Is James Webb Telescope shattering the Big Bang Theory?
There seems to be a rumor in the astronomical research environment that the latest findings
of the James Webb Telescope are causing a lot of concern among cosmologists.
Or at least, among orthodox cosmologists, those who would be willing to bet the house
on the reliability of the so-called Standard Cosmological Model, with all that the attached
Big Bang theory carries with it. How so? Well, apparently, after a mere one
month of work Webb would have already detected objects, or rather galaxies so much too young,
that according to the Standard Model they should not even exist.
Already "adult" and well-structured galaxies dating back to a time when there should not
even have been stars. And this is something that blatantly and repeatedly
contradicts the Big Bang hypothesis that the universe began 13.8 billion years ago. If
that were so, we could not see today, thanks to Webb, galaxies already recognizable as
such, formed only 200 million years after the beginning of it all. In an era of the
formation of the universe when there could not even be stars!
The Big Bang has been defended for decades as an indisputable truth by the vast majority
of cosmologists, which is why the new data brought by Webb are throwing the keepers of
the orthodoxy into a panic. Who, however, do not want to drop the bone and are preparing
to raise a thick smokescreen over what the Webb Telescope revealed, claiming the need
for further confirmation. What do you say, let's figure it out?
Deciphering what happened in the early Universe is extremely complex. We know very little
about how things happened immediately after the Big Bang. The most widely accepted scenario
is that of so-called hierarchical formation. Starting 300-400 million after the big bang,
small regions denser than the others would have begun to form condensations of dark and
ordinary matter (dust and gas) that were initially relatively small, with irregular morphology
and few stars. These protogalaxies would then have given rise to gradually larger galaxies
through a merger process caused by mutual gravitational attraction.
Thus, according to the Standard Model, currently accepted by the entire scientific establishment,
the first true, flat, spiral-structured galaxies should have emerged-as did our own Milky Way-no
less than 0.8 billion years after the Big Bang, about 13 billion years ago.
Of course, for many years now cosmologists have been trying hard to corroborate this
theory, trying to push their observations farther and farther into the past. Understanding
when and how the first stars, and then the first galaxies, were formed, and what shape
the latter had, is a mandatory step to somehow advance a scientific discipline like cosmology.
Which by its nature lives more on hypotheses than on data and observations; and which to
advance demands the use of delicate and very expensive instrumentation such as space telescopes.
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Until a few days ago, the record for the most distant (and therefore oldest) galaxy was
in fact held by GNz-11, a primordial dwarf galaxy observed by Hubble and 13.4 billion
years distant in time. Value this quite accurately, since it was
possible to highlight a very precise line in the spectrum and compare its redshift with
that of the same line observed in a normal terrestrial laboratory.
The strange name of this object comes from being in the GOODS-North galaxy survey archive
and from the number 11, which indicates the cosmological redshift value, which in cosmology
is denoted by the letter "z." The higher the value of z, the greater the
distance involved. The most distant galaxies visible with the
Hubble Space Telescope generally show a z of less than 10, while the most distant protogalaxies,
the first ones formed after the Big bang and never observed before the advent of the Webb
Telescope, are expected to show a z of more than 15.
Since the universe is expanding in a relativistic space, it is very complex to uniquely define
the distance of a very distant galaxy. It all depends on our point of view.
Just an example: imagine that two galaxies are close to each other when the expanding
universe is only 1 billion years old. Assume now that the first galaxy emits a light
pulse, and the second galaxy receives the pulse after 14 billion years.
By that time, the light pulse will have traveled 13 billion years, the galaxies will be separated
by an effective distance of about 26 billion light years, and the hypothetical astronomers
of the second galaxy will have received an image of the first galaxy when it was only
1 billion years old! As can be seen, there are thus several ways
to consider distances and ages in an expanding universe, which sometimes leads to some confusion
when popularizers talk about "oldest galaxy" or "youngest," or "most distant"
For small distances (below about 2 billion light-years, where z is roughly equal to 1)
all the various distance scales converge and become the same, so it is much easier to define
the distances of galaxies in the local universe around us.
In the case of GNZ-11, the galaxy found by Hubble, the z equal to 11 means that light
from this galaxy has traveled 13.4 billion years between the time the light was emitted
and today. It also tells us that this same galaxy is
at this moment 32 billion light-years away from us and that the image recorded by Hubble
is that of a very young galaxy, formed about 300 million years after the Big Bang.
