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Saturday, September 26, 202668 days to the Dice Letter centennialNo physics degree or shared belief required.
GOD PLAYS DICE™The magazine of big questions

THE QUESTION LIBRARY HD-BLAST RESEARCH

What future measurement could prove the HD-Blast hypothesis wrong?

Ricardo Maldonado, author of GOD PLAYS DICE, froze a five-number target for the slow gravitational-wave hum, and future pulsar data can reject it.

A huge white radio dish on a tall white lattice frame tilts toward a deep blue sky with a few small clouds, above a green lawn, with autumn-colored wooded hills behind it and two people walking at the lower right.
The Green Bank Telescope in West Virginia, one of the radio telescopes NANOGrav used to time pulsars for its 15-year data set. Its dish measures 100 by 110 meters.NRAO/AUI/NSF, via Wikimedia Commons · CC BY 4.0Image source ↗

THE SHORT ANSWER

The clearest test is pulsar timing. Ricardo’s HD-Blast hypothesis bets that the slow hum of gravitational waves bends near one cycle per year. If years more data, fully analyzed by the pulsar teams, show a straight line with no bend there, the book’s frozen benchmark fails. Teams finding the bend in different places, or giant black-hole pairs explaining the whole hum, would also count against it. That would sink this version, not every extra-dimension idea.

  • Pulsar timing arrays time dozens of spinning dead stars for years to catch slow ripples in space.
  • In 2023, NANOGrav reported evidence, not yet a firm detection, for a slow gravitational-wave hum in data on 67 pulsars.
  • The author’s HD-Blast hypothesis rests on a frozen curve for that hum, with a bend near one cycle per year.
  • If better data show no bend, or the pulsar teams disagree about where it sits, this version of the idea fails.
  • Pairs of giant black holes are the leading explanation, and they can bend the curve too, so a bend alone would not settle it.

WHERE THE EVIDENCE STANDS

How sure are we?

  • EstablishedA background of slow gravitational waves would leave a shared, predictable pattern of early and late pulses across many pulsars.The pattern, the Hellings–Downs curve, was calculated in 1983 from Einstein’s theory of gravity; NANOGrav’s 15-year paper reports correlations that follow it.
  • Supported, still debatedA slow gravitational-wave background washes through our galaxy.NANOGrav reported evidence at about 3 to 4 sigma in June 2023, below the 5-sigma bar often used for a discovery; teams in Europe, India, Australia and China reported evidence at varying levels.
  • Supported, still debatedPairs of supermassive black holes are the leading explanation for the hum.NANOGrav’s new-physics paper calls black-hole binaries “the standard interpretation”; its black-hole-binary paper finds realistic populations can reproduce the signal’s loudness and shape, but says the origin is not yet established.
  • Author’s hypothesisHD-Blast bets that the hum’s spectrum bends near one cycle per year, a bend that later data could reject.Five numbers frozen in a public Zenodo record dated 17 December 2025 and explained in Chapter 4 of the book; not yet tested on the pulsar teams’ full data.
  • Not supportedFinding a bend in the hum would show that a higher-dimensional blast happened.The book and NANOGrav’s papers note that black-hole binaries, their surroundings and analysis choices can also bend the curve.
What the labels mean

WHAT WE DON’T KNOW YET

Nobody knows yet whether the hum really bends near one cycle per year; settling it needs more years of data and a full analysis by the pulsar teams. It is also unknown whether any higher-dimensional mechanism can produce the frozen curve at all.

WHAT WOULD CHANGE THIS ANSWER

If the author derived the curve from a working mechanism, new linked predictions would give more ways to test it. If the frozen numbers were changed after new data without being dated and disclosed, the pulsar test would stop being a fair test.

Every bold idea about the universe owes its readers one answer: what would show it is wrong? Ricardo Maldonado, author of GOD PLAYS DICE, built his book around that question. His idea, HD-Blast, is an Author’s hypothesis. It says our hot early universe may be the aftershock of a brief blast in a larger space with more dimensions.

An idea like that has to meet the sky somewhere, and the book picks the place. It points to a faint, slow hum of gravitational waves. These are ripples in space itself. Astronomers listen for them with pulsar timing arrays. A pulsar is a dead star that spins and sends radio pulses toward Earth, as steady as a clock. When a slow ripple passes, some pulses arrive a tiny bit early and others late, in a shared pattern across the sky. In June 2023, the NANOGrav team reported evidence for such a hum in 15 years of data on 67 pulsars.

Here is the bet. Picture a graph of how loud the hum is at each rhythm, from slow to fast. On the kind of graph scientists use, the simplest black-hole story is a straight line. HD-Blast draws a smooth hill with a bend, or “knee,” near one cycle per year. In December 2025, the author froze five numbers that fix that curve in a public record. Freezing matters. It stops anyone from moving the target after new data come in.

