Starship Asterisk*

Visual_Astronomer wrote:This image, while both beautiful and amazing, is a far cry from what one sees in visible light. As noted above, there is a background of glowing gas (red in most photos) with a dark silhouette of the horse's head. The IR data is allowing us to see galaxies through that glowing background.

geckzilla wrote:I don't think there's really that much dust around the silhouette of the Horsehead Nebula. That is, I mean there is a distinct red glow in visible light and that is not just dust. It's glowing gas, and it's actually rather tenuous. In fact you can't see that many more stars in infrared vs. visible. The galaxies are just so faint that the glow of the gas tends to overpower them, but they glow more strongly in infrared than the glowing gas, so once you're viewing it in infrared you can pick up those background galaxies.

So I think it's a little bit of both going on. In the dustier areas, the dust is blocking visible light from passing through. In the gassier areas, the glow itself is competing with the background galaxies.

darksky2500 wrote:I did a brief search to see if I could find any previous deep images of the Horsehead where so many tiny background galaxies were visible but I couldn't turn up any. Most images of this object are in visible wavelengths where I'm assuming the background galaxies are obscured by the dust and gas of the nebula itself. What is it about this image type that makes them leap into clarity? I'm guessing that IR reveals the dusty nature of the Horse profile, but makes transparent the "colder" gaseous nature of the red material of visible wavelengths?

darksky2500 wrote:
I did a brief search to see if I could find any previous deep images of the Horsehead where so many tiny background galaxies were visible but I couldn't turn up any. Most images of this object are in visible wavelengths where I'm assuming the background galaxies are obscured by the dust and gas of the nebula itself. What is it about this image type that makes them leap into clarity? I'm guessing that IR reveals the dusty nature of the Horse profile, but makes transparent the "colder" gaseous nature of the red material of visible wavelengths?

Chris Peterson wrote:
It was a handful of images like this one (the original, much earlier in the HST program) that really made clear to me the three-dimensional structure of nebulas. Before that, all we had were the ground-based images on film, the best of which just didn't have anything like this kind of depth.

• Before this all we had was a shadow on film.

[b][color=#0000FF]GEORGE GAMOW _One, Two, Three, ... Infinity_ (1947)[/color][/b]

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"By way of analogy we can now say that although it is not possible to squeeze a four-dimensional body into a three-dimensional space without some parts sticking out, one can speak of the projections of various four-dimensional figures in our space of only three dimensions. But one must remember that just as the plane projections of three-dimensional bodies are two-dimensional or plane figures, so the projections of four-dimensional superbodies in our ordinary space will be represented by space-figures."-GEORGE GAMOW

Jimmy wrote:Just below The Horsehead I see a dog sitting and looking upward with his ears flowing downward. Then just to our right of the dog is a boy. His hair would be parted on the far side of him and combed towards us. You can clearly see his hairline outlining his face and his left ear, and then the line of his shoulder, his back and little hips and legs.

A boy and his dog. Amazing !

Chris Peterson wrote:It was a handful of images like this one (the original, much earlier in the HST program) that really made clear to me the three-dimensional structure of nebulas. Before that, all we had were the ground-based images on film, the best of which just didn't have anything like this kind of depth.