Red Stars and Blue Moons

Friends,

It is one of those special atronomical times that come around once every few years -- the blue moon. It is true that there a only certain things that happen once in a blue moon. This is the month! What is a blue moon? It does not typically mean that the moon will actually turn blue during this event, although the moon has appeared to be blue at certain times. The blue moon occurs when there are two full moons within a one month period of time -- usually at the very beginning and the very end of said month of the blue moon (as in the 1st, and 31st).
In keeping with the patriotic theme, there are some stars in our galaxy that are red hot. Many of these are red giants at the end of their life cycle -- stars such as Antares in Scorpius and Betelgeuse in Orion. The diameters of these giants would incorporate the orbits of Mercury, Venus, Earth and in many cases, Mars. Some of them will ultimately go supernova (see "A Big Bang" blog). One would think that these would be the "hottest" stars in the sky -- they are actually the coolest. Star colors follow what we know as the color spectrum, (beautifully be seen in an intense rainbow). From the coolest to hottest, there are red, orange, yellow (our sun), white, green (presumably, although I am not aware of any in this portion of the color spectrum), blue, and indigo or purple. Blue stars tend to be significantly larger than our yellow sun and are often hundred and even thousands of light years away; because of their size and strength we are able to have a clear view of some of them -- stars such as Rigel in Orion and Spica in Virgo. Because blue stars tend to burn so hot, when they die, they go supernova in a much more powerful way than any other stars on the spectrum. When you look at certain stars through a strong enough small telescope, you can actually discern their color, which is cool -- or is it hot?

Don