Engaging Essays In Cosmology by A. Tomilin

 

About the Book

A book of essays and short stories in three parts and ten chapters about the people and the achievements of the great science of the structure and development of the Universe from antiquity to the present day, composed and written on the basis of many sources by the author.

About the Author

A. Tomilin is a lecturer at an institute. Engaging Essays on Cosmology is not the first book by this author.

Young readers have repeatedly encountered his name in the pages of journals and popular
science collections. Several works have come from his pen, published by the “Children’s
Literature” publishing house, including the booklet For What – Nothing, written in
collaboration with N.V. Terebinskaya, the book Project Alpha K–2, as well as the book Engaging Essays on Astronomy, issued by “Molodaya Gvardiya.”

This English translation of the book in English by Damitr Mazanav, has an extended epilogue containing exciting new discoveries the theories from 1970s to 2026 that have fundamentally changed our views about Universe.

Translated from the Russian and typeset in LaTeX by Damitr Mazanav using Quattrocento

Illustrations: G. Kovanov and V. Kovynev

This English translation released on the Web by The Mir Titles Project in 2026
under Creative Commons Share Alike 4.0 License.

You can get the book here and here

Translator’s Note

This is the fourth book I am translating the Eureka series. The author A.N.~Tomilin has written several popular science books. We have earlier seen his book on cosmogony, titled Fascinating Cosmogony. This book is on a related theme of Cosmology. I was first introduced to ideas of cosmology and general relativity during my masters. Since then, the idea that we can infact study and make sense of the origins and structure of the universe at the largest scale have fascinated me. Translating this book in many ways was refreshing some of the ideas of cosmology and general relativity that I had learned. The quote by Corliss is indicative of how with limited data, we here on Earth, an insignificant part of the universe can make sense of it at all, constructing theories that will make sense of what we observe.

Since the book was written in 1971, several speculative hypotheses presented in the book have not been supported by data. To indicate this, at some places I have added sidenotes with my initials “DM”. I have also added an \textbf{Epilogue: Cosmology as of 2026} which summarises some of the major landmarks in the themes discussed since the book was written in 1970s. Another change that I have added is to give the chapters descriptive titles. Originally, the chapters were just numbered, but I thought giving descriptive titles would be a better choice.

The reader will occasionally encounter brief, aphoristic remarks attributed to Kozma Prutkov in the last chapter. These are not incidental embellishments, but deliberate inclusions. Kozma Prutkov was not a single individual, but a fictional author created in nineteenth-century Russia by a group of writers, including Aleksey Tolstoy and the Zhemchuzhnikov brothers. Presented as a pompous yet self-assured thinker, Prutkov’s writings consist of concise maxims, paradoxes, and satirical observations on knowledge, reason, and human pretension.

At first glance, such a figure may seem out of place in a discussion of cosmology. Yet the inclusion is not without purpose. Scientific inquiry, particularly in a field as vast and abstract as cosmology, carries with it a natural tendency towards overconfidence in models, measurements, and interpretations. Prutkov’s aphorisms serve as a quiet counterpoint to this tendency. They remind us — often with a touch of irony — that clarity is hard-won, that appearances can mislead, and that systems of thought, however elegant, may conceal their own limitations.

There is also a more practical reason. Cosmology deals with scales and concepts far removed from everyday experience. At such distances, both literal and intellectual, language can easily become either overly technical or excessively grand. A well-placed aphorism has the virtue of restoring proportion. It compresses an idea into a form that can be held in mind, even as the surrounding discussion expands beyond immediate intuition.

The remarks of Kozma Prutkov are therefore included not as commentary on specific results, but as companions to them. They are meant to be read not as authorities, but as provocations — brief interruptions that invite the reader to pause, reflect, and occasionally question the very framework within which the narrative unfolds. Mistakes and omissions (and I am sure they will be there), if any, are my own.

