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Physical cosmology. The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. [1] It is an intrinsic expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it.
8 mar 2021 · Astronomers use surface brightness fluctuations of 63 giant elliptical galaxies to measure the expansion rate of the universe within 100 megaparsecs. The result agrees with other techniques, but differs from early universe estimates based on cosmic microwave background and baryon acoustic oscillations.
The Hubble constant measures the rate of cosmic expansion, but its value is uncertain and controversial. Learn about the history, methods, and challenges of determining this key parameter of cosmology.
11 mar 2024 · Depending on the values deduced for the expansion rate, the Universe could be anywhere between 10 and 20 billion years old. Over the past 34 years Hubble has shrunk this measurement to an accuracy of less than one percent, splitting the difference with an age value of 13.8 billion years.
11 mar 2024 · The puzzle, called the "Hubble Tension," is that the current rate of the expansion of the universe is faster than what astronomers expect it to be, based on the universe's initial conditions and our present understanding of the universe’s evolution.
16 lip 2019 · A new study using Hubble Space Telescope finds that the universe is expanding faster than expected, based on the brightness of red giant stars in distant galaxies. The result adds to the mystery of the Hubble constant discrepancy and the underlying physics of the universe.
20 wrz 2023 · New data from NASA's James Webb Space Telescope show that the universe is expanding faster than expected based on the cosmic microwave background. This discrepancy, known as the Hubble tension, may indicate unknown physics or a flaw in the theory of general relativity.
