Clearing the cosmic fog

As the BBC noted, astronomers using ESO’s Very Large Telescope [VLT] have confirmed that galaxy UDFy-38135539, one of several candidates identified in the Hubble Ultra Deep Field (UDF) image of the Fornax Constellation acquired with the telescope’s new Wide Field Camera 3 last year, is the most distant galaxy ever detected. [Image credit: NASA, ESA, G. Illingworth (UCO/Lick Observatory and University of California, Santa Cruz) and the HUDF09 Team]

Spectroscopic analysis of data collected during a 16 hour observation using the VLT identified a red shift of 8.6, which corresponds to a galaxy seen just 600 million years after the Big Bang.  That’s even further back in time than Gamma Ray Burst 090423 – which I mentioned here.

Here’s an ESOcast on the subject of the most distant galaxy ever measured.

[Video credit: ESO. Visual design and editing: Martin Kornmesser and Luis Calçada.  Editing: Herbert Zodet. Web and technical support: Lars Holm Nielsen and Raquel Yumi Shida.  Written by: Richard Hook and Douglas Pierce-Price.  Narration: Dr. J. Music: movetwo.  Footage and photos: ESO, NASA, ESA, G. Illingworth  (UCO/Lick Observatory and University of California, Santa Cruz) and the HUDF09 Team, A. M. Swinbank and S. Zieleniewski, M. Alvarez (, R. Kaehler and T. Abel and José Francisco Salgado (  Directed by: Herbert Zodet.  Executive producer: Lars Lindberg Christensen.]

The research paper which appears in Nature is available here [pdf file].

As the accompanying text to the above image adds [Image credit: M. Alvarez (, R. Kaehler, and T. Abel]

At this early time, the Universe was not fully transparent and much of it was filled with a hydrogen fog that absorbed the fierce ultraviolet light from young galaxies. The transitional period when the fog was still being cleared by this ultraviolet light is known as the era of reionisation, illustrated with this still from a representative scientific simulation (see Alvarez et al. (2009) for more details).

When the Universe cooled down after the Big Bang, about 13.7 billion years ago, electrons and protons combined to form neutral hydrogen gas. This cool dark gas was the main constituent of the Universe during the so-called Dark Ages, when there were no luminous objects. This phase eventually ended when the first stars formed and their intense ultraviolet radiation slowly made the hydrogen fog transparent again by splitting the hydrogen atoms back into electrons and protons, a process known as reionisation. This epoch in the Universe’s early history lasted from about 150 million to 800 million years after the Big Bang. In this visualisation, ionised regions are blue and translucent, ionisation fronts are red and white, and neutral regions are dark and opaque.

The new study shows that the glow from UDFy-38135539 seems not to be strong enough on its own to clear out the hydrogen fog. There must be other galaxies, probably fainter and less massive nearby companions of UDFy-38135539, which also helped make the space around the galaxy transparent.

And finally, here’s a quick zoom through images from the Hubble Ultra-Deep Field towards UDFy-38135539.  [Video credit: A. M. Swinbank and S. Zieleniewski, Music: movetwo.]

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  • percy

    more johnny cash … inner space pete ..

  • Pete Baker

    As focused as ever I see, percy.

    Just not on the actual post…

  • lover not a fighter

    Is everthing trying to get as far away as possible from us (unlikely that we are that important or maybe we really really are not very nice !)

  • abucs

    Some questions from the ignorant.

    As it takes so long for light to travel large distances, is there any calculation on when in time the images from UDFy-38135539 come from and how that relates to an expanding Universe?

    Also, where does the name UDFy-38135539 come from? Is it some sort of matrix plotting?

  • Pete Baker

    I had the videos in the wrong order.

    Corrected now.

  • Pete Baker


    The observations indicate that we’re seeing UDFy-38135539 some 600million years after what we understand to be the beginnings of this universe.

    That’s over 13 billion years ago.

  • Greenflag

    Thanks Pete ,

    Fascinating as always . So they have now seen a small galaxy which came into existence about 600 million years after the big bang . Almost the very edge of the ‘universe’ . One wonders how close they can possibly go to that ‘edge ‘ and what if anything exists there bar other smaller ‘galaxies’ maybe even the outer edge of an ‘alternative ‘ or other universe ?

    Lover not a fighter

    ‘Is everthing trying to get as far away as possible from us (unlikely that we are that important or maybe we really really are not very nice !)’

    On that note some astrobiologists have suggested the Zoo Hypothesis as being the reason why we have not yet been recognised by alien civilisations and why our radio signals are not being replied to ;(

    We (Earth ) may be somebody’s Galactic Space Park our rare planet stocked with ‘animals ‘ including ourselves for safekeeping . A big fence may surround our solar system with warning signs for space travellers . ‘Earth Galactic Park’ No trespassing or tampering . The only planet with animal life for the next 10,000 light years ‘

    Could explain the eh ‘secrecy’ that seems to lie behind all of those UFO sightings and kidnappings etc ?

    Space aliens as galactic’animal species ‘ kidnappers for sale to other Galactic zoos ;)?

  • Pete Baker

    “One wonders how close they can possibly go to that ‘edge'”

    They’re just about at the limit now.

    Until that period of re-ionisation was completed it’s all a bit [hydrogen] ‘foggy’.

  • Greenflag

    It was all a bit foggy surely ? Now that it’s been cleared up (re ionisation) for eons, should the view from where they are now to the edge not be ‘visible’ as soon as the technology catches up of course ? just a thought .

  • Pete Baker

    Not quite.

    We can only observe the early universe as it was then – ie ‘foggy’.

    When the fog clears it’s no longer ‘then’, but some time afterwards.

