back to article H0LiCOW: Cosmoboffins still have no idea why universe seems to be expanding more rapidly than expected

Cosmologists are scratching their heads after the latest measurements of just how fast the universe is expanding raises more questions than answers. Scientists have been trying to pin down the exact value of the Hubble Constant, a number that describes how far galaxies are receding over a specific time and distance as the …

  1. Little Mouse

    Riddle me this:

    At what scale are the expansion effects actually happening?

    Is it that the universe is getting bigger, but the physical things it contains are not, because local forces are, for example, holding my atoms together regardless of the medium around me?

    Or is the space between everything getting bigger, and I am slowly expanding along with everything else, albeit at a rate that's only really measurable on a much larger scale?

    1. Thoguht Silver badge

      Re: Riddle me this:

      As far as I understand it (which admittedly isn't very far), the expansion only applies to things which aren't naturally holding themselves together, like you and me or the solar system, for instance.

      1. Baldrickk Silver badge

        Re: Riddle me this:

        My A-Level Physics education says that it's Space-Time that's expanding - so everything is naturally drifting apart, but the forces involved in holding things together (strong, weak, gravity) ensures that like you say, the effect is overruled by these forces.

        In fact, while it's a significant expansion taking the whole of the visible universe into account - our galactic cluster is just that - a cluster held together by gravity, even over that huge expanse (many galaxies) and is actually shrinking, despite the expansion of space time.

        This is why you have to look at distant galaxies to view a significant red-shift.

        1. Benchops

          Re: Riddle me this:

          I was speaking to an astrophysicist recently and I was surprised to find out that red-shift is now calculated not only to take account of the recessive speed of the star/galaxy where the photon was emitted from (the further away the higher the speed because of the expansion appears faster), but also because the length of time the photon is in existence, it's wavelength actually DOES get significantly stretched by the universe's expansion. I didn't ask at the time but I suppose this happens to photons because they don't have any other weak or strong forces holding them together??? (I am not a professional physicist). I think this means that if the photon was for some reason not moving, but sitting around for billions of years (presumably listening to the director's cut of Wagner's Ring Cycle) it would be "red-shifted" (or at least just stretched) by the universe's expansion over that time.

          1. Benson's Cycle

            Re: Riddle me this:

            I'm not criticising your post but I would make an observation. For a photon there is no duration. If you were able to follow the photon at a speed of c, due to time dilation there would be zero interval between its popping into existence and then being destroyed. This leads to the bizarre fact that in the photon's frame of reference it transfers energy from one place in the universe to another instantaneously, while in the frame in which it emitted it may travel for billions of years.

            A photon cannot sit around because it's the nature of electromagnetism that it can only travel at the local speed of light.

            If this worries you, don't get excited, it worries me too.

            1. Jaybus

              Re: Riddle me this:

              Yes. If a black hole is a gravitational singularity, then c is a time singularity. These singularities tend to make me think that perhaps relativity theory, like the Newtonian physics before it, is quite close in most instances but not exactly correct.

      2. TechnicalBen Silver badge

        Re: Riddle me this:

        Yes. Think of it like boats in the sea. The "sea" is spacetime to us. The boats (or anything else, fish, driftwood etc), are atoms and other physical things.

        So as a sea gets bigger, the objects in it can start to drift apart (in the spacetime example, it's happening everywhere, not at a spout/tap :P ).

        Or think of objects glued to a balloon. Inflate the balloon, and the objects move further apart.

        The physical laws are not affected (as far as we know, there might be some changes in dark energy/unknown forces yet to be discovered). Speed of light/weak force/magnetism/etc all keep the same distance affects, and thus in general you only notice things not strong enough to hold themselves together (distance between galaxies or galaxy clusters) to drift apart.

        IIRC there is a calculation of the distance difference between us an Andromeda, but I forget it. It was IIRC slower than Andromeda is heading towards us.

        1. Brewster's Angle Grinder Silver badge

          Re: Riddle me this:

          "Or think of objects glued to a balloon. Inflate the balloon, and the objects move further apart."

          I tried this once. What happened was, as the balloon expanded, the contact patch between the glue and the object also expanded, until, eventually, there wasn't enough adhesive in contact with the object to hold it in place, at which point it fell off. The object in question was a steak knife. I now have a 15mm hole in my foot.

