Big Bang Cosmology  Part 2
On June 7 I posted a link to a story about recent developments in Big Bang cosmology, described in an article in Quanta magazine. I provided excerpts and comments. This is a follow up to that post. I missed something important in my comments.
I had included this excerpt: ' The PenroseHawking "singularity theorems" meant there was no way for spacetime to begin smoothly, undramatically at a point. Likewise, Hartle and Hawking expressed the wave function of the universe — which describes its likely states — as the sum of all possible ways that it might have smoothly expanded from a point. '
I should have added this comment:
Hawking's expressing a wave function for the universe is proposing the entire universe is an isolated quantum system.
From Wikipedia: ' A wave function in quantum physics is a mathematical description of the quantum state of an isolated quantum system. The wave function is a complexvalued probability amplitude, and the probabilities for the possible results of measurements made on the system can be derived from it.
A quantum system is a portion of the whole Universe (environment or physical world) which is taken under consideration to make analysis or to study for quantum mechanics pertaining to the waveparticle duality in that system. Everything outside this system (i.e. environment) is studied only to observe its effects on the system. A quantum system involves the wave function and its constituents, such as the momentum and wavelength of the wave for which wave function is being defined. ' This theory (by Hawking and others) proposes the universe can be described using probabilities for its objects, using quantum mechanics rather than classical physics.
Quantum mechanics remains strictly theoretical. Its geometry is not testable.
Here are its 10 dimensions: 1) length 2) height 3) depth 4) time 5 ) possible worlds but different than ours 6 ) all possible worlds with the same start conditions 7 ) all possible worlds with different start conditions 8 ) all possible worlds with different start conditions branching out to infinity 9 ) all possible worlds with all possible start conditions and it has the laws of physics 10) infinite possibilities
Only the first 3 can be tested. The rest are about probabilities. This wave function also involves time, like the probability within the time before measurement. That is why 'time flowing in both directions' is in the article about this cosmology. Probabilities are not truly testable which is confirming a prediction. A coin flip is not predictable. Many tests can attempt to check the probability but the flip's result cannot be predicted every time. Testing a prediction from quantum mechanics is usually with a quantum computer because quantum particles have an uncertain position and cannot be predicted. Checking the probability not a prediction. Quantum mechanics is based on an assumed waveparticle duality where a particle as a wave has a probability for its position; After the particle is measured then the wave function (which holds all the future possibilities ) is collapsed because there is no longer a probability of it being in another position.
Positions of planets are predictable based on the limits of our measurement capabilities. Their positions are not driven by a probability; they are driven by the forces affecting their motion. The time scale certainly affects the accuracy of a prediction where a position in a few years can be predicted quite accurately (like an eclipse or occultation) whereas the position in 1000 years would have a small error margin. All these predictions are based on the knowledge of a previously observed position. These predictions are not based on probabilities but on the known forces in physics.
When the big bang cosmology is based on probabilities and the big bang event offers nothing as a foundation for any predictions then this big bang cosmology is absolutely not testable.
The article finished with this: ' "Whether we are finding the right wave function, or how we should think about the wave function — it's less clear." ' Perhaps someone will realize this mistake.
The big bang cosmology has predictions for the first nanosecond and their model based on probabilities tries to predict how the universe came to be as it is observed right now.
This is not testable science. It is literally impossible for this cosmology to predict anything in the time line from the big bang until now. I am amazed someone might make a claim of any predictability after the big bang.
Hit back to go to previous page in history. Here is the list of topics in this Cosmology Topic Group .
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