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Most of us know what that we can judge the distance of an object such as a car headlight by how bright that headlight is. The things is we know how bright car headligjts are from 1 foot away so that seems pretty obvious.
A Cepheid variables brightness is commonly used to measure the distance to the galaxy that they are within. What i don't understand is how that works becuase how do we know original brightness of the cepheid?
We can't stand next to a supernova and measure how bright it is so how can we determine its distance from how bright or dim it seems.
Do all these stars go supernova at a certain mass, and is that how we "estimate" how bright a cepheid variable is?(I have asked this before but can't get an answer or find the thread sorry)
A Cepheid variables brightness is commonly used to measure the distance to the galaxy that they are within. What i don't understand is how that works becuase how do we know original brightness of the cepheid?
We can't stand next to a supernova and measure how bright it is so how can we determine its distance from how bright or dim it seems.
Do all these stars go supernova at a certain mass, and is that how we "estimate" how bright a cepheid variable is?(I have asked this before but can't get an answer or find the thread sorry)