Contents

Translator’s Note vii
Instead Of An Introduction xvii

I. People 1

1. The Miletus Manifesto 3

1.1. When the Earth Was Flat… 4
1.2. In the Homeland of Science .
1.3. Thales of Miletus 11
1.4. Heraclitus of Ephesus 21
1.5. Philosophy + Mathematics = ? 24
1.6. Elea: Xenophanes and Parmenides 31
1.7. Zeno of Elea and His Paradoxes 35
1.8. The Atomists 40
1.9. Summa summarum of Greek materialism 43

2. The Philosopher King of Physics

2.1. Aristotle 47
2.2. The Triumph of Aristotelianism 53
2.3. At the Decline of Classical Greco-Roman Culture 58
2.4. Zigzag of History 64
2.5. Flames of Bonfires Do Not Dispel the Night 67
2.6. The Principles of Papal Infallibility 70
2.7. The Catholic Church and Progress 75
2.8. The Middle Ages and Technology 80

3. From Cusa to Calculus 89

3.1. Nicholas of Cusa 91
3.2. Cosmological Rubicon 96
3.3. The Immortality of the Great Heretic 102
3.4. Eppur si muove!. 110
3.5. René Descartes (Cartesius) 124
3.6. Isaac Newton 132
3.7. How Useful It Is When There Are No Great Discoveries 136
3.8. Newton’s Apple 142
3.9. The Universe of Sir Isaac 148

II. Successes and Doubts 157

4. The Star-Struck Philosophers 159

4.1. The World in Lomonosov’s Hands 162
4.2. The Universe as a System — Early Speculations 166
4.3. Immanuel Kant — Natural Philosopher 170
4.4. Epilogue of the Philosopher’s Life 178
4.5. Johann Lambert 183
4.6. William Herschel 187

5. The Dark Night of the Paradox 195

5.1. Olbers’ Paradox 198
5.2. Knights of the “Heat Death” 203
5.3. Hugo von Seeliger 210
5.4. A Celestial Census Saves the Situation 213

6. The Copernicus of Curves 219

6.1. What Euclid Taught 222
6.2. The King Midas of the Land of Mathematics 229
6.3. Visiting the Flatfolk 235
6.4. Gauss’s “Magnificent Theorem” 241
6.5. The Copernicus of Geometry 245
6.6. The Real Construction of the “Imaginary World”256
6.7. The Astonishing Spaces of Bernhard Riemann 261

III. Ideas 269

7. The Symphony of Space-Time 271

7.1. Can a “Decisive Experiment” Fail? 273
7.2. Overture to the Symphony of Relativity 279
7.3. In Search of the Harmony of the Universe 286
7.4. The Fourth Dimension 293
7.5. Special Theory of Relativity 302
7.6. The next step was inevitable… 305
7.7. “Look!” 314

8. The Priest, the Prize, and the Point of Origin 331

8.1. Nineteen Hundred And Seventeen, February 332
8.2. “I Only Solve The Equations” 342
8.3. Yet Another Great Discovery 354
8.4. Horizons of the Universe 365
8.5. Father Georges Solves Equations 369
8.6. Genius of George Gamow 372
8.7. “Big Bang” 377

9. A Journey Along the t-Axis 387

9.1. From “Radio Stars” to Star-like Objects 389
9.2. Quasars, or What Practice Does to Theory 395
9.3. A Journey Along the t-Axis 399
9.4. The Universe, the Year 1971 407

10. The Battle for the Soul of the Cosmos 413

10.1. When an Idea Is Not Mad Enough 415
10.2. Kabbalistics of the Twentieth Century 424
10.3. Matter + Antimatter = ? 434
10.4. The Battle of Ideas Continues 441
10.5. What Is the Universe? 446

IV. Epilogue: Cosmology as of 2026 453

11. The Dark Side of the Cosmos 455

11.1. The Mystery of the Missing Mass 457
11.2. A Hi-Res Echo of the Beginning 460
11.3. WMAP and the Age of Precision 465
11.4. Planck: The Ultimate Map (So far…) 467
11.5. Seconds after the Bang 470
11.6. The Cosmic Web: The Universe Draws Its Own Map 474
11.7. The Sloan Digital Sky Survey 476
11.8. Dark Energy and the Runaway Universe 479
11.9. The Hubble Deep Field 483
11.10. Hearing the Black Holes 487
11.11. The Future of the “t-Axis” 490
11.12. The Hubble Tension 496
11.13. The Next Horizon: The Engines of Discovery 499
11.14. The Mathematical Horizon 503
11.15. Concluding Thoughts 504