          Therefore I deduce that if the universe keeps expanding, we will all fall off and land in either heaven or hell, depending on which side of the universe we are on.

          I saw the answer to this in a paper the other day and I realised my understanding of it wasn't as secure as I thought. Unfortunately I can't quite remember what the paper said or which paper it was. But it boils down to the "force" of metric expansion being much smaller than the forces holding you together - or even the "force" holding objects in orbit. So the expansion pressure on say, an orbital electron, is dwarfed by the attractive force of the nucleus and it doesn't even enter the calculations. Space "pushes" the electron out; the "Coloumb force" "pulls" it back.

        2. TechnicalBen Silver badge

          Re: Riddle me this:

          Hahaahahahaha! 2 downvotes for my example?

          The "official" illustration many scientists use is raisins in an expanding bread/muffin. So, yeah, using the 2d representation of the sea seems to also work (or the balloon one is a common one).

          1. Michael Wojcik Silver badge

            Re: Riddle me this:

            The ways of the downvoters are mysterious. (I admit I found the "sea" analogy unconvincing - what would be making the sea larger, and why would it cause the boats to move further apart? - but that's hardly downvote-worthy.)

            There are enough pseudoscience kooks among the regular Reg readership that you may just have been downvoted for failing to mention some alternate cosmological fantasy they cherish.

    2. Boris the Cockroach Silver badge

      Re: Riddle me this:

      It was my understanding that its spacetime getting bigger

      Everything is affected by spacetime so theres a good idea that we're expanding at the same rate as the rest of the universe (maybe that explains my waistline.. burp)

      Hence the the 'big rip' idea for the end of the universe, where space time has expanded so far that the forces involved in keeping stuff together are less than the force of the expanding spacetime.

      Hence gravity loses its grip starting with galaxy clusters, down to galaxies and star systems, planets, then electro-magnetism loses its grip, followed by the weak force then the strong force .. at which point protons and neutrons are torn apart.

      Makes a better movie than a long slow heat death of the universe I think

      1. STOP_FORTH Silver badge

        Re: Riddle me this:

        How are you going to film it?

        1. Claptrap314 Silver badge

          Re: Riddle me this:


        2. Boris the Cockroach Silver badge

          Re: Riddle me this:

          Us cockroaches can survive anything.

      2. Carpet Deal 'em Bronze badge

        Re: Riddle me this:

        My understanding is that the Big Rip requires cosmic expansion to speed up to a rather large degree, since the expansionary force needs to grow a lot stronger in order to overcome the contractionary forces. The Hubble Tension might be proof this is in fact happening, if it isn't a measurement error.

        On the other hand, if the four known forces are getting stronger as well, we might manage a Big Crunch in spite of all the current evidence.

    3. PaulVD

      Re: Riddle me this:

      The Hubble constant is the reciprocal of the age of the universe, about 1/(14,000,000,000 years). Since my height is rather less than 2m and my age about 70 years, over my lifetime the expansion of the universe has increased my height by about 2*70/14,000,000,000 m, that is 10^-8 m or 100 Angstroms.

      Of course, local space-time is heavily distorted by all of the matter around me, so this calculation is only illustrative.

      1. DougS Silver badge

        Re: Riddle me this:

        No, you are not getting bigger because the molecules that make up your body are held together by forces that overcome any expansion in the space between them. Ditto for the entire Milky Way galaxy, and in fact our entire supercluster of galaxies.

        Think of as post-its stuck to a balloon. If you further inflate the balloon the post-its get further away from each other but the individual post-its remain the same size.

        At some rather large distance what gravity can do to pull two objects closer to each other in time x is overwhelmed by the expansion of space between the objects that occurs during time x. Thus they get further and further apart even as gravity still does its thing.

        1. STOP_FORTH Silver badge

          Re: Riddle me this:

          Well I'm definitely getting bigger, I used to be a baby. Don't take my word for it, my GP says I am too big.

          1. This post has been deleted by its author

    4. Jaybus

      Re: Riddle me this:

      If the space between everything were getting bigger, then certain male parts would be getting larger, but one would never know it, as the ruler used for the measurement would likewise be getting larger.

