Starship Asterisk*

The Horsehead Nebula in Infrared from Hubble

Explanation: While drifting through the cosmos, a magnificent interstellar dust cloud became sculpted by stellar winds and radiation to assume a recognizable shape. Fittingly named the Horsehead Nebula, it is embedded in the vast and complex Orion Nebula (M42). A potentially rewarding but difficult object to view personally with a small telescope, the above gorgeously detailed image was taken in 2013 in infrared light by the orbiting Hubble Space Telescope in honor of the 23rd anniversary of Hubble's launch. The dark molecular cloud, roughly 1,500 light years distant, is cataloged as Barnard 33 and is seen above primarily because it is backlit by the nearby massive star Sigma Orionis. The Horsehead Nebula will slowly shift its apparent shape over the next few million years and will eventually be destroyed by the high energy starlight.

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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.

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.

Good point, Chris.

Ann

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 !

On the other hand, infrared imagery allows for so much depth that sometimes everything gets stacked together and it's impossible to distinguish one thing from another. It's like stacking an entire forest on a flat, two-dimensional plane. It is at once both confusing and illuminating.

The Horsehead Nebula was ready for it's closeup ...

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 !

The 'Boy And His Dog' seem to have a beautiful wispy female presence floating left of the boy's face. Another small shaggy dog with a black nose above them on the right. And, while I'm seeing dogs, A large Prairie Dog, maybe a Ground hog, where the Horse's neck should be.

Wow. Now that is an image to behold. The light quality reminds me of a late spring evening on planet Earth. Woof

A series of amateurish questions: What is the elemental composition of the Horsehead Nebula? Can we us this information to speculate on its origin and the clouds around it? Supernova origins? Far older going back to the original coalescing of the galaxy?

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

The first object viewed by JWST should be a much debated topic. The Horsehead Nebula in "Near" Infrared would not be a bad object to consider? I'm sure the Pillars might be a highly likely target too.

This is a truly breathtaking image.

I have seen the Horsehead, but only with great effort, special filters, and lots of aperature, and then it is nothing more than a slight shadow on a faint background.

This image is spectacular, revealing the three-dimensional nature of the dust cloud.

Just awesome....

:---[===] *

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?

Background galaxies leap into clarity You've got to be kidding

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?

Well, that's a good observation. Galaxies can indeed be seen through the dust of the Horsehead Nebula. That's because infrared light penetrates dust, if it's not too thick. And the galaxies in question are sufficiently far away that their light has been redshift-reddened, so that it is easily picked up by infrared filters.

Ann

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.

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.

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.

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.

I'm not denying that. I'm saying that there are two reasons why the galaxies are rendered invisible within the same image. One reason is due to attenuation by dust (the "horse's body") and the other because the glowing dust (the red "backdrop") outshines the background galaxies.