- What is Entropy? (jasonfantl.com)
People say many things about entropy: entropy increases with time, entropy is disorder, entropy increases with energy, entropy determines the arrow of time, etc.. But I have no idea what entropy is, and from what I find, neither do most other people. This is the introduction I wish I had when first told about entropy, so hopefully you find it helpful. My goal is that by the end of this long post we will have a rigorous and intuitive understanding of those statements, and in particular, why the universe looks different when moving forward through time versus when traveling backward through time.
- Albireo (stars.astro.illinois.edu)
ALBIREO (Beta Cygni). One of the great small-telescope showpieces of the sky, Albireo, the third-magnitude (3.0) Beta star of Cygnus, the Swan, is a magnificent visual double whose components (magnitudes 3.3 and 5.5) have contrasting golden and blue colors.
- Albireo (Wikipedia)
Albireo /ælˈbɪrioʊ/ is a binary star designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg). The International Astronomical Union uses the name “Albireo” specifically for the brightest star in the system. Although designated ‘beta’, it is fainter than Gamma Cygni, Delta Cygni, and Epsilon Cygni and is the fifth-brightest point of light in the constellation of Cygnus. Appearing to the naked eye to be a single star of magnitude 3, viewing through even a low-magnification telescope resolves it into its two components. The brighter yellow star, itself a very close trinary system, makes a striking colour contrast with its fainter blue companion.
