Izvleček
Razumevanje strukture in razvoja vesolja ni mogoče, če ne poznamo oddaljenosti opazovanih objektov. Te ni lahko izmeriti, zato je bila še pred 25 leti lestvica vesoljskih razdalj precej negotova. V 90. letih je satelit Hipparcos Evropske vesoljske agencije metodološko neoporečno izmeril razdaljo do 118 tisoč bližnjih in relativno svetlih zvezd. Decembra 2013 je ista agencija izstrelila satelit Gaia, ki s svojimi uspehi v temeljih spreminja naše poznavanje vesolja. Lani smo objavili razdalje do dveh milijonov zvezd, čez dobro leto sledi objava veliko točnejših razdalj do več kot milijarde zvezd, v naslednjih letih pa se bodo točnim razdaljam do teh zvezd pridružile še meritve njihovih fizikalnih lastnosti in časovne spremenljivosti. Z združevanjem teh dognanj s komplementarnimi pregledi neba z Zemlje smo na pragu poznavanja podrobne slike strukture in nastanka naše Galaksije kot ene od tipičnih galaksij v vesolju.
Abstract
Gaia or How Far Away Are the Stars?
Understanding of the structure and evolution of the Universe requires knowledge of the distances of observed objects. This is no easy task, which is why even 25 years ago the cosmic distance scale was rather uncertain. In the nineties the Hipparcos satellite of the European Space Agency took precise measurements of the distance to 118 thousand of the closest and relatively bright stars. In December 2013 the same agency launched the Gaia mission. Its success is a game changer, as far as our understanding of the Universe is concerned. The distances to 2 million stars, which have been published a few months ago, will be followed next year by a list of much more accurate distances to over a billion objects. In the years to come, these will be joined by a publication of detailed physical properties and their temporal variability. By combining this unique dataset with complementary sky surveys from the ground, we are on the verge of obtaining a detailed picture of the structure and formation of our Galaxy, as one of the typical galaxies in our Universe.