The smallest known blackhole is XTE J1650-500 in a binary systemin the Milky Way. It’s mass is with just 3.8 times the mass of thesun. On the other hand, the most massive blackhole known is locatedin a super massive galaxy named Holm 15A, which is thought to havealready formed from the collision of at least 8 smaller galaxies.The BH’s mass is 40 billion times that of the Sun. Calculate theSchwarzschild radius of both blackholes.
You have discovered a new galaxy and you think you haveidentified an Type II Cepheid star with a period of 30 days. Youmeasure its brightness and with the Period-Luminosity function youcalculate the distance to the galaxy d. However, you laterfind out that in fact the star you had identified is a Type ICepheid. Is the galaxy further than, or, close to, us than wepreviously expected? By what factor should you multiply dto get the correct distance to the new galaxy?
