JWST breaks its own record with new most distant galaxy MoM-z14

No matter how well we think we understand the Universe, there’s always something new out there to discover. After all, astronomy is the study of the Universe as we observe it to be, and as we build superior instruments and telescopes, we’re bound to notice details, objects, and even phenomena that couldn’t be revealed with the tools of prior generations. In many regards, it was only with the advent of space telescope technology — including NASA’s Hubble Space Telescope — that we began to understand what the Universe looked like. Now, here in the 2020s, it’s the James Webb Space Telescope (JWST) that’s taking us beyond all of Hubble’s prior limits, discovering fainter, more distant, more primitive, and younger objects in the Universe than ever before.

Back in 2022, before JWST began science operations, we had only one confirmed galaxy from the first 500 million years of cosmic history: GN-z11, discovered with the Hubble Space Telescope. Several other ultra-distant galaxy candidates existed, but they were just that: candidates. It would take a superior tool, like JWST, to find others, as well as to confirm or refute the ones we already had.

Fast forward to today: in 2025. GN-z11 is still an ultra-distant galaxy, but it’s not even in the top 10 anymore for most distant galaxy. Hundreds of times as many luminous, early galaxies were found as were initially expected, and a new record holder, MoM-z14, was just announced on May 16, 2025. Here’s what we found, what it means, and what puzzles still remain.

This image shows the full COSMOS (Cosmic Evolution Survey) from the Hubble Space Telescope: its largest ever survey of the Universe.Hubble photographed 575 adjacent and slightly overlapping views of the universe using the Advanced Camera for Surveys’ (ACS) Wide Field Camera onboard Hubble, requiring nearly 1000 hours of observations. At full resolution the image would be 100,800 x 100,800 pixels.

What you see, above, is what’s known as the COSMOS survey: the Cosmic Evolution Survey, which is the largest deep survey of the Universe, to date, ever conducted. Constructed from a whopping 575 separate adjacent, overlapping Hubble images requiring nearly 1000 hours of total observing time, the full-resolution version of this field clocks in at over 10 Gigapixels, or more than 100,000 pixels per side. And yet, the sky is so vast that if we wanted to cover it all, it would require the equivalent of more than 20,000 COSMOS surveys to do it.

Nevertheless, within this field-of-view, an enormous number of ultra-distant galaxy candidates have been identified. While the closer galaxies can be spectroscopically confirmed from the ground — such as with the Magellan telescope, the Subaru telescope, the Canada-France-Hawaii telescope or the Very Large Telescope — the light from the most distant galaxies of all experience such severe redshifts, or stretching effects owing to the expansion of the Universe, that a new observatory is required to measure them.

JWST, humanity’s most powerful infrared space telescope in history, is ideally suited to this task. Already, before it began considering galaxies in the COSMOS field, JWST discovered and confirmed an enormous number of bright, ultra-distant galaxies in the Universe: so many that they’re approximately ~100 times more abundant than we had expected before the dawn of the JWST science era.

JADES-GS-z14-0, in the top inset box, is found behind (and just to the right of) a closer, brighter, bluer galaxy. It was only through the power of JWST spectroscopy with incredible resolution, capable of separating the two sources, that the nature of this record-breakingly distant object could be determined. Its light comes to us from when the Universe was only 285-290 million years old: just 2.1% of its current age. JADES-GS-z14-1, just below it, comes from when the Universe was ~300 million years old. Compared to large, modern-day galaxies, all early galaxies contain a paucity of stars and have irregular, ill-defined shapes.

The most common “type” of ultra-distant galaxy found by JWST are illustrated above: what we know as “little red dot” galaxies. Initially, when we first began discovering them (which was practically immediately), many jumped to the premature conclusion that cosmology is broken, and we didn’t know how galaxies formed or grew up at all. As more data poured in and more research was conducted, however, four partial explanations emerged for what JWST was seeing.

