“Astronomers detect light from the Universe’s first stars” is the headline of a Nature news article, which appeared February 28, 2018.1 It relates to observations made by a team of astronomers led by Judd Bowman of Arizona State University in Tempe. The team published their results in Nature the same week.2 According to Bowman,
“This is the first time we’ve seen any signal from this early in the Universe, aside from the afterglow of the Big Bang.”
They used a small radio-telescope situated in the Western Australian desert, far away from human settlement to minimise interference from radio signals generated by human technology. (See Fig. 1.) The antenna was tuned to a waveband of about 78 MHz, which is at the low end of FM radio, so isolation from human generated radio signals was essential.
Figure 1: The small radio telescope in Western Australia used to detect evidence of light allegedly from the Universe’s first stars. Credit: CSIRO
To understand what the astronomers interpret from this research I quote an editorial summary from Nature:3
“As the first stars heated hydrogen in the early Universe, the 21-cm hyperfine line—an astronomical standard that represents the spin-flip transition in the ground state of atomic hydrogen—was altered, causing the hydrogen gas to absorb photons from the microwave background. This should produce an observable absorption signal at frequencies of less than 200 megahertz (MHz). Judd Bowman and colleagues report the observation of an absorption profile centred at a frequency of 78 MHz that is about 19 MHz wide and 0.5 kelvin deep. The profile is generally in line with expectations, although it is deeper than predicted. An accompanying paper by Rennan Barkana suggests that baryons were interacting with cold dark-matter particles in the early Universe, cooling the gas more than had been expected.”
Let’s look at this in two stages. What was observed and what is the interpretation of the recorded data. Continue reading
A news article in appeared in Science titled “It’s official: You’re lost in a directionless universe”1 where the author Adrian Cho reported on the results of a research paper published in Physical Review Letters in September 2016. That paper is available online as a preprint.2 In the online Science article the conclusion of the research is stated that
“For the first time, we really exclude anisotropy,” [the lead author] Saadeh says. “Before, it was only that it hadn’t been probed.”
Top image: CMB temperature anisotropies map from Planck satellite. Bottom image: Simulated image from one of the models used where a preferred axis was introduced. Credits: (Top to bottom) ESA and the Planck Collaboration; D. Saadeh et. al., zenodo
The research involved simulations on a supercomputer where various forms of anisotropic structure and expansion of the universe were introduced in modelled universes. The authors looked for how those would affect any putative patterns that might be observed in the cosmic microwave background (CMB) radiation. The design was to see what would produce anisotropy in the CMB temperature data. See illustration to the right.
They found that none of the patterns they produced are observed in the CMB data from the Planck satellite. Ok, so that solves it! The Universe is isotropic and therefore the fundamental assumption for the big bang model—that is, matter is distributed uniformly throughout the Universe, on the largest scales–is correct and hence it validates the choice of the standard ΛCDM big bang model to describe the Universe. Well, no, not actually.
Firstly, for that to be true it would have to be assumed that the authors modelled all possible sources of anisotropy in the Universe. It would also have to be assumed that the patterns they generated in their modelled CMB temperature anisotropies were, in fact, indicative of large scale structure in the real Universe. There is no independent way to test that. All that researchers have available to them is supercomputer modelling. So how can you know what the Universe should look like with different types of anisotropic distributions of matter? There are no other universes available except this one, therefore we are always limited by this fundamental uncertainty. Continue reading
Caltech cosmologist Ranga-Ram Chary claims that he may have found evidence for the existence of a parallel universe. Many online articles report this.1,2,3 His claim, published in the Astrophysical Journal, suggests some sort of “cosmic bruising” — one universe bumping up against another universe — could explain an anomaly he found in the map of the cosmic microwave background (CMB). The anomaly is in regards to a mysterious blob of light found in the CMB radiation, which allegedly is leftover radiation from the big bang.
USA Today reports:
Chary, a researcher at the European Space Agency’s Planck Space Telescope data center at CalTech, said the glow could be due to matter from a neighboring universe “leaking” into ours, according to New Scientist magazine.
“Our universe may simply be a region within an eternally inflating super-region,” scientist Chary wrote in a recent study in the Astrophysical Journal.
Notes of a lecture on the historical philosophical development of the notion that the universe is very old. The lecture was given August 1st 2015. See Age and Reason Seminar Adelaide for details.
