What did galaxies in the early universe look like? Surprisingly close to our own Milky Way, according to the latest findings from the James Webb Space Telescope (JWST), whose unprecedented infrared eye has been rewriting what we thought we knew about the early universe.
Astronomers have long thought that newly minted galaxies that began merging together just after the Big Bang, about 13.7 billion years ago, were too fragile to boast any noticeable structures like spiral arms, bars or rings. Those galactic features were thought to form during a time at least six billion years after the Big Bang. According to the new study, however, these delicate shapes could've manifested as early as 3.7 billion years after the Big Bang — which is almost at the beginning of the universe.
"Based on our results astronomers must rethink our understanding of the formation of the first galaxies and how galaxy evolution occurred over the past 10 billion years," Christopher Conselice, an astronomy professor at The University of Manchester in the U.K. and a co-author of the new study, said in a statement published Friday (Sept. 22).
The new findings come at the heels of another announcement presented by a different group of researchers, also based on JWST data, which showed these early galaxies produced far fewer heavy elements than previously expected. However, the relationship between a galaxy's chemical composition and its evolution into a well-defined structure is not very well understood.
Much of scientists' previous understanding on galaxy evolution came from data gathered by the Hubble Space Telescope (HST), which is legendary in its own right but still has only so much resolution. While the HST data showed early galaxies had irregular shapes (as was expected during galaxy mergers) higher resolution data from the JWST is peering deeper into the universe to reveal that those early galaxies actually had well-defined structures like our own Milky Way. The new findings were based on an analysis of 3,956 galaxies, which astronomers say is the biggest sample that has been studied thus far with JWST data.
"For over 30 years it was thought that these disk galaxies were rare in the early universe due to the common violent encounters that galaxies undergo," Leonardo Ferreira, an astrophysicist at the University of Victoria in Canada and the lead author of the new study, said in the same statement. "The fact that JWST finds so many is another sign of the power of this instrument and that the structures of galaxies form earlier in the Universe, much earlier in fact, than anyone had anticipated."
According to the new study, the team classified the sample set of close to 4,000 galaxies from the early universe by shape — like disks, point sources and spheroids. Team members further classified them as smooth or structured, with galaxies in the latter group featuring bursts of star formation and indications of mergers with other galaxies.
Results showed that relatively well-defined structures in the universe form a lot quicker than previously thought, following what is known as the Hubble Sequence, which is the standard classification of galaxies by their visual properties as ellipticals, lenticulars and spirals.
The latest findings suggest a need for new ideas that explain how galaxies evolved over the past 10 billion years.
This research is described in a paper published Sept. 22 in The Astrophysical Journal.
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Sharmila is a Seattle-based science journalist. She found her love for astronomy in Carl Sagan's The Pale Blue Dot and has been hooked ever since. She holds an MA in Journalism from Northeastern University and has been a contributing writer for Astronomy Magazine since 2017. Follow her on Twitter at @skuthunur.
Space.com reported, "Much of scientists' previous understanding on galaxy evolution came from data gathered by the Hubble Space Telescope (HST), which is legendary in its own right but still has only so much resolution. While the HST data showed early galaxies had irregular shapes (as was expected during galaxy mergers) higher resolution data from the JWST is peering deeper into the universe to reveal that those early galaxies actually had well-defined structures like our own Milky Way. The new findings were based on an analysis of 3,956 galaxies, which astronomers say is the biggest sample that has been studied thus far with JWST data."Reply
Some thoughts here. Looks like JWST observations and findings continue to challenge the LCDM BB cosmology but the paper puts their best foot forward it seems :). From the paper cited, https://iopscience.iop.org/article/10.3847/1538-4357/acec76
"All sources were classified by six individual classifiers using a simple classification scheme aimed at producing disk/spheroid/peculiar classifications, whereby we determine how the relative number of these morphologies has evolved since the Universe's first billion years. Additionally, we explore structural and quantitative morphology measurements using Morfometryka, and show that galaxies with M* > 10^9 M⊙ at z > 3 are not dominated by irregular and peculiar structures, either visually or quantitatively, as previously thought. We find a strong dominance of morphologically selected disk galaxies up to z = 6 in this mass range. We also find that the stellar mass and star formation rate densities are dominated by disk galaxies up to z ∼ 6, demonstrating that most stars in the Universe were likely formed in a disk galaxy. We compare our results to theory to show that the fraction of types we find is predicted by cosmological simulations, and that the Hubble Sequence was already in place as early as one billion years after the Big Bang. Additionally, we make our visual classifications public for the community."..