  • lover not a fighter

    Its as good a theory as the next Greenflag

    I have often thought we may be the equivalent of an Agar dish by some super species (or not)

    and they have left us for the long time or maybe just forgot where they put us down.

  • Johnny Boy

    Preposterous! Telescopes are from the toolbox of the devil!

  • Devil Eire

    >“One wonders how close they can possibly go to that ‘edge’”

    >>They’re just about at the limit now.
    >>Until that period of re-ionisation was completed it’s all a bit [hydrogen] ‘foggy’.


    The ‘edge’ of the observable universe is the ‘surface of last scattering’ and we know
    what that looks like (in the form of the cosmic microwave background) courtesy of COBE,
    WMAP and soon, Planck. In principle, we can’t see anything from earlier because the universe
    was not transparent to electromagnetic radiation. The next frontier is to detect gravity waves
    from the era of inflation piggybacking on the CMB, encoded as a polarization in the CMB radiation.
    That will take us all the way back to 10^-36 s after the big bang. Close enough to the edge for you?

  • Greenflag

    So what we are now seeing was then , and we won’t see what is now at the then until another 13 billion years have passed . By then I suspect I may lose interest 🙁 Now then I suppose they ‘ll continue to check on the then and now, now and then in the interim ?

  • Greenflag

    I would’nt call it a theory but I’ll admit it sounds more plausible than the hey presto Usherite fable of instantaneous coming into existence on Oct 23rd at 9.30 a.m in 4004 BC 😉

    ‘maybe just forgot where they put us down.’

    Lol 🙂

    Alien A’ to Alien B

    ‘Do you remember where exactly you put down that Agar dish with that interesting DNA type life form which the Chairman of the Galactic lab told us we should destroy before it could do any damage to other life forms in the universe’

    Alien B to alien A ,

    ‘Now I remember . It was a mere 3.5 billion years ago when we were that spiral quadrant of the MW galaxy and we passed by a planet in formation close to their weak sun and I think It may have been dumped on the planet accidently . I think I may have dropped in the garbage by error .

    Please don’t tell the boss will you . I mean its probably not going to amount to much anyway 99.9999% of the time they never make it past the microbe stage anyway so who’s to know eh . Come on I’ll buy you a pint and we’ll forget all about it . By the way I can introduce to this nice chick I met in quadrant 8 from the same sector – a real beaut – she has a skin colouring like no other Reptilian you have ever seen 🙂

  • Pete Baker

    Not quite, again, Greenie.

    What is there ‘now’ will be similar to us ‘here’.

    ‘There’ has changed.

    What we can see there ‘then’ is nearly all we can see of ‘then’.

    Unless Devil Eire’s speculation comes true.

  • Greenflag

    ’10^-36 s after the big bang.’

    I guess the Planck epoch or up to 10–43 seconds after the Big Bang is eh out of the question then ?

    I guess at that point ’10^-36 s after the big bang’ there would have been no edge or it would be a very long way from where it is now I thought the next frontier would be dark and anti matter but hey gravity waves piggybacking on the cosmic microwave background sounds promising .

    Thanks for the explanation btw 😉

  • abucs

    Which would mean that ‘they’ are also seeing us as a foggy haze which occurred 13 billion years ago?

    (A star in the Galactic halo, HE 1523-0901, of our Milky Way Galaxy was measured as 13.2 billion years old in 2007).

    I wonder how far this star was from UDFy-38135539 13 billion years ago compared to today – with the expanding Universe?

    Also i wonder with space expanding how ‘new’ is our region of space? i.e. the space we occupy now – when was it created? Or do we think of it as the same space, but stretched out?


  • 😀 😀

  • Dr Concitor

    If we can see them they they can see us. Our galaxy was probably much smaller 13.2 million years ago.
    The current accepted theory is that space, along with everything else was created by the ‘Big Bang’ and has been expanding ever since, so space is just stretching.

    Hubble(who the space telescope is named after) was key in discovering expanding space by looking at the red shifts of galaxies. Red shift is caused by light travelling through expanding space and so changing its wavelength.

    The cosmic microwave background is also key in this. This was radiation released very early in the history of the universe(about 400,000 years in) when atoms first formed. These atoms would have been ‘red hot’. This has become so ‘stretched’ by expanding space that the radiation is now barely above absolute zero

  • Devil Eire

    >Unless Devil Eire’s speculation comes true.

    That wasn’t a speculation. Gravity waves are a generic feature of inflation and theorists predict that these gravity waves leave an imprint on the CMB. Detecting this (very very weak) imprint gives the energy scale of inflation (if, indeed, inflation is correct) which would be a staggering achievement. It’s a hot topic for experimental groups around the world.

  • abucs

    Thanks Doctor.

  • abucs

    So the ‘edge’ or ‘interface’ between our universe and the nothingness beyond is constantly increasing at a phenomenal rate (on all sides) as the Universe expands.

    It would be mind blowing i’m sure to travel at faster than the speed of light and catch up to this ‘edge’ to see what it looks like and how the Universe conspired to stop us from going off that edge.

  • Greenflag


    The ‘edge’ should be considered like the horizon . The nearer you get to it the further it goes away 🙂

    Unless of course you travel much faster than light in which case the result may be similar to that experienced by a certain Mr Wright

    A space time enquirer named Wright
    Once traveled much faster than light.
    He set out one day
    In a relative way,
    And returned on the previous night.

    Btw – The universe doesn’t conspire -it merely is – It could on a very bad day simply erase our Sun -our planet -our Solar System with a ray burst from a magnetar, pulsar or super nova and that would be that . Of course we are capable of doing ourselves in as well and most probably will .

  • Fearglic

    love these videos