Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Space

One Number Shows Something Is Fundamentally Wrong With Our Conception of the Universe (space.com) 260

A reader shares a report form Space.com: There's a puzzling mystery going on in the universe. Measurements of the rate of cosmic expansion using different methods keep turning up disagreeing results. The situation has been called a "crisis." The problem centers on what's known as the Hubble constant. Named for American astronomer Edwin Hubble, this unit describes how fast the universe is expanding at different distances from Earth. Using data from the European Space Agency's (ESA) Planck satellite, scientists estimate the rate to be 46,200 mph per million light-years (or, using cosmologists' units, 67.4 kilometers/second per megaparsec). But calculations using pulsating stars called Cepheids suggest it is 50,400 mph per million light-years (73.4 km/s/Mpc). If the first number is right, it means scientists have been measuring distances to faraway objects in the universe wrong for many decades. But if the second is correct, then researchers might have to accept the existence of exotic, new physics. Astronomers, understandably, are pretty worked up about this discrepancy. In April, NASA's Hubble Space Telescope confirmed that the Universe is expanding about 9% faster than expected based on its trajectory seen shortly after the big bang.

"We are measuring something fundamentally different," said Adam Riess, Bloomberg Distinguished Professor of Physics and Astronomy at The Johns Hopkins University. "One is a measurement of how fast the universe is expanding today, as we see it. The other is a prediction based on the physics of the early universe and on measurements of how fast it ought to be expanding. If these values don't agree, there becomes a very strong likelihood that we're missing something in the cosmological model that connects the two eras."
This discussion has been archived. No new comments can be posted.

One Number Shows Something Is Fundamentally Wrong With Our Conception of the Universe

Comments Filter:
  • by fredrated ( 639554 ) on Thursday September 05, 2019 @02:19AM (#59160566) Journal

    exciting?

  • I'm just thrilled (Score:5, Insightful)

    by idji ( 984038 ) on Thursday September 05, 2019 @02:28AM (#59160576)
    All my life Hubble's constant has been a bit fuzzy and vague - we are coming to a point of greater precision. It is awesome what we will discover.
    • by MrL0G1C ( 867445 )

      2nd that, both science and scifi could get rather dull if we new everything about how the universe worked, long live ignorance!!!

    • by hey! ( 33014 ) on Thursday September 05, 2019 @08:02AM (#59161190) Homepage Journal

      In science finding out you're wrong is like hitting the jackpot. Finding a disagreement between two things which ought to agree is a guarantee that careers and reputations will be made.

    • Re:I'm just thrilled (Score:4, Interesting)

      by HiThere ( 15173 ) <[ten.knilhtrae] [ta] [nsxihselrahc]> on Thursday September 05, 2019 @10:55AM (#59161826)

      I'm suspicious about the accuracy of the article. IIRC Cepheid variables are only used to measure the distance to relatively near-by objects. For an analogous measure to more distant objects the "standard supernova" (i.e. type 1a) is normally used.

      Unfortunately, in the last couple of years it has appeared that this distance measurement needs refinement, as there are (at least?) two different classes of supernova that appear to be type 1a, and they produce different brightnesses. So there's going to need to be a bunch of corrections...but supernova don't hang around (when seen from a great enough distance) so new measurements can't be taken. And this is likely to mean that many of the older measurements are unreliable. (Some will be spot on, and others will be off.)

      N.B.: I'm not an expert in this area, but this is derived from general reading. Consult an expert, but that expert needs to be up on recent studies of type 1a Supernovae.

  • Interesting (Score:4, Informative)

    by Papaspud ( 2562773 ) on Thursday September 05, 2019 @02:30AM (#59160580)
    This stuff always has my curiosity piqued... the more we learn, the more we realize we don't even understand the very basics yet... and may never. Quantum physics is almost like magic, and just think of how much of that we haven't even discovered yet.
    • by gweihir ( 88907 )

      Quantum Physics is pretty much something that, if this were a game, was artificially constructed to be exceptionally convoluted and unhelpful. The whole thing is kind of like a hint saying "Are you actually willing to believe this crap?". I would not be surprised if it turns out the whole thing is actually a lot simpler and the complexity is mostly generated by the minds of Quantum Physicists. Of course, this _would_ need a bit of yet unknown "magic", but there is ample room for that.

    • by jwhyche ( 6192 ) on Thursday September 05, 2019 @08:33AM (#59161306) Homepage

      What if Quantum physics is one huge joke that the god(s) are playing on us? Every time we are getting close they/he or she, changes one of the numbers just to send us scurrying again.

      Of course I'm only half joking here but it does seem like when we start to get close, something changes. I know the real reason is quantum physics is a really complex subject and we just don't understand all of it. But sometimes it does seem like a huge joke.

  • by PolygamousRanchKid ( 1290638 ) on Thursday September 05, 2019 @02:40AM (#59160600)

    . . . 42 . . . ?

  • Or Maybe (Score:2, Offtopic)

    by Aighearach ( 97333 )

    We should admit that this contradicts the predictions related to the Big Bang hypothesis, and maybe the Universe is a different age.

    Or maybe our lack of ability to measure long distances in space means that all the explanations explaining 14 billion year old red-shift are wrong. Maybe photons just die after that long. Then we don't even need a creation event to explain why we can't see forever.

    • we can detect photons of the cosmic microwave background produced shortly after big bang, they don't die. force carriers with no rest mass have infinite range

    • We should admit that this contradicts the predictions related to the Big Bang hypothesis, and maybe the Universe is a different age.