#Ccbysa #Oer #astronomy #bigBangTheory #cosmicMicrowaveBackground #cosmology #damitrMazanav #einstein #galaxies #galileo #historyOfAstronomy #historyOfScience #ideasAboutTheUniverse #largeScaleStructure #newton #popularScience #relicRadiation #sovietLiterature #translation

📄 Five-Year Wilkinson Microwave Anisotropy Probe Observations: Cosmolog…

Quicklook:
Komatsu, E. et al. (2009) · The Astrophysical Journal Supplement Series
Reads: 337 · Citations: 5408
DOI: 10.1088/0067-0049/180/2/330

🔗 https://ui.adsabs.harvard.edu/abs/2009ApJS..180..330K/abstract

#Astronomy #Astrophysics #Cosmology #CosmicMicrowaveBackground #CosmologyObservations

Five-Year Wilkinson Microwave Anisotropy Probe Observations: Cosmological Interpretation

The Wilkinson Microwave Anisotropy Probe (WMAP) 5-year data provide stringent limits on deviations from the minimal, six-parameter Λ cold dark matter model. We report these limits and use them to constrain the physics of cosmic inflation via Gaussianity, adiabaticity, the power spectrum of primordial fluctuations, gravitational waves, and spatial curvature. We also constrain models of dark energy via its equation of state, parity-violating interaction, and neutrino properties, such as mass and the number of species. We detect no convincing deviations from the minimal model. The six parameters and the corresponding 68% uncertainties, derived from the WMAP data combined with the distance measurements from the Type Ia supernovae (SN) and the Baryon Acoustic Oscillations (BAO) in the distribution of galaxies, are: Ω<SUB> b </SUB> h <SUP>2</SUP> = 0.02267<SUP>+0.00058</SUP> <SUB>-0.00059</SUB>, Ω<SUB> c </SUB> h <SUP>2</SUP> = 0.1131 ± 0.0034, Ω<SUB>Λ</SUB> = 0.726 ± 0.015, n<SUB>s</SUB> = 0.960 ± 0.013, τ = 0.084 ± 0.016, and Δ_{R}^2 = (2.445± 0.096)× 10^{-9} at k = 0.002 Mpc<SUP>-1</SUP>. From these, we derive σ<SUB>8</SUB> = 0.812 ± 0.026, H <SUB>0</SUB> = 70.5 ± 1.3 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP>, Ω<SUB> b </SUB> = 0.0456 ± 0.0015, Ω<SUB> c </SUB> = 0.228 ± 0.013, Ω<SUB> m </SUB> h <SUP>2</SUP> = 0.1358<SUP>+0.0037</SUP> <SUB>-0.0036</SUB>, z <SUB>reion</SUB> = 10.9 ± 1.4, and t <SUB>0</SUB> = 13.72 ± 0.12 Gyr. With the WMAP data combined with BAO and SN, we find the limit on the tensor-to-scalar ratio of r < 0.22(95%CL), and that n<SUB>s</SUB> > 1 is disfavored even when gravitational waves are included, which constrains the models of inflation that can produce significant gravitational waves, such as chaotic or power-law inflation models, or a blue spectrum, such as hybrid inflation models. We obtain tight, simultaneous limits on the (constant) equation of state of dark energy and the spatial curvature of the universe: -0.14 < 1 + w < 0.12(95%CL) and -0.0179 < Ω<SUB> k </SUB> < 0.0081(95%CL). We provide a set of "WMAP distance priors," to test a variety of dark energy models with spatial curvature. We test a time-dependent w with a present value constrained as -0.33 < 1 + w <SUB>0</SUB> < 0.21 (95% CL). Temperature and dark matter fluctuations are found to obey the adiabatic relation to within 8.9% and 2.1% for the axion-type and curvaton-type dark matter, respectively. The power spectra of TB and EB correlations constrain a parity-violating interaction, which rotates the polarization angle and converts E to B. The polarization angle could not be rotated more than -5fdg9 < Δα < 2fdg4 (95% CL) between the decoupling and the present epoch. We find the limit on the total mass of massive neutrinos of ∑m <SUB>ν</SUB> < 0.67 eV(95%CL), which is free from the uncertainty in the normalization of the large-scale structure data. The number of relativistic degrees of freedom (dof), expressed in units of the effective number of neutrino species, is constrained as N <SUB>eff</SUB> = 4.4 ± 1.5 (68%), consistent with the standard value of 3.04. Finally, quantitative limits on physically-motivated primordial non-Gaussianity parameters are -9 < f <SUP>local</SUP> <SUB>NL</SUB> < 111 (95% CL) and -151 < f <SUP>equil</SUP> <SUB>NL</SUB> < 253 (95% CL) for the local and equilateral models, respectively. <P />WMAP is the result of a partnership between Princeton University and NASA's Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team.