      1. Francis Boyle Silver badge

        Re: Riddle me this:

        It's not that space is getting bigger, which as you suggest is nonsensical, it's the universe that's getting bigger. (There's an increasing amount of space in it.) So relatively, and in in a cosmic sense, your todger is getting smaller. Makes you feel insignificant doesn't it.

    5. Mips

      Re: Riddle me this:

      I think time is the issue here. That the Hubble constant at the Big Bang may be different than now. If we were able to measure H0 now at the CMBR location it might well agree with the local H0. I do not see a way of testing this and we just have to accept the fact and make a rational explanation.

  2. nagyeger


    The outer-reaches of space-time and denizens thereof (quarks, leptons, photons etc) have heard a rumour that humanity, (including goolge, faecebok, etc) might be coming, and are very sensibly running away. It's too late for any near-by, they're already doomed.

  3. Anonymous Coward
    Anonymous Coward

    Rush hour

    Red Dwarf tail backs light the universe as far as you can see!

  4. Baldrickk Silver badge
    Paris Hilton


    “There has been an intriguing pattern of differences in the Hubble Constant that appear to depend on which end of cosmic history its value is measured,”

    So it should really be the Hubble Variable?

    1. JetSetJim Silver badge

      Re: Differences

      FTFA, the CMB method relies on a host of assumptions, which may or may not hold true (although obvs they are believed to do so!). It might be interesting to investigate what variation(s) in the assumptions for CMB would allow the two measurements to match.

      Wither that or, as you rightly put it, challenge the underlying assumption that the Hubble Constant is indeed a constant.


      1. tfewster Silver badge

        Re: Differences

        The recent increase in repulsive particles such as the Johns-on may explain why the Universe is disintegrating at an increased rate.

    2. TeeCee Gold badge

      Re: Differences

      Well done, that fixed it. Let's move on.

      1. STOP_FORTH Silver badge

        Re: Differences

        Baldrickk hasn't fixed it. Quite the reverse!

    3. Doctor Syntax Silver badge

      Re: Differences

      "Constant's aren't" is one of the basic rules of software development. Maybe it applies to universes too.

      1. Anonymous Coward
        Anonymous Coward

        Re: Differences

        "aren't" is not a noun.

        1. JetSetJim Silver badge

          Re: Differences

          So much for "Doctor Syntax"!

          1. STOP_FORTH Silver badge

            Re: Differences

            Why should "aren't" be a noun? "Constants" is not a verb. I'm more worried by the first apostrophe, to be honest.

            1. Ken Hagan Gold badge

              Re: Differences

              So was the AC.

              1. JetSetJim Silver badge

                Re: Differences

                Either the first apostrophe was possessive, in which case the "aren't" needs to be a noun, or it's a contraction in which case an adjective might be needed, and "aren't" isn't one of those either.

                1. STOP_FORTH Silver badge

                  Re: Differences

                  Well I'm not eating my mortarboard yet. Rules are normally instructions or injunctions in the form of a sentence. (Unlike, say, booktitles, which may or may not be sentences.)

                  A simple two word sentence will consist of a noun and a verb.

                  To complain that the word following a noun is not a noun is obscurantism, plain and simple.

                  You are all parsing the rule at a very superficial level, rather than a deep level like wot I am.

                  I hope you don't write compilers!

                  1. JetSetJim Silver badge

                    Re: Differences

                    > I hope you don't write compilers!

                    Not me, I just read El Reg all day, commenting on minor grammatical points without having any recognisable qualifications to do so with any authority

                    1. STOP_FORTH Silver badge

                      Re: Differences

                      Me too! Should we form a club?

                      1. JetSetJim Silver badge

                        Re: Differences

                        Sounds good, bring beer, or tipple of choice

        2. Doctor Syntax Silver badge

          Re: Differences

          Fair enough. Didn't see it in time.

    4. sbt Silver badge

      the Hubble variable

      Error C3892: 'H0': You cannot assign to a variable that is const in universe.c, line 1029432935.

      1. STOP_FORTH Silver badge

        Re: the Hubble variable

        Yes, but it's already running. How did it compile?

