Hawking - Spontaneous Creation

[Mariolee]

I'll watch it before judging.

[neo-x]

neo-x wrote:
In "a brief history of time" he wrote something like this...If there was just gravity present, the entire universe would arise out of it.


Where in the book was it written? I am curious what exactly he wrote.

I'm sorry guys, this is not from "A brief" history of time (I was just going by memory ) but rather from "The grand design", here is the exact quote.

"Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going."

[1over137]

Sorry guys for a longer quote from the Hawking's book, but I think it is neccesary to understand what he means by 'nothing', and to understand the better the issue with gravitation as well as the spontaneous creation. So here are the quotes from the book:

Why is there something rather then nothing?
Why do we exist?
Why this particular set of laws and not some other?
...
We claim, however, that it is possible to anwer these questions purely within the realm of
science, and without invoking any divine beings.
-- ch.8, p.267

An example that can help us think about issues of reality and creation is the Game of Life,
invented in 1970 by a young mathematician at Cambridge named John Conway.
...
The Game of Life is not really a game but a set of laws that govern a two-dimensional
universe. It is a deterministic universe: Once you set up a starting configuration, or
initial condition, the laws determine what happens in the future.
-- ch.8, p.267

Conway and his students created this world because they wanted to know if a universe with
fundamental rules as simple as the ones they defined could contain objects complex enough to
replicate. In the Game of Life world, do composite objects exist that, after merely following
the laws of that world for some generations, will spawn others of their kind? Not only were
Conway to demonstrate that this is possible, but they even showed that such an object would
be, in a sense, intelligent!
-- ch.8, p.275

In a physical universe, the counterparts of objects such as gliders in the Game of Life are
isolated bodies of matter. Any set of laws that describes a continuous world such as our own
will have a concept of energy, which is a conserved quantity, meaning it doesn't change in
time. The energy of empty space will be a constant, independent of both time and position.
One can substract out this constant vacuum energy by measuring the energy of any volume of
space relative to that of the same volume of empty space, so we may as well call the constant
zero. One requirement any law of nature must satisfy is that it dictates that the energy of
an isolated body surrounded by empty space is positive, which means that one has to do work
to assemble the body. That's because if the energy of an isolated body were negative, it
could be created in a state of motion so that it's negative energy was exactly balanced by
the positive energy due to its motion. If that were true, there would be no reason that
bodies could not appear anywhere and everywhere. Empty space would therefore be unstable. But
if it costs energy to create an isolated body, such instability cannot happen, because, as
we've said, the energy of the universe must remain constant. That is what it takes to make
the universe locally stable - to make it so that things dont's just appear everywhere from
nothing.
If the total energy of the universe must always remain zero, and it costs energy to create a
body, how can a whole universe be created from nothing? That is why there must be a law like
gravity. Because gravity is attractive, gravitational energy is negative: One has to do work
to separate a gravitationally bound system, such as the earth and moon. This negative energy
must balance the positive energy needed to create matter, but it's not quite that simple. The
negative gravitational energy of the earth, for example, is less than a billionth of the
positive energy of the matter particles the earth is made of. A body such as a star will have
more negative gravitational energy, and the smalled it is (the closer the different parts of
it are to each other), the greater this negative gravitational energy will be. But before it
can become greater that the positive energy of the matter, the star will collapse to a black
hole and black holes have positive energy. That's why empty space is stable. Bodies such as
stars or black holes cannot just appear out of nothing. But a whole universe can.
Because gravity shapes space and time, it allows space-time to be locally stable but globally
unstable. On the scale of the entire universe, the positive energy of the matter can be
balanced by the negative gravitational energy, and so there is no restriction on the creation
of the whole universes.
Because there is a law such as gravity, the universe can and will create itself from nothing.
Spontaneous creation is the reason there is something rather than nothing, why the universe
exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set
the universe going.
-- ch.8, p.279

M-theory is the only candidate for a complete theory of the universe. If it is finite - and
this has yet to be proved - it will be a model of a universe that creates itself.
-- ch.8, p.282

Well, I see one contradiction here. Hawking wrote: Once you set up a starting configuration, or initial condition, the laws determine what happens in the future. On the other hand he wrote: It is not necessary to invoke God to light the blue touch paper and set the universe going. He also wrote: We claim, however, that it is possible to anwer these questions purely within the realm of
science, and without invoking any divine beings.

