With the Vernal Equinox over on March 21st springs’ sprung and by the time you get this summer’s happening or at least the feel of it. The Summer Solstice is on June the 21st. June’s extra significant this year is because it’s a blue moon June! Yes, two moons in the same month makes it a blue moon month. “Once in a blue moon” is a line many of us have used to denote a not very often or very seldom and that’s true of blue moons. With about 29.53 days between full moons it is a rare event when they happen to occur in the same month. The last one was July of ‘04 and the next will be in December of ‘09. So the June 1st and 30th full moons make that rare event a real event this year .
Sometimes you’ve probably noticed the dark side of a crescent moon is actually glowing dimly. That’s earth shine. Sunlight hits the earth and bounces back through space to the moons “dark side” and filling it with a subtle and beautiful light. This is also fairly rare sight. These sightings are most common during young spring evening’s crescent moons and autumn morning’s crescent moons. So we have a good spring opportunity for this sighting.
It’s taken me decades of looking at the night sky to finally ask what is it about the moon that it moves up and down in the sky so unlike the sun’s predictable high in summer warmth and low and cold in the winter. Well it goes like this: The moon moves in that same sunly pattern but each month, instead of over a year. Moving from high to low and back again. We go around the sun in a year, the moon goes around us in a month! The full moons in winter are high when the sun is low and in summer when the sun is high the full moons are low! Go figure….. With snow on the ground that high full winter moon light can feel almost like a dim cool sun putting shadows under trees and all objects, sometimes sparkling the snow with it’s brightness. It can be stunningly beautiful on a cold still winter night. You could almost read by it if you could stand the cold!
Here’s another moon conundrum. If the moon’s small and the sun huge why are they the same size in our sky? Well there are some marvelous celestial mechanics at work to explain this one: The sun is 400 times larger than the moon and it is simultaneously 400 times farther away. The two facts cancel each other out and make them appear the same size to our eyes. I think that’s just amazing. The great creator has given us such magic and beauty! It took human kind a long time to figure that one out. Actually historically the ancients had figured that out and then the knowledge was lost till fairly recent history.
Here’s a last moon mystery for you. Why do low full moons seem so much bigger when close to the earth than when they’ve risen to mid sky? Well it’s context that gives the illusion. When you can compare the moon to things mountains, trees, buildings, etc. it appears large. When it’s the only thing in large expanse of empty sky it seems diminished in size and therefore small. In fact it’s the same size just the context [what’s around it] has changed.
It’s fun to look up and notice the marvelous universe and solar system we live in. It’s my hope that these night time observations and tidbits tempt you out a bit more and urge you to look up and observe when you are out. There’s this large wonderful universe up there to be enjoyed.
One last detail. The week of April 17 – 24th is National Dark Sky Week. It begun in 2003 to bring attention to night sky light pollution. Many places have almost lost their night skies. See www.ndsw.org for details and easy solutions. Let’s stop light pollution!