Sirius: The brightest star in Earth's night sky

Here's another tid bit from the past of interest, at least to me....

In the famous booklet from Galileo, "Starry Messenger", he introduced the "planets" circling Jupiter and he talked about the MW as being stars. He noted that the stars all looked brighter with his "spyglass". [This is what happens with any telescope or binocular.]

It was also in this booklet that he not only noted that the moons orbited Jupiter -- countering the prevailing idea that everything must orbit the Earth - but he took it one step further in stating that Jupiter traveled around the Sun - the center of the world (solar system). This was the first time he went public with his opinion favoring Copernicus over Ptolemy. [He privately wrote a letter 13 years earlier that had had adopted Cop's model.]

He also mentioned one star in particular - Sirius. He stated that Sirius was the "largest" star. Others (e.g. Tycho) claimed to see some size to the stars, not realizing that the eye can't see tiny points properly. This was very strong evidence, had it been real, for falsifying the Copernican theory since these stars would have been incredibly enoromous to not exhibit parallax. Funny how simple statements can tangle things up a bit; staining things that are pure white, after all. ;)


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