1. Optical overperformance. The galaxies we were seeing were brighter and more numerous than anticipated, in part, because JWST was gathering more light (and was kept cleaner during construction) than we expected.
2. Simulation limitations. Most simulations were conducted at medium-resolution, without focusing on the most rare but most severe small-scale overdensities. When these “rarepeak” regions are included in simulations, more bright, early galaxies are expected.
3. Bursty star-formation. Most models for galaxies rely on a constant, maximal rate of star-formation that builds up over time. But realistic galaxies often exceed those rates temporarily, forming stars in great (but brief) bursts, temporarily enhancing their brightness. Then, it’s the brightest ones at that time that we preferentially observe.
4. AGN enhancements. Nearly all galaxies, even early-type galaxies, are anticipated to have supermassive black holes at their centers, many (but not all) of which are either currently or recently active. As a result, many of these little red dot galaxies are brightness-enhanced by AGN activity, artificially (but temporarily) inflating their observed brightnesses.

With these four contributions, all combined, the Universe finally makes sense, even with the abundant presence of these ultra-distant JWST galaxies.

This image shows 15 of the 341 hitherto identified “little red dot” galaxies discovered in the distant Universe by JWST. These galaxies all exhibit similar features, but only exist very early on in cosmic history; there are no known examples of such galaxies close by or at late times. All of them are quite massive, but some are compact while others are extended, and some show evidence for AGN activity while others do not.

Previously, JWST collaborations such as CEERS (the Cosmic Evolution Early Release Science Survey), GLASS, UNCOVER (the Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization), and JADES (the JWST Advanced Deep Extragalactic Survey) had all discovered many galaxies surpassing the previously-held record of GN-z11. These very distant galaxies included:

along with many other finds that are revolutionizing our picture for how the Universe grew up.

And with that, it’s now time to add to the story further with the newest discovery: galaxy MoM-z14, which surpasses JADES-GS-z14-0 as the most distant galaxy presently known to humanity as of May 16, 2025. Like most of the ultra-distant JWST galaxies discovered, it was imaged photometrically first, at a variety of near-infrared wavelengths:

• 0.9 microns,
• 1.15 microns,
• 1.50 microns,
• 2.00 microns,
• 2.77 microns,
• 3.56 microns,
• and 4.44 microns.

Because of the neutral hydrogen present in the Universe this early on, all light of wavelengths shorter than ~121 nanometers (where the Lyman-α emission/absorption transition occurs) gets absorbed, and then the light gets stretched by the expansion of the Universe. For this object, that means that the first three filters reveal no light at all, but that the latter four filters reveal this object.

This figure shows the NIRCam (top) and NIRSpec (bottom) data for now-confirmed galaxy MoM-z14: the most distant galaxy known to date as of May 2025. Completely invisible at wavelengths of 1.5 microns and below, its light is stretched by the expansion of the Universe. Emission features of various ionized atoms can be seen in the spectrum, below, as well as the significant and strong Lyman break feature.

To measure the true distance to the galaxy, we then need to perform what we call a spectroscopic follow-up: where we break the light from this object up into its individual component wavelengths. With the incredible spectroscopic power of JWST’s NIRSpec instrument, even a galaxy that’s this far away will exhibit emission lines from the ionized atoms surrounding it. This is because of a confluence of facts.

• This galaxy has already formed previous generations of stars, meaning that heavy elements such as nitrogen, carbon, and oxygen are present, in addition to the primordial signs of hydrogen and helium.
• This galaxy, in order to be observed so far away, must be actively forming stars either right now or extremely recently, implying there are large numbers of ultraviolet photons, which can strip one or several electrons away from the atoms present.
• As electrons recombine with their ionized nuclei, they cascade down a variety of atomic energy levels, emitting “lines” at a telltale set of frequencies and wavelengths.
• And every one of those lines, if our instruments can resolve them, will reveal a galaxy’s redshift (z) because the observed wavelengths of those lines will be at the rest-frame wavelength multiplied by a factor of “1+redshift” (or 1+z).

