From the October 2011 issue

I’ve read recently about new revelations regarding Cepheid variable stars. Given that these stars are used to measure cosmic distances, will this new data change measured distances to various objects?

Kevin Thomas, Waltham, Massachusetts
By | Published: October 24, 2011 | Last updated on May 18, 2023

This excess emission could affect the distance measurement of Cepheids in infrared radiation, introducing uncertainties of several percent — unless we estimate correctly the amount of material surrounding the star. While current cosmological distances (which primarily depend on observations in visible light) are not significantly affected, these infrared nebulae will become important targets for the next generation of space telescopes.