The distance duality relation

The distance duality relation tells us how, assuming that photons propagate on null geodesics in a pseudo-Riemannian spacetime and that their number is conserved, luminosity and angular diameter distances are related, via where dL is the luminosity distance, dA the angular diameter distance and z the redshift. This relation was introduced by Etherington in 1933, …

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Tribalism in science

Last week, a tweet by Roberto Trotta drew my attention to a recent paper by Simon Portegies Zwart that studied the amount of carbon dioxide emitted by running N-body simulations in different programming languages. https://twitter.com/R_Trotta/status/1309457430267523072 The figure that caught my attention was Figure 3, copied below from the version of the paper published in Nature …

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