ADS

🌌 In 1964, persistent radio static led to a breakthrough: the cosmic microwave background, the universe’s oldest observable light, released about 380,000 years after the Big Bang.

📡 From ~3,000 Kelvin to ~2.7 Kelvin, CMB ripples seeded galaxies. Peaks reveal: ~5% ordinary matter, ~27% dark matter, ~68% dark energy.

✍️ Decode the whisper: https://TPC8.short.gy/hA9OwNxb

✨ We live inside the afterglow of everything.

#CMB #CosmicMicrowaveBackground #Cosmology #BigBang #Astronomy #Physics #Space #TPC8

Weekly Update from the Open Journal of Astrophysics – 22/11/2025

It’s Saturday again, so it’s time for the usual update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published another five papers, which brings the number in Volume 8 (2025) up to 180, and the total so far published by OJAp up to 415.

The first paper to report this week is “Probing Anisotropic Cosmic Birefringence with Foreground-Marginalised SPT B-mode Likelihoods” by Lennart Balkenhol (Sorbonne Université, France), A. Coerver (UC Berkeley, USA), C. L. Reichardt (U. Melbourne, Australia) and J. A. Zebrowski (U. Chicago, USA). This paper was published on Monday November 17th in the folder Cosmology and Nongalactic Astrophysics. It presents a way of using data from the Souh Pole Telescope (SPT) in the CMB-lite framework to constrain the level of cosmic birefringence.  The overlay is here:

You can find the officially accepted version on arXiv here and the The Fediverse announcement is here:

Open Journal of Astrophysics

@[email protected]

New Publication at the Open Journal of Astrophysics: "Probing Anisotropic Cosmic Birefringence with Foreground-Marginalised SPT B-mode Likelihoods" by Lennart Balkenhol (Sorbonne Université, France), A. Coerver (UC Berkeley, USA), C. L. Reichardt (U. Melbourne, Australia) and J. A. Zebrowski (U. Chicago, USA)

https://doi.org/10.33232/001c.147459

November 17, 2025, 8:43 am 1 boosts 0 favorites

The second paper of the week is “Radio Observations of a Candidate Redback Millisecond Pulsar: 1FGL J0523.5-2529” by Owen. A. Johnson & E. F. Keane (Trinity College Dublin, Ireland), D. J. McKenna (ASTRON, NL), H. Qiu (SKAO, UK), S. J. Swihart (Insitute for Defense Analyses, USA), J. Strader (Michigan State U., USA) and M. McLaughlin (West Virginia U., USA). This one was published on Tuesday November 18th 2025 in the folder marked High-Energy Astrophysical Phenomena and it describes a search for radio emission from a candidate “redback pulsar” J0523.5-2529 resulting in upper limits but no detection.

