Black holes may be behind why the newborn universe appeared to possess more huge galaxies than scientists could explain, a new study finds.
Astronomers made this discovery with the help of NASA's James Webb Space Telescope (JWST), the largest and most powerful off-Earth observatory to date. Launched in December 2021, the $10 billion JWST specializes in detecting infrared light, just like thermal vision goggles.
Scientists are using JWST to investigate the early cosmos. The universe has expanded greatly since it was born about 13.8 billion years ago in the Big Bang, and that means the light from early galaxies appears reddened by the time it reaches Earth, much as how an ambulance siren sounds lower-pitched to people as the vehicle drives away. JWST is designed to help capture light from the earliest galaxies, much of which has shifted into the infrared range.
When astronomers got their first glimpses of galaxies in the early universe from JWST, they were expecting miniature versions of modern galaxies. Instead, they found that some galaxies had grown very large very quickly.
Related: James Webb Space Telescope (JWST) — A complete guide
This previous research suggested that something might be wrong with scientists' thinking about what the universe is made of and how it has evolved since the Big Bang, known as the standard model of cosmology. All in all, early galaxies seemed to be larger than what the standard model expected by "roughly a factor of two," study co-author Steve Finkelstein, an astrophysicist at the University of Texas at Austin, told Space.com.
Now, Finkelstein and his colleagues find that some of these early galaxies are actually much less massive than they first appeared. They detailed their findings online Aug. 26 in The Astrophysical Journal.
Get the Space.com Newsletter
Breaking space news, the latest updates on rocket launches, skywatching events and more!
In the new study, the researchers focused on 261 galaxies from about 700 million to 1.5 billion years after the Big Bang. To estimate the mass of galaxies, scientists typically see how much light a galaxy emits and deduce the number of stars it likely possesses to generate all that light. Previously, when it came to early galaxies, NASA's Hubble Space Telescope "was only to glimpse the hottest, most massive stars," Finkelstein said. "JWST observes redder wavelengths, so is sensitive to lower-mass, cooler stars, and so can more accurately measure the total amount of stars in these galaxies."
The scientists discovered that black holes made nine of these early galaxies appear much brighter — and thus bigger — than they really are. Although black holes get their name from how their gravitational pulls are so powerful that not even light can escape, gas falling into black holes can glow brightly from the friction it experiences as it rushes in at high speeds. This extra light can make it appear that galaxies hold more stars than they actually do.
Once the researchers accounted for these black hole-affected galaxies, the standard model could account for the remaining early galaxies.
"So, the bottom line is, there is no crisis in terms of the standard model of cosmology," Finkelstein said in a press release. "Any time you have a theory that has stood the test of time for so long, you have to have overwhelming evidence to really throw it out. And that's simply not the case."
However, "we are still seeing more galaxies than predicted, although none of them are so massive that they 'break' the universe," study lead author Katherine Chworowsky, a graduate student at the University of Texas at Austin, said in the press release.
RELATED STORIES:
— James Webb Space Telescope spies never-before-seen star behavior in distant nebula (video, photo)
— What is the Big Bang Theory?
— Youthful galaxy in the early universe was a heavy metal rebel
One possible reason that JWST sees about twice as many massive early galaxies as expected from the standard model is that stars formed more quickly in the early universe than they do today. "Maybe in the early universe, galaxies were better at turning gas into stars," Chworowsky said in the press release.
A star is born when a cloud of gas succumbs to its own gravity and collapses. However, as this gas contracts, it heats up because of friction, generating outward pressure. Nowadays, these opposing forces usually make star formation slow. However, since the early universe was denser than it is today, some research suggests it was hard to expel gas during star formation, letting it happen faster.
Now "we would like to understand why we observe what we observe," Finkelstein said. "One way to do this is to study how these galaxies build up their stellar mass." Such data will come in the next few months, "which we should be able to use to better understand how these massive galaxies formed."
Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
Charles Q. Choi
Contributing Writer
Charles Q. Choi is a contributing writer for Space.com and Live Science. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica. Visit him at http://www.sciwriter.us
More about james webb space telescope
Latest
3 CommentsComment from the forums
rod 'The bottom line is, there is no crisis in terms of the standard model of cosmology.'
Okay, nothing to see hear folks, cosmology and BBT, all is well. The paper cited shows z=4-8 for galaxies studies. Using cosmology calculators like Ned Wright, z=4, comoving radial distance is some 23.873 Gly
Using z = 8, comoving radial distance is some 29.823 Gly
From earth, we cannot see what those galaxies evolved into today or what mass they may or may not have. Small issues like this show up when interpreting observations of redshifts and expanding universe modeling.