        1. sbt Silver badge

          How did it compile?

          Must have been make builduniverse rather than make installuniverse.

          Or Continuous Deployment something, something.

        2. It's just me

          Re: the Hubble variable

          Maybe it's a just-in-time or interpreted universe.

        3. Benson's Cycle

          Re: the Hubble variable

          I come late to this but it seems clear the universe actually runs on Erlang.

        4. Doctor Syntax Silver badge

          Re: the Hubble variable

          Compile? Maybe it's just running in an interpreter.

          1. Rich 11 Silver badge

            Re: the Hubble variable

            No wonder debugging the bloody thing is so difficult. Look how long it took to fix smallpox after that was introduced by the idiot who wrote the cattle domestication module.

  5. JassMan Silver badge

    The important thing the cosmologists have overlooked is that although the speed of light is a constant, time itself is slowing down so things which are further away APPEAR to have moved further than they should have. This also shows that it wasn't a big bang - more of a little pfffft but since time was faster then, it looked more impressive.

    OK. I admit I don't understand any of this cosmology stuff but it makes as much sense as dark energy. (Occams razor and all.)

    1. Paul Kinsler

      The important thing the cosmologists have overlooked ...

      I very much doubt it; they think about that sort of thing for a living.


      Mind you, their misconceptions of how DevOps works are hilarious :-)

      1. TechnicalBen Silver badge

        Re: The important thing the cosmologists have overlooked ...

        A very very slight chance (IMO) that things like the discovery of quantum time propagation (quantum superposition effects over temporal systems) may show that a tiny tiny affect in the quantum calculations, adds up to a massive one in say, something like Redshift.

        And thus, their calculations are "correct", but they are missing the cause, some tiny mathematical consideration, that makes it all fit together (as Einstein did with relativity/speed of light and Mercury's orbit).

    2. Anonymous Coward
      Anonymous Coward

      I think you've hit the nail on the head in that the assumptions about the CMB are utterly dependant on a "singularity big bang" event being the beginning of the universe.

      I suspect a universal origin something more akin to an incredibly large object shedding mass at a rate correlated with its mass could 'square the circle'.

      Perhaps a means by which "ultramassive" black holes leak particles/energy at an exponentially increasing rate based on their size, almost an opposite to Hawking radiation. You'd get a big initial pressure wave, followed by a decreasingly powerful 'fart' effect, and be left with still a supermassive black hole at the center of the universe...

      1. DougS Silver badge

        The universe has no "center"

        Expansion is happening everywhere, in every direction we look. So unless you want to claim we happen to be in the privileged position of inhabiting the exact center...

        1. old man

          Re: The universe has no "center"

          So if we were inside an event horizon we would appear to be at the centre of the universe which would be expanding in all directions away from us luckily time would appear to be slowing down

    3. KBeee

      Time isn't slowing down, it's speeding up.

      50 years ago a week was a bloody long time, now a week flies by!

  6. STOP_FORTH Silver badge

    The nice thing about Hubble constants....

    is that, like standards, there are so many to choose from!

  7. Little Mouse

    2nd question

    What's the speed of expansion in terms that I can readily comprehend?

    How much would a distance of 150 million km increase over, say, 1000 years at the currently understood rate of expansion?

    1. John Mangan

      Re: 2nd question

      Well, since you asked:

      1 MPc = 3 * 10^13 km

      1 Yr = 31 *10^6 seconds

      So take 73Km/s as H0

      Then distance = Initial Separation/MPc * H0 * Secs in a Year * 1000

      = 150*10^6/3*10^13 * 73 * 31*10^6 * 10^3

      = 150/3 *73 * 31 *10^2

      = 11.3 million Km

      (unless I made a mistake rushing it while trying not to be noticed at work).

      1. JetSetJim Silver badge

        Re: 2nd question

        Well, one of us is probably out by a factor of a million!! :)

        Looks like you're using parsecs, rather than Mega-Parsecs

        1. John Mangan

          Re: 2nd question


          I bl@@dy knew I would miss something! I wrote MPc on one side and then the value for Pcs on the other.

          I thought the answer looked a bit large but didn't have time to check my working.

          Thanks for the correction (and not laughing).

