Debunking: Stephen Hawking Says Universe is on the brink of instability and could collapse - metastable, in a false vacuum state.
Example: Stephen Hawking Says 'God Particle' Could Wipe Out the Universe
Stephen Hawking does indeed say this. But what he doesn’t make clear is that this is a very academic scientific debate about an unlikely scenario that can’t really happen right now.
Some of these scenarios are just nonsense like Nibiru and can’t happen. Some are real but low probability. You can expect a small but destructive asteroid every few thousand years or a big one every 100 million years.
But this scenario is just vastly unlikely, improbable beyond belief that it could happen right now. Let me explain:
First, if it could happen, then you’d expect it to have happened already in the first 1/10,000,000,000th of a second along with the other symmetry breaking when gravity split off from the other forces, when it was tremendously hot. For an example timeline for the other forces, see Unification of the Fundamental Forces.
Since that hasn’t happened, the false vacuum has to be very stable, or else, probably as we find new physics we find out that it is not in a false vacuum state at all.
And yes, on the basis of the measured mass of the Higgs boson, the false vacuum has to be very stable. Joseph Lykken says that an event that triggers a patch of true vacuum, if the theory is correct, happens on average once every 10, 000, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion years.
That means it is nothing to be worried about. This is so improbable that it can't really happen at all. The chance of winning the Euromillions jackpot for instance is 1 in 139,838,160. The chance of a false vacuum in any particular century is less than the chance of winning a string of twelve Euromillions jackpots one after another without a single miss. Just to win it once is incredibly unlikely. And I don’t mean the chance of anyone winning them all.
Rather, it’s as if you bought twelve tickets for Euro Millions, those were the only lottery tickets you ever bought in your lifetime, and you won it every single time. Do you think that could happen?
For those of you who live in the States, with a chance of 1 in 292 million of winning the US powerball, then if you play it 11 times, and win every time, as the only lottery you ever play in your life that's still far more likely than a false vacuum decay somewhere in the universe in the next century, if the theory was correct.
How tiny are your chances at winning the Powerball jackpot? This tiny.
To put it another way, you'd have to have an immense lifetime to be concerned. If you lived as many million years as a normal human lifetime has seconds, and then as many of those time periods as a human lifetime has seconds, and as many of those vast time periods as ... nine times, then you might have some cause for wondering if perhaps it would happen in your lifetime. It still probably wouldn't.
In detail:
So, this is just an idea that some scientists have. Normally they think of it as something that, if it happens at all, happens not just trillions of years into the future but vast time scales so vast you need 1 followed by a hundred zeros to express the number of years between then and now.
Stephen Hawking said that in theory it could happen now through "quantum tunneling". Lykken said in response that the situation is strange if matter is on such a knife edge between stability and metastability and that it may be a sign that the calculation may be wrong. He gives the example of supersymmetry - a theory according to which particles we know about have other paired much heavier particles we haven't discovered yet. According to that theory our universe would be stable.
We know in any case that the standard model of particle physics is wrong, because it doesn't explain, for instance, gravity. It’s not compatible with general relativity. So I don't think one needs to put much credence on the theory. Stephen Hawking also is fond of saying dramatic things like this.
The first answer here goes into it a bit What did Stephen Hawking mean when he said that the Higgs Boson could become metastable at energies above 100bn GeV, and why would this metastability lead to catastrophic vacuum decay?
A bit more background. The idea is that our universe might seem to be in the lowest possible energy state, but actually is metastable - that it could collapse to an even lower energy state if nudged in the right way.
This shows the idea, how if somehow we could be nudged over tht hump in the higgs potential we might fall down the other side into another state which would have different laws of physics from the ones we enjoy now. We would not survive that transition. It might go to another stable state or just fall endlessly changing all the way with no final state.
If the only other available minimum is higher than our current one then ours is a stable state and we don’t need to worry about a nudge sending our universe into another state. But if it is a lower level than ours then in principle we could be nudged over the hill as it were into that lower state so then our current state is metastable.
It’s obviously a very unlikely thing to happen because our Universe has stayed as it is for nearly fourteen billion years with nothing like this happening. But is it at all possible?
So the thing is that the stability depends on the mass of the Higgs boson. And when they found it, with the LHC, they calculated that our universe might be completely stable, or it might be that it is metastable with this lower energy state available. It is just on the edge, according to standard particle physics.
So that got physicists rethinking this question - if our universe is metastable then just possibly there may be some way it could collapse into a lower energy state. It’s a rather academic question as most think if that is possible, it happens at vast time scales into the distant future.
Anyway the calculations suggest that the universe is borderline metastable though it could be stable within the margin of error, within 1.3 standard deviations. That’s not much, so it is quite possible that it is stable. To find out exactly they need more precise values of the mass of the Higgs boson, and top quark and various other parameters.
If our universe is in a false vacuum state, then you have to ask how we got there. It’s especially puzzling because our universe was much hotter earlier on, so if it was possible for it to get out of its false vacuum state, why didn’t that happen already in the first fraction of a second? Here is Professor John Ellis talking about it:
He is saying he thinks this means that we need new physics, because otherwise why didn't the universe get out of the false vacuum in the early universe when it was much hotter? He thinks that the new physics is supersymmetry and that we have a chance to find this with the next run of the LHC. In other words he thinks that curve graph is wrong.
Here is Joseph Lykken talking about it
The relevant part is 30 minutes in, he says
"If you actually estimate the numbers, most likely it will take 10^100 years for this to happen, so probably you shouldn't sell your house and you should continue to pay your taxes.
