Conflict in Hubble constant increases with new data from Hubble and Gaia


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The uncertainty of science: New data from the Hubble Space Telescope and Gaia continues to measure a different Hubble constant for the expansion rate of the universe, when compared with data from the Planck space telescope.

Using Hubble and newly released data from Gaia, Riess’ team measured the present rate of expansion to be 73.5 kilometers (45.6 miles) per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it appears to be moving 73.5 kilometers per second faster. However, the Planck results predict the universe should be expanding today at only 67.0 kilometers (41.6 miles) per second per megaparsec. As the teams’ measurements have become more and more precise, the chasm between them has continued to widen, and is now about 4 times the size of their combined uncertainty.

The problem really is very simple: We haven’t the faintest idea what is going on. We have some data, but we also have enormous gaps in our knowledge of the cosmos. Moreover, most of our cosmological data is reliant on too many assumptions that could be wrong, or simply in error. And the errors can be tiny and still throw the results off by large amounts.

The one thing that good science and skepticism teaches is humbleness. Do not be too sure of your conclusions. The universe is a large and complex place. It likes to throw curve balls at us, and if we swing too soon we will certainly miss.

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9 comments

  • Lou

    Amazing how the more you learn, the more you realize that you don’t know much!

  • Localfluff

    There is certainly a lot more than a faint idea about the expansion of the universe! Don’t play so uneducated. They are zooming in on the decimals. What would you have guessed yourself? Probably that the Sun orbits the Earth…

    Please, show some respect!

  • Edward

    Localfluff,
    Do not confuse precision (more decimals) for accuracy (correctness). My clock may be able to precisely tell time to within a thousandth of a second (3 decimals), but if it is a minute off, it is not so accurate.

    The article notes that there are different values that differ wildly by more than the uncertainty of either or both calculations. Which one is the more accurate? No one knows whether either is accurate.

    Planck is trying to understand the expansion by predicting today’s rate from the universe as we see that it had been 13.79964 billion years ago (plus or minus 50 million years or so). Since their prediction — based upon what we “know” to be right and true — disagrees with observation — also right and true — something is wrong about our “knowledge” of the universe.

    However, the more we try to answer this question, the more we learn how to answer it.

  • wayne

    Before the Big Bang episode 7
    “An Eternal Cyclic Universe, CCC revisited & Twistor Theory”
    https://youtu.be/FVDJJVoTx7s
    55:25

  • Garry

    The link shows a graph I found years ago elsewhere (not at the link). I keep it handy on my desktop, and open it from time to time to remind myself how little I really know.

    https://blog.gardeviance.org/2008/04/three-stages-of-expertise.html

  • Garry: Most excellent. I think it used to be that our culture emphasized what this graph expresses. Now I am not so sure.

  • wayne

    Edward…..
    Speaking of Max Planck:
    “Science advances, one funeral at a time.”

  • eddie willers

    Paraphrasing Mark Twain:

    When I was 17, my father was the stupidest man on Earth. Now that I am 21, it’s amazing what the old man has learned in just 4 years.

  • Localfluff

    Edwin Hubble’s discovery of intergalactic space and that it expands was the greatest discovery in observational astronomy of the 20th century. The expansion came pretty much out of the blue and revised Einsteins relativity theory (“my biggest blunder”). Edwin himself never seems to have taken an outspoken stand on the Big Bang theory, although that’s the obvious conclusion if one traces backwards. Maybe because he was not primarily a theoretical astronomer. Maybe because he thought that the universe is weirder than we can understand. (And he didn’t get the Nobel prize with the motivation that astronomy is not physics…)

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