The existence of dark matter is supported by a wide range of observational evidence from different astrophysical and cosmological observations. This evidence includes the rotation curves of galaxies, gravitational lensing, the cosmic microwave background radiation, and the large-scale structure of the universe. Dark matter provides an explanation for these phenomena, as it interacts gravitationally but does not emit or absorb light, making it "dark" and challenging to directly detect.
While there have been ongoing efforts to explore alternative explanations for the observed phenomena attributed to dark matter, such as modifying gravity theories like Modified Newtonian Dynamics (MOND), these alternative theories have not yet provided a comprehensive and widely accepted explanation for the range of observations that dark matter can account for.
Einstein's theory of general relativity, which underlies our understanding of gravity, has been tested extensively and has withstood numerous experimental verifications. It accurately describes a wide range of phenomena, from the motion of planets to the bending of starlight around massive objects. However, it is important to note that general relativity is not considered a complete theory, as it does not account for the behavior of particles at the quantum level.
While it is always possible that future scientific advancements may lead to modifications or refinements of our understanding of dark matter or gravity, it would require substantial evidence and experimental confirmation to overturn the current understanding of dark matter and general relativity. At present, the prevailing scientific consensus is that dark matter is a significant component of the universe, and general relativity provides an accurate description of gravity on cosmological scales.