The two principal methods of calculating the universe’s expansion rate have proven to be in discrepancy.
With the universe stretching continuously, scientists desire to know the exact rate at which it expands. It seems that predictions don’t correspond with observations.
Expansion rates recorded at the European Space Agency show a slower development of the universe 13 billion years ago, while Hubble data shows a faster expansion rate. It is unclear whether the discrepancy comes from faulty measurement techniques or wrong measurements.
The universe’s expansion rate is also known as the Hubble constant. The calculations are made by comparing distances of nearby galaxies to those of farther ones, using the stars as markers. This method is called the ”cosmic distance ladder.”
In time, after multiple tests were performed, measurements have become more accurate. Compared to predictions of the early universe’s development, the Hubble constant still does not coincide.
Universe Expansion Rate Values
The latest official value of the Hubble constant is 74 kilometers per second per megaparsec. Early universe expansion rates predictions are 9% slower.
Theories That Could Explain Discrepancies
One possible cause of the difference could be the presence of dark energy in the forming stages of the universe. Dark energy has already been discussed by astronomers believing that it appeared immediately after the Big Bang. A new theory suggests that another dark-energy event took place shortly after, forcing the universe to expand even faster.
Another hypothesis is that dark radiation is present in the universe. This phenomenon is explained as an abundance of subatomic particles that travel at the speed of light.
Many theories have been made, yet the true explanation remains an enigma.
Scientists promise to find an answer to this problem, continuing to use the Hubble Space Telescope in this purpose. They are hoping to finally find the cause of the discrepancy.