The beating heart of W5

By Phil Plait | August 22, 2008 12:00 pm

Holy frak! Check out this new image from Spitzer Space Telescope:

Spizter image of nebula W5

(Click to hugely embiggen)

W5 is a nebula, a giant cloud of gas roughly 6000 light years away in the constellation of Cassiopeia. It’s enormous, spanning about 2 x 1.5 degrees of the sky (15 times the size of the full Moon on the sky), and is actively cranking out stars. The valentine-shape is actually an enormous cavern, a hollow carved out of the gas by the winds and fierce ultraviolet light flooding out from massive young stars in its… well, its heart. It’s like these stars are blowing a vast bubble in the middle of the cloud.

The stars doing the work can be seen in the image; the bright blue ones are the culprits. Mind you, this is an infrared false-color image; blue is not really blue, it’s actually light at 3.6 microns, more than four times the wavelength of visible light.

There’s another way to find those stars: look at the edges of the bubble. See the triangular or finger-like extensions of material pointing into the bubble? Those are light years-long towers of gas being eaten away by the winds and UV light from the hot massive stars, so the fingers point right to those stars. Sometimes nature is kind to us, and literally points the way.

There are stars in those towers, less massive stars (in this case, more like the Sun) being formed even as we watch. In fact, that’s what makes this image so exciting scientifically (aside from its sheer awesome beauty); it appears that we’re seeing triggered star formation. It’s not perfectly clear yet just how massive clouds collapse to form stars. Sometimes it’s from cloud collisions — cosmic fender-benders or even head-on ramming that crunch up the clouds, triggering collapse and star formation. Sometimes it might be from nearby supernovae compressing the material. Or maybe it’s from massive stars forming and then blowing bubbles in the cloud itself. That last one is the tricky bit. See how the material appears to be brighter along the edge of the bubble? That’s due to compression from the more massive stars’ sculpturing — compressed material tends to glow brighter.

If that’s true, we’re seeing the first generation of stars born in that cloud directly causing the birth of the second. From studying the light from these stars, astronomers have found that the ages of the stars get younger as you move out from the middle, supporting the idea that the massive stars in the center (which form rapidly) are aiding star formation in the outer regions. As their winds and light move outward, they leave behind a wake of stellar birth.

I have spent the past year researching all the ways the Earth can end from cosmic catastrophes for my book, Death from the Skies! Being near a young, massive star is a good way to do this: they flood out fierce light while they are alive, and they tend to explode when they die. But here we see the exact opposite: these stars are the Johnny Appleseeds of the Universe, the lifegivers, sowing the galaxy with the conditions needed for more stars to form.

In the real world, life and death are inexorably intertwined, sometimes so tightly bound that they are nearly indistinguishable. And here we see it on a scale hundred of trillions of kilometers across, so large it appears majestic and calm, yet so finely detailed we can study the processes at work and learn how the basic building blocks of the Universe came to be.

Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA


Comments (69)

  1. Wendy

    What a stunning picture! (And the embiggened version is even more beautiful.)

  2. Chanda

    Thanks for bringing that photo alive. It is 100x more beautiful to me now.

  3. DGKnipfer

    I see Satan!!!

    Don’t beat me BA. :)

  4. That is a gorgeous photo. And the fact that the blog starts out with “holy frak!” also makes me happy.

  5. MJBUtah

    Wow. You know, I feel like I get smarter every time I visit your site. Thanks BA!

  6. Inertially Guided

    Now, Phil, there you go again! Just when I’m about ready to delete your blog from my bookmarks (I’m not a Dr. Who fan…for that matter I don’t even own a television set!) you go and blow my mind with an incredible image and a powerful summary of just WHY it’s incredible. Now I don’t know WHAT to do…

    Tom Epps
    Workin’ on it!

  7. themadlolscientist

    wooooooooaaaaaaaaaahhhhhhhhhhh. stunning.

  8. Amazing picture! The full version is fantastic to watch.

  9. I second that wooooooooooooaaaaaaaaahhhhhhh….

  10. John Baxter

    Thank you for the image and particularly for the guided tour, Phil.

  11. winhoff

    Wow, this is stunning!

  12. Bigfoot

    Spitzer? I barely knew her!

  13. Chris

    I don’t remember seeing a nebula 15x the size of the moon in Cassiopeia…. Doesn’t it give off visible light?

  14. kuhnigget

    Call woah! and raise you duuuuuuuude!

    Fantastic image.

  15. This just shows how Science is not just for old guys in lab coats working with calculus and test tubes. Whether it be Blue-footed Boobies on the Galapagos or a stellar nursery (named for a beautiful, but vain queen, BTW) Science is stunning. Science is awe-inspiring.

    Science is beautiful.

    Thanks BA. And everyone involved with the SST of course!

