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Measuring the Hubble Constant Better

Posted by kdawson on from the masing-galaxies dept.

eldavojohn writes "The Hubble Constant is used for many things in astrophysics: from determining how fast things are moving away from us, to the total volume of the universe, to predicting how our universe will end. The current best value for the Hubble Constant is 74.2 ± 3.6 (km/s)/Mpc according to recent conventional methods and the recently restored Hubble Telescope. Most astronomers agree that that's within 10% of its actual value. Researchers now claim that they might be able to get to 3% using water molecules in galactic disks to act as masers that amplify radio waves, to analyze galaxies seven times as far away as the current measurements. The further away the 'standard candle' is, the more assured they can be that local effects are not skewing the measurements. From one of the researchers: 'We measured a direct, geometric distance to the galaxy, independent of the complications and assumptions inherent in other techniques. The measurement highlights a valuable method that can be used to determine the local expansion rate of the universe, which is essential in our quest to find the nature of dark energy.' Once the Square Kilometer Array is completed, they hope to get even closer to the actual value."

4 of 102 comments (clear)

  1. Hubble constant now a misnomer by Omnifarious · · Score: 3, Interesting

    From what I know, it's been discovered in the past decade or so to not be a constant. The expansion of the universe is accelerating. This is a minor nitpick, I know. :-)

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    1. Re:Hubble constant now a misnomer by cheftw · · Score: 2, Interesting

      And how come it's measured in some stupid space unit? It's a frequency so it wants hertz!

      http://www19.wolframalpha.com/input/?i=hubble+constant+in+hertz

      It's called SI. Get with the program dudes.

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    2. Re:Hubble constant now a misnomer by Khashishi · · Score: 3, Interesting

      The value in Hz gives you the scaling frequency of the universe. It makes sense to talk about the inverse of this frequency, which is in seconds, which is the time it takes for the universe to grow to e times its former size.

  2. Bad Labrador by Bad+Labrador · · Score: 2, Interesting

    I've been following Alexander F Mayers work on Minkowski's (Einsteins Maths Teacher) space time mathematics which Einstein, who didn't understand them, called "superfluous erudition'. Mayer derives a model for the universe that does not require the universe to be expanding, let alone accelerating expansion, does not require "Dark matter" nor "Dark energy", that makes a damn sight more cosmological sense than the "Big Bang" and fits the current observations, much, much better, with no free variables like "quintessence". He makes a prediction for the LRO mission as well. http://www.jaypritzker.org/index.html