Tag: astronomy

Sci Rev – II

it is November 18, 2025, as I begin this post. But now, as I continue, time has passed during which I’ve been trying to make sense out of the confusion which inevitably accompanies the early stages of a scientific revolution. It is now past Thanksgiving. That’s how it goes these days: Writing this blog is easily displaced by the many activities of my life and that is OK because occasions do arise when the busyness subsides and I can write and rewrite until what’s written feels right and can be posted.

In considering this revolution in our understanding of the cosmos one realization that I’ve had is the fact that this has been the only major scientific revolution in my lifetime, so it is a new experience for me and, in fact, for anyone who is concerned with it. The major revolution of our times, the quantum revolution, began to be resolved in 1925 and by the time I was born in 1929 the revolution was well on the way to completion. At that time the neutron hadn’t been discovered nor the positron (both discovered in 1932), but by the time I took chemistry in high school during the 1945-46 academic year the existence of these was well established, the neutron discovery leading to the atomic bomb, which had ended World War II just before that school term had begun. By the time I was trying to do physics during the early 1970’s, its cutting edge had moved on to understanding the elementary particles and “resonances” as they were experimentally discovered by increasingly energetic particle accelerators. I had a fairly good idea of what was going on as I understood how various representations of group SU3 made patterns which fit the new discoveries. In the early 70’s there were many puzzles, but nothing that called fundamental scientific realities into question. By the early 2020’s it had been 40 years or so since the “standard model” of particle physics came into being, and during those 40 years, its predictions were confirmed time and again with little hint of revolution on the horizon. In cosmology and astrophysics there were the puzzles of dark matter and dark energy, but no discoveries that were helpful in solving these puzzles. The physics and astronomy community was awaiting and hoping for a scientific revolution. Now, finally and suddenly, it is happening.

Since I have no access to any scientific journals (and likely wouldn’t understand their contents even if I did) my information about the new revolution comes from winnowing through writings on YouTube searching for gems among all the vague sensationalism. In addition, I can search the internet in the hopes of finding reliable sources and learning about subjects which are relevant for understanding what is happening.

Let me begin to make sense of this revolution by considering the cosmic microwave background radiation (CMB). This radiation has been well studied and it is difficult to find any weak links in its story. The radiation begins as high temperature black body radiation and as the universe expands, the radiation keeps the characteristic spectrum of black body radiation at an ever lowering temperature which stands today at 2.7 degrees above absolute zero. A beginning temperature for the radiation can be calculated by considering a typical ionization energy of atoms. A piece of well known background knowledge in atomic physics is that the ionization energy needed to free hydrogen’s single electron from its nucleus is 13.6 electron volts. If protons and electrons are in an environment where the average kinetic energy of particle motion is above this value, they are constantly bombarded by particles having more energy than needed to keep them apart: hydrogen atoms cannot exist.

In the latter part of the 19th century Ludwig Boltzmann discovered the remarkable connection between the average kinetic energy E of molecular motion and temperature T as measured by thermometers. A crude statement of his law is E = kT, the constant k being Boltzmann’s constant. Expressed in electron volts per degree Kelvin it has a value of 8.617 x 10¯5. To find the temperature below which hydrogen atoms can exist, you merely need to reach for your cell phone and its calculator. Enter 13.6, the divide symbol, and then 8.62. Pressing “=” gives 1.58 after rounding. Now move the decimal point 5 places to the right and get 158,000 degrees Kelvin or Celsius. (At this temperature the 273 degrees between the two is inconsequential.)

Above this temperature of around 160,000 degrees only the constituents of atoms exist in a plasma which bounces light around and is opaque. After the expansion of the universe lowers the temperature below this value, atoms form (mostly hydrogen) and space becomes transparent to the black body radiation of the former plasma and to any other radiating bodies which might be present. I’ve mentioned already in the first post about this revolution what astronomers expected; namely the very beginnings of galaxy formation, rather than well developed galaxies and primordial black holes mentioned in the last paragraph of the previous post. The latter are truly interesting because they suggest that the black holes in the center of galaxies, came about before the galaxies actually formed. The presence of black holes would speed up galaxy formation, but certainly not to the extent that JWST observed.

There are two obvious ways to avoid the dilemma posed by the impossible existence of mature galaxies and primeval black holes in an era when they shouldn’t exist. The first, and seemingly the less radical, is to push back the big bang by several billion years and assume that the early rapid inflation expansion didn’t occur, allowing time for developments before the cooling to energies allowing atom formation with its resulting transparency. If a tremendous amount of dark matter particles were created in the primeval explosion, these could cluster and form black holes. If energies remained in the mev range over a billions of years, there would be time for complex nuclei to form, much in the way we believe they form in stars. For this scenario to occur, the expansion rate of the universe would need to be slow enough to delay cooling. Since the recent conclusion that the Hubble constant for the universe expansion rate, isn’t a constant at all, but a field with different values throughout the universe, the idea of an expansion at a slow rate in the early days of the universe isn’t impossible. Let us call this scenario (with apologies to Texas) the Lone Star Universe.

