Jaw-dropping rotating 3D nebula

By Phil Plait | October 8, 2012 7:00 am

A little over 2000 light years away, toward the constellation of Cepheus, is a place where stars are being born. It’s a nebula, a gas cloud, and it’s called IC 1396. It’s monstrous, well over a hundred light years across – even at its tremendous distance, it’s wider than six full Moons in our sky.

Finnish astrophotographer J-P Metsävainio observed IC 1396, making a gorgeous image of it. But he wasn’t satisfied just doing that. He’d been playing with making 3D images for some time, and decided this might be a good opportunity to make a model of the structure of the nebula, and then create an animated GIF of it.

The results are… well, see for yourself:

Holy. Haleakala! [The filesize is 7Mb, so it may take a while to load.]

OK, let me be clear: this is not actually showing you the 3D structure of the nebula. It’s an approximation, a guess based on various assumptions on how nebulae are shaped. J-P broke the image up into layers, made a surface model of it, then remapped it all into different frames seen from different angles. He then put those together to make the animated GIF you see here.

The structure may not be completely real, but it’s still awesome… and it gives you a sense of the shape and composition of the gas cloud. The star in the center is the ionizing source; that is, it’s a hot, young, massive star blasting out ultraviolet light, and that’s what’s making the nebula glow. The dark ribbons are filaments of dust which absorb optical light (the kind of light we see). Many of them seem to point toward the central star. That’s because at their head is a dense clump of matter, and that’s getting eaten away by the light and fierce winds from that hot star. Material from the clump gets blown back and away from the star, like sandbars in a stream. It’s a very common structure in nebulae like this.

One thing that is pretty accurate is how the gas in the interior is blue, and red on the outside. This nebula used to be more filled with gas, but as the stars switched on inside it, their combined winds blew out a cavity, turning this filled sphere into a shell. Not a completely empty one, though: some gas remains inside, and its proximity to the central stars allows the oxygen in the gas to glow blue. Farther out, the starlight is too weak to make oxygen glow, so all you see is the ruddy glow from hydrogen.

I’ll note the bright star just above the nebula is mu Cephei, a massive red supergiant, one of the most luminous stars in the Milky Way – possibly over 300,000 times more luminous than the Sun! It may or may not be at the same distance as the nebula – its distance is difficult to measure – though in J-P’s animation it shows up as being closer.

Here’s what the nebula looks like in the original, 2D image:

Pretty, isn’t it?

This sort of modeling is fascinating, and really stunning. I’m not sure there’s scientific value to it just yet – like I said, it’s more art than science, since the structure you see is a guess. Still, I love the aesthetic of it. J-P has created several anaglyphs of celestial objects, and really all his astronomical imaging is lovely, and worth your time to peruse.

Tip o’ the Hα filter to PierreKerner. Image credit:


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CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (44)

  1. Weird. For some reason WordPress had comments turned off for this post. My apologies, and obviously they are back on now.

  2. Kyle

    Awesome image! Is there enough parallax in our orbit to be able to get some stereo images to get a 3d view of some of the nebulae out there? It seems it would be scientifically valuable to see these guys in 3d.

  3. Andrei

    That’s nice that you can actually see it as 3D object (this is because of wiggle 3D, though a verry slow wiggle). However, there’s something that bothers me in the animation.
    Assuming a more or less spherical shape for the nebula, this means that the light comming from the center has to pass through much less matter in order to get to us than the light passing through it’sides. That’s why we see the nebula somehow as a puffy ring.
    But the funny part is that if you change a bit the perspective (let’s say because of parallax), the “opening” of the nebula system remains in place and only the shapeof the outer ring (the position of the”puffs”) changes. In the above animation, the nebula seems like a spherical object with a real opening in our direction, moving as we change the perspective.

  4. Isabel

    That’s very cool, but shouldn’t the background stars move in position a lot less than the foreground stars? The opposite is happening- not sure why.

  5. Steve D

    Is there enough parallax in our orbit to be able to get some stereo images to get a 3d view of some of the nebulae out there?

    No. Parallax from earth’s surface doesn’t even give reliable stellar distances to more than 100 light years. HIPPARCOS got out to 300, and if GAIA flies we’ll go to 100,000. But the difference in images from opposite sides of the Earth’s orbit would be negligible. Even for point sources like stars you need ultra-precise satellite sensing to see parallax at great distances.

  6. James Evans

    The level of awesomenitude-ocity in that animated image has reached ridiculoutational proportionisticles.

    I wonder how fast the Millennium Falcon would have to be darting around this nebula to escape an Imperial Destroyer, so, standing in Ben or Luke’s cockpit spot, you could see it spinning like that outside Chewie’s copilot windows.

