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Alistair Bingham
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...does it not simply indicate that the galaxies WERE receding faster IN THE PAST?
Alistair Bingham said:...does it not simply indicate that the galaxies WERE receding faster IN THE PAST?
Alistair Bingham said:...does it not simply indicate that the galaxies WERE receding faster IN THE PAST?
PeroK said:Essentially, yes.
The observable universe grows faster than the scale factor, as light gets more time to reach us - we see more distant objects than we could see 5 billion years ago. "Size of the region that is today's observable universe" works.PeterDonis said:(If the word "size" bothers you because our best current model has the universe being spatially infinite, substitute "observable universe" for "universe".)
Yes, but due to the way the universe has been expanding, many galaxies are receding even faster today than they were when the light we see left them.Alistair Bingham said:...does it not simply indicate that the galaxies WERE receding faster IN THE PAST?
The redshift of distant galaxies refers to the phenomenon where the light emitted from these galaxies is shifted towards the red end of the electromagnetic spectrum. This is due to the expansion of the universe, which causes the wavelengths of light to stretch as they travel through space.
Redshift in distant galaxies is measured using a tool called a spectrometer. This device splits the light emitted from a galaxy into its component wavelengths, allowing scientists to determine the amount of redshift based on the difference between the observed and expected wavelengths.
The redshift of distant galaxies provides valuable information about the age of the universe. By measuring the amount of redshift, scientists can calculate the distance to a galaxy. This, along with other measurements, has allowed us to estimate the age of the universe to be approximately 13.8 billion years old.
The redshift of distant galaxies is one of the key pieces of evidence supporting the Big Bang theory. As the universe expands, galaxies move away from each other, causing their light to be redshifted. This supports the idea that the universe is expanding from a single point, as predicted by the Big Bang theory.
Currently, the most distant galaxy with a measured redshift is GN-z11, which is estimated to have a redshift of 11.1. However, due to the expansion of the universe, there is no theoretical limit to how far redshift can be observed. As technology and techniques continue to improve, we may be able to observe galaxies with even higher redshifts in the future.