Nobody expected them. They were not supposed to be there. And now, nobody can explain how they had formed.
Galaxies nearly as massive as the Milky Way and full of mature red stars seem to be dispersed in deep field images obtained by the James Webb Space Telescope (Webb or JWST) during its early observation campaign, and they are giving astronomers a headache.
These galaxies, described in a new study based on Webb's first data release, are so far away that they appear only as tiny reddish dots to the powerful telescope. By analyzing the light emitted by these galaxies, astronomers established that they were viewing them in our universe's infancy only 500 to 700 million years after the Big Bang.
Such early galaxies are not in themselves surprising. Astronomers expected that first star clusters sprung up shortly after the universe moved out of the so-called dark ages — the first 400 million years of its existence when only a thick fog of hydrogen atoms permeated space.
Related: 12 amazing James Webb Space Telescope discoveries across the universe
But the galaxies found in the Webb images appeared shockingly big, and the stars in them too old. The new findings are in conflict with existing ideas of how the universe looked and evolved in its early years, and don't match earlier observations made by Webb's less powerful predecessor, the Hubble Space Telescope.
"We had specific expectations for the type of galaxies that live in the early universe: they are young and small," Joel Leja, assistant professor of astronomy and astrophysics at Penn State and one of the authors of the study, told Space.com in an email. "Previous studies of the early universe with Hubble and other instruments tend to find small, blue, baby galaxies at early times: objects which have just recently formed out of the primordial cosmic soup and are themselves building their early stars and structures."
Young stars in general shine bright blue. With age, stars develop a redder glow as they burn through their fuel and cool down. In ancient galaxies that Webb was built to spot, astronomers had not expected to see old red stars. They also had not expected to find galaxies more massive than perhaps a billion suns. But those reddish dots revealed in Webb's deep fields appear 50 times more massive than that, Leja said.
"The most massive galaxies in our sample are estimated to have masses [two to four times lower] than that of our own Milky Way," Leja wrote. "This was astounding — we're finding galaxy candidates as massive as our own galaxy when the universe was 3% of its current age."
Leja said that before astronomers start rewriting cosmology theories to explain how these galaxies came together so quickly after the Big Bang, they will have to ensure the odd red dots they are looking at are not something else. Most of the alternative explanations, however, also require entirely new concepts, Leja said.
"For example, stars in the early universe might emit light in exotic ways due to their lack of heavy elements, and perhaps we're not incorporating those in our models," Leja wrote. "Or alternatively, perhaps our understanding of how stars form locally, e.g. how many stars form from gas as a function of the mass of the stars, is totally inapplicable in the early universe. These things would also be exciting to discover and would also overturn our understanding of star formation in the early universe — just in a very different way."
The images that revealed these puzzling galaxies were obtained by Webb's Near Infrared Camera (NIRCam) as part of the Cosmic Evolution Early Release Science (CEERS) program. Astronomers plan to soon turn Webb's mirror to these galaxies again to, this time, obtain light spectra of those distant dots. Spectra break down the observed light according to its wavelength composition and thus reveal the chemical and physical properties of its source.
"The most important thing is that spectra give very precise distances to these objects," said Leja. "The "distance" and the "identity" of these objects is correlated: if we know the distance, we can pin down the identity, and vice versa. So a spectrum will pretty immediately tell us if our hypotheses are correct."
Only a little more than six months after the Webb team released the first observations from the grand observatory, scientists are already challenged to rewrite their theories about the early universe.
"We looked into the very early universe for the first time and had no idea what we were going to find," Leja said in a Penn University statement. (opens in new tab) "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."
The study was published in the journal Nature on Wednesday (Feb. 22).
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.
Same issues here as I discussed in post #61 above. The only objective way to verify galaxy evolution models is to compare their present dimensions at their look back time distance (what we see on Earth and redshift) with what they look like at the comoving radial distances (not observable from Earth) because of the immense distances in the BB model for expansion. Something like the Sparkler galaxy in post #61 is a good example.
Understand how, as a new reader, I might become immediately skeptical of a publication's quality when their writers fail to pay attention to critically significant numbers involving the discussion.
Absolutely. But this will take a lot of time. The hubris of modern scientists (I'm looking at you Neil DeGrasse Tyson) is astonishing. They forget that every generation of scientists before also thought they had it figured out for sure.
Geocentric Universe which gave way to...
Heliocentric Universe which gave way to...
One Galaxy gave way to...
Accelerating Expansion of a finite universe will give way to...
Point is, there's no reason to think the Big Bang Theory is the end all. We still know almost nothing and we need to be ready for the next paradigm... Whatever that may be.
My observation. https://lambda.gsfc.nasa.gov/toolbox/calculators.html can be used to show calculations, z=9.1 light-time or look back distance is 13.178 Gyr or 13.178 billion light-years from Earth. The age of the universe at z=9.1 is 0.543 Gyr and comoving radial distance is 30.802 Gly. Using H0=69 km/s/Mpc space is expanding 2.1735932 x c velocity at the comoving radial distance. Any galaxies seen by JWST with such deep or large redshifts, presently sit in the universe immensely farther away and evolved into what? Unknown morphology and mass evolutionary changes it seems when comparing the look back distance with comoving radial distances in the expanding universe model. Little mysteries like this appear when you dive deeper into BB cosmology and redshift interpretations.