The distance to celestial objects is key to calculating their intrinsic properties like mass and luminosity. Distance, unfortunately, is also one of the most difficult parameters to measure. The most ...

When did the universe start? When and how did the first stars and galaxies form? What is the fate of the universe? The standard cosmological model, also known as the LCDM model, can answer most of ...

A standard candle is an object whose luminosity, or brightness, is a known quantity. Standard candles are used by astronomers to estimate the distance of the candle itself, as well as nearby features, ...

Distance indicators such as standard candles and standard rulers provide a direct route to mapping the expansion history of the Universe. By comparing observed fluxes or angular sizes of astrophysical ...

The simple answer is that the intrinsic brightness of these variable stars is strongly tied to their period. This is the famous period-luminosity relationship discovered by Henrietta Leavitt more than ...

Later this decade, the Large Hadron Collider will be upgraded to the High-Luminosity LHC. What does “luminosity” mean in particle physics? Even on the hottest and driest days, rays from the sun are ...