With not just the Lyman break feature, corresponding to the Lyman-α wavelength, but with emission lines from nitrogen, carbon, helium, and oxygen in various ionization states all observed for this object, we can definitively conclude that it’s at a redshift of z = 14.44, which sets a brand new cosmic record.

This image shows the best fit to the Lyman break feature (top left), the best fit to the identified ionized emission lines (top right), the redshift inferred from photometry, the Lyman break, and the emission lines (lower left), and the probability density of the galaxy MoM-z14 actually being at those particular redshifts (lower right). The most likely redshift peaks at z = 14.44.

A redshift of z = 14.44 means that light, originally emitted from this object with a specific wavelength, will be observed by us here on Earth (or in space with JWST) with a wavelength that is a factor of 15.44 times as great. For the Lyman-α line, emitted at 121.5 nanometers, that light was initially ultraviolet. But owing to the expansion of the Universe, that light gets stretched and stretched and stretched over a journey of more than 13.5 billion years, out of the ultraviolet (which ends at about 400 nm), into visible light (from 400-700 nm) and all the way into the infrared, where finally that signal begins appearing at a new wavelength of 1.88 microns.

This corresponds to an age of the Universe of approximately 282 million years, or just 2.0% of its current age. It corresponds to a light-travel time of about 13.53 billion years, which means that this object is now located at a distance of 33.8 billion light-years from us, making it the single most distant object ever yet discovered in the Universe.

Because we understand how the expanding Universe works, we can infer additional properties about this galaxy as well, including its size (it has a diameter of right around 500 light-years), its compact nature (its light is very concentrated and not diffuse, or extended), and its surprisingly dust-free nature (due to the steep ultraviolet slope from its light).

This figure shows the inferred absolute (intrinsic) brightness of the most distant galaxies confirmed spectroscopically, with redshift shown on the x-axis and brightness/magnitude shown on the y-axis. The squares denotes galaxies whose infrared images are depicted atop. GN-z11, the most distant galaxy known in 2022, is now just the 14th most distant known.

This “dust-free” nature is already an extremely interesting property. Remember: before JWST started observing the ultra-distant Universe, we expected to find very few of these bright galaxies at such great distances. It took a combination of four factors to explain it: optical overperformance of JWST, improved simulations, bursty star-formation, and AGN (or active galactic nuclei) enhancement of the brightness.

Well, the way AGNs typically work is by injecting energy into an accretion disk, heating it up and causing it to glow, which enhances the overall brightness of the galaxy. But this would make the ultraviolet slope of its light very shallow, and would cause the galaxy to appear quite extended in space; neither of which describes the light from the galaxy that we’re observing.

This implies that an AGN is not only not the dominant source of light for this object, but that there may be only negligible amounts of light coming from the central supermassive black hole. In fact, several of the early “little red dot” galaxies that JWST has found seem to exhibit little-to-no evidence for AGN activity: particularly the smaller, more compact ones in general. If there’s no AGN activity inside this object, then one would hope — or would even require — that there would be strong evidence of an ongoing or very recent episode of bursty star-formation inside this galaxy.

It’s very clear, from this set of images, that there are two distinct populations of ultra-distant galaxy that have emerged in the JWST era: large, extended galaxies with weak triply-ionized nitrogen signals (yellow), and small, compact, strong triply-ionized nitrogen emitters (blue), with newly discovered galaxy MoM-z14 being the most distant galaxy and the strongest nitrogen emitter of all.

And indeed, that’s exactly what the evidence shows. It looks like the star-formation rate underwent a rapid increase, by a factor of 10 or even more, over a period no longer than the past 10 million years, and has remained at this elevated value for at least the last 3-4 million years. This also explains why:

• the equivalent widths (an astronomical term for how much of the continuum intensity is needed to make up the total intensity of an observed emission line) of the emission lines detected, such as doubly ionized carbon, are so large (at about ~15 Å),
• there’s a very high degree of ionization (and hence, many atomic species are found with double or triple ionization states),
• a very high inferred gas density (some twenty times higher than for the gas-depleted former distance record-holder, JADES-GS-z14-0) is present,
• and why so much of the galaxy’s energy is found being emitted in the form of triply-ionized nitrogen: more than in any other (even much larger) galaxies found at such great distances.