A second way our of the dilemma is to assume that our universe didn’t arise our of nothingness, but issued instead, from the collapse of a predecessor universe into a “big crunch” with rebound. This scenario postpones the account of how a universe could arise out of nothingness to a day when we have a deeper understanding of physics. With this idea we avoid the idea of a singularity, always a troubling notion in physics, imagining instead a condensation of the prior universe only to the extent that its matter would be raised above a temperature where atomic nuclei would disintegrate into elementary particles including many we have not found yet. As this proto universe rebounds and expands, its elementary particles would decay into stable ones, including perhaps axions of dark matter. An interesting question concerns the fate of the massive black holes that formerly existed in the center of the old universe’s galaxies. Assuming that black holes are already compressed as much as possible, there could be no force which could disrupt them. A problem arises because if the volume of our universe in its early days is limited, billions of black holes from the previous universe would likely collide and coalesce forming galaxy centers larger that those we observe. If we can sweep this problem under a rug, we have a ready explanation of the primeval black holes and well formed galaxies that JWST has observed.

Of course, both scenarios outlined above are quite speculative. These days as the fact of a revolution is becoming more and more accepted, it is the hay day of the experimentalist making astronomical observations, finding the hard evidence that will ultimately lead to a new picture of reality for our universe. Much of this work now revolves around the expansion rate of the universe, the Hubble “no longer constant”. Since much of of our current picture assumes that this rate of expansion is everywhere the same, the shattering of this assumption is finally making it clear that we really are in the midst of a scientific revolution quite apart from the findings of the James Webb Space Telescope. I’ll mow bring this post to a conclusion and continue to search for interesting findings which will occur in the future. Back to Top

A Scientific Revolution

Crisis in fundamental science is disconcerting because it shakes up and disintegrates the very foundation of what we take to be reality. In Kuhn’s Structure of Scientific Revolutions while various revolutions are closely analyzed, we, as readers, know how these turned out because they were historic with a known future. Experiencing an actual revolution, not knowing what the future will bring, is similar to a Zen experience in which the foundations of everyday reality are ripped apart. We are, in a sense, left floating in space in an unknown galaxy in which there are no directions, no up-and-downs, no supports. One can learn to welcome this sort of experience because one knows that we humans, for all our factual knowledge, are ignorant of an actual fundamental reality; and experiencing this ignorance is a signpost on the way to enlightenment, assuming such exists.

In cosmology our reality until this year was that the universe had an age of around 13.8 billion years, beginning with a “big bang” which created the universe including its space and time out of nothingness. See the post Weird Stuff: Cosmology, etc. for the story of how this picture came about. As of now (Mid-2025) this picture must be abandoned and things are about to become really weird.. It is too soon to know what will replace the “big bang” theory. Fortunately, what we know about the universe has not been completely discredited: There are still stars, galaxies, neutron stars, black holes, supernovas and the rest of the amazing entities that we observe with optical telescopes on earth and the Hubble telescope in space. General Relativity still seems to predict accurately though, these days, it is far from being taken for granted. What’s new is that data is coming in from the James Webb space telescope. This miracle instrument was a huge dare which has panned out. (When a scientific project screws up, there’s a lot of publicity and adverse comment. When a daring project which has every expectation of failure works out, it gets the “ho-hum” treatment at least by the general public.)  This JWST (James Webb Space Telescope) was designed to be revolutionary and has lived up to its goal. For a complete detailed description, one should consult Wikipedia. The telescope has a mirror too large to be launched in one piece by our present rockets. Instead, over the years since its launch on Christmas day, 2021, the mirror was unfolded and then assembled to an unholy precision out in space from 18 hexagonal pieces. It sits at a distance further out than the moon, circling around what is called a Lagrange point where gravity from the sun, earth, and moon balance out. The telescope became operational in early 2024 and has now been accumulating data for over a year. The telescope is sensitive to long-wave infrared, in a range running from a visible 600 nanometer reddish-orange to a mid-infrared at 28,500 nm. This range allows the telescope to see back to a realm where objects are red-shifted beyond the limits of human vision; objects existing in what we supposed were the early times in the universe after its temperature cooled to where it became transparent. Infrared is heat radiation. The telescope must accordingly be cooled to a temperature below 50 Kelvin (-223 degrees Celsius) so its own thermal radiation won’t wipe out the signal it is detecting.

Cosmologists and astronomers were exited to see what the new JWST telescope would reveal in the eight-hundred million year gap between the time when the universe became transparent 200 million years after the “Big Bang” and the time about 1000 miillion years after the bang (a billion years) that the Hubble telescope could see back to. The prevailing picture at the time around 2023 before JWST became active was that as hydrogen, helium, and a few lithium atoms formed, they would clump under gravity’s influence and would become the first stars as the pressure and temperature at their centers became sufficient to ignite a fusion reaction. The resulting stars, in turn, would cluster into blobs which would, after a 5 or 6 billion year process, form the galaxies that Hubble had been able to detect. The expectation was that there wouldn’t be all that much to detect in the gap.

Instead, the first startling thing JWST found were many huge, fully formed and structured galaxies. By measuring their red shift their ages were found to be only 3 to 5 or 6 hundred million years after the “Big Bang”, well within the gap. That they were really galaxies was confirmed by detecting the spectral lines of hydrogen. Galaxies which would take 5 or 6 billion years to form were found within a few hundred millions years of the purported “Big Bang”. Even more startling were primeval black holes such as exist at the center of galaxies. However, the star were missing and the black holes unclothed. Something was drastically wrong with the enormous amount of work which had established modern cosmology. And this was only the beginning. The revolution was under way.


I’ll bring this piece to an end and post it. I’ll have much to write about in the future. Back to Top