The primary mission of the James Webb Space Telescope (JWST, seen in figure 1) is to investigate the early history of the universe. Of particular interest to researchers is the period known as the “cosmic dawn,” when starlight first illuminated the universe. This aptly named era extends from 0.2 billion to 1.2 billion years after the cosmic origin event.
Figure 1: James Webb Space Telescope The James Webb Space Telescope is 1.6 million kilometers (1 million miles) from Earth at the Lagrange 2 point along Earth’s orbit. Credit: NASA
To observe the cosmic dawn, astronomers must look many billions of light-years away. (Remember: distance means time, due to the finite velocity of light. That is, the farther away we look, the farther back in time we see the condition of the universe. Also keep in mind that due to the expansion of the universe, the most distant objects are moving away from us the most rapidly.) The visible light of objects at distances corresponding to the cosmic dawn era (12.6–13.6 billion light-years away), will be shifted into the infrared segment of the electromagnetic spectrum. For this reason, astronomers designed the JWST to detect infrared radiation.
Bright Early Galaxies One of the big surprises for astronomers using the JWST was to observe several bright galaxies in the first billion years of cosmic history—galaxies with ultraviolet luminosities as much as ten times brighter than what standard big bang models would seem to allow.1 Most big bang models had predicted that galaxies as ultraviolet bright as these would take more than a few hundred million years to form. However, this prediction relied on a lack of understanding about how early galaxies formed.
As reported in Today’s New Reason to Believe, posted on January 1, 2024, a team of astronomers has solved the problem of these early ultraviolet bright galaxies.2 The solution came from evidence confirming that star formation was just as “stochastic,” or “bursty,” during the universe’s first billion years as during the subsequent 12.8 billion years.
GN-z11 Galaxy Even before the launch of the JWST, the Hubble Space Telescope (HST) allowed astronomers to observe a cosmic dawn galaxy, GN-z11 (aka GNS-JD2, seen in figure 2). It appeared much brighter than anticipated at visible wavelengths, despite being the most distant galaxy researchers had yet discovered.
A team of eighteen astronomers, using the HST’s grism spectroscopy, measured GN-z11’s redshift to be 11.1.3 This redshift measure implied that GN-z11 is 13.41 billion light-years from Earth, a distance that corresponds with a mere 380 million years after the cosmic origin event. GN-z11 is the most highly redshifted (thus, most distant) galaxy spectroscopically confirmed using the HST.
Figure 2: GN-z11 Galaxy Credit: NASA/ESA/James Webb Space Telescope
A team of eight astronomers led by James Baldwin measured the effective diameter of GN-z11. Based on images from the HST CANDELS survey and additional observations,4 they determined the half-light diameter (the distance from the galactic core to the point where its luminosity is reduced by half) of GN-z11 to be about 500 light-years, a determination consistent with later measurements made using the JWST.5 At this relatively small size and high luminosity, GN-z11 was confirmed to be the brightest galaxy yet known at a distance greater than 13.3 billion light-years, in the early part of the cosmic dawn. For this reason, GN-z11 became a prime target for investigation by the JWST.
In September 2023, a team of sixty-three astronomers led by Andrew Bunker used the near-infrared spectrometer on board the JWST to make a more precise measurement of GN-z11’s redshift,6 which turned out to be 10.603. This measurement tells us that GN-z11 is 13.38 billion light-years from Earth. At this distance, GN-z11 appears to have formed 410 million years after the first moment of cosmic creation. This finding is astounding, given that star formation is not even possible until the universe is at least 200 million years old.
In fact, GN-z11 is not the only exceptionally luminous galaxy found in the cosmic dawn. Images taken by the JWST reveal several dozen others. The discovery of such galaxies has become a regular theme for the JWST, and this theme has spawned numerous articles in the popular media and on the web—many claiming that the big bang model needs major revision and/or that scientists are on the verge of discovering some new physics.
Why Such Brightness? While no astronomer whose work appears in peer-reviewed astrophysical literature has called for an abandonment or replacement of big bang models, a few are advocating for “a reexamination of the theoretical landscape of galaxy formation at the cosmic dawn.”7 To determine whether a reexamination is necessary, a team of thirty-six astronomers led by Cambridge University’s Roberto Maiolino undertook a detailed probe of GN-z11.
Using both the near-infrared spectrometer (NIRSpec) and the near-infrared camera (NIRCam) on board the JWST,8Maiolino’s team discovered a huge clump of gas in the galactic halo, about 7,800 light-years from the GN-z11 core. The camera revealed that this clump was so powerfully illuminated by stars in the core that its gas had been ionized. The spectrometer additionally revealed the elemental composition of the clump: hydrogen and helium, and no elements heavier than helium.
