Astronomers Locate the Oldest and Most Distant Galaxy in the Universe – Defines the Very Boundary of the Observable Universe

(Upper) The arrow points to the most distant galaxy in the universe. (Lower) Carbon emission lines observed in infrared. When it left the galaxy, the signal was ultraviolet light in the region of 0.2 micrometers, but it was redshifted and stretched to over 10 times that to about 2.28 micrometers. Credit: © Kashikawa et al.

Chemical signatures give away the distance to the most distant galaxy.

A team of astronomers used the Keck I telescope to measure the distance to an ancient galaxy. They deduced the target galaxy GN-z11 is not only the oldest galaxy but also the most distant. It’s so distant it defines the very boundary of the observable universe itself. The team hopes this study can shed light on a period of cosmological history when the universe was only a few hundred million years old.

We’ve all asked ourselves the big questions at times: “How big is the universe?” or “How and when did galaxies form?” Astronomers take these questions very seriously, and use fantastic tools that push the boundaries of technology to try and answer them. Professor Nobunari Kashikawa from the Department of Astronomy at the University of Tokyo is driven by his curiosity about galaxies. In particular, he sought the most distant one we can observe in order to find out how and when it came to be.

“From previous studies, the galaxy GN-z11 seems to be the farthest detectable galaxy from us, at 13.4 billion light years, or 134 nonillion kilometers (that’s 134 followed by 30 zeros),” said Kashikawa. “But measuring and verifying such a distance is not an easy task.”

Kashikawa and his team measured what’s known as the redshift of GN-z11; this refers to the way light stretches out, becomes redder, the farther it travels. Certain chemical signatures, called emission lines, imprint distinct patterns in the light from distant objects. By measuring how stretched these telltale signatures are, astronomers can deduce how far the light must have traveled, thus giving away the distance from the target galaxy.

“We looked at ultraviolet light specifically, as that is the area of the electromagnetic spectrum we expected to find the redshifted chemical signatures,” said Kashikawa. “The Hubble Space Telescope detected the signature multiple times in the spectrum of GN-z11. However, even the Hubble cannot resolve ultraviolet emission lines to the degree we needed. So we turned to a more up-to-date ground-based spectrograph, an instrument to measure emission lines, called MOSFIRE, which is mounted to the Keck I telescope in Hawaii.”

The MOSFIRE captured the emission lines from GN-z11 in detail, which allowed the team to make a much better estimation on its distance than was possible from previous data. When working with distances at these scales, it is not sensible to use our familiar units of kilometers or even multiples of them; instead, astronomers use a value known as the redshift number denoted by z. Kashikawa and his team improved the accuracy of the galaxy’s z value by a factor of 100. If subsequent observations can confirm this, then the astronomers can confidently say GN-z11 is the farthest galaxy ever detected in the universe.

Reference: “Evidence for GN-z11 as a luminous galaxy at redshift 10.957” by Linhua Jiang, Nobunari Kashikawa, Shu Wang, Gregory Walth, Luis C. Ho, Zheng Cai, Eiichi Egami, Xiaohui Fan, Kei Ito, Yongming Liang, Daniel Schaerer and Daniel P. Stark, 14 December 2020, Nature Astronomy.
DOI: 10.1038/s41550-020-01275-y

Funding: National Science Foundation of China (11721303, 11890693, 11991052), the National Key R&D Program of China (2016YFA0400702, 2016YFA0400703) and the Chinese Academy of Sciences (CAS) through a China-Chile Joint Research Fund (1503) administered by the CAS South America Center for Astronomy, JSPS grant(15H03645).

AstronomyAstrophysicsPopularUniversity of Tokyo
Comments ( 38 )
Add Comment
  • Roger Stout

    Sorry, but your conversion from light years to km is wrong. 134->126

  • Bokkenneth

    In the second to last paragraph it states “We looked looked at ultraviolet light specifically, as that is the area of the electromagnetic spectrum that we expected to find the redshifted chemical signatures”, shouldn’t that be the infrared spectrum where the ultraviolet lines had been shifted to, as mentioned in the caption of the photo? Also, as the spectral lines of the elements are shifted/stretched to the infrared region, shouldn’t the spacing between the lines also be stretched due to expansion? And considering the early era of this light emission, should carbon lines be this prevalent as opposed to the lighter elements?
    ‘Just curious.

    • Torbjörn Larsson

      A set of great questions!

      – “shouldn’t that be the infrared spectrum”.