  16. Simply beautiful. This is my new desktop background!

  17. CanadianLeigh

    I see a valentine day card for my wife.

  18. This image is quite striking. Thanks for making note of it. Here’s the NASA press release if you want to learn more.

  19. Cheyenne

    wooooooooooooaaaaaaaaahhhhhhh…..gets a third vote. Stunning, just stunning….

    And thanks for the description Phil. Raising the coolness factor to a power of ten.

  20. ABR.

    Very nice! Thanks for posting this picture. I just showed the picture to a buddy. He is going to be saying “hugely embiggen” for the rest of the afternoon, now. Thanks for that, too!

  21. Wow. That is one pretty picture! And an equally excellent post – Thanks Phil!

  22. Top centre – looks like Liam Neeson in profile.

  23. Breathtaking..but…
    when do we get there?:))
    It looks so evil in this colourscheme;)

  24. On the triggered star formation & where we came from note, check out this review on 60Fe by Jonathan Williams:

  25. Simple Guy

    Hmmm, am I right in that all the newborn stars look reddish?

  26. Xavier

    Hi, this is my image – thanks for the publication. How about some image credits? They’re on the IPAC/JPL/Caltech websites. Nice description though. Thanks. :)

  27. HvP


    Cassiopeia has a relatively good assortment of nebula apparently, but the human eye simply can’t collect enough light to see them well. You definitely need a telescope or better yet, a long exposure photograph for them to show. This nebula, also known as IC 1848, has an apparent magnitude of 6.5; or about the same as the dimmest star you could possibly see in a dark sky with perfect vision. Plus, the nebula is spread out which actually makes it even less visible.

    I’ll also note that the picture we are seeing was taken in the infrared range and only adjusted up to visible light by computers for examination.

  28. Xavier, thanks. And you’re right; I forgot the credit. I added it to the bottom.

    I tried finding your paper on astro-ph and NASA ADS but came up blank. It sounds interesting and I’d like to get it. Do you have a link for it?

  29. David Ratnasabapathy

    Clarification please? The article says that each finger of dust and gas points at a star. I’m reading that to mean that right at the fingertip there should be a star: and in fact at the tip of most of those fingers is a glowing point of light.

    But the article also says that the fingers are “being eaten away by the winds and UV light from the hot massive stars” — so how come they exist? Shouldn’t they have been eaten away, leaving empty space all around the star? I don’t understand how those fingers could have formed in the first place. I was thinking, perhaps a cloud of dust surrounded the star, then, after it began to shine, all but the finger was blown away; but then how did the finger survive? And why only one finger per star?

    I am guessing that the star’s gravity initially dragged a finger of dust towards it from the surrounding cloud; now, after ignition, its light burns the finger away. Is that right? It sounds freakishly weird — that even a star can pull a finger of dust across light years.


  30. Xavier

    Hi Phil,
    The paper will be out on astro-ph on Monday hopefully. The ApJ paper will be out in December.

  31. IVAN3MAN


    This nebula, also known as IC 1848, has an apparent magnitude of 6.5; or about the same as the dimmest star you could possibly see in a dark sky with perfect vision.

    Actually, it’s IC 1805:

  32. Phil Plait, the Bad Astronomer: Providing me with freakin’ cool desktop wallpaper since 2007.

  33. Russ Brown

    For anyone who’s interested, I emprettied the original pic and I think now it looks even better. I posted it to BAUT, under Bad Astronomy Stories.
    Russ B

    Hope Xavier doesn’t mind!

  34. Edward

    This is totally awesome. But I can’t embiggen.

  35. Nigel Depledge

    Edward, I get tons of emails each week offering to solve that problem!

    Anyhoo, back on-topic, thanks, BA, for bringing our attention to another wonderful image (I think this is the first Spitzer image that has made me go “Ooooooh!”). And thank you especially for sharing your enthusiasm with us. I just love when you get all lyrical about images like this.

    David Ratnasabapathy, I think tere may be a little confusion. Each “finger” points towards a star or group of stars, but that doesn’t mean that the star(s) generating the wind is/are at the tip of the finger.

    IIRC, these intense solar winds from young stars are called T-Tauri winds – I am sure if you google that term you will find more info about these phenomena.

  36. That’s an amazing picture! Just gorgeous and awe-inspiring. And the description makes it that much more interesting. Science is beautiful.

    I spent a little while just moving around the full-size version, it’s full of visual treasures…

  37. Arnold Martin

    Beautiful image. I looked closely and saw a red ring around a pink star that is just above the prominent tower or finger feature on the lower left edge of the cavern. It was in the tiff from jpl as well so I suppose its not just from jpeg compression/quality loss. Is that something that would be a product of the imaging method like lens flare or the star sparkle effect or is it an actual feature of the nebula?