The lack of any elements heavier than helium in the gas clump provided, for the first time, direct evidence that aligned with a major prediction of big bang models. According to these models, the universe begins infinitesimally small, nearly infinitely hot, and with just one element—hydrogen. Between three and four minutes after the cosmic beginning, the expanding and cooling universe passes through the temperature window at which hydrogen fuses into helium. About a quarter of the primordial hydrogen (by mass) becomes fused into helium, along with a trace amount of lithium. All other elements are manufactured later in the nuclear furnaces of future stars. Maiolino’s team was the first ever to see a gas cloud that contained only the elements produced in the initial “bang.”
To explain the level of ionization observed in the gas clump, Maiolino and his colleagues calculated that the combined luminosity of the stars illuminating the gas clump was equivalent to at least 20 trillion times our Sun’s luminosity. This high luminosity can be explained only if the stars in GN-z11’s central region are extremely massive. Based on the spectra of the gas clump, the team was able to determine that the ionizing radiation came from stars in GN-z11’s central region but not from the active galactic nucleus (AGN) in the core.
In the context of big bang modeling, astronomers have developed a range of predictions for the mass of the universe’s first stars—stars that begin their nuclear burning with 75% hydrogen, 25% helium, and a trace amount of lithium.9 These estimates range from 1–100 solar masses, 1–500 solar masses, and 50–500 solar masses, with the slight possibility that some of these first stars could be as massive as 1,000 solar masses.
The gas clump spectra taken by the NIRSpec show that the stars illuminating the gas clump are, indeed, the universe’s first-formed stars. Further, the spectra show that these stars are predominantly in the 50–500 solar masses category, with a significant fraction greater than 500 solar masses.
The luminosity of a star rises exponentially (to the 3.9 power) with its mass. A star with a mass 200 times the Sun’s mass will be ~1,600,000,000 times brighter than the Sun. A star 500 times more massive than the Sun will be about 6,000,000,000 times brighter! On this basis, we can determine that even if the GN-z11 central region contains only 20,000 stars, the light from those stars would be more than sufficient to illuminate the gas clump to the degree that Maiolino and his colleagues observed. Given that all big bang models predict the formation of 20,000+ metal-free stars (stars with no elements heavier than helium other than a trace amount of lithium) in multiple galaxies during the cosmic dawn, the population of bright galaxies observed by the JWST in no way poses a challenge to big bang creation models.
Early Supermassive Black Holes Maiolino and his team also found a second source of luminosity in GN-z11.10 They observed an extremely dense flow of gas into the nucleus of GNz-11. In this gas they detected ionized elements that clearly signify the existence of a giant black hole there, one that is aggressively accreting matter. They also observed powerful radiation spewing from the accretion disk surrounding the black hole. These observations enabled the team to calculate the mass of the black hole residing in GN-z11’s nucleus. That mass measures two million times our Sun’s mass. Thus, the nuclear black hole in GN-z11 falls into the “supermassive” category. (Astronomers classify any black hole more massive than one million solar masses as a supermassive black hole, or SMBH).
The event horizon around a black hole is a location at which the black hole’s gravitational attraction is so strong that not even light can escape it. Consequently, everything inside the event horizon appears black, while just outside the event horizon, matter is being converted into energy with 10–42% efficiency—the highest efficiency of any source in the universe. By comparison, this efficiency is 150–600 times greater than that of matter-to-energy conversion in the Sun’s nuclear fusion furnace. The brightest sources in the universe are the accretion disks just outside the event horizons of SMBHs (see figure 3).
Figure 3: The Bright Accretion Disk Outside the Event Horizon of the M87’s SMBH Credit: Event Horizon Telescope
The SMBH in GN-z11 is the most distant SMBH discovered to date. The presence of this ravenous SMBH and the brightness of first-formed stars in GN-z11 explain its luminosity, which is entirely consistent with the standard ΛCDM big bang creation model (where Λ stands for dark energy—the primary component of the universe—and CDM for cold dark matter—the second most dominant component of the universe).
Maiolino and his colleagues have confirmed that the first stars to form in the universe are likely very massive. They have also demonstrated that a dense clump of very massive stars in a cosmic dawn galaxy has a high probability of forming an SMBH. Therefore, it is not surprising that astronomers will find many bright cosmic dawn galaxies. The claim that the big bang model needs a major revision or points to new physics now appears to be nullified.