      I too was stumbling over the reference description, but – without checking with the paper – I read that as they mean that they were looking at lines generated in the UV region. The image text confirms that. “When it left the galaxy, the signal was ultraviolet light in the region of 0.2 micrometers, but it was redshifted and stretched to over 10 times that to about 2.28 micrometers.”

      – “shouldn’t the spacing between the lines also be stretched”.

      Yes, the line spacing is proportionally stretched. The wavelength difference between the [CIII] lambda= 1907 Å and the [CIII] lambda= 1909 Å lines is 0.2 nm when emitted, and when observed it is ~ 2.282 – 2.280 = 2 nm or 10 times as large.

      “And considering the early era of this light emission, should carbon lines be this prevalent as opposed to the lighter elements?”

      That is the harder, more open ended question.

      You may have read that the Borexino neutrino detector just managed to see the expected 1 % of the Sun fusion that comes from the CNO cycle. That confirms that more massive stars can have more carbon as catalyst for the cycle, since it is believed that they get their major energy output from that.

      The galaxy has stars, but does it have the later “Population I” stars that have inherited high “metallicity” element amounts from earlier stars? By sheer coincidence there was a recent find of a distant galaxy that has a story to tell [“A young but completely evolved entirely self-made galaxy” @ Phys Org].

      “This galaxy, dubbed C1-23152, formed in only 500 million years, an incredibly short time to give rise to a mass of about 200 billion suns. To do so, it produced as many as 450 stars per year, more than one per day, a star formation rate almost 300 times higher than the current rate in the Milky Way.”

      “The most massive galaxies in the universe reach masses several hundred billion times that of the sun, and although they are numerically just one-third of all galaxies, they contain more than 70% of the stars in the universe. For this reason, the speed at which these galaxies formed and the dynamics involved are among the most debated questions of modern astrophysics.”

      “”These observations showed that the formation of the most massive galaxies in the universe can occur extremely quickly, through an extremely intense star-formation process in the early universe, as for C1-23152,” says Francesco La Barbera, researcher at INAF in Naples.”

      That galaxy formation history doesn’t go quite as far back, and they are both extremes. But it promises that further observations can bridge the gap, and that star “burst” formation can happen in a blink of a galaxy’s lifetime. It’s a start to an answer.

  • Lee berry

    So find two galaxies that aren’t that far away measure distance between them. Do it again same galaxies next Thursday find out how far apart they have gotten and you will know expansion rate of universe. It’s the same as the speed of the inner part of our galaxie and the part we’re in looks like the inner part is moving faster but it’s not. It’s just we’re farther from the center (same speed). just an example but the same process is involved . Optical illusion

    • Torbjörn Larsson

      “Do it again same galaxies next Thursday find out how far apart they have gotten and you will know expansion rate of universe.”

      Did you see the ages involved? If you convert back to the local scale of days and meters, the distance of a cubic meter between the Local Group of galaxies and the next free moving group increases by 10^-10 m or 0.1 nm over a year.

      And distances -as well as radial speeds – are measured by the proxy of redshift. We know the expansion rate, roughly.

      “Optical illusion”?

      Which, what!? The paper describes what has been seen.

      “And please don’t say we don’t know where the center of the universe is because the milkyway galaxie is in fact the center of our observable universe. So the same principles would and do apply.”

      Relevance? (Or are you netretaining a pre-big bang ‘explosion’ idea!?)

      We don’t know *if* there is a center of the universe* and it is irrelevant for a century old big bang cosmology for precisely the reason you mention. Your center of your observable universe obey the same laws as the Andromeda center if observations were made from Andromeda of its (very slightly) different observable universe.

      The cosmic expansion happens everywhere, so an Andromeda observer would see GN-z11 as the same, it is so distant so perspective doesn’t matter.

      *) In modern inflationary hot big bang cosmology which was ushered in 40 years ago and now is so solidified that most astrophysicists accept it, it is apriori unlikely to be a center. It looks rather like the larger inflationary universe is infinite in volume (and age). You would have to impose constraints to avoid it, which makes it less likely.

      • Torbjörn Larsson

        “are you netretaining” = are you entertaining. (Type too fast type problem – typical.)

      • Patrick Kelley

        Of course there is a center of the universe because the universe is limited. It doesn’t just keep going on and on. How could it? It started out not much larger than a period at the end of a sentence (if that) before the rapid expansion we call the “Big Bang”.

        Unfortunately, the outer edge of the universe has gone an unknowable distance beyond what we can observe, making it exceedingly difficult, if not impossible, to determine where the center is.