So the clearest way to prove this version wrong is easy to state. Wait for more years of pulsar data, fully analyzed by the teams that collect it. If the hum stays a straight line through that range, the benchmark fails. If different teams, after matched analyses, find no common bend, the shared-knee version weakens too.

The test is lopsided, and the book says so. Pairs of giant black holes are the leading explanation for the hum, and they can bend the curve too. So a bend would not prove a blast. But no bend would count hard against this version.

THE LONG ANSWER

How do pulsars let us hear slow ripples in space?

Established. A gravitational wave is a ripple in space and time. As it passes, it stretches and squeezes distances by a tiny amount. Detectors like LIGO catch fast ripples from colliding black holes. But some ripples are so slow that one wave takes years to decades to pass. No detector built on Earth is big enough for those, so astronomers use the galaxy itself.

The tools are pulsars: collapsed stars that spin and sweep radio beams past Earth like lighthouses. The fastest spin hundreds of times each second, and their pulses are very steady. Teams time dozens of them for many years with large radio telescopes. For each pulsar they predict when every pulse should arrive, then study what is left over. A passing slow wave delays some pulses and advances others. The key is the pattern. For a background of gravitational waves, pairs of pulsars should drift together in a way that depends on how far apart they sit on the sky. That pattern is called the Hellings–Downs curve, after the two scientists who described it in 1983.

Supported, still debated. In June 2023, NANOGrav reported evidence for this pattern using 67 pulsars from its 15-year data set. The strength was about 3 to 4 sigma, depending on the method. Sigma measures how surprising a result would be if no real signal were there; 5 sigma is a common bar for a discovery. Teams in Europe, India, Australia and China reported evidence at varying levels. When the International Pulsar Timing Array compared its member teams’ results, their estimates of the hum agreed within about one sigma.

What exactly does HD-Blast bet on?

Author’s hypothesis. HD-Blast says a brief, violent event in a higher-dimensional space may have set up our hot early universe. Its surviving mark today would be part of this slow hum. The book turns that picture into a curve. Imagine a graph with slow rhythms on the left, fast ones on the right, and loudness going up. The HD-Blast curve rises, bends at a “knee,” and falls. The knee sits at 3.16 × 10⁻⁸ hertz, a rhythm of about one cycle per year.

Five numbers fix the curve: where the knee sits, how loud it is there, the two slopes, and how smooth the bend is. They were frozen in a public Zenodo record dated December 17, 2025. Zenodo is an open research archive run at CERN, Europe’s particle-physics lab. A record there fixes a date and its contents. The book states that it is not peer review.

There is an honest catch. The numbers were chosen after the author had already looked at the summary points bundled with his analysis. The book calls this calibration, not prediction. Matching the same points you tuned to shows nothing new. The fair test starts with later, independent data, or with a full analysis written down before anyone looks.

Which future results would count against it?

The book lists its own failure points. Here they are in plain words.

  • A straight line. If more years of data show the hum following a simple straight line (a “power law”) through the knee region, the benchmark weakens. The book’s glossary says a later straight spectrum would reject the version tested in the book.
  • The bend fades under a full analysis. The hint of a bend comes from a simplified screen the author ran on summary points. If the pulsar teams’ own full analysis, with all its noise modeling, finds no preference for a curve, the case weakens.
  • The teams disagree. If careful, matched analyses by different teams put the knee in different places, one shared knee is hard to defend. The book compares it to three doctors taking your temperature and getting three different numbers.
  • Black-hole pairs explain everything. NANOGrav expects finer details of the spectrum, how evenly the hum is spread across the sky, and signals from single black-hole pairs standing out above it to reveal more about the hum’s origin as data grow. If giant black-hole pairs account for all of it, the book’s glossary says the blast idea loses, and calls that fair.
  • Other guardrails. If the curve came from the early universe, its energy must stay small enough not to upset the first minutes of cosmic history or the oldest light. Its tail must also stay quiet where LIGO, Virgo and KAGRA listen, and where the LISA space mission, planned for launch in 2035, will listen. The author’s archived calculations put the curve far below today’s limits and below LISA’s planned sensitivity, which suggests these checks are less likely to be the deciding test.
  • Black holes ringing off-key. The simplest version assumes gravity today follows Einstein. If merged black holes ring, again and again, at notes that differ from his theory’s predictions, that assumption breaks. So far they match: GW250114, which LIGO scientists call the clearest gravitational-wave signal observed so far, matched general relativity in every test, within current precision.

What is the strongest objection?

The strongest objection is that a bend is not a fingerprint. Giant black-hole pairs can bend the curve too. NANOGrav’s paper on black-hole binaries says realistic models can reproduce both the loudness and the shape of the hum, though matching the loudness means pushing many model settings to the edges of their expected values, or a few well away from standard expectations. Its 15-year paper adds that binaries interacting with nearby stars and gas could weaken the hum at the slowest rhythms. A simulation study by Kelley and colleagues found that above about one cycle per year, the slope of a black-hole background carries information about how many binaries there are. That is right where the knee sits.