Bishop James Ussher was the Irish Archbishop of Armagh and primate of all Ireland. He excelled in education, was fluent in Arabic and Hebrew. In 1654, after an exhaustive investigation, he published his date for the Creation of the Universe – 4004 B.C..1 When Ussher published this Creation date it was believed. There was nothing remarkable about that. If you add up the genealogies in the Bible, and with a bit of historical knowledge, you can easily get a time since the beginning of the world of around 6000 years. It was believed that God created the world as He said in Scripture about 4000 years before Christ. For roughly 18 centuries of the Christian era such a time period was widely believed.
In the 17th century Sir Francis Bacon developed the ideas of the modern scientific method – scientific empiricism—where one developed a thesis and did experiments to test it. Bacon has been called the ‘father of the scientific method.’
And it was from the Middle Ages science was nurtured in the Christian universities of Europe and flourished after that, from the Reformation on, underpinned by the rich Christian worldview that held that the Universe was created by a rational trustworthy God, and the unchanging laws of nature are His creation. Continue reading
As a high school student, at a time when I was an atheist, I co-authored a book reviewing the various cosmological models that were discussed in the scientific literature in 1968. That was three years after the discovery of the cosmic microwave background (CMB) radiation, and the Big Bang Theory had just made a big leap forward in front of its competitor at the time, the Steady State Theory.
In our book—which by the way won us second prize in a Western Australian state-wide science competition—we outlined the two competing models. The Big Bang Theory at that time had three distinct forms:
- the cycloidal model, which would collapse back into a big crunch (and bounce out of the singularity cyclically) because the matter density of the universe was too great to resist the inevitable re-collapse (a finite closed universe);
- the coasting model, which had just the right amount of matter for an infinite universe that is neither accelerating nor decelerating in its expansion, continually expanding but never collapsing (an open infinite universe); and
- the hyperbolic model, an accelerating expanding universe, low matter density but also driven apart by a cosmological constant term (an open and infinite universe).
The most favoured of the three was the closed cycloidal model with a matter density greater than critical so it had to collapse back in a big crunch. Nowadays it is the accelerating infinite (open) universe, which is spatially flat due to dark matter and dark energy content.
On reviewing these models, and even knowing that the CMB discovery favoured these as a prediction of the big bang theorists, particularly George Gamow, I personally favoured the Steady State Theory. The Steady State Theory really had only one model, which was an infinite universe that was eternal both into the past and into the future. It had no beginning and no ending. Continue reading
Dark sector physics and the sterile neutrino
Abstract: And God saw the light, that it was good: and God divided the light from the darkness. (Genesis 1:4) In this modern era darkness has developed a new meaning. From various problems in cosmology a need has developed to postulate the existence of unknown types of energy and matter from the dark side. These are sought for in the dark sector of particle physics and in the description of the expanding universe acted upon by gravitation. Besides dark energy and dark matter, now a new dark component is being promoted—dark radiation—in the form of a sterile neutrino, which does not interact with electromagnetic radiation or matter except via gravitation. This has come about because of the dichotomy that has occurred when the total mass of the universe has been measured using two quite different methods. But this new development underlines the problems that have developed in cosmology, especially when the model (paradigm) being considered is a clear departure from the historical account in Genesis. Article first published by Answers Research Journal 7 (2014):357–361. PDF available here.
Is something dark going on in cosmology? If you thought dark energy and dark matter were hard to understand (and justify), now a new component has been added to the dark side—dark radiation.
When astrophysicists measure the total amount of matter in the universe using different methods, and different data sets, it has been found that they get quite different answers. Continue reading
In March 2014 a team of astrophysicists announced to the world, through a public press release, that they had made the biggest discovery of the 21st century. Using the BICEP2, a telescope located at the South Pole they claimed that they had discovered evidence of the early inflation epoch of the big-bang universe. In several articles I mentioned that not only I but also other physicists doubted that this would bear out. Some suggested it was dust emission from within our galaxy that caused the particular B-mode polarization of the photons in the CMB, which was their claimed signature of the putative epoch of inflation.
Map showing the tiny variations in the cosmic microwave background (CMB) observed by Europe’s Planck satellite.
Credit: ESA/Planck Collaboration
Then it was revealed that the authors of the claimed biggest astrophysics discovery of the century admit they may have been wrong. On June 20th, 2014, the BICEP2 Collaboration published a paper published in Physical Review Letters,1 making their claim. It was 25 pages long but with a half-page disclaimer saying they might be wrong and they would have to wait the outcome of the data analysis of the Planck satellite team looking at the same region of the sky and the same frequencies.
Well, that has now been published, and it’s not good news for the BICEP2 team. Continue reading