Why Stephen Hawking says universe can create itself from nothing?

big_bounce

Hello all .
I can not explain good but hope you will understand my purpose .

I read in University Oregon's website that universe came from a pure energy in vacuum
If we want to say exactly , we can say universe came from Potential energy in vacuum .

We know in physics there are some conversation laws such as conversation of energy and conversation of angular and linear momentum and son on .

And we know momentum is a quantity that can carry by objects and particles like electrons and photons and in generally any elementary particles .

And we know in early universe there aren't any particles or objects just existed pure energy .

And we know energy isn't physical object or particle .

My first question is :

1 -Was there in early universe any momentum ? conversation of momentum says it should be existed ( like energy ) but this momentum carry by what (or which ) particles or objects ?


My second question is :
2 - energy is thing or nothing ? why Stephen Hawking says universe came from nothing ? if we consider universe came from pure energy .


My third question is :
3- why we can not say universe came from pure momentum ? why we must say universe came from pure energy ?


I really confused .

Thanks for your help .

Drmarshall

Yes, momentum. But how "early" do you want to go?

Energy is a mere concept. A useful idea if the only brain you have is a poor human one

We cannot say "came from" because if so that would be "before the beginning"

MathematicalPhysicist

You should really not listen to this nonsense.

I don't care how intelligent Stephen is, nothing can be created from nothing, so does he posit that we are actually really just nothing?

Mordred

The universe from nothing model isnt quite as crazy as you might think. A lot of top level cosmologists feel that it is a strong possibility.
Here is a quick guideline on process.
Key point in order for this model to work is that energy density must balance with zero energy. Gravity being considered as negative energy.
Rapid expansion occurs this creates a false vacuum. This false vaccuum. To maintain energy conservation energy is borrowed. I cant recall what the model states its borrowed from but if I recall its borrowed from gravity.
With that energy quantum tunneling occurs from virtual particles. Some of the virtual particles tunnel to the true vacuum. Leaving real particles.

It should be noted that virtual particles are created in a large variety of sources. Cosmological horizons. =Unruh radiation. Blackholes is Hawking radiation. Schwinger particle production is electromagnetic disturbences. Parker radiation is due to expansion.
All of the above are various blackbody radiation.

There are countless other particle production methods.
What they all boil down to is a vacuum is never empty.
False vacuum being the lowest energy state has quantum fluctuations described by Heisenburg uncertainty principle. Those fluctuations in turn create virtual particles. Those virtual particles in the right circumstances become real particles.
Throughout out all this for this model the energy density must stay equal to zero with gravity and vacuum energy as part of the balancers.
However even if the energy density isnt zero the various particle production methods describe above are all still valid.
Sounds crazy however their is tons of research and models that support this ultimate free lunch.

Mordred

Here is a link to a description of false vacuum.
http://ned.ipac.caltech.edu/level5/Guth/Guth3.html

if your interested in some of the other particle producers I can post some decent articles on them

Chalnoth

Why not?

MathematicalPhysicist

Cause to create something from nothing you need to do something illogical, magical, mystical.

And that's the break of rationality, it's possible, but then I might as well also believe in witches and fairies.

Crazymechanic

I'm afraid it has been always like this, when something large is about to reveal itself the majority can't believe their eyes.
Imagine the first light bulb or the fact that most of the scientists at the time believed that nothing heavier than air could fly.
Ok I understand this is a much bigger issue here that were facing not comparable to some jumbo jets or light bulbs but if it exists and if we exist then there was a way it started we may not understand or have access to that way but that doesn't make the way it went less real or possible.

Chalnoth

Prove it.

Johninch

First, leaving aside the creation activity, you can have a positive and a negative which compensate to zero. Both exist. It depends then what you mean by something and nothing.

Secondly, creation is going on all the time in so called empty space, with matter and antimatter particles anihilating each other.

So putting the two together, we can easily have creation from nothing.

"You" don't have to do anything, if creation is an automatic and therefore inevitable process.

.

phinds

Lawrence Krause has a whole book about this, "A Universe from Nothing", in which he supports this theory.

Mordred

The reaction your having is a coomon problem. However its one that stems from lack of knowledge in current cosmology. Not everything in science is easily understood by common sense. quantum entanglement is another that defies common sense.

With that in mind Can you show another model that expains how everything can develop? In cyclic models how did the first universe start?
Same applies to commoving models.
The one advantage this model presents is its lack of needing an outside source.
However the OP did not ask for personal opinions.
His post wanted an understanding of Hawkings statement. That has been provided personal opinions aside

julcab12

So far in all our efforts 'nothing' always amount to something. It only make sense if you put constraints on nothing(vacuum/false vacuum/empty space)".

rbj

where should the burden of proof be? that nothing comes from nothing? or that something comes from nothing? why should the burden of proof be on the former rather than the latter?

Chalnoth

He made a positive statement: it is impossible to create something from nothing. I asked him to back that statement up with more than ridicule.

The default should always be, "We don't know." If somebody had stated, "The universe was created from nothing in this specific way," then that would be a statement requiring evidential support. MathematicalPhysicist made a much, much stronger statement: that there is no possible way that something can come from nothing. That statement requires a mathematical proof as support.

rbj

for those of us that don't have the book and don't expect to order it, might you summarize the best argument for this notion? i would be quite interested.

i remember listening to Michael Schermer about it, and he said "maybe something is a more stable state than nothing."

it sounded like it was kinda an appeal to the notion that the big bang was a humongous quantum fluctuation. instead of an electron or some other sub-atomic particle just appearing or disappearing somewhere due to the nature of QM, a whole primordial universe just pops into existence 13.7 billion years ago.

rbj

okay, so i'll turn it around to this positive statement: "The Universe we observe created itself from nothing approximately 13.7 billion years ago."

why should the burden of proof be applied to the contrary rather to this positive statement?

boy, am i glad to read you say that.


this requires more than "mathematical proof". again (from the other thread), the mathematical relationships we call "physical law" describe the interaction of "stuff". the math is not the "stuff". and "stuff" is not "nothing".