Post by: Karen W. on 31/08/2023 09:38:22
20230831_013318.jpg (541.06 kB . 485x647 - viewed 846 times)Happy birthday to me! Look at what the world presented me for my birthday evening this year! It's absolutely fabulous and so Beautiful! Now it is a sad thing that the fires are destroying so much acreage and homes, and in the same stroke we are able to see such displays of Beauty? What causes the smoke to make these changes in our lovely Blue moon?
Post by: Janus on 31/08/2023 16:08:49
Post by: alancalverd on 31/08/2023 16:44:49
The term simply means a full moon that is out of synchronisation with the solar calendar. The earth orbits the sun in a bit more than 365 days and the moon orbits the earth in a bit less than 28 days so there are usually 13 full moons in a calendar year, but sometimes 14. The origin of "blue" is obscure but although a blue moon is entirely predictable the phrase has reasonably come to mean something that happens very rarely.
This one was more interesting than most because it also coincided with a lunar perigee, so the moon was at its biggest and brightest.
Whilst one can be sorry about the forest fires than made the blue moon red in the USA, Normal British Weather made it invisible over most of these islands.
Post by: Karen W. on 31/08/2023 23:37:38
Smoke particles scatter light, But the scattering is not even for all colors of light. Light at the red end is scattered the least. You see a red moon because that is the light that managed to make the straight line trip from Moon to eye without being scattered.Thanks Janus... that's interesting..
Post by: Karen W. on 31/08/2023 23:46:51
And sadly, the blue moon is not blue!Thanks alan.. I understand about the blue moon and it's being out of sync.. as I understand this was out second one this month.. but I had no idea about it coinsiding with the lunar perigree.. or rather that that's what the bigger appearance of the moon was called.... I find that interesting . What causes the lunar perigree to begin with Alan. I understood it was supposed to appear bigger throughout the night but I was too pooped to stay awake to see it!
The term simply means a full moon that is out of synchronisation with the solar calendar. The earth orbits the sun in a bit more than 365 days and the moon orbits the earth in a bit less than 28 days so there are usually 13 full moons in a calendar year, but sometimes 14. The origin of "blue" is obscure but although a blue moon is entirely predictable the phrase has reasonably come to mean something that happens very rarely.
This one was more interesting than most because it also coincided with a lunar perigee, so the moon was at its biggest and brightest.
Whilst one can be sorry about the forest fires than made the blue moon red in the USA, Normal British Weather made it invisible over most of these islands.
Post by: Karen W. on 31/08/2023 23:51:22
Post by: alancalverd on 01/09/2023 09:37:01
What causes the lunar perigree to begin with Alan.The moon's orbit isn't quite circular. As Kepler and Newton explained, a circular orbit is just a special case of an elliptical one - the energetics are exactly the same regardless of the separation of the foci, with long-period comets being an extreme example .
So the moon is principally in an elliptical orbit with the earth as one focus, and the eccentricity of its orbit also wobbles a bit thanks to the presence of the sun at one focus of the earth's slightly elliptical orbit.....hence sometimes the moon is closer to us than at others.
Werewolves, journalists and astrologers think this is important.
Post by: Karen W. on 01/09/2023 11:11:49
Post by: Janus on 02/09/2023 16:43:30
The little under 28(~27.32) day period is the sidereal month, or how long it takes for the moon to make one orbit around the Earth with respect to the stars.
The period between full moons is a synodic month, and is ~29.53 days long. That means, on average, you get ~12.37 full moons a year. This works out to there being roughly a 40% chance of any year having 13 full moons rather than 12.
Post by: Karen W. on 03/09/2023 11:53:09