It is reasonable to expect a lamp’s apparent brightness to decrease with increasing distance from the source but what is the best way to determine the nature of the variation? Although there’s a theoretical answer that applies to all electromagnetic waves, based on the inverse-square law, it is important to be able to carry out … Continue reading Variation of Apparent Brightness with Distance
The Hertzsprung-Russell diagram
It is obvious that the stars in the night sky differ from one another; some look brighter, some appear larger and some have different colours. One of the earliest ideas was that all stars are the same but they look different because they are at different stages of development: it’s as simple as the fact … Continue reading The Hertzsprung-Russell diagram
