacuum, but it really doesn’t matter unless somehow they collided/connected, in which case it’d likely destroy them both

  9. Jeff Pruett says:

    So if the false-vacuum-collapse expands at the speed of light from a single point…and the universe is expanding…does that mean it is possible that this event will never reach some parts of the universe if the universe is expanding faster than the speed of light?

  10. Karthick R says:

    If the false-vacuum-collapse expands at the speed of light, then is it possible that the event has already started at some point in the universe and that we don’t know about it simply because we have not observed it yet?

    Which brings me to a different question? would we be able to observe it at all? My notion is that I wake up to a normal morning, have breakfast, go to office and then all of a sudden.. everything is gone. Is this right?

  11. The Physicist The Physicist says:

    You’re right: If (big if) a false-vacuum-collapse were to happen, then there wouldn’t be any kind of warning.

  12. Maria says:

    From what I have read about false vacuum collapse (unfortunately there isn’t a great deal on the internet), you would not know anything about it. One moment you’d be going about your usual business, the next you just wouldn’t exist any more (and nor would anything else around you). There would be no warning. You just wouldn’t know anything about it and would cease to exist.
    By the way Jeff, the universe can’t expand faster than the speed of light. Nothing can go faster than the speed of light. It’s a sort of cosmic speed limit :-)

  13. Martin says:

    Actually space can and does expand faster than the speed of light. The cosmic speed limit only applies to objects moving through space, not to space itself, so it would seem that Jeff has a valid point.
    I was wondering if the big bang might be related to the collapse of a previous false vacuum. Not sure if that makes sense though.

  14. Dan says:

    No jeff is kinda right but also wrong, yeah the intervening space could be expanding us away from the event faster than light from either reference frame, but the expanding event will still get to us, because it travels with the stretch.

  15. The Cool Dude says:

    Even considering the expansion of space, it’s still possible for such an event to not be able to reach us, it just depends on where it is. Space-Time expands with respect to how far away from something you are, not strictly to the center of the universe, which means, the farther you are, the more space-time expands, with respect to everything. As far as my knowledge goes, this effect is linear, meaning there’s a constant value that the entire universe holds to, for one given time, so that something is expanding away from you at a speed multiplied by your distance. A while ago, I did some calculus which suggests that the universe should double in size once every 654 billion years or so, assuming the rate of expansion does not change. (The rate of expansion does change, though, because the same calculus also suggests that at the same rate, 15 billion years ago, the universe would be little less than 1 billion light years shorter than what it is now, which is clearly false, so the rate is probably getting lower)
    Anyway, using the fact that space-time expands in all directions, there is certainly some point so that space-time is expanding faster than the speed of light, and if this false vacuum were to exist, even moving toward us at the speed of light, at that point where space-time is expanding at the speed of light, it would still appear to be at a stand-still, from our perspective. By definition, it would have to be outside the observable universe for us to be unaffected by it, and even more, it should never enter the observable universe, only other things can exit. (Unless the expansion rate slows down)
    The expansion of space-time is a little bit hard to understand, so to put it into terms, you can imagine it as if instead of everything getting far away, everything is just getting smaller, while staying in place, along with the speed of light getting lower with exact respect to the degree of which everything is getting smaller.

  16. jason says:

    Dear Physicist
    I come to the discussion of false vacuum tunneling through to a true vacuum via “quantum tunneling” as an explanation for the origin of the Universe(multi verse),this while trying to grasp
    Hawking and Krauss declaring “Something from nothing” how the Universe created itself out of nothing. It seems to come down to the energy in a False Universe tunneling through to a TRUE vacuum and experiencing eternal inflation . All that is needed is infinite timespace and a false vacuum.How did we get the false vacuum and infinite timespace for there to be a quantum fluctuation the caused the multi verse?

  17. Matt says:

    So Mr. Physicist, do you think that we are now living in a universe where a vacuum collapse is currently happening given what Karthic said? Or do you think we’d have been done in by now if such were the case?

  18. Matt says:

    Also I wanted to know if this article takes into account the discovery that the Higg’s Boson’s mass is around 127 GeV which is the the borderline for stability. Sorry if I’m bothering anyone, I just wanted to know.

  19. Bob says:

    I saw a Wikipedia article saying that by the Standard Model, we could determine whether or not we are living in a false vacuum by accurately measuring the masses of the top quark and the Higgs boson.

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