Witnessing Cosmic Dawn – 250 Million to 350 Million Years After the Beginning of the Universe

Witnessing Cosmic Dawn

Still of a video showing the formation and evolution of the first stars and galaxies in a virtual universe similar to our own. Credit: Dr. Harley Katz, Beecroft Fellow, Department of Physics, University of Oxford

Cosmic dawn, when stars formed for the first time, occurred 250 million to 350 million years after the beginning of the universe, according to a new study led by researchers at University College London (UCL) and the University of Cambridge.

The study, published in the Monthly Notices of the Royal Astronomical Society, suggests that the NASA James Webb Space Telescope (JWST), scheduled to launch in November, will be sensitive enough to observe the birth of galaxies directly.

The UK-led research team examined six of the most distant galaxies currently known, whose light has taken most of the universe’s lifetime to reach us. They found that the distance of these galaxies away from Earth corresponded to a “look back” time of more than 13 billion years ago, when the universe was only 550 million years old.

Analyzing images from the Hubble and Spitzer Space Telescopes, the researchers calculated the age of these galaxies as ranging from 200 to 300 million years, allowing an estimate of when their stars first formed.

Galaxy Cluster MACS0416-JD

Colour image of the galaxy cluster used to detect one of the six galaxies, MACS0416-JD, examined in a study led by researchers at University College London and the University of Cambridge. This galaxy has an estimated age of 351 million years, which means that this galaxy was formed 178 million years after the Big Bang. The stellar mass of this galaxy is one billion times the mass of the Sun. This object is currently the most distant galaxy detected with ALMA. Credit: ESA/Hubble, NASA, HST Frontier Fields

Lead author Dr. Nicolas Laporte (University of Cambridge), who started the project while at UCL, said: “Theorists speculate that the universe was a dark place for the first few hundred million years, before the first stars and galaxies formed.

“Witnessing the moment when the universe was first bathed in starlight is a major quest in astronomy.

“Our observations indicate that cosmic dawn occurred between 250 and 350 million years after the beginning of the universe, and, at the time of their formation, galaxies such as the ones we studied would have been sufficiently luminous to be seen with the James Webb Space Telescope.”

The researchers analyzed starlight from the galaxies as recorded by the Hubble and Spitzer Space Telescopes, examining a marker in their energy distribution indicative of the presence of atomic hydrogen* in their stellar atmospheres. This provides an estimate of the age of the stars they contain.


The video shows the formation and evolution of the first stars and galaxies in a virtual universe similar to our own. The simulation begins just before cosmic dawn, when the universe is devoid of starlight, and runs to the epoch 550 million years after the Big Bang when the six galaxies analyzed by Dr. Laporte and colleagues are being observed. The age of the universe in millions of years is shown in the upper left. The inset focuses on the evolution of a galaxy similar to those in the recent observational study. Purple regions display the filamentary distribution of gas, composed mostly of hydrogen. White regions represent starlight and the yellow regions depict energetic radiation from the most massive stars which is capable of ionizing the surrounding hydrogen gas. As massive stars rapidly reach the end of their lifetime, they erupt in violent supernova explosions which expel the surrounding gas enabling the escape of this energetic radiation. Galaxies such as the one shown continually accrete material from nearby smaller systems and quickly assemble to form the more substantial galaxies observed by the Hubble Space Telescope at later times. Credit: Dr. Harley Katz, Beecroft Fellow, Department of Physics, University of Oxford

This hydrogen signature increases in strength as the stellar population ages but diminishes when the galaxy is older than a billion years. The age-dependence arises because the more massive stars that contribute to this signal burn their nuclear fuel more rapidly and therefore die first.

Co-author Dr. Romain Meyer (UCL Physics & Astronomy and the Max Planck Institute for Astronomy in Heidelberg, Germany) said: “This age indicator is used to date stars in our own neighborhood in the Milky Way but it can also be used to date extremely remote galaxies, seen at a very early period of the universe.

“Using this indicator we can infer that, even at these early times, our galaxies are between 200 and 300 million years old.”

In analyzing the data from Hubble and Spitzer, the researchers needed to estimate the “redshift” of each galaxy which indicates their cosmological distance and hence the look-back time at which they are being observed. To achieve this, they undertook spectroscopic measurements using the full armory of powerful ground-based telescopes — the Chilean Atacama Large Millimetre Array (ALMA), the European Very Large Telescope, the twin Keck telescopes in Hawaii, and Gemini-South telescope.

