Tonight we are having what is called a blue moon, which is the second full moon in a month and doesn’t actually have anything to do with the colour. The original definition of a blue moon was when there occurs a fourth full moon within a single season. For some reason it was changed and stuck.
I was discussing the stars in a previous post and decided to do some research on the star Sirius. It turns out that it is actually two stars. Sirius A is the bright star that we can see which is about three times the mass of our sun and ten times brighter. It has a twin, Sirius B, which is a “white dwarf” which has the same mass as our sun but only four times the diameter of our earth, which makes it very dense. Sirius B was only discovered by modern astronomers in 1862 but the Ancient Egyptians knew about it thousands of years ago and would mark the heliacal rising (the first visible rising of the star after previously being unseen because of the sun) of Sirius as the first day of their calendar. Unknown to most people, our calendar begins at the time when Sirius is at the mid-way point in our sky, when the earth’s orbit around the sun places us closest to the star. The time between the rising of Sirius to the next time it rises is called a Sothic year and is almost exactly 365.25 days, which is the same as our Julian calendar.
This is so interesting to me and I will be digging deeper into the subject, bringing you new information when I discover it. Until then, Happy New Year! (or maybe, Happy New Sothic Year!)









