2014-10-09 – I have scoffed at Super Moons. But I don’t scoff at lunar eclipses. We had a chance to see one yesterday and I was there.
With my wife Kit.
Lunar eclipses take several hours, so we weren’t there for the start. We got up at 5 AM and took our dog Lefty to the park across the street. The moon was already approaching totality. Only a little sliver remained. Kit took pictures. She has a real camera. I only have my iPhone. While it takes excellent pictures of normal scenes, it doesn’t have the telephoto capabilities you really need to take pictures of the moon. (If you went to the link above, you saw the best moon picture I’ve been able to get out of it.)
Before long, the moon was completely in the shadow of the Earth. Although it was a bit chilly, we were dressed for it and we met a neighbor who had come to the park, also to see the eclipse, so we chatted while we waited for the totality would pass. Honestly, I didn’t know if we would even see that. The eclipse was so late in the night that I thought it might be possible for the moon to set before we saw any motion. The moon was red. They call it a “blood moon.”
Lefty didn’t notice anything special.
Sometime around 6 (I didn’t look at the time), the “top” of the moon (as we were looking at it; it was really the edge facing east) began to become bright. The moon was very low in the sky. Sparse clouds were coming from the north and the moon was close to setting behind the trees. To our backs, that is, to the east, the sky was growing bright with first light.
To me this felt like the closest I would ever come to actually being able to “see” what happens during an eclipse. If you are inclined to get up to watch the dawn, you may notice that tall things, like buildings and trees, catch the first rays of the sun before the ground becomes lit. The moon, being a very tall thing was catching those first rays of dawn.
Every night, we live in the shadow of the Earth, but we rarely see the shadow cast on any object. We see this during a lunar eclipse. Lunar eclipses are not terribly rare. You see them, usually, once a year. This year, apparently, there were four—though I didn’t know about them all. Maybe it was cloudy for some of them. It is rare, however, for a lunar eclipse to coincide with the dawn.
Every day we see the shadow that is night pass. Yesterday we also saw the shadow simultaneously pass from the face of the moon—or we saw it begin to pass, because the moon dropped below the line of trees.
Light is invisible.
Oh, we see things by means of light, but we don’t see the photons of light zipping by. We didn’t see the photons streaming from the sun, past the edge of the Earth, and light up the moon. We really have to infer this. (When you see rays of sunlight, you aren’t seeing streams of photons. You are seeing clouds or smoke being illuminated, just as solid objects are illuminated.)
Yesterday morning, we looked to the moon in the west. Our backs were to the rising sun in the east. On rainy summer afternoons, we go into the park to see a rainbow. With an afternoon rainbow, we face east to see the rainbow, which is caused by the sun, which is at our backs in the west. You never see the whole transaction. Not the sun and the rainbow. Not the sun and the eclipse in one view.
Lefty’s reaction to all this was to poop.
He does this every morning that we take him to the park. Yesterday, it was a little early, but he didn’t stand on ceremony. He squatted. In Chicago, you are required, by law, to pick up the poop, but it was still dark. Kit asked if my iPhone had a flashlight. It does.
One way to test the effect of light is to turn it on and off. I did that with my iPhone flashlight. I turned it on, pointed it at the grass in the vicinity of where Lefty was when he was squatting, and the grass was illuminated . . . and so was the poop. You can turn the light on and off. Or you can wave your hand in front of the light to cast a shadow in the darkness.
The Earth passing between the sun and the moon was like waving your hand in front of a flashlight. When the moon was in the shadow, the moon was dark. When the shadow moved away, the moon was lit up again.
Like I say, it’s rare to see all the parts of the transaction in one view.
One other thing. The moon in the shadow of the Earth was red, not black. Why is that? You could see the reason for that in the dawn as well. Light going through the Earth’s atmosphere at a low angle is bent and is visible as red light. We see that at dust and and dawn. A person on the moon, looking at the Earth during this eclipse would see the red as well, as a faint halo around the Earth. That red light illuminates the lunar landscape and that is what we see.