The Universe Is 10 Times More Vast Than We Thought

By Nathaniel Scharping | October 13, 2016 12:22 pm

A composite of images from the Hubble Ultra Deep Field study. (Credit: NASA/ESA)

The universe seems a little less lonely today.

Astronomers from the University of Nottingham conducted a new survey of the universe’s galaxy population and concluded that previous estimates lowballed the census by a factor of about 10. Using data from Hubble and telescopes around the world, as well as a new mathematical model, they estimate that there are ten times more galaxies in the observable universe than we thought; previous estimates put the number of galaxies in the universe at around 200 billion.

Looking Through Time and Space

To understand how the researchers accomplished their task, we first need to understand what they mean by the “observable universe.” Because the speed of light is fixed, we can never get a true picture of what the universe looks like right now. As we look farther and farther away, we must necessarily look further back in time as well.

So, in discovering how many galaxies exist in the observable universe, the Nottingham researchers haven’t discovered how many galaxies exist right now, they’ve found out how many galaxies we would be able to see if our instruments were good enough. This may seem like a big caveat, but it’s the only way can observe the far-flung universe. Being able to look back in time has its advantages, however.

To reach their conclusion, the researchers looked at the rate of galaxy mergers throughout the universe. Most galaxies likely started small, and grew through a series of mergers with other galaxies as time went on. Because the researchers could see clusters further and further back in time as they looked deeper, they could compare the concentration of galaxies long ago to more recent times — relatively speaking.

They found that galaxies appear to clump together as time goes by, forming larger structures while also reducing the total number of galaxies present. By running this rate backward, and extrapolating beyond what we can currently see, the researchers concluded that around 90 percent of the galaxies out there are too faint and too far away to view with current telescopes. This is what allowed them to drastically increase our estimation of the number of observable galaxies.

The researchers released their paper Tuesday on the preprint server arXiv, it is set to be published in the Astrophysical Journal.

Why Can’t We See Them?

This new galaxy census gives us an answer to a decades-old question known as Olbers’ paradox. If there are so many stars and galaxies out there, why can’t we see them all? Given the nearly unimaginable number of stars and galaxies out there, the night sky should be awash in light. In fact, there are so many galaxies that we should see one at every point in the sky.

The answer, say the researchers, lies in the huge distances that separate us from most galaxies. Because the universe is expanding, the light that reaches us is subject to a phenomenon called “redshift.” Similar to the Doppler effect that alters the pitch of a passing ambulance, as distant celestial objects move away from us, the wavelengths of light they emit appear to stretch out. Go far enough, and the light will redshift below the level discernible by the human eye, and eventually telescopes. In addition, galaxies and the interstellar space between them is filled with tiny particles of dust that absorb and filter out light.

Some of this radiation shows up as background light, a faint diffuse glow of light that appears to have no source. The rest, however, disappears before it ever reaches us.

The James Webb Telescope, set to launch in 2018, may be able to pick out some of these elusive stars. Until then, we’ll just have to believe.

[Update: 2:57 pm CST. NASA has released an updated version of their press release stating that the number of galaxies suggested by the study is ten times greater than previously thought, rather than 20. Our story has been revised accordingly.]

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: cosmology
  • Uncle Al

    they estimate that there are two trillion galaxies in the observable universe; previous estimates put the number of galaxies in the universe at around 100 billion.” Did LIGO event GW150914 with its three solar mass-equivalent flash still outshine the rest of the entire universe?

    • Slowly Rotating

      We still have a good handle on the size of the “observable” universe, 46Bly radius. It’s the population surprises us.

      • Uncle Al

        Planck: 13.82 Gyr; 68.3% dark energy, 26.8% dark matter, 4.9% baryonic matter
        WMAP: 13.75 Gyr; 72% dark energy, 23% dark matter, 4.6% baryonic matter


        • Slowly Rotating

          The age of the CMB observable universe is 13.82 Gyr, but, due to cosmic inflation, the diameter is 92Gyr.

        • William Burke

          “Sigh”, indeed!

