Dark energy and dark matter are not simply "hypotheses and beliefs," but rather scientific concepts that have been proposed to explain certain observations and phenomena in the universe. While they are not yet fully understood, there is a substantial amount of evidence supporting their existence.
Dark matter is a term used to describe a type of matter that does not interact with light or other forms of electromagnetic radiation. It was originally proposed to explain discrepancies between the observed gravitational effects in the universe and the amount of visible matter that could account for those effects. Over the years, numerous independent lines of evidence have emerged that point towards the existence of dark matter. For example, the rotational speeds of galaxies, gravitational lensing, and the distribution of matter in the large-scale structure of the universe all suggest the presence of dark matter. While the exact nature of dark matter remains unknown, these observations strongly indicate its existence.
Similarly, dark energy is a theoretical form of energy that is thought to permeate all of space and drive the accelerating expansion of the universe. The concept of dark energy arose from observations of distant supernovae, which indicated that the universe's expansion rate was accelerating rather than slowing down as previously expected. In addition to supernovae data, other independent measurements, such as the cosmic microwave background radiation and large-scale structure surveys, also support the existence of dark energy.
Scientists do not claim that dark matter and dark energy are "100% proven, observed, testable, and undeniable hard facts" in the same way that some established principles of physics, such as the laws of motion or the theory of gravity, are considered facts. Instead, they are proposed explanations based on the available evidence, and ongoing research continues to refine our understanding of these concepts. However, the accumulated evidence strongly supports the existence of dark matter and dark energy, and they are widely accepted within the scientific community as the most plausible explanations for the observed phenomena.
It is important to note that science is a process of continuous exploration and refinement, and our understanding of the universe evolves as new evidence emerges. Therefore, scientific concepts, including dark matter and dark energy, are subject to revision and further investigation based on future observations and experiments.