Quantitative measures of galaxy structure and morphology also present stringent constraints for numerical simulations to reproduce. In recent years, full hydrodynamic simulations (Schaye et al. 2015; Nelson et al. 2019; Lovell et al. 2021; Marshall et al. 2022) have enabled resolved morphologies to be predicted in a self-consistent manner, and recent novel simulation approaches allow these to be tested out to the highest redshifts (Roper et al. 2022). There are a number of difficulties when comparing morphologies between simulations and observations, but simple measures of the abundance of, e.g., disk and elliptical galaxies can provide hints as to the underlying mechanisms leading to morphological evolution. However, what we know from early JWST work is that the morphological and structural features of galaxies at z > 1 are much different than what was found with HST (e.g., Ferreira et al. 2020), and therefore a more thorough analysis is needed to address these fundamental problems. Thus, in this paper we explore the morphological properties of 3956 galaxies observed with JWST through visual galaxy classifications and quantitative morphology, from z = 1.5 to 6."
The cosmology calculators for z=6.0, show the age of the universe since BB event at "The age at redshift z was 0.942 Gyr." using Ned Wright with defaults. Plug in H0 = 73 km/s/Mpc and "The age at redshift z was 0.898 Gyr.", https://lambda.gsfc.nasa.gov/toolbox/calculators.html
It does appear now that JWST is finding objects with large redshifts that pose some real challenges now to the BB model to explain how the universe assembled into what we see today using our telescopes.
If we see back far enough could we see the Milky Way in its infancy?Reply
Might sound plausible at first but think about this. If we spoted the MW in another time/distance shell, at what velocity would it have to travel to get to the other shell........in the allotted time and with that distance?Reply
I hear what you say but figure this. If we see the sun how it was 8 minutes ago we should be seeing -through the 4th dimension of time - a younger MW if week zoomed into the universe simply because the universe started from a point. Nothing else in life does that. It does not mean it is not true. Those galaxies 13.4 b miles away must be have changed by now. Into us. So it will be a chaotic soup of stars back then rather than a replica of the MW now. Methinks.Classical Motion said:Might sound plausible at first but think about this. If we spoted the MW in another time/distance shell, at what velocity would it have to travel to get to the other shell........in the allotted time and with that distance?
That is one SPACETIME curvature we don't see into, unless we were positioned 10-billion x 9.6-triilion kilometers from the Milky Way. Even there and now, the intervening vortex of universe shift and nonlocal velocities of galactic vortices (in other words an interference of complexity and chaos), particularly regarding times (plural) as well as spaces (plural), would not permit it. Nonlocally we don't exist in just one universe of space and time. We never have. We exist in parallel universes.Classical Motion said:Might sound plausible at first but think about this. If we spoted the MW in another time/distance shell, at what velocity would it have to travel to get to the other shell........in the allotted time and with that distance?
As travelers (I always like to deal in the universe traveler), if we move away from the Earth and the Milky Way in space and time, we could not maintain a rearward focus on either one of the first within either one of the second. We'd be accelerating in turning (verse: turn: to turn) in ever tighter loops of spacetime trying to keep focus, being thrown out into an ever-widening, ever expanding, loop impossible of allowing sustained focus behind on any particular object (particularly when that object is devolving to the Horizon (particularly when our traveler's Relativity to Earth and Milky Way, to their spacetime, is accelerating in quickening in breaking down (Relativity predicts its own breakdown . . . its own collapse in horizon)).
Essentially, we'd be doing the considered impossible (a "spooky action at a distance"). We'd be departing a black hole horizon (THE distant PBB(B(W)H) Horizon) by being literally tossed out of it. The only real local effect from our location resets at 0-point-center of the universe between horizons, though, would be to observe the most distant horizons of the (fractal zoom) universe to be the same as we observe them in the farthest distances from our 0-point-center of infinity now.
In other words, we'd be doing something like negative curvature. We wouldn't be stupid enough to accelerate into such an ever-tightening curvature like the LHC accelerator at Cern.
Seeing back means seeing far ... We can see other galaxies far away, but we can't see our own galaxy (the Milky Way) from far away ...SpaceBoyBen said:If we see back far enough could we see the Milky Way in its infancy?