    • joseph2237

      “Did three solar mass-equivalent flash still outshine the rest of the universe” It is the rest of the universe that is growing and makes GW150914 a false equivalency. That little dot in the sky with thousand of galaxies is not the only dot in the sky with thousands of galaxies.

  • OWilson

    So in the last few years we have been told that in the universe, there are at least 90% more galaxies, 90% of matter and 90% of the energy is invisible and unaccounted for.

    Yet the “settled science” folks continue to lecture as if they knew everything.

    A little humility and perspective, please!

    A brave new world is emerging in which we can be ruled by “expert consensus”, no matter how wrong they are.

    If the Media says it is true, it effectively is! Move along citizen.

    We should be grateful there is no political expediency or political imperative at present in reporting on Cosmology.

    (Climate Science is a different story)

    • Slowly Rotating

      We learn as we go, unlike you who knows it all.

      • OWilson

        It is important to know what you don’t know, rather than make assumptions which make you look like an arrogant fool!

        • Slowly Rotating

          You’re a touchy little twerp making foolish statements and starting arguments based on how much you know about how little you know.

          • OWilson

            There, there!

            Feel better now?

          • James R. Gray

            OWilson, I doubt if you know it all, but you usually make more sense than the average contributor to the discussions.

          • OWilson

            I am a perpetual seeker of knowledge, more so as I age.

            I have little patience for establishment politics or establishment science. The science I love is daily compromised by the Media, journalists and politicians. They have something to sell you

            The scientists themselves are far more skeptical.

            There is presently a “crisis” at the LHC/CERN, according to its Director Fabio Gianotti. Current particle physics is going nowhere. They can create new particles at will, by increasing the energy levels, (otherwise known as E=mC2). But there are many more “Higgs like” particles out there. Just need more money, but actually no real answers. Despite the $billions and literally hundreds of thousands of scientists from over 100 countries.

            The man who single handedly saved The Big Bang theory by invoking an illogical, “Inflation”, Alan Guth, admits it is a kludge to keep an unsatisfactory theory afloat.

            No reputable individual scientist is warning that because of a relatively slight warming trend, “Climate Catastrophe” is imminent.

            What most folks know about these very basic issues, they get from the Media, and people like Bill Nye, David Suzuki, and politicians like Al Gore, Obama and John Kerry. People who use and abuse and misquote science for their own purposes. Their “tipping points”. come and go like your local bus.

            But questioning the establishment can be bad for your career, as history shows.

            Not to mention the name calling you draw on blogs like this. :)

          • Ürge Štefan

            Fabiola Gianotti – she is a woman :-)

          • OWilson

            I overlooked your post. Thanks for the correction!

            Forgive me, I quoted the wrong source!

            Here is what I was referring to:

            “”We are struggling to find clear indications that can point us in the right direction. Some people see in this state of crisis a source of frustration. I see a source of excitement because new ideas have always thrived in moments of crisis.” – Gian Giudice, head of the Theory Department at CERN.”

          • William Burke

            Thank you for that superb word, “kludge”!

            But ho – “they can create new particles at will”! But “matter cannot be created or destroyed”! Whose finger is on the scales?

          • Slowly Rotating

            There’s plenty more where that comes from.

          • William Burke

            Does it come from the rotation?

        • okiejoe

          I thought I made a mistake once but I was wrong.

          • OWilson

            “In a soldier’s stance, I aimed my hand at the mongrel dogs who teach

            Fearing not that I’d become my enemy in the instant that I preach”

            Ah but I was so much older then, I’m younger than that now”.

            – Nobel Prizewinner Robert Zimmerman

          • William Burke

            Thank you; I am inevitably led to those verses, as well.

        • jbjbklk kioki

          You’re retarded.

    • Michael Todd

      Isaac Asimov, The Relativity of Wrong. Read it…

      • OWilson

        I agree with my old “friend” Asimov.

        He uses the tern “incomplete” to describe the state of science at any given time, so far.

        I don’t think he would have had too much patience for the advocates of “settled science”, either! :)

        • William Burke

          From where I stand, the Big Bang Theory appears as Religion disguised as Science.