      Or maybe our lack of ability to measure long distances in space means that all the explanations explaining 14 billion year old red-shift are wrong. Maybe photons just die after that long. Then we don't even need a creation event to explain why we can't see forever.

      Or maybe people who know nothing about physics should speculate about it. Hint. Hint.

  • /me pulls letters from a scrabble bag... "What do you get if you multiply six by nine"
  • scientists estimate the rate to be 46,200 mph per million light-years

    Or 0.069 light-year per billion light-years.

    • scientists estimate the rate to be 46,200 mph per million light-years

      Or 0.069 light-year per billion light-years.

      Or not.

      Your units don't match - the scientists are using units of length/time/length, you're using length/length....

  • That's exactly how it is supposed to be!

    New measurements, new facts and you adapt your theory and move on.

    • Re: (Score:2, Insightful)

      by XxtraLarGe ( 551297 )

      That's exactly how it is supposed to be! New measurements, new facts and you adapt your theory and move on.

      Except climate change. That science is SETTLED !

      • Re:It's science! (Score:5, Insightful)

        by spikenerd ( 642677 ) on Thursday September 05, 2019 @09:51AM (#59161546)

        Except climate change. That science is SETTLED !

        Don't be misleading. The spectral absorption properties of CO2 are settled. The approximate amount of CO2 being emitted into the air by humans is settled. The measurable increase in CO2 concentration in the air is also settled. What that means for the future is certainly not settled. But only a handful of ignorant people really claim that anyway. So yes, "climate science" is technically still unsettled, but your implication that the impact humans made on the climate remains unsettled is deceptive.

  • Well here's your problem, right here...

    Named for American astronomer Edwin Hubble, this unit describes how fast the universe is expanding at different distances from Earth.

    We keep telling you that Earth isn't the center of the universe. This just proves it.

  • by Antique Geekmeister ( 740220 ) on Thursday September 05, 2019 @04:30AM (#59160772)

    The idea that we're missing something important seems completely reasonable. The stretch of universe over which we are making measurements is vast. The level of detail is _poor_. and we extrapolate wildly from the limited detail to understand and to predict the observations for more and more of the array of the universal. It would be _shocking_ if there weren't surprises in the process.

    It is interesting that there is a possibility of some system errors in our measurements, errors which when corrected avoid the need for extremely exotic forms of matter in our models. Given the consistency of matter that we have seen and do know about, that would be the way to bet.

    • It is interesting that there is a possibility of some system errors in our measurements, errors which when corrected avoid the need for extremely exotic forms of matter in our models. Given the consistency of matter that we have seen and do know about, that would be the way to bet.

      I'm not so sure. A lot of the hypothesized particles would have a density & distribution such that we would be unlikely to come across them on this tiny little speck of dust we call home. If you think about how comparatively long we've known about any fundamental particles at all, it should be obvious that we've likely only scratched the surface. The universe is 13 billion years old. We've been doing particle physics for something like 0.000000008 billion years. To be sure that we've discovered all form

  • Of course some scientific "authorities" will see it as a crisis, since it may well invalidate their results. That makes them bad scientists though. The whole thing is pretty interesting and any good scientist will see it as an exciting opportunity, not as a problem.

    • I don't know any physicists, but I'd imagine they'd call it a crisis because it is a looming mathematical problem that needs to be solved before they can update their models. Waiting for better data always feels like a crisis :)
    • Comment removed based on user account deletion
      • So far, it's the only known conscious thinking entity on or Planet at our level.

        Dolphins?

        Orcas?

        Some of the modern dinosaurs?

        Depending on what you count as "our level", of course. Hopefully you're not aiming for a narrow definition just so that we're the only thing that fits....

    • by Mal-2 ( 675116 )

      Lawrence Krauss calls this situation a crisitunity -- a crisis to the current order, but ultimately an opportunity for badly needed understanding. He does this specifically to point out that researchers should run toward the fields in crisis, rather than away from them.

  • ..... no problem in physics so great that it can't be solved with a liberal application of plutonium nyborg.
  • They should consider that matter converts to space, affecting the rate of expansion at distances due to the greater volumes encompassed.
  • With recent world events it makes sense that nothing makes sense! Maybe the idiots are right and we should just chuck science out of the window and go fishing!
  • Why does the expansion have to be constant throughout the entire universe?

    • by Mal-2 ( 675116 )

      It doesn't. In fact, the Eternal Inflation model basically says that the observable universe is a patch that fell out of inflation somehow, but that it is embedded in a larger structure which continues to expand, and that there may be other patches which have similarly fallen out of inflation which could have different fundamental parameters. There are even testable hypotheses what to look for as evidence our bubble has bumped into some other bubble, but they rely on equipment we don't have yet. (Fortunatel

  • Some observations seem to show a slight difference in the Fine Structure Constant, being slightly higher looking one direction and slightly lower in the opposite. (This would seem to imply that we should at least be looking for an expanding wave of change coming from a point.) But any variance would cause variable stars to behave in ways we're not familiar with in our own galaxy, so maybe we're misreading the distances to them because they're not pulsating at the expected rate for their mass. Finding a syst

  • Vernor Vinge has known this all along.
  • by sinij ( 911942 ) on Thursday September 05, 2019 @10:47AM (#59161788)
    One possible explanation - server lag.

Children begin by loving their parents. After a time they judge them. Rarely, if ever, do they forgive them. - Oscar Wilde

Working...