This makes the test lopsided. Finding the knee would not prove a blast. It would move the idea up one rung, from a curve on paper toward a feature in real data. Missing the knee would hurt it badly. The book accepts that trade and says a lasting bend would not identify a higher-dimensional blast by itself.

A second objection is sharper. No working blast mechanism yet produces the curve. The book says so, and the author’s newest HD-Blast record, from September 2026, lists a hot-Big-Bang mechanism as not established. A critic could ask: if the knee fails, won’t a new curve simply replace it? The book’s answer is a set of rules. Keep the old record. Date every change. Say what failed and why. A later dataset is not a fair test if the target is quietly adjusted after the new points are seen.

What do people often get wrong?

  • “Evidence” is not “detection,” and neither is “source.” NANOGrav reported evidence for a background. That is a big result. It does not yet say which source made it.
  • “New physics fits better” is not new physics. NANOGrav’s own new-physics paper found that many early-universe models fit the signal, some with Bayes factors of 10 to 100 over the black-hole model. (A Bayes factor is a ratio of how well two models explain the data.) The team warned that these results depend strongly on assumptions about the black holes and “should not be regarded as evidence for new physics.” The same caution applies to HD-Blast.
  • A DOI is not a stamp of approval. The book states that a Zenodo DOI preserves a public record. It does not mean peer review, independent checking, or endorsement by CERN or any pulsar team.
  • Failing this test would not end every extra-dimension idea. The book says a rejection would reject the canonical version tested there, not every possible higher-dimensional cosmology. That is scope, not an escape hatch. The version on the table would be gone.
  • The author’s life story is not evidence. The book’s first chapter is memoir. It explains why the question matters to him. It adds no weight to the hypothesis.

How can you check it yourself?

  1. Open NANOGrav’s 15-year evidence paper and find the plot of the spectrum, often shown as a row of separate points. Look at the right-hand, faster end. That is where a knee near one cycle per year would show.
  2. Read the authors’ most careful sentence. The paper says the signal fits black-hole-binary expectations, but that more unusual sources cannot be excluded.
  3. Open the December 17, 2025 Zenodo record and write down the five numbers. When new pulsar results arrive, check whether the same numbers are being tested, or new ones.
  4. Ask the book’s five questions of any headline. Did the feature last as data improved? Did the teams agree after matched analyses? Does the energy fit the early universe? Does the curve stay under limits in other bands? Are the black-hole tests based on real events, or on a demo?
  5. Watch for the International Pulsar Timing Array’s third data release. It had not come out when this page was checked in September 2026. It is designed to combine data from pulsars timed by more than one team.
Deep dive (optional)

The five frozen numbers

The benchmark is a “smooth broken power law”: one slope below the knee, another above it, and a smooth join. The archived point is fk = 3.16 × 10⁻⁸ Hz (the knee), Ωk = 8.00 × 10⁻⁹ (the curve’s height at the knee, written as a fraction of the universe’s energy density), α₁ = +3.0 and α₂ = −2.0 (shape exponents) and Δ = 2.0 (smoothness). In the book’s sign convention, the curve grows like f² well below the knee and falls like f⁻³ well above it.

Where the knee sits in the data

One cycle per year is about 3.17 × 10⁻⁸ Hz, because a year lasts about 31.6 million seconds. NANOGrav’s standard 15-year analysis used 14 frequencies from about 2 to 28 nanohertz. The knee, near 31.6 nanohertz, sits just above that range. The book notes that the highest-frequency pulsar-timing point carries the most weight for the apparent curvature. If that point shifts in later releases, the case could change.

How strong the author’s screen really is

In a simplified screen run on bundled summary points, the knee curve scored about 24 units of BIC (a model score where lower is better) ahead of a fixed black-hole template, and about 13.6 ahead of a free straight line. (The record gave 26.21 for the first gap; the book, using one comparison method throughout, gives about 24.) A separate curvature check scored about 8. The book calls these internal screening scores that cannot be promoted to publication-grade evidence.

The December 2025 record’s own summary used stronger words. It called the knee curve “strongly favored,” quoted about 3.2 sigma for the curvature check, and marked a cross-team overlap score as a pass. The book walks those labels back. It says the curvature score is not a 3.2-sigma detection, and that the overlap score came from a workflow demonstration with stand-in inputs, not from teams measuring the same knee. That is the Chapter 11 lesson in action: a number can survive while the sentence around it has to shrink.