The overlay is here:

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

@[email protected]

New Publication at the Open Journal of Astrophysics: "Radio Observations of a Candidate Redback Millisecond Pulsar: 1FGL J0523.5-2529" by Owen. A. Johnson & E. F. Keane (Trinity College Dublin, Ireland), D. J. McKenna (ASTRON, NL), H. Qiu (SKAO, UK), S. J. Swihart (Insitute for Defense Analyses, USA), J. Strader (Michigan State U., USA) and M. McLaughlin (West Virginia U., USA)

https://doi.org/10.33232/001c.147516

November 18, 2025, 8:42 am 1 boosts 0 favorites

Next one up is “The role of turbulence in setting the phase of the ISM and implications for the star formation rate” by Tine Colman (Université Paris-Saclay, France) and 13 others based in France, Germany, Italy and the UK. This was published in the folder Astrophysics of Galaxies on Tuesday November 18th. It descrtibes using a suite of stratified box simulations to explore the link between star formation, turbulence and the thermal state of the multi-phase interstellar medium (ISM).

The overlay is here:

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

@[email protected]

New Publication at the Open Journal of Astrophysics: "The role of turbulence in setting the phase of the ISM and implications for the star formation rate" by Tine Colman (Université Paris-Saclay, France) and 13 others based in France, Germany, Italy and the UK.

https://doi.org/10.33232/001c.147517

November 19, 2025, 8:19 am 0 boosts 0 favorites

The fourth paper of the week is “A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II” by Alice M. Luna (U. Chicago, USA) and 8 others based in the USA, Korea and Canada. This was published on Wednesday November 19th in the folder Astrophysics of Galaxies. It decribes low-resolution Magellan/IMACS spectroscopy of 167 stars in the ultra-faint galaxy Reticulum II, revealing a clearly bimodal distribution.

The overlay is here:

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

@[email protected]

New Publication at the Open Journal of Astrophysics: "A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II" by Alice M. Luna (U. Chicago, USA) and 8 others based in the USA, Korea and Canada.

https://doi.org/10.33232/001c.147696

November 19, 2025, 8:37 am 0 boosts 0 favorites

The fifth and final paper for this week is “Cool Gas in the Circumgalactic Medium of Massive Post Starburst Galaxies” by Zoe Harvey, Sahyadri Krishna, Vivienne Wild & Rita Tojeiro (U. St Andrews, UK) and Paul Hewett (U. Cambridge, UK). This was published on Thursday November 20th in the folder Astrophysics of Galaxies.

The overlay is here:

The officially accepted version can be found on arXiv here. The Fediverse announcement is here:

Open Journal of Astrophysics

@[email protected]

New Publication at the Open Journal of Astrophysics: "Cool Gas in the Circumgalactic Medium of Massive Post Starburst Galaxies" by Zoe Harvey, Sahyadri Krishna, Vivienne Wild & Rita Tojeiro (U. St Andrews, UK) and Paul Hewett (U. Cambridge, UK)

https://doi.org/10.33232/001c.147836

November 20, 2025, 9:02 am 1 boosts 0 favorites

And that concludes the update for this week. I will do another next Saturday.

#arxiv250303305v4 #arxiv250616462v2 #arxiv250622287v3 #arxiv250815435v2 #arxiv251007928v2 #astrophysicsOfGalaxies #cosmicBirefringence #cosmicMicrowaveBackground #cosmologyAndNongalacticAstrophysics #diamondOpenAccess #diamondOpenAccessPublishing #highEnergyAstrophysicalPhenomena #interstellarMedium #openAccess #openJournalOfAstrophysics #polarization #redbackPulsar #reticulumIi #spectroscopy #theOpenJournalOfAstrophysics #turbulence #ultraFaintDwarfGalaxy

Anomaly in the Cosmic Microwave Background That Nobody Can Explain - YouTube
https://www.youtube.com/watch?v=9ncjebD_Bpc

#Astronomy #Cosmology #CMB #CosmicMicrowaveBackground

Anomaly in the Cosmic Microwave Background That Nobody Can Explain

YouTube

R.I.P. George F. Smoot (1945-2025)

George F. Smoot (1945-2025)

I’m very sad to have to report the death, at the age of 80, of eminent cosmologist George Smoot, who passed away at his home in Paris on 18th September. The news has been reported in France, where George had been living in recent years, but doesn’t seem to have been covered in the international media yet. I thought I would just record some personal relfections and reminiscences here, rather than try to pre-empt the official biographies.

