@ARTICLE{Pietrzyński_Grzegorz_Cosmic_2017, author={Pietrzyński, Grzegorz}, number={Nr 1 (53) 2017 Freedom}, journal={ACADEMIA. The magazine of the Polish Academy of Sciences}, pages={34-37}, howpublished={online}, year={2017}, publisher={Polish Academy of Sciences}, language={eng}, abstract={Measuring cosmic distances is one of the most important, fascinating and difficult challenges facing astronomers today. The objective is not just to identify the distances between objects in space – such distances are also key to finding out how our Universe is structured and how it evolves. They also evidence the amount of energy emitted by objects and makes it possible to determine their nature.}, type={Article}, title={Cosmic ruler}, URL={http://so.czasopisma.pan.pl/Content/112418/PDF-MASTER/034-037%20pietrzynski_ang.pdf}, keywords={cosmic distances, Universe}, }