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  • Stars

    FAS Astronomers Blog, Volume 30, Number 5. Stars are huge balls of hydrogen plasma powered by nuclear fusion reactions at their core. Stellar Distances Except for the Sun, which is 93 million miles away, stars are a vast distance from us. Therefore, it isn’t always practical to measure these distances in miles, so astronomers use…

  • Cosmic Distances, Stellar Brightness, and The Hubble Constant

    FAS Astronomers Blog, Volume 30, Number 3. The Hubble Constant The Universe is expanding. The farther a galaxy is from us, the faster it is moving away from us. We measure this expansion using something called the Hubble constant, which is the rate with which galaxies are receding from us as a function of their…