George Smoot was an experimental astrophysicist who is best known for his research in observational cosmology, particularly on the cosmic microwave background. In 2006, jointly with John Mather, he was awarded the Nobel Prize for Physics for measurements made by the COBE satellite that, without exaggeration, ushered in a new era of cosmology. George led the paper Structure in the COBE Differential Microwave Radiometer First-Year Maps that reported the first detection of variations in temperature of the cosmic microwave background across the sky predicted by theories of cosmological structure formation.

I was fortunate enough to meet George many times over the years and to get to know him quite well. The first time was at a meeting in Durham for which this was the conference photo:

George is just to the left of centre in the front row with the red-and-white sweater.

What I remember about that meeting is that I gave a contributed talk there (a short one, because I was a mere postdoc at the time). Some time after that, George Smoot gave an invited talk during the course of which he mentioned (positively) the work I had spoken about. I was gobsmacked to have my little contribution recognized by someone so eminent, and it did wonders for my scientific self-confidence. I got the chance to have a conversation with George in person some time later at that meeting and found him very good value: he was both interesting and amusing to talk to. He was someone who took mentorship seriously, and didn’t confine it to those people he was working with directly.

Over the years I met George regularly at scientific meetings, including numerous times at the (then) Daniel Chalonge schools in Sicily and in Paris where we often chatted about science and other things over coffee breaks and dinner. I always found him hugely knowledgeable about many things, but he also had an almost child-like curiosity about things he didn’t previously know. He didn’t quite jump up and down with excitement when he learnt something interesting, but almost. He could also be very direct when disagreeing, which meant that some people found him a bit abrasive. He fell out with other members of the COBE time when he threw away the agreed protocol for the announcement of results in 1992. That caused a lot of bad feeling at the time, but it seems that by the time the Nobel Prize was awarded, some degree of reconciliation had been achieved. I was lucky enough to attend the Prize Ceremonies and at the ball afterwards chatted with both George and John Mather who seemed on very amiable terms then.

Anyway, in the early noughties George invited me to spend some time at the Lawrence Berkeley Laboratory, a visit that I enjoyed enormously. He was a very generous and thougtful host and I was looked after very well. One day at LBL he asked me if the hotel was OK. I replied that it was, but one thing I didn’t like about staying in a hotel was that I liked to cook and that was impossible in a hotel room. I thought nothing more of that conversation until the end of the day when George appeared and asked me if I wanted to “do dinner” at his house that evening. I answered in the affirmative so he drove me to his house, which was very fancy, set into the hillside overlooking Berkeley – like the sort of place I imagine a film star would live – and had a very large and well-provisioned kitchen.

It soon became clear that I’d misunderstood the invitation, in that “do dinner” didn’t mean “eat dinner” but “make dinner”. Although I was slightly taken aback I set about finding what he had in the refrigerator and on the shelves. There being a plentiful supply of spices, I decided to make a tandoori-style dish of chicken baked with yoghurt, with a couple of side dishes, none of which took long to cook. When everything was getting ready I wanted to add some lemon juice but couldn’t find any lemons in the fridge. I asked George if he had any lemons, at which point he showed me into the garden where he had several lemon trees in full fruit. I’ve never lived anywhere that this would be possible! I think he enjoyed the dinner because he paid me back a few days later with a dinner at Chez Panisse. He was quite the bon viveur.

(After that short visit, I was planning to spend a sabbatical year in Berkeley in 2005, but the United States Embassy in London put paid to that idea and I went to CITA in Toronto instead.)

The last encounters I had with George were online; he was in the audience when I gave talks in the Chalonge-de Vega series organized by Norma Sanchez in 2021 (here and here). I think he had already moved to Paris by that time. The first of these talks was about open access publishing in astrophysics; George subsequently co-authored a paper in the Open Journal of Astrophysics.

My favourite quote from George came during a discussion we had at Berkeley when I suggested that some methods used for studying the cosmic microwave background could be applied to the distribution of galaxies. His response was “Galaxies are shit”. To avoid offending my friends who work on galaxies, what he meant by that was that he thought galaxies were too messy for any statistical measurements to sufficiently reliable to compete with the CMB. I think he would have preferred a universe in which all galaxies were identical, like electrons.

