Final answer:
The age of the Universe is best estimated to be 13.8 billion years old, based on the expansion rate indicated by the Hubble constant and evidence like cosmic background radiation.
Step-by-step explanation:
The best estimate for the age of the Universe is 13.8 billion years old. This estimation is derived from various observations and measurements, including the rate of expansion of the universe, characterized by the Hubble constant, and the cosmic microwave background radiation. Current models relying on such data suggest that the universe began with the Big Bang, and over time, we have refined our measurements to reach this consensus on its age.
The Hubble constant helps astronomers determine the rate at which the universe is expanding. Though there's an uncertainty of about 5% in the measurements of the Hubble constant, which translates to the age estimation, the general agreement is that the universe is approximately 13.8 billion years old. This figure is corroborated by other astronomical evidence, including the apparent age of the oldest stars and cosmic background radiation.
The 13.8 billion-year figure also considers the contents of the universe, where about 68.5% is dark energy and 31.5% is matter. Overall, the study of the universe's evolution, expansion, and various forms of cosmic background radiation supports this age estimation.