  38. David Ratnasabapathy

    Ah, cheers, I get it. The fingers are knots of denser gas or dust, something like that? The light stuff gets blown away, leaving the finger behind.


  39. Very nice! Thanks for sharing this. I love these types of photos! When I first look at these nebula photos they make me think that they are just a stones throw away and are just beautiful photos of well lit clouds in the night sky. Then reality kicks in and I remember just how far away and just how large these nebula are! Simply amazing! Again thanks for sharing!

    PS. Just because I also LOVE paraedolia… I noticed what looks like a big red skull in the middle of this nebula. Proof that there may be some truth to this 2012 thing? HA! sorry I couldn’t resist ūüėČ


  40. Nathan Myers

    Of course there is not a speck of gas anywhere in the image, embiggened or otherwise. It’s all plasma, from top to bottom, obeying plasma fluid dynamics, not weather.

    Never let a plasma-denialist astronomer pretend skepticism.

  41. Nathan– Oh, for Pete’s sake. If you think a plasma isn’t a gas, then you don’t have any right at all to lecture me.

    “Plasma denialist” indeed. I got my PhD studying ionized gas, specifically the metastable [OIII] transition at 5007/5010 Angstroms. I understand quite a bit about plasma, thank you very much.

    If you don’t understand that plasmas obey hydrodynamics, then you need to hit the books. Just because you have a plasma doesn’t mean you have large scale currents of electricity. That seems to be the most basic thing Electric Universe proponents just can’t seem to understand.

  42. Knurl

    That image definitely makes one of the best wallpapers I ever had.

    How big is this thing across?

  43. Nathan Myers

    You might as well say, “if you think gas isn’t a liquid…” Hey, it’s not. Plasma fluid dynamics is as different from ordinary hydrodynamics as wind is different from rivers. The presence of large-scale magnetic fields does, in fact, imply all the large-scale currents anyone could ask for, all denial notwithstanding.

    I don’t know what an “Electric Universe proponent” would be; E-M and plasma phenomena are directly observed. Many astronomers, yourself included, seem instead to be Infinite-Conductivity Universe or Gravity-Only Universe proponents, both of which are unphysical and, frankly, ludicrous. When you find yourself reaching for unobservables like neutron stars and dark matter to avoid applying well-known (albeit too “fiendishly difficult”) physics, recognize that you’re in a hole and stop digging.

    Maybe you’re used to other astronomers giving you a free pass? We both know you can understand all about photon absorption without knowing the first thing about plasma fluid dynamics. Paleontologists and chemists don’t bluff and bluster on their blogs, they’re completely open about how little they really know. Why must astronomers blow smoke?

  44. Jon Owen

    It reminds of Heavy Water Light Show’s cover for Santana 3 ,which I think has an image of the Crab Nebula,but this is much, much more beautiful….

  45. IVAN3MAN


    I tried to submit a logical response to Nathan Myers, with links to various articles, and it got “spammed” by the system!

  46. Arnold Martin

    Nathan – I’m no scientist but I think that Phil may have been suggesting that YOU Nathan Meyers, if that is your real name, are an Electric Universe Proponent. A link in his own article about magnetic phenomena observed by Hubble points out that people like you seem to discredit modern astronomy and cosmology by making claims like yours that modern cosmology disregards magnetic effects. Wow its frustrating to reason in circles with quacks and pseudo-scientists. Who needs an Aspirin?

  47. Nathan Myers

    Arnold: “I‚Äôm no scientist…” Oh, an astronomer, then? “people like you”, “quacks”, “pseudo-scientists”. Like name-calling, much? Works better for you than facts? Hey, Phil, is that you?

  48. Nathan Myers

    Seriously, Phil, you would do better if you asked your apologists here not to embarrass you further. Your posse is most unprepossessing.

    @MERDE!: Facts, please. Logic depends on facts.

  49. IVAN3MAN

    Attention Dr. Phil Plait, I tried to submit a response to Mr. Nathan ‘Know-it-all’ Myers with various links to informative web-sites to set him straight with the “facts” — presuming that his mind is still receptive to “logic” instead of pseudoscience woo-woo! — but this web-site’s bloody computer buggered it up by spamming it!

    Fortunately, I saved the draft copy of it onto WordPad, so I can submit my comment again if the bloody computer will let it through!

    This over aggressive spamming of one’s legitimate comment(s) could be avoided if potential commenters were required to register before submitting a comment, as is the case on and JREF, the latter of which you, Phil, are El Presidente (Congratulations! James Randi couldn’t have picked a better person).

    Subsequently, if anyone then abuses their membership with inappropriate comments, links to offensive web-sites, or foul language, they can be banned to the troll — mentioning no names — thread after “three strikes and your out!”.

  50. IVAN3MAN

    P.S. An editing feature would also be useful, Phil, as I’ve just realized that I should have written “three strikes and you’re out!”, not “your”. Goddamnit! I used to be a bloody proofreader! A spelling mistake like that is an hanging offence! (N.B. In Britain, we spell “offence” with a “c”.)