I’m sure many others will have their own personal reflections on their interactions with George Smoot, but he also had a huge influence on many people who never met him personally, through his enormous contributions to astrophysics and cosmology. We will no doubt read many professionally-written official obituaries in days to come, but all I can say in a personal blog post is that he was a character, a very original thinker, a fine scientist, and a very nice man. Along with many others, I will miss him enormously.

Rest in Peace, George Fitzgerald Smoot III (1945-2025) .

Update: Here is an `In Memoriam’ piece from from the Berkeley Lab.

#COBE #CosmicBackgroundExplorer #CosmicMicrowaveBackground #GeorgeSmoot #JohnMather #largeScaleStructureOfTheUniverse #NobelPrizeForPhysics2006

No More CMB-S4…

There was some sad news for cosmologists last week in that the Government of the United States of America – specifically the National Science Foundation (NSF) and the Department of Energy (DOE) – has cancelled the next generation of ground-based cosmic microwave background experiments, called CMB-S4. This would have been the fourth generation This would have consisted of several dedicated telescopes equipped with highly sensitive superconducting cameras.

The plan was that these telescopes would spend about seven years listening to the microwave sky at two locations already recognized for their suitability: the South Pole, which was to host several telescopes of varying sizes to observe across a wide range of microwave frequencies; and the Atacama Plateau in Chile, a high-desert site which would have hosted two large telescopes that can also observe several different frequencies. The South Pole telescopes were to conduct an ultra-deep survey of 3% of the sky, while the Atacama telescopes would conduct a complementary ultra-wide and deep survey of 70% of the sky. Together, the two sites promised to provide a dramatic leap forward in our understanding of the fundamental nature of space and time and the evolution of the Universe.

Longstanding readers of this blog will remember that in 2014 the BICEP2 experiment at the South Pole was claimed to have detected the B-mode polarization signal that would be a diagnostic of primordial gravitational waves generated during a burst of cosmic inflation. That result was later shown to be dominated by Galactic dust emission which could not be identified from its spectral properties, as BICEP2 operated at only one frequency. With an order of magnitude more detectors than previous ground-based CMB experiments, wider frequency coverage, and better control of systematic errors, CMB-S4 would have reduced the limits on earlier observations by a factor of five, enabling either the direct detection of primordial gravitational waves or ruling out large classes of inflationary models and dramatically impacting current thought on cosmic inflation.

For more technical information about CMB-S4 see the 2021 White Paper here.

Despite its very strong science case, and the fact that it was ranked as second-highest priority in the 2020 Decadal Survey, it seems that CMB-S4 is no more. Sad.

#2020DecadalSurvey #AtacamaDesert #CMBS4 #CosmicMicrowaveBackground #Cosmology #SouthPole #Stage4CosmicMicrowaveBackgroundExperiment

The Cosmic Poltergeist

Last night I stayed up long past my usual bedtime to watch the film Poltergeist. This film, about the haunting of a family house by malevolent spirits, was a huge hit when it came out in cinemas back 1982, and I was interested to see how well it has endured. I think it stans up pretty well actually. The special effects could be done better nowadays, but it is still credibly scary.

The idea of a poltergeist is not new, but the film cleverly combines the old legends with new technology, in the way that the first manifestation of an evil presence is through a TV set. It is the youngest child of the house in question, Carol Anne, who is able to detect the ghosts when all we can see on the screen is static. The implication is that the young are the most receptive to paranormal phenomena.

Most of the static produced in a TV set when it is not tuned to a broadcast frequency is produced by thermal noise in the receiver, but around 1% of it comes from the cosmic microwave background (CMB). I’ve used static on a TV screen as a gimmick in public lectures on several occasions, with the joke that it may only be 1% but the birth of the Universe is far more interesting than most things you can see on TV!

The CMB is a ghost of the Big Bang. Watching Poltergeist last night, it occurred to me that when cosmologists study this relic radiation, we are all a bit like Carol Anne, trying to make sense of an eery presence that is always with us, but is barely perceptible. Such studies involve extensive use of spectral analysis.