          It had might as well be the Big Bean Theory. Yes – the Cosmos sprang in an instant from an immense bean that became too gaseous to exist in place. . .

    • Weismonger

      If you you are hinting there is a God-you are an idiot

      • William Burke

        If you think he was hinting, God thinks you are an idiot.

    • jbjbklk kioki

      You’re retarded. I’m sorry that not everyone is as learning-challenged and fervently ignorant as you are. If I was to judge you just based on this post of yours, one could only come to the conclusion that you lack basic critical thinking skills of a third grader. Really, I’m sorry, I hope you can get over that hump some day and actually learn how reality works.

      This reply seems angry, because it is. I’m angry that you have a say in anything that I even remotely have to be involved with. I would honestly rather you be locked up in a political prison then you casting your vote for a president or some legislation, or making any decisions that have any influence on anything other than yourself.

  • Slowly Rotating

    “As we look further[sic] and further[sic] away, we must necessarily look further back in time as well.” Should be “farther” away.

    • okiejoe

      Only in the US, in Britain and the Commonwealth “farther” is hardly ever used and “further” has both meanings.

      • Slowly Rotating

        We ask how far are you going, not how fur are you going? Two different words.

        • William Burke

          Where is the victory in this battle?

          • Slowly Rotating

            May the English language emerge victorious.


    In a feeble way this article has confirmed what I have speculated all along, that as we see that light of a star or galaxy, because of the speed of light with the implied distance, some of those stars or galaxies may very well have gone nova and “died out”.

    • Slowly Rotating

      Stars are born and die every day all over the observable universe.

      • William Burke

        “Every day”, indeed! For an infinite number of days. So far! 😉

  • joseph2237

    Every time we get to look into a new telescope we see thing never before seen. There is no reason to believe this small truism will ever change. The further out we can see the more there is to see. I hope I am around to see the Webb Telescope remake of these deep field images just to see what we are missing.

    • OWilson

      There are strange and wonderful things out there.

      in fact, “Not only is the universe stranger than we imagine, it is stranger than we CAN imagine”. Sir Arthur Eddington.

      We can never get past even the first most basic questions, what is the Universe, where did it come from, and why there should be a Universe instead of nothing?

      (Then there’s the little matter of life!) :)

      • joseph2237

        Those answers are two hundred years off into the future if even then. It may not be that we will ever have the wisdom or the intuition to answers something that can’t be proven. Might as well say it matters less than a little and get on with a meaningful life.

        • William Burke

          Those answers will beget new and previously unimagined questions. It goes on thusly, as long as there is a questioner…

  • joseph2237

    Can’t hardly wait till the Webb telescope hacks away at those vast empty spaces between galaxy clusters of the Sloan Sky Survey.

  • tjrich

    Some cosmologists now believe the the extent to what we can see – 13.3 billion light years, is simply the horizon and that there is a lot more universe beyond that. We can see 13.3 billion light years in every direction meaning if we assume we are at the centre of the universe. It has to be at least 26.6 billion light years across. And really I doubt we are at the centre of the universe.

    • William Burke

      Well…. if it goes on infinitely, as I believe it must, then we are at the “center”, in a manner of realizing.

      (And it if doesn’t go on infinitely, what’s to be found if you keep on going further (ahem!)?

      • tjrich

        LOL- that is the question that has burned in my brain since I can remember. What’s beyond the farthest star?

        • William Burke

          A sign that declares UNIVERSE ENDS 500 MI. ?

          What happens if you continue in that direction?
          They will act as if we are childish and “not serious” to ask such questions. And they’ll never answer.

          • tjrich

            LOL :)

  • assegid

    OWilson, you articulate my school of thought so very well, thank you.

    On the article, I feel so much better knowing there is more real estate option for my next investment.

    • William Burke

      You get to keep multiplying by ten whenever you feel like doing so!

  • Weismonger

    Science asks questions-and corrects itself-religion does not. Religion only demands that you believe it’s magical garbage .


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