- Oliver Pereira, MSc Part II

In our last encounter with the cosmic distance ladder, we saw how distances of stellar objects were measured, at varying scales. We talked about scales ranging from the moon to our Milky Way galaxy. Now, we continue up the ladder, climbing further into the vast expanse of space.

Going back to the candle analogy, suppose we knew that a far way candle was the exact same type as a nearby one whose distance can be measured, we can assume the far away one has the same luminosity. As we have seen previously in the HR diagram, stars come in a range of luminosities and temperatures, so we cannot do this directly for any star. We need to look for other measurable parameters.