        It’s probably still a part of the observable universe, though I’m not sure we even know that for sure.

        • Torbjörn Larsson

          I thought I was very clear with that the idea of confusing the observable universe and its expansion with the entire universe was a pre-big bang idea. And I don’t think you do that since you yourself note that the universe is larger, so how could the observer dependent “center” be a real distance based center? To use sophistry: how could it?

          When you claim that the universe has a center, you must be careful with definitions. As I said, we don’t know if the larger inflationary hot big bang universe which our cosmology tries to describe has a center. Since space looks flat and inflation looks correspondingly eternal – Planck collaboration 2018 saw a slow roll, i.e. most likely eternal, inflation process – it may arguably be unlikely.

          But if you define the “universe” as the one resulting from the hot big bang that this part of the universe saw, it should have a center. That would depend on the size of the inflation field fluctuation that kicked the local slow roll over the hill. The birth statistics would look like a Poisson process, so I guess we consistently could assume the local universe originates where Planck see the field potential hill top. If I take the largest visible fluctuations (which was sent outside the horizon but came back), and multiply them with the smallest possible expansion factor of 10^26, I get ~ 1 Gpc*10^26 or 10^33 Gpc radius for inflaton fluctuations of the early universe. So a guesstimate is that our local universe could be 10^75 times larger than the observable universe in volume. I can’t say in what direction the center – defined as comoving equidistant within the hot big bang volume – would lie. But I can say that it is at best a 10^-75 likelihood to lie within our observable universe – but likely much smaller. From such a small number it seems like a very uninteresting concept, and we already know that it is a source of confusion, so I tend to not use it.

          No, we don’t know any of this for sure. We know about gravity for sure, we know that water is one oxygen and two hydrogen atoms for sure, and so on for more tangible facts of nature. Much of the rest are observation based estimates from theory at appropriate scales – we are pretty sure it’s the best we can ever do. Caveat emptor, but it’s the only business in town.

        • Torbjörn Larsson

          By the way – and I don’t want to overwhelm you, but this may be useful – the shift from pre-big bang cosmology “explosion from a center” over big bang cosmology “expansion from a small volume” to the inflationary hot big bang cosmology “space is big – you just won’t believe how vastly, hugely, mind-bogglingly big it is” is paralleled by the deflation of “a center”.

          While the transition from a pre-big bang cosmology is a century old we still live with the transition into inflationary hot big bang cosmology that started 4 decades ago but got a boost by the discovery of dark energy that made cosmology self-consistent 2 decades ago. (I.e. universe and star ages et cetera converged from conflicting 100 % difference in estimates to a consistent precision cosmology at currently 1 % uncertainty of average.)

          “There are a lot of people who mean “the initial singularity” when they say “the Big Bang,” and to those people, I say it’s long past due for you to get with the times. The hot Big Bang cannot be extrapolated back to a singularity, but only to the end of an inflationary state that preceded it. … Inflation came first, and its end heralded the arrival of the Big Bang. There are still those who disagree, but they’re now nearly a full 40 years out of date. When they assert that “the Big Bang was the beginning,” you’ll know why cosmic inflation actually came first.” [Astrophysicist Ethan Siegel writing for Forbes in “What Came First: Inflation Or The Big Bang?]

          So no singularity “center” associated with the hot big bang. Siegel’s article is not bad, but another astrophysicist [Katie Mack] scripted a short video that describes modern cosmology (but without mechanisms) in overview: https://www.youtube.com/watch?v=P1Q8tS-9hYo . There one can see why the universe is so mindboggingly big.

          I also wanted to note that, while I’m no expert and thus am naive on the details and possibilities, the larger inflationary multiverse was boosted – despite early vocal criticism from some experts – by the eBOSS galaxy survey collaboration 20 year data release this year. They shortlisted Weinberg’s “anthropic multiverse” as the oldest and simplest viable explanation for the observed low value of vacuum energy [dark energy] density in their cosmological paper [“The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory” @ arxiv].

          “Nevertheless, the observed consistency with flat ΛCDM at the higher precision of this work points increasingly towards a pure cosmological constant solution, for example, as would be produced by a vacuum energy finetuned to have a small value. This fine-tuning represents a theoretical difficulty without any agreed-upon resolution and one that may not be resolvable through fundamental physics considerations alone (Weinberg 1989; Brax & Valageas 2019). This difficulty has been substantially sharpened by the observations presented here.”

