Scope: Lectures 07-08 · Purpose: Convert the Planck 2018 reported 100 theta-star summary, propagate its quoted error, and distinguish an angular-scale datum from a full CMB likelihood.
Setup and data
- Use Planck 2018 TT,TE,EE+lowE flat-LCDM published summary only.
- Do not treat the theoretical acoustic-peak SVG as Planck bandpower data.
- The official archive bandpower fetch was unavailable during preparation; the source limitation is recorded.
Procedure
- Convert 100 theta-star=1.0411±0.0003 to radians, degrees, and arcminutes.
- Propagate the quoted symmetric uncertainty through the factor of 100 and radians-to-degrees conversion.
- Sketch the dependency theta-star=r_s/D_M and list one early-time and one late-time model dependency.
- Compare a fractional angular-scale precision to the much broader assumptions required for H0 inference.
- Write a source note that distinguishes the paper summary from the inaccessible archive product.
Deliverables
Deliver: units-checked calculation, a dependency diagram, provenance record, and a 250-word explanation of why theta-star alone is not an H0 measurement.
Assessment criteria
Rubric: conversion/uncertainty 30%; physical interpretation 25%; model dependency 20%; provenance accuracy 15%; clarity 10%.
Uncertainty and interpretation
Report numerical precision, input uncertainty, model assumptions, and covariance availability separately. Label every output as directly measured, published summary, derived, or model/synthetic. A successful script run is not evidence that the scientific interpretation is valid.
Revisions and resubmissions are encouraged. Credit is based on defensible reasoning, validation, provenance, and clear limitations.