These measurements enabled the team to confirm that looking at these galaxies corresponded to looking back to a time when the universe was 550 million years old.

Co-author Professor Richard Ellis (UCL Physics & Astronomy), who has tracked ever more distant galaxies over his career, said: “Over the last decade, astronomers have pushed back the frontiers of what we can observe to a time when the universe was only 4% of its present age. However, due to the limited transparency of Earth’s atmosphere and the capabilities of the Hubble and Spitzer Space Telescopes, we have reached our limit.

“We now eagerly await the launch of the James Webb Space Telescope, which we believe has the capability to directly witness cosmic dawn.

“The quest to see this important moment in the universe’s history has been a holy grail in astronomy for decades. Since we are made of material processed in stars, this is in some sense the search for our own origins.”**

The new study involved astronomers at the University of California-Santa Cruz, the University of California, and the University of Texas.

The researchers received support from the Kavli Foundation, the European Research Council, the National Aeronautics and Space Administration (NASA), and the National Science Foundation (NSF) in the United States.

The NASA-led James Webb Space Telescope, the successor to the Hubble observatory, is scheduled to be launched into space in November. It will be the premier observatory over the next decade, serving thousands of astronomers worldwide. It consists of an infrared observatory, an immense mirror 6.5 meters wide, and a diamond-shaped sunshield. UCL scientists at the Mullard Space Science Laboratory have built and tested key hardware components for the NIRSpec (Near-Infrared Spectrograph), one of the telescope’s four instruments.

*Atomic hydrogen is hydrogen that has not been split into protons and electrons.

**All the heavier elements in the universe — everything except for hydrogen, helium, and lithium — are synthesized in stars and then seeded across the universe when the stars explode at the end of their lives. This includes the elements that make up humans — the calcium in our bones, the iron in our blood.

Reference: “Probing cosmic dawn: Ages and star formation histories of candidate z = 9 galaxies” by N Laporte, R A Meyer, R S Ellis, B E Robertson, J Chisholm and G W Roberts-Borsani, 24 June 2021, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stab1239

13 Comments on "Witnessing Cosmic Dawn – 250 Million to 350 Million Years After the Beginning of the Universe"

  1. Yeah but the universe is electric and there was no big bang.

  2. geoffrey rose | June 25, 2021 at 1:44 pm | Reply

    what first started the “universe”. What made the “big bang”
    scientists hate to say it. but as science goes forward, the more creation becomes apparent.
    cant make a universe out of thin air. who made the air, the space, the water, ect.
    perhaps an act of god. or just a simulation for people to live and experience all 12 lives all 12 feelings.

  3. Why does this type of nonsense keep getting posted?!?
    We CANNOT see back any farther than half the age of the universe because:
    1.No matter can move faster than the speed of light
    2.Light moves at the speed of light
    3.All matter started at the origin point of the Big Bang and flew outward
    4.So did light from those events.
    5.It has taken us 14 billion years to arrive at our position now
    5.We cannot tell where the center of the universe is, so
    6.We are not flying outward at 99.97% of c, otherwise there’s be a some sense of our origin, and therefore
    7.Light emitted by the Big Bang and afterwards has long since passed by us on outward to the event horizon.

    • What nonsense? You mean all those physicists are idiots and you know more than they do? The speed of light limit does not apply to expansion of space. Because of the way space expanded, first faster than speed of light soon after Big Bang, then slowed down later, it is possible for us to observe light that was emitted from that early period.

  4. F’cken moron

  5. Stuart Hester | June 25, 2021 at 6:28 pm | Reply

    James. What do you mean it’s electric? Artificial light? That would be a neat trick to have electricity back when space/stars, were first documented thousand’s of year’s ago.

    • The only Light in the Universe is the spark of the divine imprisoned within you.
      The Sun is a ball of fire. It’s friction, destruction, it’s electric.
      True Light does not have a velocity.
      God is “Living” Light.

      What is the speed of God?
      The measure of Love?
      Truth cannot bend or it is not the Truth.
      Science without Truth has no Truth in it.

      Electricity is never alive. It is not (living) Light. It is fire.
      Everything in the universe is fire including you.

      The flesh is no more alive than a bulb is alive when switched on or off.
      There is no life in electricity. Flesh is death. Spirit is Living Light.

      Our ancestors understood all of this thousands of years ago in all spiritual teachings in all countries but today you are brainwashed with a science that rejects Truth so all of it is garbage.