          1. JetSetJim Silver badge

            Re: 2nd question

            When I started replying to yours I wasn't quite sure whose was wrong as I rushed to my answer too, or if we needed to meet in the middle. Yours resulted in a ~10% increase over 1000 years, which did seem a bit off :)

            Easy mistake to make, and one I'm surprised I didn't make....

      2. Wellyboot Silver badge

        Re: 2nd question

        One Parsec is ^13 so a Megaparsec (MPc) =^19

        The answer drops to 11.3 Km

        edit: that'll be me not getting Jet Set Jims next post while typing this.

        over intergalactic distances & billions of years the increasing distances really add up.

    2. JetSetJim Silver badge

      Re: 2nd question

      If my crap maths is anything to go by, the answer is approximately 11.25km...

      73km/sec/megaparsec is expansion rate

      1 megaparsec is 3.08*10^19 km

      1000 years = 3.16*10^10 seconds (with some rounding to 2dp)

      Expansion = 73.3 km * 3.16E+10 seconds * (150,000,000 / 3.08E+19) megaparsecs

      So, ignoring the fact that the earth and the sun are linked via gravity cos they're relatively close, and so this probably doesn't apply, this is saying that the distance between the earth and the sun (~147 million km) will increase by 11.25km over the period of 1000 years due to the universe expanding

      1. Anonymous Coward
        Anonymous Coward

        Re: 2nd question

        'So, ignoring the fact that the earth and the sun are linked via gravity cos they're relatively close, and so this probably doesn't apply, '

        Struggling with the general assumption on the thread that bodies and matter will be static relative to each other due to gravity. The theoretical and physical discovery of gravity waves says this is not the case. Gravity bound bodies move apart and together due to fluctuations in spacetime.

        As I understand it, this includes the subatomic particles as well. This being the case, a Hubble constant applies to all physical matter as it is underpinned by, and exists within spacetime.

  8. aregross

    The universe will keep expanding until it bumps into the other one....!

    1. Swiss Anton

      The universe can't bump into another one - uni means there is only one. Maybe we should change its name in case there are other verses out there.

      1. Doctor Syntax Silver badge

        Multiverses seem to have their own branch of cosmology.

    2. Ken Shabby Bronze badge

      Second verse, same as the first

      A little bit louder and a little bit worse...

  9. Andy The Hat Silver badge

    And ...

    this all of course relies on the standard candle actually being a standard candle. IIRC this was questioned in a paper a couple of days ago which, for a couple of reasons, will impact the CMB figures and the distance estimates used by this paper. On that basis the astro-boffinry may decide that astronomical distance measurement relying on that standard is invalid, thereby inferring that accelerating universe and dark energy are the results of spurious calculations ... unless it is and they aren't.

    Fundamentally, if current measurements are right, we're wrong but if measurements are wrong we're right and can throw out the acceleration/dark energy stuff and worship at the feet of Hubble again ...

    1. Claptrap314 Silver badge

      Re: And ...

      If you don't have a standard candle, you cannot measure distance, true.

      However, there are a number of other ways to argue that highly-redshifted observations are of older things. Specifically, stars tend to be metal-poor. Galaxies are less uniform. Etc.

      This argues strongly for an expansive Universe.

      1. JetSetJim Silver badge

        Re: And ...

        > If you don't have a standard candle, you cannot measure distance, true.

        I shall go down the shops and purchase 4 to be sure. Then nothing can go wrong. Back in a bit...

  10. deconstructionist

    not just the expansion

    density measurements are also at odds, , we get a value of 0 now which means the universe is open flat , but CMB tells us it is +1 closed spherical, so it is not just expansion rates that don't match , and the answer might be it hasn't changed it just our point of perception , so it could be argued the expansion rate is fixed but relative to the expansion of the universe we( Byronic matter) now move through space/time at an accelerated rate offering us the illusion of an increase expansion rate, but that still wouldn't answer the question why the density values differ which is a bigger mystery which affects the structure of universe and not just it's expansion rate.

    1. sum_of_squares Bronze badge
      Black Helicopters

      Re: not just the expansion

      The universe is not expanding, but EVERYTHING IS SHRINKING. And therefore the distances are getting bigger.

