nothing is 'unstable'

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Reality Check

 

Why Is There Something Rather Than Nothing?

 

VICTOR STENGER

 

Why is there something rather than nothing? This question is often the

last resort of the theist who seeks to argue for the existence of God

from science and finds all his other arguments fail. In his 2004 book

Why There Is Something Rather than Nothing, philosopher Bede Rundle

calls it " philosophy's central, and most perplexing, question. " His

simple (but book-length) answer: " There has to be something. "

 

Clearly, many conceptual problems are associated with this question.

How do we define nothing? What are its properties? If it has

properties, doesn't that make it something? The theist claims that God

is the answer. But, then, why is there God rather than nothing?

Assuming we can define nothing, why should nothing be a more natural

state of affairs than something?

 

In fact, we can give a plausible scientific reason based on our best

current knowledge of physics that something is more natural than

nothing! Of course, that requires providing a physical definition of

nothing. Can I imagine a physical system that has no properties? Yes,

as long as you do not insist on playing word games with me by calling

the lack of properties a property.

 

Suppose we remove all the particles and any possible non-particulate

energy from some unbounded region of space. Then we have no mass, no

energy, or any other physical property. This includes space and time,

if you accept that these are relational properties that depend on the

presence of matter to be meaningful.

 

While we can never produce this physical nothing in practice, we have

the theoretical tools to describe a system with no particles. The

methods of quantum field theory provide the means to move

mathematically from a state with n particles to a state of more or

fewer particles, including zero particles. If an n-particle state can

be described, then so can a state with n = 0.

 

Let us start with a monochromatic electromagnetic field, which is

described quantum mechanically as system of n photons of equal energy

E. The mathematical description of the field is equivalent to a

harmonic oscillator whose quantum solution is a series of energy

levels equally spaced like the rungs of a ladder by an amount E, each

rung representing a field with one more photon than the field

represented by the rung below. Stepping down the ladder you find that

the bottom rung corresponding to a field of zero photons is not zero

energy but rather E/2. This is called the zero-point energy.

 

This result is true for all bosons, particles that have zero or

integral spin. On the other hand, fermions that have half-integral

spin, such as the electron and quark, have a zero-point energy of -E/2

(negative energy is no problem in relativistic quantum mechanics; in

fact, it is required by the simple mathematical fact that a square

root has two possible signs).

 

In the current universe, bosons outnumber fermions by a factor of a

billion. This has led people to conclude that the vacuum energy of the

universe, identified with the zero point energy remaining after all

matter is removed, is very large. A simple calculation indicates that

the energy density of the vacuum is 120 orders of magnitude greater

than its experimental upper limit. Clearly this estimate is wrong.

This calculation must be one of the worst in scientific history! Since

a non-particulate vacuum's energy density is proportional to

Einstein's cosmological constant, this is called the cosmological

constant problem.

 

Instead of using numbers from the current universe, we can visualize a

vacuum with equal numbers of bosons and fermions. Such a vacuum might

have existed at the very beginning of the big bang. Indeed this is

exactly what is to be expected if the vacuum out of which the universe

emerged was supersymmetric-that is made no distinction between bosons

and fermions.

 

This suggests a more precise definition of nothing. Nothing is a state

that is the simplest of all conceivable states. It has no mass, no

energy, no space, no time, no spin, no bosons, no fermions-nothing.

 

Then why is there something rather than nothing? Because something is

the more natural state of affairs and is thus more likely than

nothing-more than twice as likely according to one calculation. We can

infer this from the processes of nature where simple systems tend to

be unstable and often spontaneously transform into more complex ones.

Theoretical models such as the inflationary model of the early

universe bear this out.

 

Consider the example of the snowflake. Our experience tells us that a

snowflake is very ephemeral, melting quickly to drops of liquid water

that exhibit far less structure. But that is only because we live in a

relatively high temperature environment, where collisions with

molecules in thermal motion reduce the fragile arrangement of crystals

to a simpler liquid. Energy is required to destroy the structure of a

snowflake.

 

But consider an environment where the ambient temperature is well

below the melting point of ice, as it is in most of the universe far

from the highly localized effects of stellar heating. In such an

environment, any water vapor would readily crystallize into complex

structures. Snowflakes would be eternal, or at least will remain

intact until cosmic rays tear them apart.

 

What this example illustrates is that many simple systems are

unstable, that is, have limited lifetimes as they undergo spontaneous

phase transitions to more complex structures of lower energy. Since

" nothing " is as simple as it gets, we would not expect it to be

completely stable. In some models of the origin of the universe, the

vacuum undergoes a spontaneous phase transition to something more

complicated, like a universe containing matter. The transition

nothing-to-something is a natural one, not requiring any external agent.

 

As Nobel Laureate physicist Frank Wilczek has put it, " The answer to

the ancient question 'Why is there something rather than nothing?'

would then be that 'nothing' is unstable. "

 

VICTOR STENGER

 

 

 

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..b bobji baba