One More Gift from the JWST A fundamental prediction of all big bang models is the existence of three distinct star populations. Astronomers refer to stars formed during the most recent five billion years as Population I stars. These stars are characterized by a high abundance of elements heavier than lithium. Why? Because they formed from the ashes of stars that formed and burned up before these younger stars existed. Our Sun, for example, is a Population I star.
Stars older than Population I stars contain fewer heavy elements because they formed from the ashes of stars that formed and burned up at earlier times in cosmic history. The earlier in cosmic history, the lower the abundance of elements heavier than lithium available in interstellar space. Astronomers call these stars Population II stars. Most globular cluster stars and most stars in the halos of galaxies are Population II stars.
Population III stars are those that formed from the universe’s primordial gas: hydrogen, helium, and a trace amount of lithium. Astronomers had previously detected low-mass Population III stars in the halo of the Milky Way Galaxy.11 These stars did, indeed, form from the universe’s primordial gas; however, they took a very long time to fully form—hundreds of millions of years or more. Thus, before they began shining as nuclear-burning stars, their atmospheres had been polluted by the ashes of nearby very high-mass Population III stars, which had quickly burned up and exploded, sending their ashes into interstellar space.
Until now, though, astronomers have lacked the telescope power to detect these “metal-free” Population III stars or to detect the universe’s primordial gas. In fact, many astronomers have expressed doubt that the JWST possesses the necessary observing power to make such a detection. Maiolino’s team has now raised hopes that the JWST can make this detection. The team’s two papers end with a call for follow-up observations of GN-z11 to affirm their findings and to detect similar cosmic dawn galaxies. Given the importance of their findings, such observations likely will be forthcoming soon.
Philosophical/Theological Implications For thousands of years, the Bible has stood alone in describing the fundamental features of the big bang.12 No other cosmic origin model has been subjected to as many independent, rigorous tests as the big bang.13 Thanks to the power of the JWST and the research efforts of Maiolino and his team, the big bang has passed yet another set of tests. Their success provides still greater evidence to support the biblical claim that a Causal Agent beyond space and time created our universe and exquisitely designed it so that billions of humans can reside on our planet and develop a technologically advanced civilization. Their success also confirms the Bible’s power to predict, accurately, future scientific discoveries. This power affirms the supernatural inspiration and accuracy of the Bible, with its assurance of God’s desire and capacity to redeem fallen (as in self-serving, self-exalting) humanity.14
Endnotes
Guochao Sun et al., “Bursty Star Formation Naturally Explains the Abundance of Bright Galaxies at Cosmic Dawn,” Astrophysical Journal Letters 955, no. 2 (October 1, 2023): id. L35, doi:10.3847/2042-8213/acf85a.
Hugh Ross, “Big Bang Model Is Not Dead,” Today’s New Reason to Believe (blog), Reasons to Believe, January 1, 2024.
Pascal A. Oesch et al., “A Remarkably Luminous Galaxy at Z = 11.1 Measured with Hubble Space Telescope Grism Spectroscopy,” Astrophysical Journal 819, no. 2 (March 10, 2016): id. 129, doi:10.3847/0004-637X/819/2/129.
James O. Baldwin et al., “A Size Estimate for Galaxy GN-z11,” Research Notes of the AAS 8, no. 1 (January 2024): id. 29, doi:10.3847/2515-5172/ad220a.
Roberto Maiolino et al., “A Small and Vigorous Black Hole in the Early Universe,” (January 17, 2024), arXiv:2305.12492.
Andrew J. Bunker et al., “JADES NIRSpec Spectroscopy of GN-z11: Lyman-a Emission and Possible Enhanced Nitrogen Abundance in a z = 10.60 Luminous Galaxy,” Astronomy & Astrophysics 677 (September 2023): id. A88, doi:10.1051/0004-6361/202346159.
Sun et al., “Bursty Star Formation Naturally Explains,” p. 1.
Roberto Mailino et al., “JWST-JADES. Possible Population III Signatures at z = 10.6 in the Halo of GN-z11,” submitted to and accepted for publication in Astronomy & Astrophysics (June 6, 2023), arXiv:2306.00953v2.
Kimihiko Nakajima and Roberto Maiolino, “Diagnostics for PopIII Galaxies and Direct Collapse Black Holes in the Early Universe,” Monthly Notices of the Royal Astronomical Society 513, no. 4 (July 2022): 5134–5147, doi:10.1093/mnras/stac1242.
Maiolino et al., “A Small and Vigorous Black Hole in the Early Universe.”
What role should scientific theories play in translating the Bible? That’s a complex question. However, to the extent that science is allowed to play...
