- #1
Darkmatrix
- 4
- 0
Hi, I'm wondering what the main theories for the state/structure of the universe are and what they consist of? Not the creation but the current state/structure of it.
It is true that the Harrison-Zel'dovich (scale invariant) spectrum is claimed by WMAP7 to be ruled out at 3 sigma, favoring instead a power law spectrum with a spectral index, n, centered at around n=0.97. However, when model selection is taken into consideration, this conclusion no longer holds up to scrutiny. Model selection concerns itself with the question: suppose we have a base model, where n = 1 is set and not free to vary (the Harrison-Zel'dovich (HZ) model), and suppose we have a competing model where n is allowed to vary freely within some range. The second model has one more additional free parameter than the first, and will consequently provide a better fit to the data simply on account of this additional freedom. Model selection works to ensure that the addition of this free parameter is warranted by the data in the first place. So, it's not simply a matter of counting sigmas; one must also determine whether the data favors a more complex model. When this analysis is carried out, it is found that the evidence against the HZ spectrum is not substantial. See http://arxiv.org/abs/arXiv:0912.1614.BillSaltLake said:I think that perfect scale invariance of the spectrum is not what is observed and that the degree of deviation from scale invariance is very important. Am I correct in the assertion that if it were perfect scale invariance, then the density deviations over length scales typical of the whole observed last scattering surface would be much less than observed?
The Big Bang Theory is the most widely accepted scientific explanation for the origin and evolution of the universe. It suggests that the universe began as a singularity, a point of infinite density and temperature, and has been expanding and cooling ever since.
The Multiverse Theory proposes that there may be multiple universes, each with its own set of physical laws and properties. This theory is still speculative and has not been proven, but it is currently being investigated by scientists.
The Theory of Relativity, developed by Albert Einstein, is a fundamental theory in physics that describes the relationship between space, time, and gravity. It is important in understanding the large-scale structure and behavior of the universe.
Dark Matter is a type of matter that cannot be seen or detected by conventional means, but its existence is inferred through its gravitational effects on visible matter. It is believed to make up about 85% of the total matter in the universe and plays a crucial role in the formation and evolution of galaxies.
No, the universe is a complex and ever-evolving entity that cannot be fully explained by a single theory. Scientists use a combination of theories, observations, and experiments to understand different aspects of the universe, but there is still much to be discovered and understood.