How Do Scientists Measure Distance Using Standard Candles?

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Standard candles, such as type Ia supernovae, are used by scientists to measure astronomical distances due to their consistent luminosity. When observing two supernovae, the one that appears brighter is closer, allowing astronomers to determine relative distances based on brightness differences. The uniformity in luminosity arises from the specific mass and conditions under which type Ia supernovae occur, leading to similar explosion intensities. Understanding the distinction between luminosity (intrinsic brightness) and apparent brightness (how bright an object appears from Earth) is crucial for accurate distance measurement. This method is fundamental in astrophysics for mapping the universe.
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I'm kinda confused about how standard candle works. I know they use type 1 supernovae since their luminosity is the same everywhere but how do scientists know how far a star is if their luminosity is the same everywhere. I don't really get how they measure distance with it. Can someone please explain to me! thanx^^
 
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If the luminosity of two objects are the same they will appear to be equally bright when viewed from a equal distance. They will not appear to be equally bright when viewed from different distances. Thus if we see two type 1 supernovae, and one is brighter than the other, we know that it is closer to us than the other. And by how much brighter we can tell how much nearer it is.
 
I think that scientists can infer that all type I supernova have about the same luminosity because of the physics behind this specific type of supernova. I believe it only occurs with a certain mass of star, so the explosions are relatively the same intensity for all of them. The other half is what Janus said :)
 
hmmmm I see because I was confused of luminosity and brightness like the difference from those two.
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
Why was the Hubble constant assumed to be decreasing and slowing down (decelerating) the expansion rate of the Universe, while at the same time Dark Energy is presumably accelerating the expansion? And to thicken the plot. recent news from NASA indicates that the Hubble constant is now increasing. Can you clarify this enigma? Also., if the Hubble constant eventually decreases, why is there a lower limit to its value?
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