At first glance, the distance of 32 billion light-years might seem absurdly large in a
Universe that is only 13.8 billion years old. However, due to the expansion of the Universe,
the distance of 2.7 billion light-years that existed between GN-z11 and the Milky Way at
the time light was emitted increased by a factor of (z+1)=12 to measure 32.2 billion
light-years during the 13.4 billion years it took light to reach us.
Be that as it may, the fact that such a massive galaxy existed so soon after the first stars
began to form is to be considered a challenge to ii current theoretical models of galaxy
formation.
Then, in April 2022, HD1 was found, observed only from Earth with suitable infrared instrumentation.
This was a fluke, due to the object's intrinsic brightness and the very long exposure time
with which the image was captured. The result was a rather "strange" object since
it can only be an "outburst" galaxy, i.e., one capable of forming several giant stars
in a very short time (100 solar masses per year!) or a quasar, such as to indicate the
presence of a black hole of at least 100 million solar masses.
The redshift z was found to be 13.3, which is equivalent to saying that the object is
33.3 billion light-years away and that its light took 13.44 billion light-years to reach
us, starting 330 million years after the Big Bang.
If its age was just that, it would certainly not be easy to explain how it could have already
created stars so bright and at such a rate or, otherwise, how it could have already possessed
a black hole of such a size...
So much for the past. But, now, Webb has arrived. What is the big difference between Hubble
and ground-based telescopes? That it can collect much more light for the same exposure time
and that it can observe very well in the infrared up to wavelengths of 5 microns (as opposed
to Hubble's 1.6). In short, what used to be flukes may be much
more frequent and common occurrences for Webb. And indeed, even though he just started observing,
Webb was able to detect in his first Deep field two galaxies located almost the same
distance from HD1! But that was not the end of it... A few days
passed...and as part of the CEERS (Cosmic Evolution Early Release Science Survey) program,
the HD1 record was even shattered with the discovery of a galaxy - CEERS-93316 - showing
a z of 16.7! Such a high redshift tells us that the galaxy
light collected by Webb may have started just 233 million years after the Big Bang!
We use the conditional because. it is important to emphasize that these Webb measurements
are not spectroscopic in the strict sense of the word, as such objects are too faint
to record their spectra with a resolution that would allow us to highlight particular
lines in emission and absorption; which would allow us to clearly and unambiguously establish
the redshift. All the results announced so far are therefore
subject to possible alternative interpretations, even if unlikely, and we have no absolute
certainty about the magnitude of the redshift. However, the authors point out the non-stellar
appearance of these objects, further supporting their galactic nature,
Another objection put forward by the staunch defenders of the Big bang Theory is that these
galaxies could be "imposter galaxies," meaning that they could be such dust-rich objects
that their very high redshift could come from the resulting reddening rather than from their
distance. A team led by Jorge Zavala (National Astronomical
Observatory of Japan), even claims that this galaxy may actually have a much smaller redshift
of 5, corresponding to a galaxy only 12.6 billion years away in time...
In many of the articles that have been published so far commenting on these latest sensational
findings, the authors state that their results, if confirmed, could instead challenge the
standard model of cosmology, according to which the very first galaxies should have
formed no earlier than 300 million years after the Big Bang; and what is more, in the form
of very few extended, faint objects with few stars.
Instead, some of the remote galaxies found by Webb appear to be already highly evolved
in terms of structure, with some already containing about 1 percent of the mass of our galaxy;
and in numbers ten times larger than previously assumed.
Finally, studies of galactic chemistry also show a very complicated picture. An early
Deep field analysis carried out by Webb examined the light emitted by galaxies with a redshift
of 5 or higher, finding a surprising richness of heavy elements, such as oxygen.
This finding is again at odds with what the standard model predicts, according to which
the chemical enrichment process (in which stars fuse hydrogen and helium to form heavier
elements) should take much longer. More broadly, according to a large staff of
researchers, the first images produced by the Webb telescope would show dozens, hundreds,
perhaps even a thousand times more bright galaxies in the early universe than predicted
up to a month ago. And there is no way that so many large galaxies
could have been generated in such a short time...
In short, it certainly looks like James Webb Telescope is poised to rewrite the astrophysics
textbooks on which thousands of students have trained for years.
Are you also ready for the great revolution?