The 5 Coolest Things in Outer Space

5. Cepheid Variable Stars source: astro.princeton.edu What are they? Stars that pulsate so that the diameter and temperature change over time. This means that the brightness (or luminosity) changes at regular intervals. In the early 1900s, Henrietta Leavitt discovered that period of oscillation is related to the luminosity, with brighter stars having a longer period. … Continue reading The 5 Coolest Things in Outer Space