      Truth never changes ever. Science without Truth is rewritten every-other day of the week because it’s always wrong. Einstein got his 186,400 mph from the Tribe of Juda (children of Light) in the Bible. He calculated fire and not Light and he was wrong of course.

      For True Living Light look within and nowhere else.

      Peace be with you.

  6. So they’ve figured out the age of the Universe based on the most distant point observable which happens to be 13.4 billion light years away. But what about the space beyond that point which we don’t have the technology yet to observe? Our understanding of the Universe is closely tied in with our technological advancements. The further we advance the more we discover. Most recent advancements in Microscopes and telescopes are perfect examples of this which have allowed us to get a clearer focused view of a single atom or a black hole. So at some point when are able to see further beyond the 13.4 billion light years and discover it just continues on and on, is the age of the Universe just going to keep growing as well?

    • Torbjörn Larsson | June 29, 2021 at 12:00 pm | Reply

      The relation between age and radius of the observable universe is not linear in general relativity [ https://en.wikipedia.org/wiki/Scale_factor_(cosmology) ].

      But yes, it may be so – it grows on us. 😉 The universe looks on average perfectly flat 3D space, meaning the inflation process that looks eternal agree with observations. The final Planck collaboration cosmological summary 2018 definitively preferred eternal slow roll inflation and specifically slightly a simple Higgs like scalar field as the energy form that drives an exponential expansion.

      ““There have been two changes to the way physicists think about this cosmological timeline,” Prescod-Weinstein wrote in New Scientist. “The first is that research on inflationary models, which study the exponential expansion of space-time, indicate that inflation may be an eternal process.”

      “As in, the universe may not have had a beginning moment, and we may live in what is called an eternally inflating universe,” she continued, “one that was expanding exponentially even before what we call the big bang.”

      [ https://futurism.com/the-byte/physicist-universe-expanding-eternally ].

      (For more cherry picked references, see the link to “What came first, inflation or the big bang” in another comment, or the recent eBOSS galaxy survey 20 year summary cosmological paper that shortlists Weinberg’s inflationary multiverse among the explanations for the observed low vacuum energy density value.)

      If you adopt that model the size of local hot big bang universes are set by the quantum fluctuations of the effective quantum inflation field theory as they tend to initiate the final roll down to a hot big bang potential energy release. But if you scale their by necessity smaller expansion rates with the larger inflation universe they become a point like Poisson swarm process, like in statistics they have volume “mass” but it sums to zero in the scaled map.

      I imagine the inflation process may be a frustrated ground state, which wants to roll down but expands faster than that happens. I.e. eternal, and the multiverse at large is empty (apart from the inflation vacuum field).

    • Torbjörn Larsson | June 29, 2021 at 12:01 pm | Reply

      The relation between age and radius of the observable universe is not linear in general relativity [“Scale_factor_(cosmology)”, Wikipedia].

      But yes, it may be so – it grows on us. 😉 The universe looks on average perfectly flat 3D space, meaning the inflation process that looks eternal agree with observations. The final Planck collaboration cosmological summary 2018 definitively preferred eternal slow roll inflation and specifically slightly a simple Higgs like scalar field as the energy form that drives an exponential expansion.

      ““There have been two changes to the way physicists think about this cosmological timeline,” Prescod-Weinstein wrote in New Scientist. “The first is that research on inflationary models, which study the exponential expansion of space-time, indicate that inflation may be an eternal process.”

      “As in, the universe may not have had a beginning moment, and we may live in what is called an eternally inflating universe,” she continued, “one that was expanding exponentially even before what we call the big bang.”

      [ https://futurism.com/the-byte/physicist-universe-expanding-eternally ].

      (For more cherry picked references, see the link to “What came first, inflation or the big bang” in another comment, or the recent eBOSS galaxy survey 20 year summary cosmological paper that shortlists Weinberg’s inflationary multiverse among the explanations for the observed low vacuum energy density value.)

      If you adopt that model the size of local hot big bang universes are set by the quantum fluctuations of the effective quantum inflation field theory as they tend to initiate the final roll down to a hot big bang potential energy release. But if you scale their by necessity smaller expansion rates with the larger inflation universe they become a point like Poisson swarm process, like in statistics they have volume “mass” but it sums to zero in the scaled map.

      I imagine the inflation process may be a frustrated ground state, which wants to roll down but expands faster than that happens. I.e. eternal, and the multiverse at large is empty (apart from the inflation vacuum field).

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