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posted by martyb on Friday May 11 2018, @07:45AM   Printer-friendly
from the whatever-happened-to-42? dept.

Submitted via IRC for Runaway1956

A new estimate of the Hubble constant – the rate at which the universe is expanding – is baffling many of the finest minds in the cosmology community

[...] "The fact the universe is expanding is really one of the most powerful ways we have to determine the composition of the universe, the age of the universe and the fate of the universe," said Professor Adam Riess, at the Space Telescope Science Institute in Baltimore, Maryland, who led the latest analysis. "The Hubble constant quantifies all that into one number."

In an expanding universe, the further away a star or galaxy is, the quicker it is receding. Hubble's constant – proposed by Edwin Hubble in the 1920s – reveals by how much.

So one approach to measuring it is by observing the redshifts of bright supernovae, whose light is stretched as the very space it is travelling through expands. A challenge, though, is pinpointing the exact distance of these stars.

Riess, who shared the 2011 Nobel Prize for Physics for providing evidence that the expansion of the universe is accelerating, is part of a team focussed on developing ultra-precise methods for measuring distances.

The latest Gaia observations have advanced this effort by identifying dozens of new Cepheid stars, which have the special feature that their light flickers at a rate that is directly linked to their brightness at source. So through observing the pulsations of these so-called standard candles, scientists can work out their original luminosity and, therefore, how far away they and their native galaxies are.

The new data puts the Hubble constant at 73, which translates to galaxies moving away from us 73km per second faster for each additional megaparsec of distance between us and them (a megaparsec is about 3.3m light-years).

However, a separate estimate of Hubble comes from observations of the Cosmic Microwave Background, relic radiation that allows scientists to calculate how quickly the universe was expanding 300,000 years after the big bang.

"The cosmic microwave background is the light that is the furthest away from us that we can see," said Riess. "It's been travelling for 13.7bn years... and it's telling us how fast the universe was expanding when the universe was a baby."

Scientists then use the cosmic equivalent of a child growth chart (a computational model that roughly describes the age and contents of the universe and the laws of physics) to predict how fast the universe should be expanding today. This gives a Hubble value of 67.

Until recently, scientists had hoped that as measurements became more precise, this mismatch would narrow, but instead the difference has widened and the latest calculation gives a chance of only 1 in 7,000 of the discrepancy being down to chance. "If this continues to hold up we may be dealing with what we call new physics of the universe," said Riess.

[...] The crisis in cosmology, as it was described a meeting of the American Physical Society last month, could soon be resolved through new measurements of the Hubble constant based on gravitational wave observations by the Ligo collaboration. "Within the next five years, we'll probably nail this," said [John] Peacock [professor of cosmology at the University of Edinburgh].

Source: https://www.theguardian.com/science/2018/may/10/the-answer-to-life-the-universe-and-everything-might-be-73-or-67


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  • (Score: 2) by looorg on Friday May 11 2018, @11:59AM (15 children)

    by looorg (578) on Friday May 11 2018, @11:59AM (#678321)

    So the answer to life, the universe and everything might be 73, or 67 or 42. Why does it have to be just one of them? Can't we just declare that it's an non strict interval between 42 and 73 or that it's an array {42,67,73} ?

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  • (Score: 0) by Anonymous Coward on Friday May 11 2018, @12:39PM

    by Anonymous Coward on Friday May 11 2018, @12:39PM (#678330)

    You mean binary tree.

  • (Score: 3, Touché) by realDonaldTrump on Friday May 11 2018, @12:44PM (4 children)

    by realDonaldTrump (6614) on Friday May 11 2018, @12:44PM (#678335) Homepage Journal

    69 was tremendous for me. And 71 is amazing!

    • (Score: 0) by Anonymous Coward on Friday May 11 2018, @01:34PM

      by Anonymous Coward on Friday May 11 2018, @01:34PM (#678352)

      I'm sure it was, unfortunately it apparently wasn't earth moving for Mrs. Daniels.

    • (Score: 2) by stretch611 on Friday May 11 2018, @04:05PM (2 children)

      by stretch611 (6199) on Friday May 11 2018, @04:05PM (#678435)

      2019 will be great for the rest of us. (after you are impeached.)

