DoobleD said:
If the CMB power spectrum were simply a scale-invariant Gaussian random field, then its power spectrum plotted with that vertical axis would be essentially flat (up to variation due to cosmic variance/instrumental noise). I believe the factor ##\ell(\ell+1)## stems from the fact that the spherical harmonics are not strictly flat plane waves.DoobleD said:
The CMB (Cosmic Microwave Background) power spectrum is a graph that shows the distribution of energy in the CMB radiation at different angular scales. It is a crucial tool for studying the structure and evolution of the universe.
The vertical axis of the CMB power spectrum represents the amount of energy present at different angular scales. This can tell us about the density and distribution of matter in the universe, as well as the properties of the early universe.
The vertical axis of the CMB power spectrum is determined through measurements of the CMB radiation using specialized instruments like the Planck satellite. The data is then analyzed and plotted on the power spectrum, with the vertical axis representing the level of energy at each angular scale.
The peaks and dips on the vertical axis of the CMB power spectrum correspond to different features in the CMB radiation. The first peak represents the largest structures in the universe, while subsequent peaks represent smaller structures. The dips, or valleys, represent regions with lower energy levels.
The vertical axis of the CMB power spectrum provides strong evidence for the Big Bang theory. The distribution of energy on the vertical axis matches the predicted pattern from the Big Bang model, providing confirmation of the theory's predictions about the early universe.