This line of thinking led me to my new theory of the Universe. Perhaps it was built on the remains of an earlier, deceased Universe which is now trying to make contact this one in order to wreak revenge for the violation of its grave…

#CosmicMicrowaveBackground #Cosmology #Poltergeist

The Shaw Prize for Astronomy 2025

Dick Bond (left) and George Efstathiou (right)

I’m a few days late on this, as the announcement on 27th May came at a very busy time, but it’s a pleasure to pass on the news that the 2025 Shaw Prize for Astronomy has been awarded to Dick Bond and George Efstathiou. Congratulations to both on a very well deserved award!

The full citation can be found here, but the first paragraph reads:

The Shaw Prize in Astronomy 2025 is awarded in equal shares to John Richard Bond, Professor of the Canadian Institute for Theoretical Astrophysics and University Professor at the University of Toronto, Canada and George Efstathiou, Professor of Astrophysics at the University of Cambridge, UK for their pioneering research in cosmology, in particular for their studies of fluctuations in the cosmic microwave background. Their predictions have been verified by an armada of ground-, balloon- and space-based instruments, leading to precise determinations of the age, geometry, and mass-energy content of the universe.

One of the first papers I was given to read when I started my postgraduate studies in 1985 was the pioneering Bond & Efstathiou (1984) “Cosmic background radiation anisotropies in universes dominated by nonbaryonic dark matter”. Here is the abstract:

This work was hugely influential and prescient in many ways. It does remind me, though, that in the 1980s, before the detection of large-scale anisotropies by the Cosmic Background Explorer (COBE) announced in 1992, the prevailing mentality was to find models in which the predicted cosmic microwave background anistropies were as small as possible. The COBE fluctuations turned out to be rather larger than those predicted in the model discussed in the paper, which was one reason why the standard cosmological model now has a lower density of dark matter than then.

On a more technical level, the paper also reminds us that it was to be a while until the angular power spectrum, as opposed to the correlation function, became the standard tool it is now for quantifying the statistical properties of these temperature fluctuations.

The Shaw Prize wasn’t awarded for just this paper, of course, but I think it’s emblematic of the sustained importance and influence of the work of the Laureates over many years.

#CosmicMicrowaveBackground #Cosmology #DickBond #GeorgeEfstathiou #ShawPrizeForAstronomy

Results from the Atacama Cosmology Telescope

Today is going to be a very busy day on the cosmology front – with the Euclid Q1 Data Release coming out at 11am GMT – but I’ll start off by sharing news of final data release (DR6) by the Atacama Cosmology Telescope. This was announced yesterday and includes former colleagues at Cardiff University, so congratulations to them and all concerned. Here is a pretty picture showing one of the beautiful cosmic microwave background polarization and intensity maps:

Intensity and Polarization maps from ACT: arXiv:2503.14451

There are three related preprints on the arXiv today:

There’s a lot to digest in these papers but a quick skim of the abstracts gives two pertinent points. First, from the second paper:

We find that the ACT angular power spectra estimated over 10,000 deg2, and measured to arcminute scales in TT, TE and EE, are well fit by the sum of CMB and foregrounds, where the CMB spectra are described by the ΛCDM model. Combining ACT with larger-scale Planck data, the joint P-ACT dataset provides tight limits on the ingredients, expansion rate, and initial conditions of the universe.

They also find that, when combined with CMB lensing from ACT and Planck, and baryon acoustic oscillation data from the Dark Energy Spectroscopic Instrument (DESI Y1), the ACT data give a “low” value for the Hubble constant: H0=68.22 ± 0.36 km s-1 Mpc-1.

The third paper also says

In general, models introduced to increase the Hubble constant or to decrease the amplitude of density fluctuations inferred from the primary CMB are not favored by our data.

The “Hubble tension” remains!

#ACT #arXiv250314451 #arXiv250314452 #arXiv250314454 #AtacamaCosmologyTelescope #CosmicMicrowaveBackground #Cosmology #HubbleTension

Atacama Cosmology Telescope

Atacama Cosmology Telescope