An honest, although possibly dumb question: Does that dustcloud and whatever other particles make up the nebula move, drift, change shape and/or appearance over time? By that I mean; this nebula was probably given its name a long time ago. Was there a time when it looked more like a witch’s head and is slowly drifting and changing appearance? Or is the drift and change over time morphing it even more into a shape suggestive of a witch’s head?
How long ago was it named, and could there come a time when it, and other nebulae with other names morph into other shapes which may or may not be suggestive of something else, or even suggestive of nothing at all?
Tilt your head to the right. Or basically, it looks like the side of someone’s face looking down to the right. Somewhat reminds me of the witch in the original Wizard of Oz movie.
Time and distance are inextricably linked on the astronomical scale. This nebula is very close, at 900 ly, but very large in the sky, at 3 X 1 degrees. If we figure that the various parts of the cloud can be moving at 1/1000 the speed of light, or 200 miles per second, a high estimate, I think, we get apparent movement of 1/900,000, or say 1/1,000,000 radians per year or 60/1,000,000 degrees per year. So in 1000 years, under this assumption, we would see change on the scale of 60/1000 or .06 degrees, compared to the 1 degree scale of the scene.
So, all in all, I would say that the appearance hasn’t changed much in the last few hundred years, but over a few thousand years it may. Just “back of the envelope” !
Yes, very slowly. You won't likely ever notice or detect movement in your life time, or the next two or so generations for that matter. In fact, unless something happened out of the ordinary within the nebula long ago, it should appear relatively the same from earth, for another 1000 years or so.
Most items like this weren’t given ‘names’ until the advent of astronomical photography. It would have to been in the last 150+ years because no one could have seen in before that.
Or, if they did, it wouldn’t look like that.
Yeah, the name makes no sense to me either, should be called “Casper the Friendly Ghost Nebula” or somethin’.