On the other hand it may already have happened and it might be on its way here now. And you won't know because it is going at the speed of light so there's not going to be any warning.
Now more interesting to us as physicists is fact that when you do this calculation, using standard physics which we know about, it turns out that we are right on the edge between a stable universe and an unstable universe. That's essentially why it will take so long. If you change those numbers a little bit we would have been wiped out already., or it would never happen. But we are sort of right on the edge, where the universe can last for a long time but eventually it should go boom. So that's very interesting to physicists, so why is it happening, why are we right on the edge? There is no principle that we know of that would put us right on the edge. So one of two things is happening here.
Either we are living right on the edge between a stable and an unstable universe, in which case we would like to explain that, or the calculation is wrong and everything I just told you is just the wrong calculation, but in that case there is something else that has to go into the picture that has to be to do with the Higgs boson and must be very fundamental because it has to change this fundamental property of how the Higgs boson works. And I have two candidates for you for that. One is dark matter which I already mentioned, and the other is supersymmetry, which I'll mention in a moment."
He means that it is incredibly unlikely for it to happen at any time.
YOU’D NEED AN IMMENSE LIFETIME FOR IT TO BE REMOTELY POSSIBLE WITHIN YOUR LIFETIME
According to their calculations then it’s only likely to happen within your lifetime if you have an immensely long life.
If you lived for
10, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000 years,
or in trillions,
10, 000, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion years
then there is an evens chance that it might happen at some point within your vast lifetime. If you have a lifetime of only a century or a few thousand years or even a few billion years, it’s so incredibly unlikely to happen in your lifetime that you might as well say it is impossible.
CONSIDER A BRICK
Some people find it hard to understand how something can be so improbable that for all practical purposes it is impossible. Why do people writing about this, and even Joseph Lykken say that it could happen at any moment, when really, it couldn’t?
So to understand this, consider a brick.
Like almost any object that’s not close to absolute zero, its molecules jiggle about because of heat all the time. Suppose that at some moment all the molecules that made it up happened to be jiggling in the same direction, out of the ground. Just by chance, nobody is doing anything to it. Normally when one atom jiggles up, another one somewhere in the brick jiggles down and it stays in the same place. But this time, just by chance, every atom jiggles up in the same moment of time. An accidental brick wide synchronized jiggle. If that happened, it would leap up in the air.
However that’s just a theoretical impossibility because the chance of that is so tiny. You don’t need to keep an eye out for flying bricks leaping out of the ground as a result of the random heat motion of their atoms.
Now if bricks had only a half dozen atoms, yes they could leap out of the ground. But they have so many atoms that for all practical purposes it is impossible for them to do this.
So, it’s like that. Theoretically it could happen right now, right here, anywhere, if the theory was correct. But in practice, no it couldn’t. You might as well call it impossible, for the same reason that you’d say it is impossible for a brick to leap into the air from its thermal agitation.
To put it another way. In any given century, well the chance of it happening at all, anywhere in the universe, is roughly equal to the chance of throwing a fair dice 128 times.
If you did this once only in that year, your chance that you get 128 sixes in a row is the same (approximately) as the chance of it happening in that year.
If you throw a dice 128 times and get a six every single time - the chance of that happening is around 1 in 4 * 10^99.
That’s about the same as the 1 in 10^100 chance of the false vacuum turning into a true vacuum in any particular year, anywhere in our universe - if the theory is correct (which it probably isn’t as our physics is incomplete)
So, not something to worry about. That’s so improbable that it can't really happen.
NEW PHYSICS
However it's also very likely that we just don't understand the situation fully, as we know our understanding of physics is incomplete. In that case, then we would expect to find an explanation which would probably show that the universe is stable and it doesn't have even that tiny chance of happening.
In particular
- If there is dark matter that has mass like ordinary matter through the Higgs field it can't happen.
- If supersymmetry is correct it can't happen.
- If we have more than one Higgs boson it can't happn.
And there are probably lots of other things we don't know about that would mean it can't happen.
It’s only a few years since we found the Higgs boson. Up until then many thought it wouldn’t exist and hardly anyone thought it would have this mass in just the right region for a false vacuum state.
After all, Stephen Hawking lost a $100 bet when the Higgs boson was discovered. Now he is predicting it will be metastable. He could easily be wrong about that too. He has a track record of predicting scientific doomsday things without putting a great deal of thought into them. See my Debunked - Stephen Hawking puts an expiry date on humanity. He is not as bad as Michio Kaku in this respect, but he does seem to relish his doomsday forecasts.
Anyway - Stephen Hawking is very likely to be wrong again. As they do the next runs on the LHC they might find more Higgs bosons or prove supersymmetry or find dark matter and any of that could make the theory false.
At any time we have numerous theories in astrophysics. At most one of those theories can be true as they contradict each other. But most likely they are all false and the truth is something nobody has thought of so far.
That it's possible at all is puzzling to physicists, it should either happen or not, and it takes a lot of explaining to understand why it would be so right on the edge as that and it could be that it is due to dark matter or supersymmetry stabilizing the universe.
So, in short, they may well end up proving that the universe is stable after all and that this scenario is not possible at all. It is all very speculative at this stage, and if the universe is unstable then it’s only on mind bogglingly huge time scales. You’d need to have a lifetime of about
10, 000, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion years
for it to be something to lose any sleep about.
See also Will the Higgs Boson Destroy the Universe???
And this BBC news story explains it quite well for ordinary folk Cosmos may be 'inherently unstable' - BBC News
Also this one by Pauline Gagnon is good: Quantum Diaries
This is good too, and has an excellent explanation of what “metastable” means using analogy of a bar stool.