CMB ANOMALY LAB

COSMIC MICROWAVE BACKGROUND · PLANCK PR3

The oldest light,
examined.

From measured sky pixels to mathematical physics. An open investigation of the largest patterns in the cosmic microwave background.

One measured sky.

Blue-orange Mollweide map of the measured Planck PR3 SMICA temperature sky in Galactic coordinates
Full-sky display of measured SMICA temperatures. Some pixels are excluded from the statistical analysis; select Confidence mask to see them. The custom blue-orange palette represents temperature, from −300 to +300 μK.

Data: ESA / Planck Collaboration · NASA/IPAC IRSA
Rendering and analysis: Biswajit Jana

Download the map ↓

The coloured regions are temperature fluctuations, not individual galaxies. Their interpretation involves density perturbations, velocities, gravitational redshifts and the propagation of photons. The visual map is produced directly from the released FITS measurements.

Every cell.
Every assumption.
Actual outputs.

The introductory Python notebook takes you from the archive file to a finished map, then through the statistical and physical experiments.

All 19 code cells were executed in a local Python kernel. The saved notebook is Google Colab compatible; no execution on Google infrastructure is claimed.

  1. 01

    Verify the measurements

    Download official spectra and the SMICA FITS map. Check hashes, units, coordinates and pixel ordering.

  2. 02

    Make the Planck map

    Convert kelvin to microkelvin, project the sphere, apply the blue-orange palette and inspect the confidence mask.

  3. 03

    Ask statistical questions

    Calculate correlations, draw Gaussian skies and repeat the same mask and direction searches on every realization.

  4. 04

    Test a physical alternative

    Propagate primordial suppression with CAMB and inspect its temperature and polarization consequences.

Running it yourself

Use a Python CPU runtime and run cells in order. The first run retrieves about 2 GB of official data. The original map stays at the scientific archive; this website hosts the notebook, generated figures, results and report. No Google Drive access is required.

Unusual patterns.
Careful conclusions.

0.0081

Large-angle correlation

Local lower-tail probability for the defined masked-sky statistic. Accounting for the four baseline map diagnostics gives a family probability of about 0.031.

Inspect the map results →
0.075 → 0.484

Shared quadrupole information

Holding the measured quadrupole fixed makes the spectral correlation statistic less unusual. This diagnoses dependence; it does not explain the quadrupole.

Inspect the spectral results →
0.265

A modest model improvement

The tested primordial-suppression family is not compellingly preferred after repeating its parameter search on 100,000 null spectra.

Inspect the physical model →
Measured cut-sky correlation compared with the pointwise ranges from matched Gaussian sky simulations
Measured SMICA correlation and pointwise Gaussian simulation ranges. These are not simultaneous confidence bands. Vector PDF

What these numbers establish

They quantify results under stated, idealized models. The map null includes the chosen mask and nuisance-mode projection, but does not propagate realistic noise, foreground-cleaning uncertainty or cosmological-parameter uncertainty. The studies do not establish a new physical origin for CMB anomalies, and their probabilities are not combined into a project-wide discovery claim.

Power is only part
of the pattern.

Hold every angular power fixed. Rearrange the harmonic structure. Then rotate the complete measured sky relative to the Galactic mask.

Three controlled experiments separate questions that a single anomaly probability cannot answer.

13 more executed Python cells

The advanced notebook runs 18,432 null and randomized skies, followed by 5,120 paired signal injections. Saved outputs include measured and randomized maps, simultaneous correlation envelopes and detection-power curves.

All 13 cells executed locally with real Planck inputs. The notebook is Colab compatible.

Comparison of four CMB statistics under Gaussian, fixed measured power and globally rotated sky ensembles
Each ensemble answers a different question. Error bars measure Monte Carlo counting uncertainty. These probabilities are not pooled into a discovery significance.
Independent calibration and held-out validation
Null ensembleCorrelation S lower-tail pHemisphere upper-tail pHeld-out envelope coverage
Gaussian theory0.00810.082094.7%
Measured powers fixed0.02220.028394.6%
Measured pattern rotated0.07150.498296.0%

Can the test detect an injected signal?

Five toy dipole-modulation amplitudes are tested against a threshold fixed by independent Gaussian skies. Detection power and direction recovery reveal what a nondetection can—and cannot—tell us.

Read the results and injection curves →

Where the inference stops

These experiments use processed full-sky coefficients. Foreground uncertainty and mixing across mask boundaries remain. The modulation is injected after smoothing; it is not a fitted primordial amplitude.

Read the derivations and limitations →

Three independent held-out sets check the 95% simultaneous prediction envelopes on 121 specified angles. Validation record · Download numerical outputs

The mathematics
behind the map.

Expand the sky in spherical harmonics, estimate angular power, then reconstruct correlations. A physical alternative must also predict polarization through the same transfer functions.

Temperature is a sum of spherical harmonic modes; angular power is the mean squared harmonic amplitudeTemperature and polarization power spectra are integrals of primordial curvature power times transfer functions
Read the equations and derivations →
28
numerical tests passed
10,240
primary and validation Gaussian maps
161
distinct primordial grid models
21
primary papers in the reading guide

Read. Reproduce. Build on it.

Source code and README on GitHub ↗Download the citation ↓