New Measurements Add To Cosmic Confusion Surrounding Expansion Rate Of Universe - World Truth


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Friday, July 13, 2018

New Measurements Add To Cosmic Confusion Surrounding Expansion Rate Of Universe

There is a source of tension in cosmology and new observations have turned this puzzling situation into a full-blown problem. The rate of expansion of the universe is higher today than it was 13 billion years ago. This goes against what our theories suggest.

The latest measurements, as reported in The Astrophysical Journal, were conducted with the combined power of Hubble and the European Space Agency’s telescope Gaia. Astronomers used the two instruments to refine the cosmic ladder, which allowed them to estimate the expansion rate of the universe. The value they ended up with is 73.5 kilometers (45.6 miles) per second per megaparsec.

In other words, for every megaparsec (equivalent to 3.3 million light-years) a galaxy is away from us, it appears to be receding 73.5 kilometers per second faster. The measurement of the expansion rate made using the first light in the universe, the cosmic microwave background, put the value at 67 kilometers (41.6 miles) per second per megaparsec. This 9 percent difference is vast, in fact, its four times the combined uncertainty for the two telescopes. The expansion rate was assumed to either decrease or stay the same, not increase as the universe ages.

“The tension seems to have grown into a full-blown incompatibility between our views of the early and late time universe,” lead author and Nobel Laureate Adam Riess, of the Space Telescope Science Institute and Johns Hopkins University, said in a statement. “At this point, clearly it’s not simply some gross error in any one measurement. It’s as though you predicted how tall a child would become from a growth chart and then found the adult he or she became greatly exceeded the prediction. We are very perplexed.”

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