What is the method used to find out the distance of Andromeda galaxy from us?
Asked by: Nidhi Answer Distances to deep-sky objects such as the Andromeda galaxy are often determined using what are referred to as “Standard Candles”, which means that astronomers look for objects located within the target for which they believe they know the intrinsic luminosity (how bright it actually is). For any light-emitting object, it’s apparent luminosity (how bright it appears to us) decreases with the square of the distance between the object and the observer; so, if we know the intrinsic luminosity of an object, we can measure the apparent luminosity and perform a straightforward calculation to obtain the approximate distance to the object. An example of such a “Standard Candle” are what are called Cepheid Variable stars. These are young, massive, bright stars (about 1000 times more luminous than our Sun) that undergo periodic changes in luminosity. It has been found that the period of the Cepheid variable is related to its intrinsic brightness, such that if one measures h
