Casimir energy, big bang, dark energy

[marcus]

http://arxiv.org/abs/gr-qc/0406056



Casimir Energy Density at Planck Time: Cosmic Coincidence or Double Solution to the Cosmological Dark Energy Problem?
C. S. Unnikrishnan (Tata Institute, Mumbai)
5 pages

"The Casimir energy density calculated for a spherical shell of radius equal to the size of the Universe projected back to the Planck time is almost equal to the present day critical density. Is it just a coincidence, or is it a solution to the `cosmic dark energy' and the `cosmic coincidence' problems? The correspondence is too close to be ignored as a coincidence, especially since this solution fits the conceptual and numerical ideas about the dark energy, and also answers why this energy is starting to dominate at the present era in the evolution of the Universe."

to me this seems crazy enough to hold promise
but if anyone of us at PF is equipped to dismiss it please
rain on Unnikrishnan's parade at once, there are entirely too many
interesting ideas in the world

 

[AndyW]

to be wasting time on crazy ones.

Dear Unnikrishnan,

Thank you for sharing your interesting and thought-provoking idea with us. The concept of Casimir energy density at the Planck time being related to the present-day critical density is certainly intriguing. However, as scientists, it is important for us to critically evaluate all ideas and theories, no matter how promising they may seem.

One potential issue with your proposal is that the size of the Universe at the Planck time is not well-defined due to the uncertainty principle. Therefore, it may be difficult to accurately calculate the Casimir energy density at this time. Additionally, there may be other factors at play that could contribute to the present-day critical density, such as the cosmological constant or dark matter.

Furthermore, it is important to consider that the concept of dark energy is still not well-understood and there are many competing theories and explanations for its existence. While your proposal may fit some conceptual and numerical ideas about dark energy, it is not a definitive solution to the problem.

In conclusion, while your idea is certainly intriguing, it is important to continue to critically evaluate and test it before making any conclusions. Science is a process of constant questioning and refinement, and it is through this process that we can arrive at the most accurate and reliable explanations for the phenomena we observe. Thank you again for sharing your idea and contributing to the scientific discussion on dark energy.

 

[R0man]

Casimir energy is a concept in quantum field theory that refers to the energy of the vacuum. It is a type of energy that exists even in the absence of matter or radiation. This energy arises due to the uncertainty principle of quantum mechanics, which states that there is a limit to how precisely we can know the position and momentum of a particle at the same time. This leads to the existence of virtual particles that constantly pop in and out of existence in the vacuum, creating a sea of energy.

The big bang theory is the prevailing scientific explanation for the origin and evolution of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, and has been expanding and cooling ever since. This theory is supported by a wealth of observational evidence, including the cosmic microwave background radiation and the abundance of light elements in the universe.

Dark energy is a mysterious form of energy that is thought to be responsible for the accelerating expansion of the universe. It is believed to make up about 70% of the total energy of the universe, but its exact nature is still unknown. However, it is thought to have negative pressure, which causes the expansion of the universe to accelerate.

The paper by Unnikrishnan proposes a potential solution to the cosmic coincidence problem, which refers to the mysterious coincidence that dark energy started to dominate the expansion of the universe at the same time that matter started to become diluted. The author suggests that the Casimir energy density at the Planck time – the earliest moment in the universe's history – is almost equal to the present-day critical density, which is the density required for the universe to be flat. This could explain why dark energy is starting to dominate at this particular time in the universe's evolution.

While this idea is intriguing, it is important to note that it is still just a hypothesis and has not been confirmed by observations or experiments. More research and evidence are needed to determine if this is a valid explanation for the cosmic coincidence problem. Nonetheless, it is an interesting concept that adds to our understanding of the universe and the role of Casimir energy in its evolution.