      There, I said it. Now arrest me, timecops. But mankind had to know this.

  11. Anonymous Coward
    Anonymous Coward

    "but CMB tells us it is +1 closed spherical"

    That's not yet the concensus though, is it?

  12. This post has been deleted by its author

  13. Chris G Silver badge

    The Mad Hatter Principal

    States that, as the Early Universe early, it didn't have to rush about much so it just pootled along at 67 kilometers per second per megaparsec.

    However, the Late Universe being somewhat perturbed at being late has had to up it's velocity to get to where it's going and to arrive on time, hence the increase to 73 kilometers per second per megaparsec.

    The burning question that faces us now is where exactly is it going and why must it be on time?

    And of course has it got a towel?

    1. JassMan Silver badge

      Re: The Mad Hatter Principal

      Don't forget the peanuts. And a babelfhelp might help.

    2. Psmo Bronze badge

      Re: The Mad Hatter Principal

      And does it have a handkerchief and pocket watch?

    3. MCMLXV

      Re: The Mad Hatter Principal

      Don't fancy going to his college...

  14. Gene Cash Silver badge

    Thanks, El Reg

    Yet another important and interesting story covered by El Reg, and only by El Reg.

  15. Anonymous Coward
    Anonymous Coward

    Can you find me

    a) Pulsars at the centers of galaxies where you expect black holes to be.

    b) a correlation between the set (a), and an 'edge on' metric of the galaxy. The more edge on, the more likely to have a pulsar detected at its center.

    i.e. I'm suggesting that pulsars are my actually my "late stage black holes ejecting their inner universe" from the resonating electric model.You're simply viewing that black hole edge-on as its spin-plane waddles with respect to us.

    You've found the wave in galaxies, showing they're not flat, that is the waddle, but can you find correlation b).

    It would also be nice if you then matched the pulsar waddle to the wave in the surrounding galaxy, but I'll settle for b). Can't have everything.

  16. Anonymous Coward
    Anonymous Coward

    double double its a bubble

    Our universe is an n dimensional bubble - right? And matter is like the thin smear on the bubble surface?

    I am assuming the constant takes into account the N dimensions?

    So it should be called the bubble constant :-)

  17. 89724102172714182892114I7551670349743096734346773478647892349863592355648544996312855148587659264921 Bronze badge

    Uranus is too big

  18. Doctor Syntax Silver badge

    Is it time to reintroduce Fred Hoyle's continuous creation theory?

  19. old man

    Sometimes think that maybe we are inside event horizon of supermassive black hole and it's not the universe expanding but us contacting luckily time would be slowing down for us so probably would never know

  20. ILLQO

    Expansion Question

    I am reaching real hard into past science classes so if I am completely wrong please let me know.

    But from my understanding Space is not really empty, its filled to a real low degree with the basic elements, for example hydrogen. I am assuming that there is a finite amount of matter in the universe, so as the universe expands the "Pressure" of hydrogen through out the universe should go down, if we get to a point where there is not enough hydrogen to fill all available space do we get pockets of space that have 0 physical matter inside of them and if this occurs what happens in this area?

    I remember reading somewhere about matter being created and destroyed instantly in areas where there is 0 matter, doing a quick google this is known as zero point energy. If the universe is spreading apart creating pockets where there is 0 local matter, then I am conceiving of points where matter is created from the zero state fluctuation of the universe, it seems "usually" this matter self annihilates, but would this self annihilation impart some energy into the system. So if the universe is spreading fast enough, it could be powering that spread using this energy, which then produces more and on and on and on. 1 case out of near infinity some matter could survive its annihilation just like during the big bang and thus more matter is created, so along an "infinite timeline", "infinite energy" and "infinite matter" could be created.

    Gathering from the local conversation it looks like galaxy physics hold onto their forms due to the "strong" forces, so individual galaxies may suffer heat death, but the overall heat death would not occur due to the slow inclusion of new matter from these points. Overall that means that the few endings of the universe that I learned growing up could be non starters (heat death, big crunch, etc...).

    … So I apologize I did not mean to throw that word vomit at you. But if someone wants to pick this apart and correct the weird model I am forming I would appreciate it.

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