  7. berndb

    @5 I’m sure we’d get a bit more parallax if we were to juxtapose images of a given part of the stellar neighbourhood taken from Earth to those taken from the Voyager spacecraft. Maxed out by placing them on opposite sides of the Sun. That’s got to be better than the width of Earth’s orbit alone.

  8. Andrei

    @berndb 7
    At Voyager’s distance, the relative positions of the Earth and the Voyager spacecraft with respect to the Sun are only an error term, with less than 1% difference.

  9. dessy

    Just so people are aware – this should really be considered ‘art’ or an ‘interpretation’.

    Now someone hurry up and invert commercially viable holographics so I can have this as a centrepiece in my den.

  10. DanM

    People were trying to measure the parallax of stars for hundreds of years after the invention of the telescope. The first successful measurement was in the 1830’s, when Bessel measured the parallax of a star that is about 11 light-years away. It is a *tiny* effect that requires many months of exceedingly careful observation (and this for an object that is, on cosmic terms, very near). It turns out that the effect is even small compared to the abberation effect, which displaces the image of a star (relative to its actual position) due to the relative motion of the star and the observer (an effect which is due to the finite speed of light).

    There is an interesting book (called Parallax) which tells the story of all the measurement attempts leading up to Bessel’s success, and those that followed. I recommend it, it is a fun read for astronomy nerds.

  11. Isabel

    #9 of course, and I am a long-time “winky” fan, but until the background is stabilized and stops moving more than the foreground, especially in the bottom part of the image, I think this one fails. The farther away something is, the less it should move in a 3-d image. Unless those millions of stars in the background are all suppose to be part of the nebula (which I do not thin is the case). The nebula is huge, and the distant parts are very far away compared to the foreground, but I am assuming that many/most of the smallest-appearing background stars are much farther away. To be “artistically” effective, the background should move very little, the next closet layer should move slightly compared to the background, the next layer a bit more, and the closest layer more.

  12. Roshan

    @Isabel
    I think the camera is meant to be revolving around the nebula, not just sliding sideways. So objects behind the nebula move in one direction and the objects in front of it move in the other. The centre of the nebula appears still. Really far-away stars will actually appear to move more than the closer ones.

  13. Leonidas

    “…I’m not sure there’s scientific value to it just yet – like I said, it’s more art than science”

    Science IS art!

  14. Michael Goble

    I don’t know whether it is art or science but it is beautiful, and hypnotic.

  15. Isabel

    @12, I think you are right about the rotating. It would be nice to see a full rotation. The site doesn’t explain how he handled the stars.

    “The centre of the nebula appears still”

    It is actually moving back and forth – I can’t figure out where the center is. Nothing is still. Everything is moving.

    “Really far-away stars will actually appear to move more than the closer ones.”

    They do seem to be moving more, but I find it distracting. A nebula is only supposed to be one star (remnant), but it looks like millions of stars are in its vicinity… maybe that is what’s bothering me.

  16. Jaz

    Good one. I’m almost inspired to do the same with today’s APOD.
    http://apod.nasa.gov/apod/image/1210/mbp_2011-11_Simeis147Andreo.jpg

    But since that would take me about a century, I’d probably have to invent an elixir of youth first, and that’s just too much of a bother…

  17. The results are…

    Superluminous, ie. beyond mere brilliance! Cheers. :-)

    @13. Leonidas : Yup. There’s an art to science and a science to art.

    *****

    PS. Link to Kaler’s page on Mu Cepehei – otherwise known as Herschel’s Garnet Star and one of the most luminous and large in our Galaxy in my name here.

  18. ctj

    this needs to be added to celestia pronto!

  19. Jon Hanford

    @ Jaz(17)

    The astroimager who created that wonderful APOD of Simeis 147, Rogelio Bernal Andreo, also created another stunning picture featured at APOD, this one a widefield mosaic of the Cepheus-Cassiopeia region including our featured object, IC 1396, and several other well-known deep sky objects: NGC 7380, NGC 7635(Bubble Nebula) and M52: http://deepskycolors.com/pics/astro/2010/08/mb_2010-07-08_BubblesTrunk.jpg

    (Actually, Rogelio has had several images featured at APOD. You can check out his website for more of his amazing images: http://blog.deepskycolors.com/ )

  20. Menyambal

    For those asking about parallax from Earth’s orbit: Our orbit is about 16 light-minutes across, while the nearest star is about 4 light-years away. I’ll bet you could spend sixteen minutes writing a reply to this comment, and not even remember it four years from now.