Although we cannot yet know with current observations (although future NIRSpec and/or ALMA observations might be able to find out) whether there is a population of older stars present alongside these newly-forming ones, we can strongly conclude that the majority of the light that we’re seeing from this galaxy was from stars that have formed relatively recently in its cosmic history: within the past 10 million years or so.

Based on the data acquired for galaxy MoM-z14, we can infer that it has a mass of approximately 100,000,000 Suns, overall, and that all to nearly-all of the detectable light comes from stars that formed recently: within the past 10 million years or so. It is possible that an older population of stars exists alongside the newer ones, but these observations were insufficient to reveal either their presence or absence.

All of this points to the big puzzle — or, by a different way of thinking, the big “reveal” — that JWST has brought to us about the early Universe: the unexpectedly large abundance of these very bright, ultra-distant galaxies. While we think we can explain them now, after they’ve already been discovered, it’s important to recognize that our initial thoughts about how frequently we expected to find them were gross underestimates: by a factor of ~100 or even ~200. The discovery of this new galaxy, known as MoM-z14, confirms this picture very well. In addition, certain new questions are raised.

The particular features of the light from this distant galaxy indicate that there’s very little neutral gas present. However, the Universe shouldn’t become fully reionized until some ~550 million years after the Big Bang, whereas MoM-z14 comes to us from a time when the Universe was barely half of that age. How is there so little neutral gas present in this region so early on. Is it possible that the intergalactic medium around this object somehow became fully ionized hundreds of millions of years earlier than elsewhere?

Furthermore, unless there’s something exotic going on at very early times, like an unexpected evolution in star-formation efficiency or the presence of some exotic form of energy (like evolving dark matter or early dark energy), even most of the JWST-inspired models have difficulty explaining the presences of MoM-z14 and JADES-GS-z14-0 at such great distances and early times.

The presence of “little red dot” galaxies has caused us to re-evaluate just how abundant these galaxies ought to be. With better simulations and a better understanding of JWST’s performance, the two major contributors to the abundance and brightness of these objects are star-formation and AGN enhancement, but additional scenarios, including modified star-formation efficiency, initial mass functions, or even exotic forms of energy could all change the story still further.

It’s worth pointing out that the reason for this galaxy’s name, MoM-z14, is not because this is “the mother of all galaxies” that needs to be abbreviated as MoM, but rather because the discovery paper for this galaxy represents the first result from the “Mirage or Miracle” survey, which has been designed to spectroscopically test the abundance and nature of luminous galaxies (and luminous galaxy candidates) from the first ~500 million years of cosmic history. It’s been confirmed that this galaxy is not a mirage; hence, by the survey team’s definition, it’s a (scientific) miracle.

With this discovery — likely the first of many ultra-distant galaxies that will be revealed by this survey, as well as the larger-field COSMOS-Web survey — we can be confident that many of the early “little red dot” galaxies that are out there are going to show little evidence for large AGN contributions, and will instead be compact and dominated by a burst of recent star-formation. Galaxies GN-z11 and GLASS-z12 already display this as well, but with MoM-z14 having been revealed too, perhaps they aren’t outliers after all.

Finally, this galaxy, even at such an early time, is fairly massive: at about 100 million solar masses, or comparable to the Small Magellanic Cloud. Will this grow into a cosmic behemoth? Will it grow into a dwarf galaxy? Or does it represent one of the largest and most massive examples of an early globular cluster? With a strong agreement between all the different sources of data we have for this example, we can be confident that future observations, both of MoM-z14 as well as other galaxies sure to be found at similar, comparable distances, we’re in a very favorable condition to better understand how our Universe grew up to become the fascinating way it is today.