P.S.: I will come back to the M-theory when I finish Hawking's book: Grand Design and Brian Greene's book: The fabric of the Cosmos. Greene was designated by Times to be a new Hawking but better. He also wrote the Elegant Universe. He is well-known string theorist. His books I highly recomend.

[SnowDrops]

Yeah, it's quite nice, but Hawking never really tells us why there was gravity (or any law for that matter) in the first place.

[Mariolee]

I'm not exactly privy on the whole space science act, but I want to know if my understanding of Hawking's theory is correct: the laws of gravity designate and even force the universe to keep a constant balance, not to be outweighed from negative or positive energy, and because of these laws, it is impossible to have a purely empty space, and so the universe was created in order to maintain the balance.

But if that is so, and I hate to keep using this argument because apologists use it all the time and it reminds me of a little child always asking "why, why, why", BUT...
If this was so, and we have evidence of the universe starting at one point since we know it is always expanding, then if we turn back the clock we can find the point where the universe first came into conception. So, obviously, there was a point where these laws of gravity created the universe. Then...what was before that? Unless, time didn't exist at that point, which also means that gravity couldn't have had the same laws or maybe it didn't exist? But then, if it didn't exist, then how could it come to be? Also, why is there empty space in the first place? Why does anything exist, even emptiness?

Maybe it's because I'm thinking on a time-linear scale here, and haven't gotten a good grasp on physics and the sort (I am only in High School after all), so if anyone could explain this to me, that would be fantastic!

[SnowDrops]

I'm not exactly privy on the whole space science act, but I want to know if my understanding of Hawking's theory is correct: the laws of gravity designate and even force the universe to keep a constant balance, not to be outweighed from negative or positive energy, and because of these laws, it is impossible to have a purely empty space, and so the universe was created in order to maintain the balance.

But if that is so, and I hate to keep using this argument because apologists use it all the time and it reminds me of a little child always asking "why, why, why", BUT...
If this was so, and we have evidence of the universe starting at one point since we know it is always expanding, then if we turn back the clock we can find the point where the universe first came into conception. So, obviously, there was a point where these laws of gravity created the universe. Then...what was before that? Unless, time didn't exist at that point, which also means that gravity couldn't have had the same laws or maybe it didn't exist? But then, if it didn't exist, then how could it come to be? Also, why is there empty space in the first place? Why does anything exist, even emptiness?

Maybe it's because I'm thinking on a time-linear scale here, and haven't gotten a good grasp on physics and the sort (I am only in High School after all), so if anyone could explain this to me, that would be fantastic!

The real problem is Hawking is still assuming some things, which means he isn't actually talking about nothing. And he provides no explanation for them.

[1over137]

I want to know if my understanding of Hawking's theory is correct: the laws of gravity designate and even force the universe to keep a constant balance, not to be outweighed from negative or positive energy, and because of these laws, it is impossible to have a purely empty space, and so the universe was created in order to maintain the balance.

The laws of gravity do not force the universe to keep a constant balance. What Hawking said is that if there is a law like gravity the positive energy of the matter can be balanced by the negative gravitational energy on the scale of the entire universe.

Whether it is impossible to have empty space? Well, it is possible to have an empty space. But because of the existance of the law like gravity, it is also possible to have unempty space, like one we live in.

To your other questions: Well, quantum theory of gravity does not exist yet which could provide more insight. Check also this site: http://www.astrosociety.org/pubs/mercur ... thing.html.

And why does anything exist, even emptiness?

[SnowDrops]

I want to know if my understanding of Hawking's theory is correct: the laws of gravity designate and even force the universe to keep a constant balance, not to be outweighed from negative or positive energy, and because of these laws, it is impossible to have a purely empty space, and so the universe was created in order to maintain the balance.

The laws of gravity do not force the universe to keep a constant balance. What Hawking said is that if there is a law like gravity the positive energy of the matter can be balanced by the negative gravitational energy on the scale of the entire universe.

Whether it is impossible to have empty space? Well, it is possible to have an empty space. But because of the existance of the law like gravity, it is also possible to have unempty space, like one we live in.

To your other questions: Well, quantum theory of gravity does not exist yet which could provide more insight. Check also this site: http://www.astrosociety.org/pubs/mercur ... thing.html.

And why does anything exist, even emptiness?

Emptiness does not exist. It is lack of existence, just like darkness is lack of light.