      --
      Now with 5 covid vaccine shots/boosters altering my DNA :P
      • (Score: 2, Offtopic) by realDonaldTrump on Friday May 11 2018, @05:20PM (1 child)

        by realDonaldTrump (6614) on Friday May 11 2018, @05:20PM (#678491) Homepage Journal

        We both know the 115th Congress isn't going to impeach me. Because I have too many loyal guys & gals in there. The 116th starts on Jan. 3. And maybe the VERY CROOKED Dems will rig enough elections, get enough seats, that I could be impeached. That could happen. You know that there's a trial, right? And believe me, I have the best lawyers. And I could lose, that's so true. Anybody could lose when a bunch of very unfair Dem Senators are making the decision. But if I stay in office past Jan. 20, .@VP [twitter.com] Pence is eligible for two full terms as President. After he finishes out my term. President Clinton -- Bill Clinton -- loves the women, he has a lot of fun with the women. And he got in a little bit of trouble over that. And I love the women, I've had some very good times with the ladies. I'm amazing with the ladies, as everybody knows. A sex god. Maybe I'll get impeached for that, who knows, right? But Mike Pence, he does what they call the Billy Graham rule. Meaning, he's never alone with a woman, except Karen. He's never had sex with a woman, except Karen. He's never had a blowjob. Never done anal. And obviously no gay stuff. The Dems try to get him on sex stuff, they'll be laughed out of office. They impeach me, get ready for almost 10 years of President Pence. Enjoy!!!!

        • (Score: 0) by Anonymous Coward on Friday May 11 2018, @09:30PM

          by Anonymous Coward on Friday May 11 2018, @09:30PM (#678576)

          and I prefer you to pence anyday. he looks and behaves like a sith like emperor palpatine

  • (Score: 1, Funny) by Anonymous Coward on Friday May 11 2018, @12:44PM (4 children)

    by Anonymous Coward on Friday May 11 2018, @12:44PM (#678336)

    Why can't the answer be a vector?

    • (Score: 4, Funny) by DannyB on Friday May 11 2018, @02:10PM (1 child)

      by DannyB (5839) Subscriber Badge on Friday May 11 2018, @02:10PM (#678381) Journal

      I can't stand the stress of a vector victor. That would make me tensor and tensor.

      --
      People today are educated enough to repeat what they are taught but not to question what they are taught.
    • (Score: 2) by looorg on Friday May 11 2018, @03:08PM (1 child)

      by looorg (578) on Friday May 11 2018, @03:08PM (#678407)

      Vectors imply force, which makes the answer to life kinda rapey ...

      • (Score: 2) by DannyB on Friday May 11 2018, @04:41PM

        by DannyB (5839) Subscriber Badge on Friday May 11 2018, @04:41PM (#678457) Journal

        Maybe a tuple which is less stressful than a tensor.

        --
        People today are educated enough to repeat what they are taught but not to question what they are taught.
  • (Score: 2) by PiMuNu on Friday May 11 2018, @12:47PM (2 children)

    by PiMuNu (3823) on Friday May 11 2018, @12:47PM (#678338)

    I think the point is that there is evidence for a non-constant constant i.e. new physics (variable speed of light etc).

    • (Score: 2) by arulatas on Friday May 11 2018, @02:06PM (1 child)

      by arulatas (3600) on Friday May 11 2018, @02:06PM (#678377)

      Does this mean that "light speed" travel might be possible as the speed of light may be variable depending on local conditions?

      --
      ----- 10 turns around
      • (Score: 2) by ben_white on Saturday May 12 2018, @03:53AM

        by ben_white (5531) on Saturday May 12 2018, @03:53AM (#678691)

        No. Spacetime can expand faster than the speed of light, but nothing can move through spacetime faster.

  • (Score: 2) by All Your Lawn Are Belong To Us on Friday May 11 2018, @02:59PM

    by All Your Lawn Are Belong To Us (6553) on Friday May 11 2018, @02:59PM (#678403) Journal

    I hereby declare a new unit of Belongies (B). One B is a set range between 1.595 and 1.738 km/s/∆MPc

    You may now rest assured that The Answer can be expressed as 42 B by itself, with my compliments. You may even just leave off the unit designation since everybody knows what a B is now.

    --
    This sig for rent.