        • Torbjörn Larsson

          I forgot the key quote from Siegel’s piece:

          “Among most people who study the early Universe, inflation is accepted as the new consensus theory.”

  • Lee berry

    And please don’t say we don’t know where the center of the universe is because the milkyway galaxie is in fact the center of our observable universe. So the same principles would and do apply.

  • Torbjörn Larsson

    Awesome. Who needs the James Webb telescope? 😀

    A redshift calculator gives that the time since hot big bang at redshift z=11 was 0.419 Gyrs.

  • Lee berry

    But does it if we were in the farthest galaxie we can see and looked back at the milkyway.we would be saying look how fast the milkyway is moving away but if fact it’s not do you see my point here. We know the milkyway isn’t moving away that fast. So it stands to reason that the farthest one we can see isn’t either it just appears to be because of the distance from the center of the universe our observable universe. So the same must be happening there. That’s the secret that’s been missing in all the theories. Everywhere you are in the universe is the center of the universe it’s the distance from each center to the farthest that creates the illusion of the expansion speeding up when in reality it’s the same everywhere it’s a matter of perspective . Don’t forget the name

    • Torbjörn Larsson

      “the illusion of the expansion speeding up”

      Ah, that is what you meant – the page didn’t update so I missed that.

      It seems to me you don’t understand that the further we look back the older is the objects at the time the light emission happened. In this case, as stated in the article, the galaxy was just a few hunderd million years older than big bang but around here we are 14 billion years older.

      There is a development over time – of the universe, of its galaxies and of its stars (which is what Bokkenneth asked a good question on).

      And the light that reach us “now” have been traveling different distances so is different old, but join to a series of photon thin “shells” that hit Earth. I think I’m allowed 1 link: https://www.sdss.org/surveys/eboss/ . See the image how the observer geometry works out.

      An observer in Andromeda would see much the same shells, and so on.

      • Torbjörn Larsson

        And note that they show aged staggered shells, but light that hits us come from all distances so are “merger” shells. But there isn’t any good images on that (yet) that I know of, you have to use your noggin’.

  • Lee berry

    Light has a constant speed correct the light doesn’t slow down or speed up it changes color at distance but doesn’t slow down or speed up its our perception of the light that changes not the light itself. So the expansion doesn’t change just our perception of it. Am I starting to make sense to you now. wOW

  • Bill

    My comment is, first, Several years ago, a discovery was made of an X-ray particle from some similar undescribable distance , too far to comprehend, as is This discovery, Nobody that I have heard of though has made the leap that is, to describe ” eternity ” that that X-ray would also likewise travel in Every concevable direction Equally as undifinably as was That , And so also to be absolutely sure in the opposite direction from that ” furthest Known ” universe, giving Just a LITTLE clarity and definition to the very idea of ETERNITY, And That’s ALL a God thing, ETERnal.

    • Torbjörn Larsson

      Superstition.

  • Gregory Dawson

    God said let there be light and it was so ,so Gods word is what created all these and only 6000+ yrs and if you like sodom and the rest of the wicked donnot repent then God has no choice but to let you go to hell for eternity .

    • Torbjörn Larsson

      Superstition, over several comments.

  • Gregory Dawson

    Its amazing the bible says that if the heavens could be searched out then israel will cease to exist and guess what the heavens will never be searched out with you orbiting robotic thats abled to take pictures and send them back cant search the entire universe so israel will never cease and the bible is true every last word ,line dot and title .

  • Christian Detje

    Like Roger Stout commented, please correct the kilometer conversion. It’s very, very wrong: 13 billion light years in km are not a 130 followed by 30 but by 21 zeros: 9.4×10^12 km x 1,3×10^10 ly = 1,22×10^23 km

  • Bumm

    Trump said he knew everything about the universe. Better than anyone.
    You guys are all rrong, fake news!
    I know everything about fake news. Better than anyone!
    He knows more than he can tell ya’I say!

  • Sean

    Yeah Hitler and Jesus voted for Trump he won that ducking election. It’s rigged the 😈’s in on it

    • Torbjörn Larsson

      You forgot the /s tag.

  • Nathan

    I’m assuming the religious posts are trolls but can’t tell with Lee Berry.

    Of course is we were in GN-z11 looking back at the Milky Way it would appear to be moving away very quickly, as that’s how relative movement works. Though I don’t think the Milky Way is old enough that anyone there if it’s still around could see us yet.