[1over137]

Hey guys. I was reading on one physics forum about a universe from nothing. I am not a cosmologist, so I do not understand everything, but still I has learned from that forum. They also spoke about Hawking as well. Here are for you some quotes:

Hawking and religion do not speak about the same type of creation and Hawking really misunderstood the issue here or at least pretended to do so. What Hawking means with creation is creation in the sense as we understand it within the context of quantum field theory. You have creation and annihilation operators on some Hilbert space, a non-free Hamiltonian and a vacuum state. So, the vacuum state may evolve into a state with particles. This is precisely what third quantization of gravity is about ...

Hawking assumes that the universe started out in a euclidean phase and that time did not exist. Then, due to a quantum fluctuation, time arose spontaneously and the universe evolved.

There is no observational evidence that directs cosmologists to favor one origin of the universe theory over any other. Currently, science has no epistemological traction on questions regarding the big bang or other origin theories. Maybe one
day, but for now we must be happy to content ourselves with understanding the universe from fractions of a second after the Planck density.

Also, there is a big difference between "nothing" and (even a perfect) vacuum. The vacuum which many think of as "empty space" in fact includes space (distance, an entity) as well as vacuum fluctuations even if that geography is isolated from the rest of the universe. We so far believe that at another type of singularity, that of a black hole, space and time and matter cease to exist and yet mass remains.So it appears they may be combinations of things we know and things we don't in combinations we know and combinations we don't: dark matter and dark energy, for example. What's up with them??

One point of view is that 'nothing' is invariant under every conceivable symmetry, and hence, a lot of physical laws apply to it -- in particular, time translation symmetry implies energy conservation, gauge symmetry implies quantum mechanics
(as argued by Victor Stenger), and supersymmetry holds; so if we want to create a universe ex nihilo, we need something like gravity to balance the books, and since we have QM, we can nucleate a universe Vilenkin-style. From Hawking's point of
view, supersymmetry is then needed to get everything to give out finite answers, with the most general supersymmetric theory of quantum gravity being M-theory.

I don't like Hawking's writing very much. In general situations (expanding universes, ...) energy cannot even be defined uniquely in GR. Of course energy density (or better: the energy-momentum tensor) is well-defined and is conserved locally;
but the global concept of "energy within a region" is still a matter of debate. But As soon as energy is no longer well-defined, the idea of "cancellation of gravitational and normal energy" becomes even more foggy. In addition there are extensions of Einstein's GR (Einstein-Cartan-theory - which seems to be a much more natural framework for gravity and perhaps quantum gravity) where even
local conservation laws are modified! Of course Hawking knows all this - but he misses to explain to his readership that
there are fundamental conceptual problems. That's why I think his popular books are not always a helpful for physics and physicists.

But the lack of physical laws in "nothing" means that there is nothing to prevent sponteneous events from occuring - that is to say, even if there was originally nothing, it was bound not to last since its lack of physical laws resulted in infinite instability.

That is certainly the broad view I have, and was the view expressed by various philosophers like Anaximander and CS Peirce.
In particular, what you put your finger on was the argument that physical laws are global constraints. The unstable fluctuations in a sea of raw potential must produce their own stabilising constraints along with the substance that gets constrained. You need the two things working synergistically for a universe to grow and become something self-organised and long run. This gets round the need for quantum field theory or other "laws of physics" contexts to pre-exist the fluctuations that are generated. They become part of what is also generated.

First of all "nothing" has always been defined in the context of some theory which means there is already a mathematical structure, physical laws and some interpretation on top of it. Even the absence of matter, energy and forces can not be made rigorous
in a typical quantum theory b/c that would mean that "nothing" is a state that is annihilated by all observables which would mean (I guess) that this state is not |0> but 0 and from 0 nothing can emerge.I agree that this is not "creation out of nothing" in the philosophical / ontological sense.
Perhaps one idea which could bring us closer to "creation out of nothing" is the mathematical universe hypothesis (MUH, Max Tegmark). But even MUH requires "more than nothing" to start with as there must exist mathematics, (consistent) mathematical
structures etc.

So, again, there are better authors than Hawking, e.g. Brian Greene, Roger Penrose.
Concerning the emptiness, Mariolee might have on his mind the vacuum.

[narnia4]

Interesting stuff, basically confirming what many have said. Its really pretty dishonest of Hawking if you think about it, and arguments like the KCA clearly still apply.

I just don't see how you get away from the problem, really.