    Which is to say the differences are too great. Voyager 1, our furthest probe is, only a 17 light-hours out, and this nebula is 2000 light-years away. If Jesus were to come back this afternoon, instead of tomorrow morning, would the pope say that He had been hurrying all this time, but another seventeen hours is just slacking?

    I do agree that the gif would have been better if the center star had held still, but my big question has to do with the stars that appear to be within the hollow. Is that what this is all about? That center star went blooie, and as the dust cloud went out, some bits of it collected into new stars? Wow!

    If it is an hundred light years across, there is plenty of room. I guess the dust is being driven by light pressure, so globs and stars would tend to slow and stop, due to the central star’s gravity … and we see that in the pillars.

    So I guess that is what it is, new stars within the cloud’s hollow. Wow!

    Um, what about stars that were already in the neighborhood? They’d stay, but might get dusted up some, although the dust is actually still a vacuum, by all standards.

    I need to go look at dust clouds where the center star went out, instead of still giving off light.

    As always, Phil, thanks for posting such amazing art and science.

  21. Menyambal

    If you look at the pillar down and to the right of the central star, the brightest one, you can see a blue star inside the head of it. I was just thinking that a new star would blow the dust away from itself, and I went up and looked, and there it is. A new star has formed in that glob, and has blown itself a hollow, and the big star is also blowing the dust away in a pillar. Wow!

    Wow.

  22. reidh

    It really helps me. I found this site whilst searching for anaglyphic pictures on the web. Before I saw what this guy has done, I never had any real sense of the structure underlying what ever pictures/photos I was looking at, even with the Hubble, with exception of the pillars in the Orion neb.
    Now i slap on a pair of anaglyph goggles and I am amazed as I gaze upon the apparent depth and thereby comparative ( sensed ) scale of these celestial objects. It may not have scientific value, but perhaps it could become a meaningful way to communicate the science into a visualization that a layperson could comprehend. ( speaking of and for myself, anyway )
    I hope he is able to continue and present his work for always and that his technique might be supported and developed into a sort of science of its own, if its not already.

  23. John Halas

    If someone would like to “fine tune” the science of this image, please do so. A more accurate representation may have some scientific application. As for me, I appreciate the labor involved and the visual aid to my understanding of nebulas. It is beautiful, and awe inspiring. Keep up the good work and thanks for sharing!

  24. Matt B.

    And this is why we should be putting parallax probes into Neptune’s orbit. A Neptunian parsec is very close to 100 cy (~99.91).

  25. Isabel

    Thanks, dbur! MUCH better.

  26. Jaz

    @Jon Hanford
    Thanks for the links. I recognize quite a few of the images, as I have them in my desktop background rotation, but I didn’t realize they came from the same dude.

    @Matt B.
    Yea, it wouldn’t be bad if NASA flung its recently adopted pair of HubbleST-type spy satellites out to Neptune.

  27. Pete Jackson

    Although the parallaxes of stars of the stars and nebula are too small to reliably measure at 2000 light years away (less than a milliarcsecond), there is a way to get useful distance info for the background stars, at least in a statistical sense. That is to use ‘proper motion’, the motion, in arcseconds per year, of a distant star across the sky caused by its space velocity. Unlike parallax, proper motion keeps increasing the longer one photographs the system. If you compare the photo here to one taken 100 years ago, the proper motions would typically amount to about 1/10 arc-second – definitely measurable. The proper motions of stars associated with the nebulosity would all be similar in magnitude and direction. For other stars, closer ones will, statistically, have higher proper motions, and in random directions. Any stars behind the nebula will have lower proper motions (Note: The proper motions of field stars will not be totally random because of the effects of galactic rotation.).

    So, if Mr. Metsävainio were to assign distances to each star based on its proper motion, I think that this visualization would really come alive, and with considerable scientific merit as well!

    I know it’s a lotta work, would probably need the help of a collaborator at an observatory.

  28. Matt B.

    The point of using parallax probes within the cosmeme is not actually to give a 3-D look directly, but to be able to calculate distances enough to create the kind of image in this post. It would also enhance the accuracy of other methods of determining distance.

  29. Peter Foley

    Isn’t second image rotated 90 degrees? Why?

  30. For anyone interested in learning how to create 3D images of celestial wonders, our previously published articles by Chris Ford (Pixar) on 3D Visualization of Astronomical Objects are now available as a free download in a single PDF. Download it directly from here:
    http://www.astrophotoinsight.com/articles/3Dvisualizations

  31. the 3D image seems graphical representation of an atom!

  32. @27 thanks Dbur – enlightening stereo pair – of course at the vantage point required to see this view in space, 2 1/2″ eyeball parallax would still be giving us 2D – I wonder about the actual distance between L & R views illustrated in that stereographic.

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