The possibility of a bouncing universe challenged by new studies

However, the Planck space observatory's cosmic microwave background (CMB) radiation measurements revealed unexpected microwave radiation changes, prompting researchers to consider alternate hypotheses.

Loop quantum cosmology and the question of entropy

Loop quantum cosmology (LQC) is one model that seeks to correct the Big Bang theory's flaws. LQC integrates quantum mechanics and classical physics, avoiding the troublesome singularities related to the Big Bang. 

According to this theory, a past universe would have shrunk due to gravity before switching to expansion without experiencing a singularity. An inflationary phase, comparable to the one thought to have existed in our universe, may have also been a part of this process.

Ivan Agullo, a physicist, suggested that the "bispectrum"—a property of the CMB data—could be used to identify the presence of a bounce. However, the Planck CMB data investigations could not find any conclusive proof of a bispectrum imprint, ruling out bouncing universe models that depended on LQC to explain CMB abnormalities.

Even the universe is mortal

Entropy poses a severe obstacle to the theory of an endlessly spinning cosmos with infinite bounces. In a cyclic world, entropy, related to the degree of disorder and usable energy in a system, rises with each bounce. 

This implies that the cosmos must have had a significant bang-like beginning even if further cycles occur. According to new cyclic theories, the universe expands greatly during each process to reduce entropy before collapsing. This answer, however, suggests that the cosmos is not eternal and most likely had a beginning.

Supporters of endless cycles are yet to weigh in on the ongoing discussion about cyclic worlds. The scientific evidence now points towards the idea of a singularity-driven one-time event that began the cosmos, despite some academics' claims to the contrary.

These discoveries offer critical new understandings of the nature of cosmic evolution as research into the universe's beginning continues. However, the search to fully comprehend the enigmas underlying the universe's origins and potential cycles is far from over.