The accelerating expansion of the universe is not an illusion caused by time dilation. It is a well-established phenomenon supported by a substantial body of observational evidence, including measurements of the cosmic microwave background radiation, supernovae data, and galaxy clustering.
The concept of time dilation, as described by the theory of relativity, involves the relative slowing down or speeding up of time depending on the relative motion or the presence of gravitational fields. While time dilation does have important implications for our understanding of the universe, it is not responsible for the observed accelerating expansion of space.
The accelerating expansion of the universe is attributed to a property known as dark energy. Dark energy is a theoretical form of energy that permeates space and exerts negative pressure, driving the expansion of the universe to accelerate. This effect counteracts the gravitational pull of matter and causes the expansion to accelerate over time.
The role of dark energy in the expansion of the universe was first inferred from observations of distant supernovae in the late 1990s. These observations indicated that the expansion of the universe was accelerating, rather than slowing down as previously expected.
The concept of time dilation, while important in its own right, is not directly related to the accelerating expansion of the universe. Instead, the observed expansion is primarily attributed to the influence of dark energy, a mysterious component of the universe that drives this accelerated expansion.