Reply
Unclear Engineer It is no surprise to me that the BBT cosmologists can "explain" practically anything we are currently capable of observing, even if it was not what their model predicted before the observations were made. There are just so many unconstrained assumptions in the model that it is extremely malleable.
But, it seems that there is still a question about how such large black holes developed so quickly.
Frankly, if the universe was many hundreds of times more dense with matter back when the light was emitted from which these observations were now made, it would not surprise me if the star formation rate was higher than we see today. And, if central supermassive black holes tend to suppress star formation in their galaxies, then perhaps the galaxies grew quite rapidly until they could produce black holes large enough to suppress growth.
But, it still bothers me that the assumption seems to be that atoms then are the same size as atoms now, rather than they too got larger as the space around them and inside them became larger. In terms of cross sectional areas for interactions, and thus reaction rates for frictional heating, chemical reactions, etc., that seems like an important assumption when trying to figure out the dynamics of early galaxy formation.
Reply
Torbjorn Larsson Possibly other groups can criticize that almost all the "red dot" galaxies are excluded due to problems with estimating their masses. But that just points to how they are likely accretion disk controlled as a recent model explaining early black hole growth with magnetic rigidity allowing for super-Eddington growth rates says .
The remaining high star rate formation is ironic, since ten years ago models had problems turning the natural rate down to match late universe galaxy counts. But that discrepancy was a factor 10, now it is merely a factor 2 in the other direction.
Unclear Engineer said:
It is no surprise to me that the BBT cosmologists can "explain" practically anything we are currently capable of observing, even if it was not what their model predicted before the observations were made. There are just so many unconstrained assumptions in the model that it is extremely malleable.But, it seems that there is still a question about how such large black holes developed so quickly.
It is a fact that the cosmological models are still somewhat malleable, but it is also a fact that the surveys agree on most general parameters. Full star formation models are auxiliary (and complicated) models that only show up in cosmological simulations, not in plain vanilla BBT models of hot big bang universe expansion.
Regarding supermassive black hole early growth (and coincidentally, red dots), a recent first complete model may have explained it in a series of papers (but the first paper suffice here): https://astro.theoj.org/article/94757-forge-d-in-fire-resolving-the-end-of-star-formation-and-structure-of-agn-accretion-disks-from-cosmological-initial-conditions , https://astro.theoj.org/article/93066-forge-d-in-fire-ii-the-formation-of-magnetically-dominated-quasar-accretion-disks-from-cosmological-initial-conditions , https://astro.theoj.org/article/93065-an-analytic-model-for-magnetically-dominated-accretion-disks.
It has recently become possible to zoom-in from cosmological to sub-pc scales in galaxy simulations to follow accretion onto supermassive black holes (SMBHs). However, at some point the approximations used on ISM scales (e.g. optically-thin cooling and stellar-population-integrated star formation and feedback ) break down. We therefore present the first cosmological radiation-magnetohydrodynamic (RMHD) simulation which self-consistently combines the FIRE physics (relevant on galactic/ISM scales where SF/FB are ensemble-averaged) and STARFORGE physics (relevant on small scales where we track individual (proto)stellar formation and evolution), together with explicit RMHD (including non-ideal MHD and multi-band M1-RHD) which self-consistently treats both optically-thick and thin regimes. This allows us to span scales from ~100 Mpc down to <100 au (~300 Schwarzschild radii) around a SMBH at a time where it accretes as a bright quasar, in a single simulation. We show that accretion rates up to ∼10−100M⊙yr−1 can be sustained into the accretion disk at ≪103Rschw, with gravitational torques between stars and gas dominating on sub-kpc scales until star formation is shut down on sub-pc scales by a combination of optical depth to cooling and strong magnetic fields. There is an intermediate-scale, flux-frozen disk which is gravitoturbulent and stabilized by magnetic pressure sustaining strong turbulence and inflow with persistent spiral modes. In this paper we focus on how gas gets into the small-scale disk, and how star formation is efficiently suppressed.
Unclear Engineer said:
But, it still bothers me that the assumption seems to be that atoms then are the same size as atoms now, rather than they too got larger as the space around them and inside them became larger.Spectra are the same after accounting for cosmological expansion redshift, so it is the same atom physics.
Atoms are cohesive systems, also helping by way of molecular forces in building cohesive stars and planets and organisms, so they easily resist the cosmological expansion from general relativity.
In fact, gravity suffice to resist space expansion up to the scale of our Local Group, which seems to be bound and hence see no space expansion within. The cosmological space expansion in between galaxy clusters is locally very slow at currently a 10^-10 rate in space and time or in other words 1 nanometer per meter and per year.
Reply