    I’m not sure how any part of any of this refutes expansion to you. Doppler shift has been an important tool in measuring expansion

    • Torbjörn Larsson

      I agree on the comments, and thanks for adding your perspective.

      Interestingly, the recent merger tree paper implies that Milky Way is exceptionally old and calm so it may possibly (though less likely) rival GN-z11. [“Kraken reveals itself – the merger history of the Milky Way reconstructed with the E-MOSAICS simulations”, Kruijssen et al., Monthly Notices of the Royal Astronomical Society, Volume 498, Issue 2, October 2020, Pages 2472–2491, Monthly Notices of the Royal Astronomical Society, Volume 498, Issue 2, October 2020, Pages 2472–2491, https :// doi.org /10.1093/mnras/staa2452]

  • xABBAAA

    … ”Astronomers Locate the Oldest and Most Distant Galaxy in the Universe”,
    hmh, what about that one. Is it the oldest or oldest that human kind knows of..

  • EDGAR Baumanis

    YES I WANT TO GO THERE TO HAVE A LOOK AT THE ACTION HA.

  • David O

    If we determine this galaxy is 13.4 billion light years away, is it not true that we are seeing where it was 13.4 billion years ago? The light we see now left it then. So where is it now, if we extrapolate its motion from then to now?

    • Torbjörn Larsson

      Yes, the light travel time is 13.4 billion years, so the emission is that old when it reaches us and so is the galaxy. (Assuming it travels with normal speed and is gravitationally dominant, else you have special and relativistic effects that affects its “clocks”.)

      A great place to quickly calculate remaining data on a cosmologically distant object – as well as get links to texts describing them – is “Ned Wright’s Redshift Calculator” [ http://www.astro.ucla.edu/~wright/CosmoCalc.html ]. We can iterate* until we get the redshift or use the value given in the article (10.957). If I do that and press the “[space is] Flat” button the script returns the comoving radial distance of 32.132 Gly – that is the estimated distance between us and GN-z11 right now.

      The reason why it isn’t the same distance as the age is because space expanded during the time the emission traveled to us. It didn’t quite expanded 10 times as is the expansion factor of the photons – see the image on how the two C lines started out as about 190 nm [1900 Å] and are now about 2280 nm – because the expansion rate has increased over cosmological time [click the link on “comoving radial distance” for a technical description, or see “Scale factor (cosmological) @ Wikipedia for an easier explanation].

      It is mainly the expansion of space that moves the galaxy to give it its cosmological redshift. The galaxies so called “peculiar motion” is insignificant as we look at distant galaxies that are all redshifted, only nearby galaxies can have blueshift if they travel in our direction. That is why it is legitimate to extrapolate their distances from a cosmological model (as used in the calculator).

      *There are other calculators written by students that avoid that, but they aren’t all as comprehensible as the calculator I describe.

      But of course YMMV, and it is anyway a good idea to play around with several until you find one that suits you and your questions.

      • Torbjörn Larsson

        Oops – the factor 10 of photons (versus 3ish for distance traveled) was an order of magnitude number. My bad! I should say 11 as is given to avoid confusion.

  • Frank Rogers

    What a waste of time and energy. All of this has no bearing to life in the 21st Century. These scientist just want people to know how smart they are. Spend your time and energy helping people of today live a better life.

  • Aero

    Can’t find the edge, can’t find the center, two places that will never be found. It is too big and we, as humans, are too small. Big Bang? Speculation. Edge of the universe? One person’s perception.

  • Joey

    Shouldn’t we just go ask it how old it is

  • Shawn Weinpert

    I’ve always wondered where we are in Relation to the Center of the Universe. Going on the preconception that the Universe began at a central location. It seems to me that many of our perceptions about the Universe may be skewed without a point of Origin.

  • RONALD W Born

    I find it so “Human”(= arrogant) for Scientists to preen & pat themselves on the back..mystery of the evolution of “the ” Universe SOLVED! What I have read..the Universe isn’t expanding into anything…there is no ” outside” it is expanding into… but…at the same time we are led to believe a singularity was the beginning point of the Big Bang(?).OK… that’s interesting..and the singularity existed where? What came BEFORE the singularity? I know we live to find answers..but are the answers real and correct?

  • Harry Costas

    When all said and done there is no Big Bang.
    We cannot create or destroy matter.
    Matter may change from one form to another.
    To understand the workings of the universe, one needs to understand, chiral Super Symmetry dipolar electromagnetic condensates and the various stages of transients.
    From chaos you have simplicity.