The guardrail numbers

For the assumed curve, the author’s calculation gives an extra early-universe radiation of ΔNeff ≈ 7 × 10⁻⁴; the record calls this well below typical limits of about 0.06 to 0.3. It also gives Ω ≈ 2.3 × 10⁻³⁵ at 25 hertz. LIGO, Virgo and KAGRA found no background there and set limits of about 2 to 3 × 10⁻⁹, depending on the assumed spectrum. Both figures are conditional calculations under stated assumptions, not measurements.

THREE THINGS TO REMEMBER

  1. The clearest test is the shape of the slow hum: a bend near one cycle per year, or none.
  2. Finding the bend would not prove a blast, because black-hole pairs can bend the curve too.
  3. A failed benchmark would sink this version of HD-Blast, and the book commits to saying so.

WHERE THE AUTHOR’S RESEARCH TOUCHES THIS

Author’s hypothesis. This whole page is about Ricardo’s research, so here is where the public record stands. After the December 2025 snapshot, later Zenodo records set out stricter tests. A February 27, 2026 record adds a sharper “fingerprint” shape for the curve and lists explicit kill-switch criteria. The book notes that no full, noise-aware pulsar analysis has yet passed that stricter test. The newest HD-Blast record, from September 23, 2026, studies a five-dimensional model. It lists stability and a hot-Big-Bang mechanism as not established, and it states that AI tools assisted the work and that internal reviews are not external peer review.

WORDS WORTH KNOWING

Pulsar timing array
A set of steadily spinning dead stars, timed for years with radio telescopes, used as a galaxy-sized detector for slow gravitational waves.
Gravitational-wave background
Many overlapping gravitational waves blended into a steady murmur, the “hum,” instead of one loud event.
Spectrum
How a signal’s strength is spread across rhythms, from slow to fast.
Power law
A curve that looks like a straight line on the log-log graphs scientists use; the simplest black-hole model of the hum.
Knee
The bend in HD-Blast’s frozen curve, near one cycle per year. Part of the Author’s hypothesis, not a measured feature.
Calibration
Choosing a curve’s settings using data already seen. Matching that same data later is not a prediction.

Sources & further reading

  1. GOD PLAYS DICE, Volume One: “The Knee in the Noise,” “When Black Holes Ring Like Bells” and “How We’ll Know”The knee, the five frozen numbers, calibration versus prediction, the assumption that gravity today follows Einstein, the evidence ladder, and the list of ways the benchmark weakens or fails.
  2. GOD PLAYS DICE, Volume One: “How to Watch the Dice Roll,” “How Science Kills and Crowns Ideas,” Appendix and GlossaryFive questions for reading headlines, watching for retuning, how corrections should appear, why a failure has a scope, what a Zenodo DOI does not mean, the glossary entries for the knee and black-hole binaries, and the note that Chapter 1 is memoir, not evidence.
  3. Listening Beyond Four Dimensions: Higher-Dimensional Blast — … Canonical Snapshot & Tool-Kit ↗Public record dated 17 December 2025 (DOI 10.5281/zenodo.17968738), CC BY 4.0; title shortened here (the full title includes a version tag). Lists the five benchmark numbers, the screening scores and the conditional guardrail calculations. A Zenodo deposit, not peer reviewed.
  4. The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background ↗67 pulsars; Hellings–Downs correlations at about 3 to 4 sigma; consistent with black-hole binaries, other sources not excluded.
  5. The NANOGrav 15 yr Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational-wave Background ↗Black-hole-binary models can reproduce the hum’s amplitude and shape; the origin is not yet definitively established. A 2026 erratum (ApJL 1006, L67) fixed two software bugs and left this conclusion unchanged.
  6. The NANOGrav 15 yr Data Set: Search for Signals from New Physics ↗Many early-universe models fit, some with Bayes factors of 10 to 100 over the black-hole model, but the team says this should not be regarded as evidence for new physics. A 2024 erratum (ApJL 971, L27) corrected the phase-transition models with only mild changes.
  7. Comparing Recent Pulsar Timing Array Results on the Nanohertz Stochastic Gravitational-wave Background ↗Australian, Chinese, European, Indian and North American teams reported evidence at varying levels; the IPTA member teams’ background estimates agree within 1 sigma; previews IPTA Data Release 3.
  8. The Gravitational Wave Background from Massive Black Hole Binaries in Illustris: spectral features and time to detection with pulsar timing arrays ↗Simulated black-hole-binary backgrounds: a low-frequency turnover points to environmental effects; above about one cycle per year the slope can reveal the number of sources.
  9. Scientists use Exotic Stars to Tune into Hum from Cosmic Symphony ↗Plain-language release: 15 years of data, millisecond pulsars that spin hundreds of times each second, waves with periods of years to decades, the Arecibo, Green Bank and VLA telescopes, and black-hole pairs as one possible source.
  10. Black hole spectroscopy and tests of general relativity with GW250114 ↗GW250114, described as the clearest gravitational-wave signal observed so far, matches general relativity in every test, within the precision of current observations.

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