  51. Mark Hansen

    Nathan, you object to name-calling immediately after insulting the poster. That’s rather hypocritical, isn’t it? Or if you prefer, pot calling the kettle black. Also; your reading of posts is rather scrappy if you can’t pick the difference between a name and a comment. IVAN3MAN was the name, MERDE was the post. And the comment wasn’t even directed at you. So add paranoia to the inability to read.

  52. Davidlpf

    IVAN3MAN,The BA does have message board along with universe today called bautforums(dot)com, there is a link in the blogroll.

  53. IVAN3MAN

    Thank you for the information, Davidlpf!

  54. Davidlpf
  55. Nathan Myers

    @Mark Hansen: MERDE! isn’t really his name, but (1) neither is IVAN3MAN, (2) anyone scanning for his comment would find it more easily under “MERDE!”, and (3) MERDE! seems a more apt pseudonym, if we must have them. So, you really feel that to be taken for an astronomer is an insult? You reveal too much. Really, Phil would do better without your sort of help, or MERDE!’s.

    @MERDE!: Look up “proponent”. Compare to “advocate”. Discuss.

  56. Bobby Thomas

    I’m curious.

    What is this controversy that needs to be taught.

  57. Mark Hansen

    *Sigh* I ought to know better but…

    Nathan, it is the way you use the “I’m no scientist”, “Oh, an astronomer, then?” phrasing. Please don’t insult my intelligence by pretending it wasn’t an insult. And speaking of intelligence, IVAN3MAN (yes, I am well aware that probably isn’t on his driver’s licence) used merde as an expression of frustration. Try looking it up; an online dictionary should be adequate. Here’s another word to look up; troll. Beyond the definition of a mythical creature, you will find another that fits your behaviour here.
    Oh, and you could match up comments to their authors a little better. I believe that it was Arnold Martin that used the word “proponent”. Sloppy work like that does you no credit. If your plasma “work” is as riddled with errors, it’s going to be hard to get people to take you seriously.

  58. You made me look up the American Buddha on WP. Knowledge to me, kudos to you.

  59. Nathan Myers

    @Mark Hansen: It was Phil who first used the word “proponent”, not Arnold. (I doubt Arnold knew it, before.) My suggestion to MERDE! was for his education. Your notion that MERDE! refers to IVAN3MAN’s state of mind is speculation that, in any case, has nothing to do with intelligence. “And speaking of intelligence”, I feel entirely incapable of insulting yours, so no worries.

    Which “plasma ‘work'” are you imagining? Plasma fluid dynamics is a mature field. Maxwell’s electromagnetics is more than a century old. For Phil to call mere mention of details of these topics “antiscience” or “pseudoscience”, and to report them dishonestly, is trolling of the first order. To level random accusations at anyone who calls attention to such dishonesty compounds it. Why not be part of the solution? Learn, and educate.

  60. Mark Hansen

    Nathan, I could point out that you’ve quite clearly missed the merde reference that IVAN3MAN made but why bother? You obviously are too lazy to check. Enjoy your trolling…

  61. Torbjörn Larsson, OM

    @ Nathan Myers:

    Logic depends on facts.

    No, it is the other way around, facts and theories can usefully need logic to be constructed and tested.

    But there ends the dependence. I find it curious indeed that people tries to assign static truth values to facts, as they are a dynamical property of the process of knowledge gathering. Facts and hypotheses doesn’t have truth values; before observation respectively verification they are in degrees “not known, possible, impossible, likely, unlikely”, and after they are “accepted, rejected”. Formal logic comes up empty in describing this process.

    For Phil to call mere mention of details of these topics ‚Äúantiscience‚ÄĚ or ‚Äúpseudoscience‚ÄĚ, and to report them dishonestly, is trolling of the first order.

    It is antiscience simply because you attack verified science without a factual basis. If anyone attacks verified science from a factual basis he is either a crank or, unlikely, correct – but a factually empty antiscientist is a fraud, “not even wrong”.

    Btw, a poster can’t troll, as he is responsible for answering on his post. A troll is “a person who is deliberately inflammatory on the Internet in order to provoke a vehement response”. Such as, say, yourself.

    While Phil’s intention is to enjoy himself, (obviously) present the science from his basis as a scientist, and keep a semblance of order on his blog. Which reasonably means keeping trolls short and, on a science blog, point out when people drags antiscience into it.

  62. firemancarl

    So, despite all the batshit wackaloonery going on here… Phil surely this will end up on your Top 10 Photos of 2009???

    I am more inclined to listen to someone with an OM than a poster on here who calls out the owner of the blog, who just happens to be a Phd and best seller.

    But, WaddaIknow?


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